I I I I I I I I I I I I I I I I I s Marine Biological Laboratory Library Woods Hole, Mass. Presented by The ThoDdst Press Jime 26, 1962 I I I I I I I I I I I I I I I I I 83 THE DIGNITY OF SCIENCE f CO THE DIGNITY OF SCIENCE Studies in the Philosophy of Science /^^^^t^r^^^ '^» '^ presented to Z^;; Jijs« A3IY) ^ •^' WILLIAM HUMBERT KANE, O.P. '^s^*;^ EDITED WITH INTRODUCTION BY JAMES A. WEISHEIPL, O.P. in collaboration with THE THOMIST AND THE ALBERTUS MAGNUS LYCEUM Preface by Michael Browne, O. P., S. T. M. THE THOMIST PRESS 1961 Originally published as a SPECIAL ISSUE OF THE THOMIST Volume XXIV, Nos. 2, 3, & 4 April, July, October 1961 THE DIGNITY OF SCIENCE WITH Introduction by James A. Weisheipl, O. P. Copyright, 1961 Dominican Fathers, Province of St. Joseph Cum permissu sujperiorura Library of Congress Catalog Card Number: 61-15888 THE THOMIST PRESS Printed in U. S. A. WILLIAxM HUiMBERT KANE, O. P. CONTENTS PAGE Letter of the Master General, Michael Browne, O.P., S.T.M, Ph.D V Introduction: The Dignity of Science xvii By James A. Weisheipl, O.P., D.Phil. (Oxon.) PART ONE SCIENTIFIC METHODOLOGY Demonstration and Self-Evidence 3 By Edward D. Simmons, Ph.D. (Marquette Univ.) The Significance of the Universal ut nunc 27 By John A. Oesterle, Ph.D. (Univ. of Notre Dame) William Harvey, M.D.: Modern or Ancient Scientist? 39 By Herbert Ratner, M.D. (Loyola Univ., Chicago) PART TWO HISTORY OF SCIENCE Medicine and Philosophy in the Eleventh and Twelfth Cen- turies: The Problem of Elements 75 By Richard P. McKeon, Ph.D. (Univ. of Chicago) The Origins of the Problem of the Unity of Form . 121 By Daniel A. Callus, O.P., S.T.M., D.Phil. (Oxford Univ., England) VII 79879 VIU CONTENTS PAGE The Celestial Movers in Medieval Physics 150 By James A. Weisiieipl, O.P., Ph.D., D.Phil. (River For- est, 111.) Gravitational Motion according to Theodoric of Freiberg 191 By William A. Wallace, O.P., Ph.D., S.T.D. (Dover, Mass.) ' Mining All Within ': Clarke 's Notes to Rohault's Traite de Physique 217 By Michael A. Hoskin, Ph.D. (Cambridge Univ., Eng- land) PART THREE PHILOSOPHY OF SCIENCE Darwin's Dilemma 231 By Charles DeKoninck, Ph.D. (Universite Laval, Quebec) 4)Y5I2: The Meaning of Nature in the Aristotelian Philos- ophy of Nature 247 By Sheilah O'Flynn Brennan, Ph.D. (St. Mary's Col- lege, Notre Dame) Order in the Philosophy of Nature 266 By Melvin Glutz, C.P., Ph.D. (Passionist Monastery, Chicago) Motionless Motion 283 By Roman A. Kocourek, Ph.D. (College of St. Thomas, St. Paul) Time, The Measure of Movement 295 By Sister M. Jocelyn, O.P., Ph.D. (Rosary College, River Forest) CONTENTS IX PART FOUR SPECIAL PROBLEMS OF SCIENCE PAGE Evolution and Entropy 305 Bj^ Vincent E. Smith, Ph.D. (St. John's Univ., Jamaica, N.Y.) From the Fact of Evolution to the Philosophy of Evolutionism 327 By Raymond J. Nogar, O.P., Ph.D. (River Forest, 111.) The Rhythmic Universe 366 By Sister Margaret Ann McDowell, O.P., M.S., Ph.D. (St. Mary of the Springs, Columbus) Mind, Brain, and Biochemistrys 383 By Albert S. Moraczew^ski, O.P., Ph.D. (Texas Medical Center, Houston) Conscience and Superego 408 By Michael Stock, O.P., Ph.D. (Dover, Mass.) PART FIVE SOCIOLOGICAL ASPECTS Contemporary Challenge to the Traditional Ideal of Science . 447 By Ambrose McNicholl, O.P., Ph.D. (Angelicum, Rome) A Social Science Founded on a Unified Natural Science . . 469 By Benedict M. Ashley, O.P., Ph.D. (River Forest, 111.) The Role of Science in Liberal Education 486 By Sister M. Olivia Barrett, R.S.M., Ph.D. (St. Xavier College, Chicago) American Catholics and Science 503 By Patrick H. Yancey, S.J., Ph.D. (Spring Hill College, Mobile) Notes on Our Contributors 521 The Writings of William Humbert Kane, O.P. ... 524 LETTER OF THE MASTER GENERAL ff*3 hsr. Roma, (8-48) Convento S. Sabina (Aventino) CASA QENERALIZIA OELL'ORDINE OEI FRATI PREDICATORI It was with great pleasure that we learned of this special occasion to honor the Very Reverend William Humbert Kane, O. P., founder of The Albertus Magnus Lyceum at River Forest, Illinois. We were particularly pleased to hear that this homage on the part of brethren and Sisters of our Order as well as religious of various other Orders and a host of eminent laymen transcended nationalities and provincial boundaries. It is only by cooperative effort among learned men that the sublime ideal of St. Albert the Great can be realized in a troubled world. No one can view recent developments in atomic physics without grave concern not only for the future of humanity, but also for the very scientists who have merited the respect of their peers and the admiration of the masses and withal have come to feel a certain uneasiness of their own consciences. Scientists have become accustomed to the adulation of the general public. This adulation, growing with every new dis- covery, led them to spurn the traditional channels of wisdom, and to close their eyes ever more to the legitimate claims of supernatural religion, moral principles, perennial philosophy, and other elements of culture which contribute to a truly human life. In the nineteenth century certain specialists in a particular branch of physics, chemistry, biology or psychology XI Xll LETTER OF THE MASTER GENERAL were willing to be considered the oracles of all human wisdom. The narrow confines of a specialized branch of natural science, as we know, provided no vantage point. Consequently, what- ever could not be comprehended by the specialized principles was misinterpreted, ridiculed or rejected. However, recent developments within many branches of science have shaken these imprudent positions. From the turn of the century to the present day an ever increasing number of scientists have found themselves asking questions which formerly were looked upon by them as purely " philosophical." Pope Leo XIII saw clearly that all social errors, and conse- quently a large part of social evils, are ultimately traceable to false philosophical principles. These are as erroneous today as they were in the nineteenth century. Throughout his encyclicals he used the principles of St. Thomas Aquinas, that " prince and master " of all Scholastic doctors, to analyze prevailing thought and to outline the rehabilitation of Christian society. In his immortal encyclical Aeterni Patris he observed: " If anyone will but turn his attention to the sad condition of our times, and contemplate thoughtfully the state of things which exists publicly and privately, he will surely perceive that the fertile cause of the evils which actually surround us, or of which we fear the coming, consists in this, that the wicked maxims on divine and human things which have recently sprung from the schools of the philosophers have invaded all classes of society, and are approved by a very great number." ^ Consequently, he urged all Bishops, teachers and students " to restore the illustrious system of St. Thomas Aquinas to its former glory " that the coming generations may nourish themselves " abun- dantly from those purest streams of wisdom that flow from the Angelic Doctor, as from an inexhaustible and precious foun- tain." " That same pontiff in the year 1880, by his Apostolic Letter Cum hoc sit,^ made and declared Thomas Aquinas, " who ever shone as the sun in his doctrine and virtue," the heavenly patron of all Catholic schools, commending him ^ AAS, XII (1879) , 98. ' Ibid., p. 112. =* AAS, XIII (1880) , 56-59. LETTER OF THE MASTER GENERAL Xlll especially as the guardian, leader and master of philosophical and theological studies.* The call of Pope Pius XI, Ite ad Thomam, rings as clear today as it did in 1923 when he addressed Studiorum Ducem to the whole Catholic Church/ In more recent times, a deep need was felt by many for a heavenly patron in the natural sciences. In the solemn Decree Ad Deum of December 16, 1941, the late Pope Pius XII wrote: " It is no wonder, then, that the universities and the more important Catholic colleges, not only in Italy, but in Germany, France, Hungary, Belgium, Holland, as well as in Spain, America and the Philippine Islands, besides numbers of pro- fessors of physics and other natural sciences, at the present time look upon Albert the Great as a beacon shining in a world engulfed in gloom. To make sure of the help of Almighty God in their exacting researches into the world of nature, they eagerly desire to have for their guide and heavenly intercessor him who, even in his own day, when many, puffed up with a hollow science of words, were turning their eyes away from the things of the spirit, has taught us by his example how we should rather mount from the things of earth to the things above." ^ Speaking of the important role played by Our own predecessor. Father Martin S. Gillet, the late Holy Father continues: " It is, there- fore, with sentiments of deepest pleasure that we accede to the wish expressed by the Catholic Academicians at their recent convention in Trier, by universities and by other international gatherings of scientists, and brought to Our notice by the Master General of the Order of Friars Preachers, who, on behalf of himself and of the Order over which he presides, adds a fervent plea that We may deign to constitute Saint Albert the Great the heavenly Patron of students of the natural sciences." ^ The Decree Ad Deum, constituting Albert the heavenly Patron of those who cultivate the natural sciences, was issued on the * Cf. Letter of Pius XII to Martin Stanislaus Gillet, March 7, 1942. AAS, XXXIV (1942), 89. ^ AAS, XV (1923), 323. "AAS, XXXIV (1942), 90. ' Ibid. XIV LETTER OF THE MASTER GENERAL tenth anniversary of the Decree In thesauris sapientiae by which Pope Pius XI enjoined upon the universal Church the veneration of Saint Albert the Great, Bishop and Confessor, with the additional title of Doctor.^ We have watched with paternal concern the growth of The Albertus Magnus Lyceum at the Pontifical Faculty of Phi- losophy in River Forest, Illinois. Since its small beginnings in the Autumn of 1950 under the inspiration of Father Kane and the support of the Very Reverend Edward L. Hughes, at that time Provincial of the Province of St. Albert the Great, it has grown in wisdom and prestige. This growth has taken place to a great extent under the care of the Very Reverend Edmund J. Marr, Provincial of the Province of St. Albert the Great. We have been particularly pleased to observe the devotion of its members to the solid principles of St. Thomas and St. Albert, and at the same time the concern of its members with vital problems of modem science. Problems such as the relation of Thomistic philosophy to modern science, the foundations and nature of modern science, the true constitution of matter, the biological problem of evolution as distinct from evolutionism, the validity of depth psychology, the influence of physiological and biochemical factors on mental diseases and many other problems, cannot be solved without the mutual cooperation of well trained minds. The Albertus Magnus Lyceum has grad- ually enlisted the cooperation of Our sons in other Provinces, the cooperation of Our Sisters of various communities, and most important, perhaps, it has enlisted the cooperation of eminent laymen. We are aware that the inspiration for the Lyceum was due in large measure to the vision and zeal of its founder, Father Humbert Kane. Despite many difficulties and obstacles, he saw the need of cooperation within a specially recognized institute, and he did not falter. It is indeed a happy coinci- dence that the tenth anniversary of The Albertus Magnus «AAS, XXIV (1932), 5-17. LETTER OF THE MASTER GENERAL XV Lyceum should coincide with the sixtieth anniversary of the birth of its founder. We take this opportunity to impart our paternal blessing to Father Humbert Kane, on the occasion of his sixtieth birthday, and to The Albertus Magnus Lyceum, founded by him ten years ago. We ask the blessing of St. Thomas Aquinas and of St. Albert the Great for all his associates concerned with problems of philosophy and science. Given at Rome, from the Convent of Santa Sabina, on the Feast of St. Margaret of Hungary, V. O. P., January 19, 1961. yy^fHiM, Fr. Michael Browne, 0. P. Master General INTRODUCTION The Dignity of Science WHEN the first atomic bomb struck the populous seaport capital of Hiroshima on August 6, 1945, the entire civilized world was profoundly shocked at the horror unleashed by science. Ordinary citizens and inter- national leaders recoiled at the awful potential of the atomic bomb. Science no longer meant the production of useful gad- gets, discovery of effective drugs, or development of quicker and better means of communication. It meant something much more, something that affects human consciences and destiny. The moral issues involved in the Hiroshima bombing and in nuclear warfare in general have been widely discussed, some- times with considerable vehemence. But even apart from the moral issues, it is clear to many today that scientific progress has reached a precarious ledge in its lofty climb. Careful maneuvering along the ledge can indeed lead to still further heights. It is the sight of some new height still to be conquered that urges the scientist, as well as the mountain climber, for- ward with confident step. But a single misstep at such heights could bring on a landslide or a plunge to final doom. The alternatives are clear, and have been clear since Hiroshima: the possibility of further progress or the annihilation of civili- zation. Henceforth mankind has to work out its salvation in the shadow of the mushroom cloud. The successful launching of Sputnik I in October of 1957 threw government departments, military officers, scientists, educators and journalists into panic. Incredible as it seemed, the Soviet Union had overtaken the United States in missile thrust and guidance systems. American prestige dropped, par- ticularly in uncommitted countries; investigations were begun into the so-called " missile lag," and educators hastened to build xvii XVIU JAMES A. WEISHEIPL up the science program in schools of all sizes. Despite the fact that Soviet students of science are thoroughly indoctrinated with the philosophy of Dialectical Materialism, some American educators urged diminishing, and eliminating if possible, courses in the humanities in a frantic effort to produce more trained scientists. The panic instilled by Sputnik I almost obliterated the vision and hope of wiser educators: the molding of a human being, whether he be a theoretician or a technician. Before Sputnik I many educators realized the inherent danger to society and to the individual of excessive specialization, which neglects history, literature, culture, sound philosophy, religion and even ordinary grammar. These educators tried to give potential scientists an appreciation of the real dignity of science through the history of science, the philosophy of science, or a study of the Great Books of mankind. Because of Sputnik I this movement has suffered a temporary set-back. Perhaps after the fear and panic have subsided, there may still be the possibility of educating human beings intelligently devoted to science, rather than technicians unaware of the dignity of their pursuit. Long before the atom bomb came to the attention of the ordinary man, an important revolution had been taking place within science itself, a theoretical revolution which, in fact, made the atom bomb possible. The story of this transition from the mechanical age of physics to the age of relativity and quantum mechanics has been written many times in this gener- ation. The path which leads from Clerk Maxwell's hypothesis identifying magnetic and luminiferous media to the theories of relativity and quantum was constructed by many experimental and theoretical physicists. It is a path which leaves far behind the assurances of Newtonian solids in a void, the fallacy, as Whitehead called it, of " misplaced concreteness." The tran- sition from classical mechanics to the two principal theories of modem physics, relativity and quantum, had an unsettling effect on philosophers of physical theory. Before the end of the nineteenth century Carl Neumann, Ernst Mach and Karl Pear- INTRODUCTION XIX son had already perceived some of the weaknesses of Newton- ian axioms and some of the ambiguities in Newtonian concepts. But they were not wilHng to reject the basic theory of New- tonian science. Even after Planck's paper of 1900 and Einstein's theory of 1905, theoreticians of science, such as Henri Poincare and Pierre Duhem, were unwilling to reject Newtonian prin- ciples as erroneous. Instead they conceived all scientific theories as conventional constructs and approximations of the truth. A scientific theory may be induced from experimental data; its predictions may be verified in every detail. But, for Poincare and Duhem, the theory was only one way out of many for interpreting the data; it was an hypothetical approximation. The same data could be interpreted with equal verification by other hypotheses. The irreconcilability of relativity theory and quantum mechanics, as well as the wave and particle theories of light, gave much weight to this interpretation of scientific theory. Later authors, it is true, have considered Poincare's interpre- tation of science and hypothesis to be somewhat naive and over- simplified, and they have rejected certain details of his conven- tionalism {commodisme) . Nevertheless, the fundamental ele- ments of his view have been incorporated into the generally accepted theory of science today. His insistence on the hypo- thetical character of scientific theory has, in fact, been extended by modem theoreticians beyond the limits intended by Poin- care himself. He was willing to grant certainty at least to the first principles of scientific investigation and to other types of knowledge. Obviously, he did not reduce his own philosophical speculations to the status of mere convention and hypothesis. In the currently accepted view of scientific knowledge, ex- pounded in philosophies of science, there are three fundamental points which ought to give us pause. (1) It insists that no scientific knowledge can be taken as absolutely certain, that is, without an intrinsic doubt concerning its alterability. The hypothetical character of all scientific knowledge, it is said, requires that we accept current scientific knowledge on a tenta- XX JAMES A. WEISHEIPL. tive basis only. (2) It insists that all true knowledge must be ' scientific,' and therefore hypothetical. This means that even the first principles of scientific investigation must be regarded as hypothetical and tentative. (3) It restricts ' scientific knowl- edge ' to investigations modeled on, and employing the scien- tific method of modern physics. This means that the various branches of speculative and practical philosophy, theology, history and so forth are not at all scientific, while biology, psychology, anthropology and sociology deserve the name of ' science ' only insofar as they employ the unique ' scientific method ' of physics. Here is not the place to controvert these fundamental points. However, a brief comparison of modem scientific theory with the scientific optimism of Aristotle and the ancients is most revealing. Modern theoreticians apparently have abandoned hope in the power of man's speculative reason; they seem to be content with universal uncertainty and a solitary path to knowl- edge. Whatever may be said of Aristotle's science, he was, at least, much more confident in the powers of human reason and more appreciative of the dignity of scientific knowledge. (1) The tentative status of hypotheses and theories proposed by modem theoreticians falls far short of Aristotle's ideal of scien- tific knowledge. Science, for Aristotle, is the attainment of true and certain causes within reality. Such causes are, of course, discovered only after careful research and analysis. Whatever hypotheses, theories or suspicions one may have during the investigation, they are not to be confused with genuine science. Such hypotheses are indispensable and inevitable, but they are only means to the ultimate goal of scientific explanation. (2) Aristotle's lofty, and perhaps unattainable, ideal of scientific knowledge did not blind him into thinking that all true knowl- edge must be of this type. Defending the dignity of science against the skeptics of the Academy on the one hand, and pro- testing the universality of science on the other, Aristotle saw that not all knowledge can be ' scientific,' that is, demonstrable, for then there would be no beginning. He insisted that the INTRODUCTION XXI starting point of scientific investigation must be prior and more certain than the torturous path leading to a true solution. This starting point is the light of absolutely first principles, known with certainty before all scientific demonstration. The complex process of investigating nature was recognized as extremely difficult, but Aristotle did not think it hopeless. There is the security of an immoveable starting point. (3) For Aristotle the investigation of nature occupied a preeminent place in the pursuit of knowledge; he himself devoted most of his life to it. But he did not claim this as the only pursuit of mankind. Even in the study of the world and man Aristotle recognized various approaches, each of which is legitimately called ' science.' In other words, ' science ' is an analogical term, and its dignity requires that it be recognized in its diversity and complemen- tarity. The pluralist approach to reality respects the principles, method and limitations of each legitimate endeavor. No one branch can be erected into a monolithic idol without destroying the integrity of truth and the dignity of science. The warfare between scientists and religion cannot be sub- dued for long. This is not because of any intrinsic incompati- bility between science and true religion, but because of the third point mentioned above. If the scientist refuses to acknowledge any theories other than those proposed by his own method, con- flicts are bound to break out periodically. Today the conflict is most evident in the conception some neo-biologists have of evolution on the one hand, and the testimony of sound phi- losophy and revelation on the other. This was evident in the Darwin Centennial held at the University of Chicago in 1959. Some biologists claimed the triumph of science over revelation, since evolutionary theory now proves that man is no more than a form of evolved matter, and religion a superstition. Even apart from the embarrassing fact that the methodology of pre- history is far removed from that of modern physics, we might pause to marvel at this strange note of triumph. Man is no more than the beast, the weed, the puff of air! Rejoice! Man is not very much after all! Dialectical Materialism has been XXll JAMES A. WEISHEIPL saying this for over a century. Will there be no voice to defend the nobility of man and the dignity of science? II We have every right to expect Catholic philosophers and scientists to enter the arena in defence of human dignity, be- cause they know from revelation and the perennial philosophy that man's soul is spiritual, made to the image and likeness of God. We also expect Catholic philosophers and scientists to make positive contributions to science and its theoretical foun- dations. In other words, we expect Catholic philosophers and scientists to appreciate the true dignity of scientific knowledge and research — not because they might be more gifted, but because they have the advantage of the true faith and the resources of a philosaphia perennis. This does not mean that Catholics are in a position to judge scientific details a priori, or without careful study. Scientific research and analysis are laborious occupations for everyone, Catholic and non-Catholic; and progress in scientific knowledge is a result of cooperative effort, utilizing every means at one's disposal. Nevertheless, Catholics start out with the assurance that the truths revealed by God are absolutely certain and that no truth discoverable by science can contradict them. These revealed truths include both supernatural realities beyond the scope of reason and certain natural realities within the competence of reason and science, such as the existence of God and the immortality of the human soul. Further, the Catholic starts with the assurance that all truth is from God and can lead back to Him if the whole pattern of reality is considered. Finally, the Catholic has at his disposal a font of ancient wisdom which Leo XIII called the philosophia perennis. This perennial philosophy, of course, is not a matter of divine revelation; nor does it pretend to contain all the answers. But it does propose true answers to some of the more basic questions of science and human life, answers which can be evaluated by natural reason, and which can be accepted as a starting point for further serious investiga- INTRODUCTION XXIU tion. Even the method whereby fruitful investigation can be continued today is to be found in the perennial philosophy of the ancients. Only an unreasonable or prejudiced thinker would dismiss this wisdom of the ancients without fair study. An ancient truth does not cease to be true just because it is ancient. Nor does the perennial philosophy cease to be philosophy just because someone else thought of it first. When Leo XIII called for the restoration of the philosophia perennis in Catholic schools, he explicitly desired this to be the light by which modern problems of natural science, social ethics and metaphysics are to be worked out. " Even physics, the study which is now held in such high esteem, and which by its many wonderful discoveries has secured to itself everywhere special admiration, will not only receive no detriment but a powerful help from the restoration of the ancient philosophy." Leo XIII pointed out that the consideration of facts and the observation of nature are alone not sufficient for the fruitful appreciation and advancement of natural science. One needs discussion of more fundamental questions of science, reflection on the data obtained, synthesis of various aspects, analysis of scientific theory itself and epistemological evaluation in the light of human knowledge as a whole. " To these investigations it is wonderful what light and powerful aid is afforded by scholastic philosophy, if it be wisely handled." The examples of St. Thomas Aquinas and Blessed Albertus Magnus were pro- posed to modern investigators of nature by Pope Leo. Over half a century later Pope Pius XII gave modern scientists St. Albert the Great for their heavenly patron, " in order that stu- dents of the natural sciences, bearing in mind that he had been given them as their guide, might follow in his footsteps and not cling too tightly to the investigation of the fragile things of this life, nor forget that their souls are meant for immortality, but use created things as rungs in a ladder that will elevate them to understand heavenly things and take supreme delight in them." Leo XIII had ordered the restoration of scholastic philoso- XXIV JAMES A. WEISHEIPL phy, particularly that of St. Thomas Aquinas, in all centers of Catholic learning — seminaries, colleges, institutes and uni- versities — that Catholic intellectuals might contribute to the solution of modern problems. The carrying out of this directive was a difficult task. There are some observers today who claim, with considerable justification, that the Leonine directive has never been earned out fully even to this day. However, there were special difficulties in the 1880's. Scholastic philosophy was a philosophy, and ' philosophy ' since the time of Leibniz and Wolff meant metaphysics and ethics. Metaphysics, for Wolff and his innumerable disciples, was divided into general ontology and special ontology, embracing cosmology, psychology and theodicy. Consequently some Catholics fancied that Thomistic philosophy had to be truncated to fit the Procrustean bed of Wolffian metaphysics. Furthermore, the acquisition of scien- tific knowledge is a difficult task, requiring special training and devotion. Professional philosophers in seminaries and universi- ties could hardly be expected to acquire detailed knowledge of highly developed sciences. Consequently it seemed more ex- pedient to let science alone and concentrate on a metaphysical type of cosmology and rational psychology. The first university to attempt to fulfill the wishes of Leo XIII was the Catholic University of Lou vain. In a papal brief of December 25, 1880, the bishops of Belgium were directed to establish a chair of Thomistic philosophy. By July, 1882, arrangements had been made with the University, and Canon Desire Mercier, professor of philosophy at the Seminary of Malines, was appointed to the chair. To prepare himself for this new and unique post. Dr. Mercier (with beard and with- out clerical garb) undertook formal training in psychology under the famous Charcot in Paris. At Louvain he followed the formal courses and laboratory work in physiology, neurology, chemistry, mathematics and linguistics. He was convinced that no domain of modem science can be considered foreign to Thomistic philosophy. In 1888 Msgr. Mercier founded, with the enthusiastic approval of the pontiff, the Institut Superleur INTRODUCTION XXV de PhUosophie, or Ecole saint Thomas d'Aquin. Outlining the program of the Institut, Msgr, Mereier said, " The science of today is above all a science of the most exact individual re- search. . . . Let us train, in greater numbers, men who will devote themselves to science for itself, without any aim that is professional or directly apologetic, men who will work at first hand in fashioning the materials for the edifice of science." The new Institut was to be a center of study and research where work would be done on " science in the making." Msgr. Mereier accepted the tripartite division of speculative knowledge ex- plained by St. Thomas: natural philosophy, mathematics and metaphysics. Natural philosophy and experimental science constituted a unified discipline of mind, quite distinct from metaphysics. But, as Mereier expressed it, Thomistic natural philosophy seeks ' ultimate ' causes (projiter quid) , while ex- perimental science seeks ' proximate ' causes (quia) . Mercier's distinction, which was accepted by his distinguished associates, Michotte and Nys, is still found in many modem manuals of scholastic philosophy. The influence of Mereier was very great, both at Louvain and elsewhere. The example of Louvain was soon followed by the Catholic institutes and universities of Munich, Milan, Paris, Cologne, Miinster, Fribourg, Nijmegen, the " Gregorian," the " Angelicum " and the Catholic University of America. After the death of Cardinal Mereier in 1926, a number of Louvain professors under the inspiration of Femand Renoirte have come to see a sharp distinction between the non-causal explanations of modern science and the causal explanations of Thomistic philosophy. For them St. Thomas' natural philoso- phy seems to be of the metaphysical order and different from the technique of modern science. In effect, this was a return to the Wolffian conception of philosophy, although today it is presented as the authentic teaching of St. Thomas. Alumni of Louvain have made this view widely known in the Netherlands and in the United States. According to this view the philosophy of nature is a metaphysical study, differing essentially from the XXVI JAMES A. WEISHEIPL experimental sciences, because it reaches " a level of thought in which no sense-perceptible element is retained and therefore no verification by the senses is possible." In " support " of this view, proponents invariably quote, out of context, a passage from St. Thomas' In Boethium De trinitate, q. 5, a. 1 ad 6. However, apart from the impossibility of justifying this view in the writings of St. Thomas, St. Albert or any of the schoolmen, it seems to be unsatisfactory for many reasons. It is based on what seems to be a misconception of metaphysics; it apparently ignores the genesis of analogical concepts; and it widens the chasm between philosophy and science, returning to the in- soluble situation of Wolffian Idealism. It denies the dignity of natural science by giving it too little intellectual content, and it denies the dignity of natural philosophy by rarefying it be- yond sense contact. There is no doubt that the physical uni- verse can be studied ' metaphysically,' but only at the expense of those very details of interest to the natural philosopher. The universe which interests the natural philosopher is full-blooded, and quite un-metaphysical. A more realistic approach to the relation of philosophy to science was made by Jacques Maritain in his monumental Distinguer pour JJnir: ou Les Degres dii Savoir (1932) and in his detailed La Philosophie de la Nature of 1935. This dis- tinguished Thomist learned contemporary philosophy from Henri Bergson and biology from Hans Driesch before finding his home in Thomism. First, Maritain accepts the traditional division of speculative philosophy into natural philosophy, mathematics and metaphysics. Second, he realizes that the experimental sciences have developed greatly since the time of Aristotle and St. Thomas Aquinas. Third, he examines modem ' science ' and sees that it is not a homogeneous whole; in fact, it includes two specifically different types of knowledge. One type is formally mathematical, even though empirical. This type Maritain calls eTnpiriometrique, because it is concerned solely with the measurable aspect of empirical observation. This concern is characteristic of all parts of modern physics INTRODUCTION XXVU and a great part of modern chemistry. However, for Maritain, this type of knowledge was familiar to Aristotle and St. Thomas as scientiae mediae between pure mathematics and natural phi- losophy. The second type of knowledge found in modem science is essentially empirical, descriptive of phenomena, ' perinoetic ' and somewhat hypothetical in character. This type Maritain calls empirioschematique, because it is concerned solely with ordering empirical observation by means of non-mathematical constructs. This concern is characteristic of such experimental sciences as biology, botany, anthropology, physiology, neu- rology and psychology. Finally, Maritain comes to reconciling his analysis of modern science with the traditional division of speculative knowledge. The empiriometric sciences present no difficulty, since they are scientiae mediae between mathematics and the first degree of abstraction. The empirioschematic sci- ences, however, present a problem. They do not attain the essential natures of material things; they are rather descriptive, hypothetical and superficial (perinoetic) . Aristotle's natural philosophy, on the other hand, intuitively attains the essential, ontological natures of changeable being; it is ' dianoetic,' pro- found and certain. Therefore Maritain suggests that Aristo- telian natural philosophy and modem empirioschematic science belong to two dift'erent levels of intelligibility within the tradi- tional first degree of abstraction, the former resolving its definitions to ' being,' the latter to sense and ' mobility.' The view of Jacques Maritain, therefore, is similar to that of Car- dinal Mercier, except . that Maritain alone accounts for the unique position of physics in modern science. There is no denying the acumen of M. Maritain's analysis and the astuteness of his solution. There is only one difficulty: if the empirioschematic sciences are as superficial and hypo- thetical as Maritain believes, then they are not sciences at all, but only dialectical preparations for science. Scientific knowl- edge, as understood by Aristotle and St. Thomas, consists in true demonstration, that is, a causal explanation of essential properties. But this is impossible without dianoetic knowledge XXVm JAMES A. WEISHEIPL of essential natures. In other words, without knowledge of the essential nature of the subject and the property, there can be no demonstration; there can be no scientific knowledge properly so called. The anomaly of M. Maritain's position is that he reconciles modern empirioschematic science with Thomistic philosophy of nature by depreciating modern science. Un- doubtedly there are many areas of modern ' science ' which are superficially descriptive, tentative and dialectical in content. If, on the other hand, there are areas of modern science which truly attain essential natures and through them demonstrate characteristic attributes, as often seems to be the case in the biological sciences, then the situation is very different from that presented by M. Maritain. A better solution was recognized by Fr. Aniceto Fernandez- Alonso, O. P. In 1936 he published a remarkable paper entitled " Scientiae et Philosophia secundum S. Albertum Magnum." Examining the scholastic scene of the 1930's, Fr. Fernandez saw that all scholastics wished to recognize a real distinction between modem science and Aristotelian philosophy. This dis- tinction was variously described as one of content (accidental relations vs. substantial essences, phenomena vs. noumena, sensible vs. intelligible) or one of method (inductive vs. de- ductive, proximate causes vs. ultimate causes, quia demonstra- tions vs. propter quid demonstrations) . Fr. Fernandez then went on to show that none of these can differentiate the specu- lative sciences, for every science, whether it be called empirical or philosophical, must deal with substance and accidents, must be intelligible and sensible; further, every science must be in- ductive and deductive, must demonstrate through immediate (propter quid) and remote (quia) causes. Fr. Fernandez's own view can be summarized briefly in three propositions, each of which he proves at great length. (1) All modern science and all natural philosophy are specifically distinct from metaphysics. (2) All sciences formally illuminated by mathematical prin- ciples are specifically distinct from sciences of nature, although materially they all study the same physical universe. (3) Aris- INTRODUCTION XXIX totelian natural philosophy and the so-called empirical, or experimental sciences constitute one specific discipline, both materially and formally: they are two parts of one and the same science concerning ens mobile, and each part has need of the other. These propositions are all justifiable according to the principles of Albertus Magnus. Fr. Fernandez concludes his study by saying, " The division of human knowledge into philo- sophic and scientific as into two species necessarily and always distinct by the very nature of the objects and the formal inde- pendence of one from the other is an assertion which can be made in Platonic, Cartesian, Hegehan and Bergsonian philoso- phy, but cannot be made in Aristotelian or Albertine philoso- phy, nor according to the truth of the matter." Today the view of Fr. Fernandez is defended by the Very Reverend William Humbert Kane, O.P., and the Albertus Magnus Lyceum. On reading the paper in 1936, Fr. Kane immediately recognized the merits of this view, and his own quest for a solution fell into place. Through his stimulating classes! and informal discussions he developed a group of dis- ciples and friends who were equally convinced of the impor- tance of a unified view of Thomistic natural philosophy and modern investigations. By 1950 sufficient unified interest was shown in the study of natural philosophy and modern prob- lems to warrant suggesting a special institute directed by Fr. Kane for serious work in this area. The idea of such an institute was, indeed, unique in the Dominican Order; on the other hand, nowhere in the Order were there so many men con- vinced of the importance of Thomistic natural philosophy for the solution of modern problems. The idea of an institute de- voted to special research was also unique among Dominicans in the United States; on the other hand, the time was ripe for such a venture in this country. Consequently the idea was formally presented to the Provincial of the Dominican Province of St. Albert the Great, the Very Reverend Edward L. Hughes, O. P., by the Regent of Studies and President of the Pontifical Faculty of Philosophy at River Forest, Illinois, the Very Rev- XXX JAMES A. WEISHEIPL erend Sebastian E. Carlson. By special decree of the Provincial, the Albertus Magnus Lyceum was established at River Forest in 1951, its official date of inception being celebrated on Novem- ber 15, the feast of St. Albert. On this tenth anniversary of its establishment the Lyceum takes great pleasure in presenting this volume of studies to its founder and former director on his sixtieth birthday. The volume reflects the wide interest of its members and friends. From small beginnings the Lyceum has grown to include Dominicans of other Provinces and many non-Dominicans. It has developed a serious interest in scientific methodology, the history and philosophy of science, various technical problems of physics, biology, evolution and psychology; and it has had a decided influence on the teaching of natural science in the schools. Of course, much remains to be done in these vast areas of natural science and more specialists are needed even now. Here one can apply the phrase of St. Thomas: Fiat aliqualiter per plura, quod non potest fieri per unum. The Lyceum's view of natural philosophy and the modem sciences has been presented in innumerable writings, lectures, symposia and discussions. Nevertheless, its view has been frequently misunderstood and misrepresented by those who, presumably, disagree with its position. Presumably they have read at least some of the writings which they attack. But it is unreasonable to expect fruitful discussion and disagreement without mutual understanding. By far the most commonly misunderstood point is the Lyceum's (and Maritain's) dis- tinction of modern sciences. Neither Maritain nor the Lyceum considers * modern science ' to be a single, homogeneous body of knowledge. They make a careful distinction between those sciences which are formerly mathematical and those which are not. Formally mathematical sciences {empiriometrique, scien- tiae mediae, mathematical-physical sciences) are acknowledged to be really distinct from the philosophy and science of nature. Although extrinsic, the mathematical-physical sciences are of utmost importance to the naturalist in the examination of prob- INTRODUCTION XXXI lems and in the quest for proper solutions, demonstrative or tentative. Conversely, the natural sciences are of importance to the mathematical physicist in giving him the extrinsic foun- dation for his own science. Further, the Lyceum considers the non-mathematical parts of modem science to belong to a single science concerning ens mobile ut mobile. In practice, courses in natural philosophy rarely get beyond general considerations, and courses in experimental science rarely get beyond particular considerations and experiments. However, the Lyceum con- siders that in both the general and particular parts of this unique discipline there are to be found diverse types of cer- tainty: demonstrative, most probable, tentative, hypothetical, factual and even historical. Finally, the Lyceum maintains that the single science of nature is autonomous in its own field, and in the order of learning prior to and independent of metaphysics. There are many advantages to this view. First, it recognizes the dignity of a scientific study of the natural world which includes man, animals, plants and inanimate realities. Second, it recognizes the importance of this science for moral, meta- physical and theological concepts. Third, it offers a real possi- bility of cooperation between the professional philosopher and the experimental scientist. Fourth, it is consistent with the teaching of St. Thomas and St. Albert, for whom natural science is incomplete unless after studying the general theory found in the Physics, one proceeds to more and more particular species and varieties of living and non-living natures. Fifth, it is con- sistent with the actual practice of modern scientists, who begin with very particular varieties and gradually ascend to a more embracing unity, usually in old age. Here the statement of Heraclitus would be applicable: " The way up and the way down is one and the same." in It is not very often that an institution can celebrate its own anniversary and that of its founder at the same time. Hence it is a privilege for the Lyceum to celebrate its tenth anni- versary by presenting these special studies to Fr. William XXXll JAMES A. WEISHEIPL Humbert Kane on his sixtieth birthday, July 12, 1961. His inspiring devotion to study, to teaching and to the Dominican way of life deserve some recognition from his brethren and friends besides the normal courtesies of academic and religious life. This Festschrift is presented to him with warm affection, deep respect and eternal gratitude. It is a token, indeed a very small token, of our great esteem. Those who esteem Fr. Kane's life-long work recognize his influence on the intellectual life in the United States, both within and without the Dominican Order. Those who have not had the privilege of knowing him will find in this volume the fruits of much of his labor. William (Dean) Kane was born in La Grange, a suburb of Chicago, on July 12, 1901. After completing Lyons Township High School and attending Aquinas College in Columbus, he entered the Order of Preachers in Somerset, Ohio, in 1920, and took the religious name of Humbert. After the normal course of studies he was ordained to the priesthood in Washington on June 9, 1927. But while he was studying theology at the Do- minican House of Studies in Washington, he studied pre- medicine at the Catholic University of America (1923-26) and medicine at Georgetown University School of Medicine (1926- 28) in preparation for the Chinese missions. Successfully com- pleting his Lectorate dissertation, " The Criterion of Philo- sophical Truth," in 1928, he was sent to the Collegio Angelico in Rome for two years graduate study in philosophy. His ex- amination and dissertation on " Finality in Nature " obtained for him the Doctorate of Philosophy summa cum laude in June of 1930. His life thereafter was completely devoted to teach- ing, and it is for this that he is best known. In thirty years of teaching — biology, logic, natural philosophy, metaphysics and theology — he has given much serious thought to the text of St. Thomas and to modem problems. From 1933 until 1940 Fr. Kane was Lector Primarius in the House of Philosophy at River Forest, and from 1940 until 1948 he was Pro-Regent of Studies for the newly created Province of St. Albert the Great. On December 17, 1944, the River Forest studium was established INTRODUCTION XXXlll as a Pontifical Faculty of Philosophy, and Fr. Kane became its first President. On that day, too, he received the ring and biretta of a Master in Sacred Theology, a degree which he had rightfully earned through his teaching. Returning to Rome as Professor of Natural Philosophy in 1948, he created such an impression on the students that he was thought to be more European than American in his devotion to study. In 1951 when the Albertus Magnus Lyceum was established, he re- turned to the United States to be its director. The bulk of his writings date from this return to River Forest. Now at sixty, the Very Rev. William Humbert Kane feels that his work is just beginning, but he has the assurance that his ideals have taken root in the minds and hearts of his disciples. We extend to him our gratitude, prayers and best wishes AD MULTOS ANNOS. For the preparation of this volume special gratitude is due not only to the eminent contributors, who enthusiastically en- dorsed the project from the start, but also to those members of the Albertus MagTius Lyceum who are not represented here. Particular acknowledgement must be made to the President, the Very Rev. Sebastian E. Carlson, and to the Secretary of the Lyceum, the Rev. William B. Mahoney, whose tireless efforts supported the whole project. The Lyceum gratefully acknowledges the encouragement and contribution of the Master General of the Order of Preachers, the Most Rev. Michael Browne, and his Socius for the North American Provinces, the Very Rev. John A. Driscoll. Our sincere grati- tude is offered to the Very Reverend John E. Marr, O. P., Provincial of the Province of St. Albert, who has given his en- couragement and support to this volume. Since the effort has reached beyond provincial boundaries, we extend this same gratitude to the Very Reverend W. D. Marrin, O. P., Provincial of the Province of St. Joseph. Above all, we are grateful to The Thomist Press and the editorial staff of The Thomist who have joined with the Albertus Magnus Lyceum in honoring our Father William Humbert Kane, O. P., S. T. M. James A. Weisheipl, O. P. D.Phil. (Oxon.) Part One SCIENTIFIC METHODOLOGY DEMONSTRATION AND SELF-EVIDENCE I. Scientific Methodology IT can be forcefully argiied that there is no place in phi- losophy for an " epistemological critique " of knowledge, as though the integrity of the intellect stood in doubt till it was somehow philosophically " cleared." ^ Surely, for reason to attempt to establish the trustworthiness of reason is for it to try to pull itself up by its own epistemological boot straps. The history of thought gives ample evidence that criti- cal attempts to justify the philosophical effort are in vain. No m.atter how honest the epistemological critique in intention, it results characteristically in an unnatural imposition of artificial limits placed upon our capacities to know. Witness the divergent streams of extreme rationalism and extreme empiricism which find their source in the critique of Descartes.^ Significantly, St. Thomas did not find it necessary to initiate his philosophical effort with a critique of knowledge. A Thomist speaks meaningfully of epistemology best in reference to a metaphysical inquiry into the character of intentional being. He takes epistemology as an attempt to understand what it is to know, not an attempt to defend the radical integrity of our ^ Cf., Gilson, fitienne, Realisme Thomiste et Critique de la Connaissance (Paris: J. Vrin, 1947) ; Realisme Methodique (Paris: P. Teque, 1935) . ^ Gilson 's frequently quoted remark on Berkeley and the Cartesian critique bears repetition here: " Everyone is free to decide whether he shall begin to philosophize as a pure mind; if he should elect to do so the difHculty will not be how to get into the mind, but how to get out of it. Four great men have tried it and failed. Berkeley's own achievement was to realize at last, that it was a useless and foolish thing even to try it. In this sense at least, it is true to say that Berkeley brought Descartes' ' noble experiment ' to a close, and for that reason his work should always remain as a landmark in the history of philosophy." The Unity of Philosophical Experience (New York: Chas. Scribner's Sons, 1937) , pp. 196-197. 4 EDWARD D. SIMMONS capacities for knowledge. That we can know is evident. It is both futile and unnecessary to attempt to prove this.* Although St. Thomas did not hamper his capacities for knowledge by imposing a 'priori restrictions upon them, he saw that, in a sense, they imposed restrictions upon him. There is no question, from the very start, as to the radical integrity of sense and intellect. Despite the fact that we are sometimes in error, it is evident that we can, and adequately, know what is. But our capacities for knowing are in no sense unlimited. Honest reflection upon the epistemological facts reveals that the human intellect is that lesser type of intellect which is at once a reason. For us all doctrine and discipline is from pre- existing knowledge.* We learn by moving from what is already known to what follows from this. The fact is clear that, as far as learning is concerned, the human intellect is naturally discursive. Moreover, the price of discursive advance in knowl- edge is the construction within the intellect of logical artifices such as definitions and argumentations. The method of con- struction which is called for by the demands of discourse is in no sense arbitrary. As always, the final cause is the cause of the causality of the other causes. The end of the logical con- struct requires certain determinate rules according to which the objects known are to be ordered in knowledge in reference to one another. Thus, there are definite rules of procedure which constrain the intellect in its discursive progress.^ These * Cf., Smith, Gerard, S. J., "A Date in the History of Epistemology," in The Maritain Volume of The Thomist (New York: Sheed and Ward, 1943), pp. 246-255. * In I Post. Anal., lect. 1, n. 9: " Omnis autem disciplinae acceptio ex prae- existenti cognitione fit." (The quotations from St. Thomas will be taken from the Leonine for the Summa, the Decker for the De Trinitate, the Lethielleux for the Sentences, and from the respective Marietti editions for each of the other works cited.) The general rules of discursive procedure, we shall note, are one with the laws of logic. Logic is simultaneously an art and a science. As an art it is directive of a productive activity — precisely, for logic, the construction within the reason of the instruments of discourse, such as definition and argumentation. The character of any work-to-be-produced sets the standard according to which the artistic effort is to be effected. Thus every art has its own determinate rules of procedure. In the case of logic, of course, these are the rules of sound discourse. And in the case of DEMONSTRATION AND SELF-EVIDENCE 5 can be said to constitute a method, and the reflexive investi- gation of them can be spoken of as methodology. It should be clear that this is not method in the manner of Cartesian method, nor is it methodology in the manner of epistemological critique. There is for man but one reason. Hence, there is generally but one method, that is, the discursive method which measures up to the demands of that one reason. But there are many different things to be known, on radically different scientifically relevant levels. As a consequent, the general method of the reason must be proportioned to each scientifically different object for each formally different scientific effort. The general method of the reason is logic. Logic is at best analogously common to every scientific inquiry. By itself it is inadequate to any particular scientific subject matter. Logic must be con- tracted, and in analogously different ways, to the needs of every scientifically different subject. This contraction of logic is realized in the particular scientific methods proper to each formally different scientific subject.^ Note that while logic by itself is inadequate to any given scientific inquiry because of the special demands of the proper subject of that inquiry, there can, because of the demands of the reason itself, be no particular logic, because discourse is aimed ultimately at a fully defended scientific knowledge of things, the rules of the art must themselves be evident in themselves or demon- stratively defended. Since only the most fundamental rules of logic are evident in themselves the majority of them must be demonstrated. Thus, in order for logic to be the art that it is, it must be at once the demonstrative science of the rules of discourse. As a matter of fact, the rules of discourse are the canons which express the demands of the second intentions which accrue to objects as known and m virtue of which these objects are to be ordered in discourse. Thus logic is simul- taneously the art of sound discourse and the demonstrative science of second intentions or rules of discourse. For a more complete exposition and defense of this position, cf., Simmons, Edward, " The Nature and Limits of Logic," The Thomist, XXIV (January, 1961), pp. 47-71. ®In In Boeth. de Trin., q. 6, a. 1, St. Thomas distinguishes between the demon- strative method characteristic of natural science (rationabiliter) , the method of mathematics (disciplinabiliter) ,. and the method of metaphysics {intellectualiter) . These represent different contractions of the general logic of demonstration in favor of formal differences in diverse scientific subjects. 6 EDWARD D. SIMMONS scientific method which is not generally logical. Clearly, the investigation into general logical method is methodology in one sense, while the investigation into the precise method of any given scientific inquiry is methodology in another (related) sense. We can refer to the former as general methodology and the latter as particular or special methodology.^ In this paper we shall concern ourselves with the role of the self-evident proposition in the theory of demonstration. This is a study in general methodology. The point made will be of a common character, and the methodological principles uncovered will be only generally relevant for scientific inquiry. In every case an appropriate contraction of the doctrine pre- sented will be necessary before it is proximately adequate to any given scientific effort. Before proceeding, however, there remains one more distinction to be made, the better to locate the discussion of this paper. General methodology is identical with logical theory, and, as such, admits of the distinction between formal and material logic. This is a distinction which is both legitimate and significant, but it is a distinction which is frequently misunderstood. Although it is a distinction which should be made within the limits of general logical theory, it is not infrequently understood in such a way that formal logic is identified with general methodology while material logic is asso- ciated intrinsically with particular scientific methodology. This mistaken view makes logic less than adequate to the demands of reason even in abstraction from the particular demands of any given scientific subject. And, while it may not positively vitiate the investigation into particular scientific method, it places an unreasonable burden upon it. Just as there are general rules of logical procedure to be followed if discourse is to be consistent or valid, so there are general rules of procedure to be followed if discourse is to be of some determinate scientific force. Categorical syllogism is defined in terms of validity. The rules which must be followed to make the syllogism pre- cisely a syllogism (e. g., the middle term must be fully ^ Cf., In II Met., lect. 5, n. 335; In II De Anima, lect. 3, n. 245. DEMONSTRATION AND SELF-EVIDENCE 7 distributed at least once) are canons of valid or consistent discourse. Demonstration, on the other hand, while pre- supposing validity, is defined in terms of scientific force. And there are general rules, able to be determined apart from any- particular scientific subject, which must be followed if a syllo- gism is to be demonstration (e. g., the premises must be necessarily true) , and even more determinate general rules which must be followed if the demonstration is to be of a certain type (e. g., explanatory demonstration must have a middle term which is related to the scientific subject as its real definition) . These rules, while quite clearly remaining of a general logical character (i. e., open to contraction in the face of special scientific subject matter, but not yet con- tracted ) are canons of properly scientific, and not simply con- sistent, discourse. Rules such as these are proper to material logic, while the rules of merely consistent discourse are rules of formal logic. There are reasons which explain why formal logic is sometimes confused with the whole of logic and why material logic is sometimes confused with particular scientific methodology.* But these reasons only help to excuse the man * The formal subject of the science of logic is the second intention. Second inten- tions are logical forms or relations of the reason which accrue to objects (first intentions) precisely as known. Some second intentions accrue to an object properly in virtue of its mode of signifying (e. g., predicate, middle term, and syllogism) . Others accrue directly in virtue of the intelligible content of the object (e. g., species, immediate, and demonstration) . The former are second intentions in formal logic, and they set the demands for valid discourse. The latter are second intentions in Tnaterial logic, and these set the demands for scientific discourse. Although St. Thomas explicitly distinguishes between formal and material logic only on the level of the logic of the third operaton (cf., In I Post. Anal., prooem., nn. 5-6) , the distinction makes sense also on the levels of the first and second operations, as the examples above illustrate. [Cf., Simon, Yves, " Foreword," The Material Logic oj John of St. Thomas, translated by Yves Simon, John Glanville, and G. Donald Hollenhorst (Chicago: Chicago University Press, 1955), pp. ix-xxiii.] The subject matter for logical theory is always the second intention, and never directly the first intention to which the second intention accrues. Thus, there is a sense in which logic is only formal (investigating logical forms) and never material (discussing the mtelligible content of first intentions, which is the matter of dis- course) . And even apart from this, it is clear that second intentions in material logic are more proximately connected with the intelligible content of first intentions 8 EDWARD D. SIMMONS who is confused. They do not defend the confusion as a noetic fact. The theory of demonstration in general remains, as much as the theory simply of syllogism, the concern properly of the logician. It must be assumed and contracted to the needs of the special subject matter for any given scientific inquiry. Thus the concern of this paper is within the limits of logic, but it belongs to that branch of logic which is material logic rather than formal logic. This brings us significantly closer to the area of particular methodology than a paper in formal logic would, but we remain in logic without trespassing beyond. II. Self-evident Proposition — The Basic Truths OF Demonstration Early in the Posterior Analytics, after determining the nature of scientific knowledge (in brief, certa cognitio per causas ^) , than are those in formal logic. The connection is so intimate that Simon and his fellow translators suggest that the Jwhitus of material logic is reduced in actual use to the science which employs it (ibid., note 39, pp. 594-595) . Whether this is the case or not, it remains true that the formal subject of material logic as well as the formal subject of formal logic is no more nor less than a logical form or second intention. This means, of course, that material logic is integrally a part of logic proper and is not, as a science, to be confused with any (and every) particular sicence of the real. (Cf., Simmons, E., op. cit.) ' The Posterior Analytics, Book I, Ch. 2, 71b9-12: " We suppose ourselves to possess unqualified scientific knowledge of a thing . , . when we think we know the cause on which the fact depends, as the cause of that fact and of no other, and, further, that the fact could not be other than it is." [Translation from The Basic Works of Aristotle, edited by Richard McKeon (New York: Random House, 1941), p. Ill] There should be no need to insist that, in the face of current usage, this gives a highly restricted (and exceedingly strict) meaning to " science." As we begin to speak of this kind of science as demonstrated knowledge there is, of course, a proportionately strict understanding of the meaning of " demonstration." Still, the terms " science " and " demonstration " admit of analogous impositions, even as used by us in this paper. For example, demonstrations differ analogously from one genus of speculative science to another — so that mathematical demonstration is only proportionally like metaphysical demonstration (cf. In Boeth. de Trin., q. 6, a. 1; In I Post. Anal., lect. 41), and even within a given science — so that a propter quid demonstration in one science is only proportionally like a quia demonstration in that same science (cf ., ibid., lect. 23) . Having introduced this strict meaning of science in the second chapter of The Posterior Analytics, Aristotle has set the stage to demand of the scientific syllogism that its premises be necessarily true and DEMONSTRATION AND SELF-EVIDENCE 9 Aristotle defines demonstration in terms of its final cause as a syllogism productive of science. Then, using this definition of demonstration itself as a principle of demonstration, he pro- ceeds to demonstrate the definition of demonstration in terms of its matter. He argues that if a syllogism is to produce the kind of conclusion which is properly scientific it must proceed from premises which are true, primary, immediate, better known than, prior to, and cause of the conclusion. This is to say that it must proceed from necessarily true, absolutely first propositions, which look to no prior proposition for their evi- dence but are calculated to supply evidence for other proposi- tions. We speak of these propositions as self-evident. Scientific knowledge is proven in a demonstration whose premises mani- fest the truth of the scientific conclusion. As principles of the conclusion these premises are properly premises. In any given case, however, they may also be conclusions from other premises. But it is impossible, of course, that every premise be itself a conclusion from a prior premise. We must arrive ultimately at premises which are only premises, at propositions which are not shown to be evident by way of prior propositions but whose evidence is found within themselves. These absolute premises are ultimately the complex principles ^° of scientific knowledge, themselves not properly scientific, but rather pre- scientific. They are self-evident propositions, the propositions spoken of in the Posterior Analytics as " the immediate basic truths of syllogism " or, more determinately, of demonstration. immediately so (Ch. 3) . It is important to note that, for the most part, the sub- sequent discussion of the requirements for demonstration is centered upon the strictest type of propter quid demonstration and is only proportionally relevant to other types. ^° The absolute premises of demonstration are significant principles of demonstra- tive discourse. So too is the middle term of the demonstration (which is not identical with any premise, though it is built into each) . The former are complex principles of demonstration. The latter is an incomplex principle. We are concerned primarily with the complex principles of demonstration in this paper, although, as we shall note, the definition itself plays a significant role in the discussion of these complex principles. As a matter of fact Aristotle lists the definition as a type of demonstrative principle in the very context of the discussion of immediate premises (cf., St. Thomas' explanation for this, op. cit., lect. 5, n. 9) . 10 EDWARD D. SIMMONS St. Thomas speaks of these " basic truths " as per se nota propositions. Although this is an apt expression, there is some danger of confusion here. First of all, St. Thomas may some- times use the term per se nota of a proposition which is not evident in the way in which the basic truths of demonstration are self-evident." Secondly, St. Thomas frequently speaks of the modes of perseity (the modi dicendi per se) ,^" and, despite the terminological suggestion to the contrary, it is not true that whenever we have a proposition which involves a mode of perseity we have a per se nota or self-evident proposition. These points will have to be clarified before we are through. For the premises of demonstration to be at all they must be true, for the esse of a proposition is an esse verum. For them to be principles of manifestation for the scientific con- clusion they must be necessarily true, for necessity is of the essence of science. And for them to be basic truths, that is absolute premises, the premises of demonstration must be, at least reductively, imviediate propositions. Here is precisely where the scientific proposition differs from its pre-scientific principle. The scientific proposition is necessarily true, and it is a conclusion. The scientific principle is necessarily true, but it can be (ultimately) in no sense a conclusion. The conclusion of a syllogism is characteristically mediate, for the connection between its extremes is manifested in a syllogism by way of a term commonly identified with both extremes, thus functioning as a middle. The basic truths of syllogism or the absolute premises must themselves be evident without a middle. The predicate must belong immediately to the subject lest we admit the infinite regress which would make deduction totally ineffec- tive. Two things, at least, should be pointed out here. First of all, there is a significant and not unrelated use of the term " immediate " which is not intended at this point. For example, having three angles equal to two right angles is necessarily ^^ In II Pkys., lect. 1, n. 8: " Naturam autem esse, est per se notum, in quantum naturalia sunt manifesta sensui." " Cf., In I Post. Anal., lect. 10; In II De Anima, lect. 14, n. 401; In V Met., lect. 19, nn. 1054-1057. DEMONSTRATION AND SELF-EVIDENCE 11 true of both triangle and isosceles triangle. But it is true of isosceles triangle only insofar as isosceles triangle is triangle. Thus we might well say that this property belongs immediately to triangle and mediately (through triangle) to isosceles triangle. However, the proposition Every triangle has three angles equal to two right angles can be demonstrated as the conclusion of a syllogism employing the essential definition of triangle as its middle term. Insofar as it is able to be proven through a middle, it is clearly not immediate in the sense in which self-evident propositions are immediate. " Immediate " here means, rather, commensurately universal or convertible {primo or possessed of the intention spoken of as did ut universale) . As a matter of fact, not every proposition which is commensurately uni- versal is self-evident and not every self-evident proposition is commensurately universal.^^ Secondly, even though we under- stand the self-evident proposition to be immediate in such wise as to lack a demonstrative middle, it is not the case that every proposition which is immediate in this sense is self-evident. A self-evident proposition is a proposition with a subject and a predicate in necessary matter, and with a subject and predi- cate so proximately connected with one another that the necessary truth of the proposition can escape no one who understands this subject and predicate. Hence, propositions are said to be self-evident precisely insofar as they can be seen necessarily to be true once their terms are known. ^* These '^^For St. Thomas' position on the did ut universale, cf., In I Post. Anal., lect. 11. We shall see that the prime instance of the self-evident proposition has a predicate which is of the definition of the subject. If the predicate is the whole of the definition of the subject it is, of course, convertible with the subject, and we have a commensurately universal proposition. Every man is capable of speech is com- mensurately universal without being self-evident, and Every man is animal is self- evident without being commensurately universal. ^* Only this type of proposition is so necessarily true, while being at the same time immediate, that it can ground the necessity of a scientific conclusion. In IV Met., lect. 5, n. 595: "Ad huius autem evidentiam sciendum, quod propositiones per se notae sunt, quae statim notis terminis cognoscuntur. . . ." De Mala, q. 3, a. 3, c: " Unde intellectus ex necessitate assentit principiis primis naturaliter notis. . . . Unde in intellectu contingit quod ea quae necessariam cohaerentiam habent cum primis principiis naturaliter cognitis, ex necessitate moveant intellectum, 12 EDWARD D. SIMMONS propositions are not totally non-empirical, for, as we shall note, they are known by way of an immediate induction from sensible data. Yet they do not depend directly upon empirical data for verification. Assent to them is founded upon an intelligi- bility built into them such that it is impossible to think the opposite. Thus, if one understands the meanings of the terms in the proposition The whole is greater than any of its parts one immediately assents to this proposition quite apart from the existence of this or that sensibly existing whole or part. The motive for assent is, in a sense, built into the proposition itself. The self-evident proposition is immediate because it looks to no prior proposition for its evidence, but there are propositions which are evident in this way without being self evident. These are the factually evident propositions which are true, because they report accurately on the way things happen in fact to be, whether they could be otherwise or not. Examples of propositions like this are This pencil is yellow, The weather is pleasant today, and / feel great. These proposi- tions are immediate since they do not depend on prior proposi- tions to manifest their truth. The evidence for them is found immediately in the factual situation. Insofar as a factually evident proposition is formally characterized by its commit- ment to what happens to be the case, the factually evident proposition cannot intend the necessity needed for an absolute premise of demonstration. Thus, though each is immediate, the factually evident proposition differs radically from the self- evident proposition.^^ In the Commentary on the Physics St. sicut conclusiones demonstratae, quando apparent; quae si negentur, oportet negari prima principia, ex quibus ex necessitate consequuntur." Cf., among other texts of this type, In I Post. Anal, lect. 5; lect. 19; De Ver., q. 11, a. 1; Stimma, I, q. 17, a. 3 ad 2; q. 82, a. 2; q. 85, a. 6; De Malo, q. 16, a. 7 ad 18; Quodl., VIII, a. 4. ^^ What I refer to as the " factually evident " proposition is usually spoken of simply as " evident," but since the self-evident is (at least) evident it seems better to use a more determinate expression. There is nothing highly sophisticated intended by my use of " factually," despite the fact that the word " fact " does frequently take on a very specialized meaning in philosophical discussion. Note that none of my examples involves necessary matter in any sense. This helps to make the notion of the factually evident quite clear. Nonetheless it seems to me that This whole DEMONSTRATION AND SELF-EVIDENCE 13 Thomas says that it is 'per se notuvi that nature exists because natural things are manifest to the sense /"^ Natural things exist is an immediate proposition. But it is not self-evident — for, since natural things are existentially contingent and need not be, we cannot assent to the proposition Natural things exist simply because we understand the meaning of its terms. It is immediately evident only on the basis of the empirical fact unmistakably given in our sensory-intellectual grasp of the exis- tence of sensible existents immediately present to the external sense. This is clearly a factually evident proposition. It is of significant relevance for the philosophy of nature, but it is not relevant in the way in which a self-evident proposition is relevant,^^ despite the fact that St. Thomas describes it as per se nota. One more clarification at this point. The immediacy of the self-evident proposition makes it indemonstrable. But not all indemonstrable propositions are immediate (consider conclusions of dialectical or probable argumentation) . Nor even, of course, are all immediate and indemonstrable proposi- is greater than its parts can be taken as a proposition which intends simply a report on a concrete situation. As such this is factually evident, and it is not the same as the proposition Every whole is such that it must be greater than any of its parts. This second proposition is, of course, self-evident, and it is certainly known by anyone who can express the former proposition (because the terms which must be known in order that the former be expressed immediately make evident the latter) . Although the most perfect instance of propter quid demonstration involves two premises each of which is self-evident, there is no reason why less strict demonstration cannot include one factually evident premise. The necessity needed in the antecedent of a demonstration would be lacking if every premise were factually evident, but it can be supplied by one self-evident proposition coupled with a factually evident premise. As a matter of fact, demonstration makes sense only in reference to scientific subjects known to exist. "Where both premises are self-evident it is a requirement that the existence of the scientific subject be known prior to demonstration and presumed within demonstration. The existence of the scientific subject can be expressed within a demonstration when one of its premises is factually evident, ^* Cf., supra, note 11. ^^ There would be no reason for a philosophy of nature if natural things did not exist; but since they need not exist, the proposition which reports on the fact of their existence cannot be used as a necessary premise manifesting the scientific necessity of any conclusion. 14 EDWARD D, SIMMONS tions self-evident (consider the examples given above for the factually evident proposition) . Certainly true propositions in contingent matter are indemonstrable because of a deficiency in matter. Self-evident propositions are always in necessary matter, and their indemonstrability springs from their excel- lence rather than from some deficiency in matter. Demonstra- tion makes evident something which is not already evident. To be demonstrable entails a privation. Because they are evident in themselves, self-evident propositions do not have this privation.^^ Self-evident propositions are necessarily true and immediate. This makes them at once primary: they have no propositions prior to them (upon which they depend for evidence) , and they are presupposed to the mediate propositions which look to them for evidence. Insofar as they supply evidence for these mediate propositions they cause them to be conclusions. And they can be related to the conclusion as cause to effect only insofar as they are prior to and better known than the conclu- sion. The " basic truths of syllogism " are basic insofar as they admit of no prior propositions necessary to make them evident. They are truths of the syllogism insofar as they are principles from which conclusions can be generated. III. The Types of Self-evident Proposition We have noted that a self-evident proposition is one which is known to be necessarily true once its terms are understood. The most perfect instance of this is found in the proposition in which the predicate is of the definition of the subject.^^ Once ^* Though scientific or demonstrated knowledge is spoken of as perfect knowledge (cf., In I Post. Anal., led. 4, n. 5) , it is clear that it is inferior to the pre-scientific absolute premises of demonstration. ^* Summa, I, q. 17, a. 3 ad 2: " Nam principia per se nota sunt ilia quae statim intellectis terminis cognoscuntur ex eo quod praedicatum ponitur in definitione subiecti." As Cajetan points out in his Commentary on the Posterior Analytics (Book I, Ch. 19) , St. Thomas does not intend in texts such as this one strictly to define the self-evident proposition but to manifest the principal case. An example of a self-evident proposition which does not have its predicate within the definition of its subject is Every rational animal is capable of speech. DEMONSTRATION AND SELF-EVIDENCE 15 the subject is understood in its definition the identity of subject and predicate is grasped, and the intellect is moved to commit itself irrevocably to the truth of the proposition. If a proposi- tion has a predicate within the definition of its subject, but this subject defies definition by any man, then this proposition can be described as self-evident in itself, but not self-evident to us. If, on the other hand, its subject can be defined by us, it is self-evident both in itself and to us. If the subject is able to be defined only by those who are habituated to operate within a given scientific field, the proposition is said to be self- evident only to the learned. But if is is a common concept understood by every one, it is, of course, self-evident to all. Thus, it is rather easy to see, at least apropos of the prime type of self-evident proposition, the rationale of the traditional division of the "per se nota proposition into the 'per se nota in se and the per se nota quoad nos, and the subdivision of the latter into the per se nota quoad sapientes and the per se nota quoad omnes.-° St. Thomas appeals to the fact that the proposition God is is not self-evident quoad nos even though it is self-evident in itself."^ Were we to know the essence of God we could not — nor would we need to — demonstrate His existence, for His essence is His existence. Yet, since we do not know His essence we are able from His effects, which are known to us, to prove His existence. Aristotle and St. Thomas supply several examples of per se nota propositions which are known to all because their terms are common conceptions easily and surely grasped by all men. These examples include: The sanfie thing cannot he and not he; The same proposition does not admit simultaneously of affirmation and denial; The whole is greater than any of its parts; Things equal to one and the same thing are equal to one another; Equals taken away from equals leave ^° This traditional division of the self-evident proposition is explained by St. Thomas in several texts, including: De Ver., q. 10, a. 12; In IV Met., lect. 5, n. 595; In I Post. Anal., lect. 5, nn. 6-7; In Boeth. de Hebd., lect. 1. Cf., also Cajetan, op. cit., Ch. 3. *^ Summa, I, q. 2, a. 1; De Ver., q. 10, a. 12. 16 EDWARD D. SIMMONS equals.'^ These propositions are called dignitates or axioms because they are the absolutely ultimate and common prin- ciples which guarantee the integrity of all discourse and into which all discourse is resolved. Discourse would be impossible for anyone ignorant of these axioms. Propositions per se nota quoad sapientes are related to the axioms as the proper is related to the common. They can be known only by the learned because the terms involved are more deteiTuinate than the common notions which alone are able to be understood by the academically unskilled. St. Thomas illustrates this by suggesting the proposition All right angles are equal. This is a proposition which is immediately evident only to one who knows that equality enters into the definition of right angle; and this is a definition, of course, which escapes the knowledge of many. Another example which is traditionally offered is the proposition Incorporeal substances are not situated in place. We can add to these any proposition in which the essential definition or some part of it is predicated of a specific subject, such as Every man is a rational animal. A proposition of this type is known as a positio or thesis."^ The axioms are necessary if we are to demonstrate in any scientific area, but the theses proper to a given area are necessary only for demonstrations properly within this area. Axioms may or may not be used explicitly as premises in demonstration, but theses are principles of demonstration only if they appear explicity as premises. Axioms can be distinguished generally into those which are ontological in character (e. g., the principle of identity) and those which are logical in character (e. g., the principle of contradiction) . Those which are ontological in character are ^^/ra 1 Post. Anal., lect. 5, n. 7; In IV Met., lect. 5, n. 595. "^ St. Thomas considers the division of the immediate principles of demonstration especially in lessons 5, 18, and 19 in the first book of his Commentary on the Posterior Analytics. We have already noted the inclusion of definition as a principle (although incomplex) of demonstration. St. Thomas also speaks of a proposition taken as though it were immediate in one science, but proved in another (lect. 5, n. 7) . This proposition is called a suppositio or hypothesis. We are not concerned properly with this proposition in this paper. DEMONSTRATION AND SELF-EVIDENCE 17 presupposed to any demonstration, even when they are not explicitly expressed as premises, precisely because the knowl- edge of proper concepts which is required for theses presupposes and in a sense depends upon a prior grasp of common con- cepts.^* Those which are logical in character function neces- sarily as methodological principles which guarantee the integrity of discourse without being built into it as doctrinal principles. For example, the principle of contradiction is an absolutely common methodological principle without which there could be no discourse at all. No proposition can function properly as a principle of demonstration except that it be firmly accepted that the affirmation of its opposite is excluded in the face of its own affirmation.^^ Of course axioms of an ontological character (when illumined by the light of metaphysical abstraction) can be used as premises in metaphysical discourse, just as axioms of a logical character must be built into proofs in logical theory as explicit premises. The reason for this is that metaphysics and logic are common sciences, so that the principles common to the other sciences are proper to them. As a matter of fact, these common propositions can even be used as explicit pre- mises in the particular sciences, though here they become principles of dialectical rather than demonstrative discourse .^^ ** Consider the relation of being to all other concepts. De Ver., q. 1, a. 1, resp.: " Elud autem quod primo intellectus concipit quasi notissimum, et in quo omnes conceptiones resolvit, est ens; " In III Met., lect. 5. Cf. Cajetan, Comm. In De Ente et Essentia, q. 1. "^ In IV Met., lect. 6, n. 603: " Si igitur quis opinetur simul duo contradictoria esse vera, opinando simul idem esse et non esse, habebit simul contrarias opiniones: et ita contraria simul inerunt eidem, quod est impossibile. Non igitur contingit aliquem circa haec interius mentiri et quod opinetur simul idem esse et non esse. Et propter hoc omnes demonstrationes reducunt suas propositiones in hanc proposi- tionem, sicut in ultimam opinionem omnibus communem: ipsa enim est naturaliter principium et dignitas omnium dignitatum." Cf., also In I Post. Anal., lect. 6, n. 7. ^' Though the direct use of logic is methodological, supplying either the rules of demonstrative or dialectical discourse, logic can, along with metaphysics, because of the correlatively common character of the formal subjects of each, supply premises for argumentation in the particular sciences. Since demonstration requires premises appropriate to the conclusion, the argumentation in some particular science with a premise from metaphysics or logic will be dialectical at best. 18 EDWARD D. SIMMONS IV. The Genesis of the Self-evident Proposition As St. Thomas teaches, the self-evident absolute premises from which scientific conclusions are generated are natural to the human intellect.-^ However, this does not mean, on the one hand, that they are possessed from the very start as fully formed conceptions dependent in no sense upon experience or, on the other, that they are no more than mental constructs fabricated by the intellect totally out of its own " stuff." In the final lesson of his Commentary on the Posterior Analytics St. Thomas finds fault with those who suggest that we already possess the principles but do not know this from the beginning. This is absurd since the principles of demonstration must be better known than the conclusions they generate, and it is impossible to know demonstratively and not be aware of this. St. Thomas also disputes with those who say that self-evident propositions arise in us from nothing. Experience indicates and reason demands that they come from something. But they cannot come from prior intellectual knowledge, for then they would not be immediate. They are generated from previous sense knowledge by way of an immediate induction."^ However, to say this is not to imply that they are easily achieved. ^^ This is simply not the case for the large majority of self-evident "'' Summa, I, q. 117, a. 1: " Inest enim unicuique horaini quoddam principium scientiae, scilicet lumen intellectus agentis, per quod cognoscuntur statim a principio naturaliter quaedam universalia principia omnium scientiarum." "® I say immediate induction to distinguish this from the mediate induction of a conclusion whose evidence is supplied by a sufficient enumeration of singulars. ^' Our students seem to be easily misled into identifying the self-evident with the easily understood. This may be because in our classroom approach to them our examples of the self-evident proposition are almost exclusively axioms which are self-evident to all (e. g., The whole is greater than any one of its parts.) , or it may be because of a tendency on the part of a student to give a psychologically sub- jective reading to what must be understood objectively (i. e., to think " self- evident " means evident to myself rather than in itself) . This confusion is not limited to our students. For example, Joseph Brennan, in The Meaning of Phi- losophy (New York: Harper and Bros., 1953) , p. 94, suggests two meanings to " self-evident," namely, indemonstrable or completely clear to m,e. That the type- writer I am using is gray is both indemonstrable and completely clear to me. But it is in no sense self-evident. DEMONSTRATION AND SELF-EVIDENCE 19 propositions. It takes a sufficient experience (spoken of by St. Thomas as an experimentum which comes about from many memories) ^° of the singular manifestations of a universally necessary truth before we are ready to penetrate beyond the accidentals of these singulars to the underlying necessity. This experimeiituvi is not always easily achieved. And the intuitive insight (into the necessity potentially in the expeiimentum) effected by the possible intellect through the light of the agent intellect is difficult as a matter of course. More often than not, it seems, propositions which are self-evident in themselves are not seen to be self-evident by us; and when they are, it is only by way of a tremendously difficult dialectical procedure. ^^ To grasp the truth of a self-evident proposition one must first grasp the meaning of the terms involved. Hence, the search for ^"In II Post. Anal., lect. 20, n. 11; In IV Met., lect. 6, n. 599. ^^ Thus far I have used the expression " dialectical " to refer to probable argu- mentation. This type of dialectical discourse is supplementary to demonstration. We can also speak of a pre-demonstrative dialectic — which prepares the way for demonstration by manifesting the absolute premises of demonstration. This is the way the term is used here. There is no question of a proof, in any strict sense of the word, for a self-evident proposition. Assent to the self-evident proposition depends upon and comes with an insight into the intrinsic intelligibility of the proposition itself. The assent is automatic with the insight, but the insight may be difficult to achieve. The way to insight may require long and complicated discourse involving division, defuiition, and even argumentation. For example, one typical dialectical device for manifesting the truth of a self-evident proposition is the reduction of its contradiction to absurdity. (Cf. In III Met., lect. 5, n. 392.) The important point is that once the threshhold of insight is achieved the assent is made in virtue of the intrinsic intelligibOity of the proposition itself. The dialectic is a scaffolding which can now be torn down, for it is not needed as a defense of the self-evident proposition once seen (no matter how instrumental it might in fact have been prior to msight) . Here precisely is where the immediate induction of the principles of demonstration differs from the mediate induction of a conclusion from a sufficient enumeration of singulars. The induced conclusion is assented to precisely in vhtue of the enumeration of singulars and cannot be known without pointing to them for evidence. This is not the case for the induced principle. No matter how many singular wholes and parts have to be observed before a man sees into the meaning of whole and part so that he knows the whole must be greater than its parts, the proposition is seen to be true independently of each and all of these singular wholes and parts. (In III Sent., d. 24, q. 1, a. 2, q. 1 ad 2: " Termini principiorum natm'aliter notorum sunt comprehensibles nostro intellectui: ideo cognitio quae consurgit de illis principiis, est visio. . . .") 20 EDWARD D. SIMMONS self-evident propositions is at least as difficult as the search for definitions. Cajetan suggests that it is more difficult than this. At the end of his Cornmentary on the Posterior Analytics he discusses the induction of the per se nota proposition. He contends that induction is necessary, not only as the source of the incomplex terms of the complex principles, but that it is necessary as well for the composition of these terms in the proposition. He argues that we would not know that equals taken from equals leave equals if we knew only the meaning of " equal," " to be taken from " and " to leave." For this reason he holds that for the genesis of this self-evident proposi- tion there must be induction, not only of the meanings of the terms, but even of their conjunction in this proposition. In some texts at least, as we have seen, St. Thomas indicates that the induction of the terms is sufficient for the intellectual grasp of first principles. Appeal to personal experience, after the sug- gestion of Cajetan, seems to indicate that sometimes the induc- tion of the terms alone suffices (as, for example, with the self- evident proposition Every man is a rational animal) , and that sometimes more is required (as in the example cited by Cajetan) . The self-evident proposition is not simply a report on a factual situation. Yet it is not a priori, and it does have an empirical reference. If it were not the case that some things happen to be such and such precisely because they cannot be and not be such and such, we would never grasp the self-evident proposition. It is only through sufficient contact with the things in question that an insight into the necessity which dictates the facts (that is, the way in which these things are) is achieved. ^^ It is true that we can be sure that the whole is greater than any of its parts even though we are not presently confronted by a concrete whole and its parts. The truth of this proposition is guaranteed by the very meanings of whole '"There is no intention here to suggest that all facts are necessitated. I refer simply to the necessity that belongs to those facts which are necessary (e. g., that this whole is greater than its parts) . DEMONSTRATION AND SELF-EVIDENCE 21 and part. Still I would never know the meaning of whole and part if I never knew any concrete whole and its parts. And, what is more important, there is no intelligibility at all to whole or part except that there are (at least possibly) con- cretely existing wholes and parts. The whole is greater than any of its parts precisely because that's the way wholes and parts are. For every whole and its parts there is the fact that this whole happens to be greater than each of its parts — and behind this fact is the necessity which demands it, a necessity which is one with the intelligible structure of whole and part. The fact and the necessity which dictates it are equally real. Yet they differ. The fact is incommunicable, and it alone can be expressed in a factually evident proposition. The necessity behind the fact is impervious to sense. Yet it is potentially in what is sensed (and in what is reported on in a factually evident proposition) , and it is, of course, fundamentally uni- versal. It can be known only by an intuitive insight which is the result of an abstractive induction, and when known it is expressed in a formally universal proposition. The self-evident proposition comes into being only when it is inductively achieved from an experience of singulars — and it is meaningful only insofar as it bears finally upon singulars. However, the self-evident proposition is only materially dependent on experi- ence for its verification. It is directly verified in its own intrinsic intelligibility, which precludes the possibility even of conceiving the opposite. V. Per Se Nota and Modi Dicendi Per Se There is a temptation to identify per se nota or self-evident propositions with propositions involving a modus dicendi per se or a mode of perseity. However, such an identification can be seen to be erroneous once it is noted that the conclusion of a strict propter quid demonstration involves the second mode of perseity. As conclusion, and not premise, the proposition in the second mode of perseity is obviously not a self-evident proposition. Hence, not every per se proposition is per se nota 22 EDWARD D. SIMMONS or self-evident. The modes of perseity of concern to us here are the first, second, and fourth. A proposition involves the first mode of perseity when its predicate falls in the definition of its subject, the second when its subject falls in the definition of its predicate, and the fourth when the subject is related to the predicate as a necessary and proper cause .^^ In a strict "propter quid demonstration the major premise has the fourth mode of perseity (e. g., Evei-y rational animal is capable of speech) , the minor premise the first mode of perseity (e. g., Every man is a rational animal) , and the conclusion the second mode of perseity (e. g.. Every man is capable of speech) .^* " Per se " here indicates an essential rather than accidental connection between subject and predicate, and it refers exclu- sively to the objective structure of the propositions. Per se nota, on the other hand, refers rather to intelligible structure apropos of our knowledge of it, i. e., with or without a middle term, on the basis of intrinsic intelligibility or empirical data) . A per se nota proposition is one known immediately on the basis of its intrinsic intelligibility. Every proposition (including the conclusion) in a strict propter quid demonstration must be per se, but only the premises must (and can) be per se nota. Yet the case of the proposition in the second mode of perseity cannot be easily disposed of. True enough, as conclusion this proposition cannot be self-evident — at least not to us. But why isn't it self-evident to us? And is it, while not self-evident to us, self-evident in itself .^^ It is necessary prior to demonstra- tion that we know something about the subject and predicate of our conclusion and about the premises from which the con- clusion is generated — that they are and/or what they are. Concerning the predicate of the conclusion, namely, the proper ^^ Cf., sufra, note 12. '* In I Post. Anal., lect. 13, n. 3: " Sciendum autem est quod cum in demonstra- tione probetur passio de subiecto per medium, quod est definitio, oportet quod prima propositio, cuius praedicatum est passio et subiectum est definitio, quae continet principia passionis, sit per se in quarto modo; secunda autem, cuius subiectum est ipsum subiectum et predicatum ipsa definitio in primo modo. Conclusio vero, in qua praedicatur passio de subiecto, est per se in secunda modo." DEMONSTRATION AND SELF-EVIDENCE 23 passion to be proven of the scientific subject, we must know only its nominal definition. In fact we cannot, prior to demonstration, know its essential definition, for this is what is to be proved. To know, prior to demonstration, the essential definition of the proper passion in the demonstration, is to know its inherence in its proper subject (i. e., the scientific subject of this demonstration) , for the proper subject is in- cluded in the essential definition of the passion .^^ It would seem that a proposition "per se in the second mode, with a proper passion predicated of its subject, is self-evident in itself, since the subject itself is in the definition of the predicate, but not self-evident to us, precisely because we fail to understand the essential definition of the passion short of demonstration. Cajetan seems to agree with this position, for when he points out that the per se nota proposition whose predicate falls into the definition of its subject is only the principal type of per se nota proposition, he adds a second type in which a passion is said of its proper subject.^® If this type of proposition is self- evident it cannot be self-evident secundum nos, since it can be demonstrated, but in se tantum. Suppose this is the case, why should it be that this is per se nota only in se? The reason may be found in the type of causality exercised by the proper subject in reference to its proper passion. This is at least material causality, and in the case of the second mode of perseity it is precisely material causality which is actually involved." But matter as such is not proportioned to manifest. The connection between the subject and its property is mani- fested to us only by way of the form which is implied by the subject and which is the active cause of this property. The conclusion can be said to be virtually in the fourth mode of perseity because its subject implies this form. It is only in explicating this in the propter quid demonstration that we see "" Ibid., lect. 2. '' Catejan, In I Post. Anal, Ch. 19. " In I Post, Anal., lect, 10, n. 4. 24 EDWARD D. SIMMONS the necessary (but not, to us at least, immediate) connection between the subject and its property .^^ IV. In Conclusion At the very beginning of the Posterior Analytics Aristotle faces up to the famous dilemma of Meno. How can one ever be said to learn anything? Either he already knows what he learns — and this is not learning. Or he is ignorant of what he seeks to learn and thus cannot recognize it when he does come upon it — so that learning is impossible. ^^ The difficulty reminds us of the Parmenidean dilemma apropos of motion. Aristotle, of course, defends the possibility of motion by introducing the ** There is, of course, no difPerence between the major premise in the strict type of propter quid demonstration and its conclusion unless there is a difference between the fourth mode of perseity and the second mode of perseity. And there is no difference here unless there is a difference between a real definition and the thing it defines. There can be, of course, no difference in re between the definition and the thing defined, so that the distinction between them must be a distinction of the reason rather than a real distinction. There is not even a foundation in the real for this distinction, so that it cannot be said to be a virtual logical distinction. Yet it must be more than the distinction exemplified between subject and predicate in the proposition John is John, for this is sheer tautology. If the definition and what it defines do not differ somehow as objects so that a proposition in the first mode of perseity is more than a tautology, then the prime instance of the per se nota proposition loses its significance and ceases to function meaningfully as an absolute premise at the same time that the major premise and conclusion of the strict type of propter quid demonstration became formally identical. This is, quite clearly, the death of demonstration. There is, however, a legitimate distinction to be made between the definition and what it defines. True, there is no advance in knowledge from thing to thing in defining. But there is in the definition a more perfect (clear and distinct) grasp of something known obscurely and confusedly prior to definition. This is enough to make the definition, from the point of view of the manner in which it is conceived, an object different from the defined; though, in itself, it remains identically the defined. This in turn is enough to make the per se nota proposition whose predicate is of the definition of the subject something more than tautologous. It is enough to guarantee a difference between the major and con- clusion in the strict propter quid demonstration, and thus to guarantee the advance in knowledge without which demonstration would be meaningless. Cf. Simon et al, op. cit., note 14, p. 618; McArthur, Ronald, "A Note on Demonstration," The New Scholasticism, XXXlV (1960), pp. 43-61; and especially Cajetan, In I Post. Anal., ch. 3. ^» Plato, Meno, 80D-86D. DEMONSTRATION AND SELF-EVIDENCE 25 notion of potential being (which in a sense represents a middle ground between being simpliciter and non-being simpliciter) . In a similar fashion he defends the integrity of discourse by- introducing the notion of the self-evident proposition. Self- evident propositions are the basic truths of demonstration, and in them scientific conclusions exist in potency. The demonstra- tive movement represents a true advance in knowledge from the potentiality of the scientific conclusion to its actuality. Prior to discourse the conclusion is not known simpliciter; but at the same time it is not unknown simpliciter. It is potentially known in its principles. The actual grasp of the self-evident proposition is the potential grasp of the scientific conclusions virtually contained therein. The premises of demonstration — taken as premises, that is, seen together to involve a middle term — function after the fashion of efficient causes which actuate the potentiality of the conclusion and make it be.^° The whole of the Posterior Analytics is concerned to investigate the logical vehicle (namely, demonstraton) which brings us from the self-evident principles to our scientific conclusions. In the first book demonstration and its types and properties are investigated. The second book concentrates on definition precisely as the medium of demonstration. Quite significantly the last chapter of this second book — which completes the Posterior Analytics — comes full round to the topic of the very first chapter. Meno's dilemma is absolved in terms of the uni- versally necessary and immediate basic principles of discourse. Scientific conclusions are truly conclusions insofar as they are different from these basic truths but are generated from them. They are truly scientific insofar as the basic truths of discourse into which they are resolved are primary and incontrovertible affirmations of the real. Upon the integrity of these basic truths or principles of demonstration depend the integrity of demon- *" Quodl., Vni, a. 4; " Insunt enim nobis naturaliter quaedam principia primo com- plexa omnibus nota, ex quibus ratio procedit ad cognoscendum in actu conclusiones quae in praedictis principiis potentialiter continentur. . . ." Cf., also De Ver., q. 11, a. 1; Surmna, I, q. 117, a. 1. 26 EDWARD D. SIMMONS stralion and the worth of its conclusions. Thus, in this final chapter, Aristotle defends the integrity of the principles them- selves in terms of an intuitive induction from the incontro- vertible data of sense experience. St. Thomas points out that the difference between dialectical discourse and demonstration is the difference between unterminated and terminated dis- course.'*^ The dialectician falls short of being a scientist pre- cisely because dialectical conclusions are not finally grounded in the real. The dialectical method can be referred to as a " rational method " precisely insofar as its conclusions remain within the reason. The demonstrative method is the method of science because it grounds its conclusions necessarily in the real — and it does this insofar as it resolves them into self- evident propositions. There is no science save that there be a rational progression from principles to scientific conclusions. Thus the scientific intellect is of necessity a ratio. But, at the same time, there is no science save that there be an intuition of basic principles — so that the scientific intellect is also an intellectus.^^ Demonstration may be an instrument of the intellect as reason, but there can be no meaningful theory of demonstration save that the per se nota proposition, itself properly the object of intellect as intellect, be significantly a part of that theory. Edward D. Simmons Marquette University, Milwaukee, Wisconsin. ^^ In Boeth. de Trin., q. 6, a. 1 ad 1: "Alio modo dicitur processus rationalis ex termino, in quo sistitur procedendo. Ultimus enim terminus, ad quem rationis inquisitio perducere debet, est intelleclus principiorum, in quae resolvendo iudicamus; quod quidem quando fit, non dicitur processus vel probatio rationabilis, sed demon- stratio. Quandoque autem inquisitio rationis non potest usque ad ultimum terminum perduci, sed sistitur in ipsa inquisitione, quando per probabiles rationes proceditur, quae natae sunt facere opinionem vel fidem, non scientiam, et sic rationabilis pro- cessus dividitur contra demonstrativum." *^ Summa, I-II, q. 57, a. 2: " Verum autem est dupliciter considerabile; uno modo, sicut per se notum; alio modo, sicut per aliud notum. Quod autem est per se notum, se habet ut principium, et percipitur statim ab intellectu; et ideo habitus perficiens intellectum ad huiusmodi veri considerationem vocatur intellectus qui est habitus principiorum." In Boeth. de Trin., q. 6, a. 1 ad 1: "Ultimus enim terminus, ad quem rationis inquisitio perducere debet, est intellectus principiorum, in quae resolvendo iudicamus. ..." THE SIGNIFICANCE OF THE UNIVERSAL UT NUNC (TfO IN his commentary on the Posterior Analytics of Aristotle, St. Thomas notes that did de omni, sometimes translated as " true in every instance," is treated differently in the Posterior Analytics from the way it is in the Prior Analytics. In the latter work, which is concerned with the form of the syllo- gism and therefore with what is common to any syllogism, did de omni is treated only commonly, disregarding the differences attaching to a demonstrative or dialectical use. In this context, it is enough to say that did de omni is realized whenever the predicate is found to be in each of those things which are con- tained under the subject. Once, however, we begin to consider the syllogism on the part of matter, we must say more about did de omni. Hence, immediately after saying that the predi- cate is found in each of those things which are contained under the subject, St. Thomas adds: " This can happen either ut nunc, and in this way the dialectician sometimes uses did de omni, or absolutely and for all time, and in this way only the demon- strator uses it." ^ In discussing the ancient and medieval theory of universals, we are apt to overlook this distinction between the verified did de omni and the provisional one called universal ut nunc, and we tend to ignore the importance the latter has as a tool particularly for the investigation of nature. An example of the verified did de omni was the common property of every para- bolic triangle, ' to have its three angles equal to two right angles.' An instance of the universal ut nunc was ' white ' predicated as a common property of swans. The former property was based upon a propter quid demonstration; the latter was based upon, or rather derived from, an incomplete ^ " Hoc autem contingit vel ut nunc, et sic utitur quandoque did de omni dia- lecticus; vel dmpliciter et secundum omne tempus, et sic solum utitur eo demon- strator." In I Post. Anal., lect. 9, n. 4. 27 28 JOHN A. OESTERLE induction: no one reporting about swans had ever seen a black one. We come therefore at once to the following question. Since " white," as a common property, was not certain, why is it that we could use the universally distributive ' all ' and say that all swans are white? Why not use a roundabout expression and state: " It appears that some, if not all, swans are white." Or why not say, even more simply, " swan is white," as we say " man is white." In this more simple way of putting the matter we would be plainly predicating something of a universal (" swan ") by reason of something found in one or some individuals. The point then is whether this would be regarded as a universal ut nunc, a universal " for the time being." Pre- sumably not, for what we are aiming at is an enunciation like " man is an animal," an essential predication. But why use this mode of enunciation before it is warranted? What we are in fact faced with is two distinct modes of essential predication: a true one and a hypothetical one. What is the foundation for this distinction? Why are hypothetically essential predications required? Why not use unambiguous circumlocutions that show the essential predication to be only hypothetical? After all, many essential predications are in fact no more than hypothetical. To answer such questions — which in effect are one question — about the distinction between true and hypothetical essential predications, it will be opportune, first of all, to make a further distinction by comparing the notion of " triangle " with what we intend by " swan." We can define the first as to what it is, namely a three straight-sided figure whose exterior angle is equal to the two opposite interior angles. But what about " swan "? We define, not the swan, but the name by pointing to individual instances, or by describing the figure and habits that set swans apart from chickens, turkeys, geese, and so on. Now surely there must be in nature something that accounts SIGNIFICANCE OF THE UNIVERSAL UT NUNC 29 for these differences. But' what is this exactly? As St. Thomas says: " That nature is, is fer se known, insofar as natural things are manifest to sense. But what the nature of any thing is, or what its principle of motion, is not manifest." ^ Meanwhile, we have the name " swan " and whoever knows this name, using it with the meaning agreed upon, does not confuse swans with chickens or geese. Still, there may exist somewhere, or there may have existed, some types of fowl between swans and geese which could make us hesitate about using the name to stand for what is assumed to be a definable nature. The opposition of contradiction between " swan " and " non-swan " is plain enough, but where and how it actually applies may be uncertain. Such is the case whenever the positive term referred to is imperfectly known. Lacking defini- tive knowledge, we have agreed to use the word in a way that is at least in practice meaningful. In the measure that certain sensible signs set swans apart from other feathered creatures, we are confident that our naming has some determinate basis in nature, that swans do in fact have a nature. Just what this is, however, we have to acknowledge that we do not know. Let us recognize, however, that even if we knew exactly what a swan is as we know what a plane triangle is, the term " swan " by itself, apart from an enunciation, would be neither true nor false. The same applies to the nominal definition of the name, whether obtained by designation or by description of what it stands for: " a large-bodied, web-footed water bird of the genus Cygnus, having a long neck and sort legs placed far back," etc. We can, of course, go further and state that there are such animals. However, the truth of this statement does not imply that we know exactly what a swan is. Accord- ingly, we are forced to acknowledge a hiatus (a) between the truth of the statement and the relative indetermination as to what a swan is; (b) between the name itself, used to stand for " Naturam autem esse, est per se notum, inquantum naturalia sunt manifesta sensui. Sed quid sit uniuscujusque rei natura, vel quod principium motus, hoc non est manifestum." In II Phys., lect. 1, n. 8. 30 JOHN A. OESTERLE a universal that is predicable of certain individuals, and the way it would signify if we knew, once and for all, just what a swan is as we know what a plane triangle is. In other words, we can name things before we know precisely what the thing is that we name. The history of biology proves that what we had long considered to be a species turns out to be a genus. That simple naming, as distinguished from enunciation, does not presume that we know exactly what it is that we name is strikingly plain in the instance of the word " atom." It is taken from the Greek " indivisible," in common usage. Democritus imposed a further meaning upon it to signify what he believed to be the indivisible elements of all things, differing from one another by their geometrical figure. Dalton, for quite different reasons, was led to an analogous conception, but his minute spheres still retained the meaning of " indivisible." Rutherford finally broke down these indivisibles, and they are becoming unceasingly the opposite of what the name was first intended to mean. The word " atom " continues to make history, a history reflecting progress in our knowledge of the basal entities of the physical world. But the original meaning has dropped from sight, and the physicist will no longer refer us to nature except most indirectly. He will explain what he means when using this word by relating certain observations, such as the Brownian movement, and operations of measure- ment which led to interrelated measure-numbers permitting him to establish equations, etc., which he then goes on to explain in terms of hypotheses and theory that lead to further experiments, etc. This elaborated understanding becomes very atomic in one sense, if you will, but Democritus might well be puzzled about his word " atom." Of course, someone might say of Democritus that he did not know what he was talking about, and the same of Dalton. But of course they knew. What they were ignorant of was the real import of what they said, which could be no more than vague, as the history of science has proved. What we must recognize is that there can be uncertainty, not only as to SIGNIFICANCE OF THE UNIVERSAL UT NUNC 31 whether B belongs to A, or whether B is common to A and C, or a commensurate property of B, but that there can also be uncertainty concerning what the term A exactly stands for. If A and B are known exactly, then their relationship can be known exactly too. But if they are not known exactly for what they are, their relationship will be proportionally vague and provisional. There is a difference, then, between a universal ut nunc as a simple term, viz.. A, and as a subject or a property in an enunciation, such as "All A is B." The following questions remain open: "Is A.?" ''Is B.? " "Is AB.? " The first two concern the bearing of the names: do these definite names refer to something we know definitely? The answer to the other question is obvious: the relation of A to B is either definitely known or it is provisionally posited. Yet why should we posit names and relations provisionally .^^ Why not wait until we know the named exactly and, in the case of enunciation, until we know the exact relation .^^ This brings us to the very heart of scientific method and to the relevance of the theory of positing a universal " for the time being " in the practice of science. We must, for the time being, posit such universals and wait to see what happens for having posited them. But let us not suppose that " to see what happens " is merely a passive attitude. The very positing must suggest an activity, a further induction or experimen- tation, with attendant hypotheses and theory which give further meaning to the original positing. To posit a universal ut nunc is to advance something that not only requires further testing but also suggests it. Now had we confined ourselves to predicating something of a universal nature (or of a quasi-universal nature) by reason of what is verified in its inferior singulars, the matter would be immediately closed and settled. For, if Socrates walks, we are quite justified in saying that " man walks," and that's the end of it. But if we say " man is an animal," this must be true of every man, not just of this man. However, this mode of 32 JOHN A. OESTERLE predication, as we have suggested, need not be reserved to cases that are certain. Mere likeliness may suffice to posit propositions in that mode, such as " man came about by mutations that occurred in lower living beings," but they will be 'posited and require further proof. In other words, the universal ut nunc appears both in the order of simple appre- hension and in the order of composition and division, with all that this entails in the order of argumentation. Now there is a further aspect to this type of universality. It is, in a sense, pragmatic: we may have to do something about it. This " doing " can mean a speculative operation, as when we are inclined to believe that there is no last prime number: the statement is a challenge that sets us on to attempt a proof. But the doing may also be more strictly a practical operation, such as experimentation, or careful isolation for further induction. And this brings us face to face with an important distinction. Suppose that we have laid down a thermodynamic theory, which is a coordinated ensemble of posits, and construct on the basis of it a machine that works. Does this prove that the theory is true.^^ Pragmatically, it does. It is in this sense that as to truth, scientific theories are in the main pragmatic. But so far as sheer knowledge is con- cerned, pragmatic proof can do no more than indicate that as to speculative truth the theories are on the right track, that we are moving in the direction of the truth, not that we possess it. The whole point is, then, that we would not be moving on toward the truth if we did not take the liberty of constructing posits in the mode of universal terms and universal proposi- tions for the immediate purpose of seeing what happens when we do this. If our mind had to confine itself to terms and propositions that we know well and could only use these for further argu- ment, there is very little that we could ever come to know.^ This would not only preclude advances in scientific knowing, but also in vast areas of what we now regard as philosophy, for the " eternal truths " of philosophy occupy a relatively small position in relation to the whole. Indeed, it might be said SIGNIFICANCE OF THE UNIVERSAL " UT NUNC " 33 Tentatively we must go beyond what we know, starting from hints, as it were, and then proceeding from what we have posited as if it were true. It is as if, to move on, our mind must come to rest, provisionally, in a myth, a verisimilitude, and even in strictly logical fictions. But it must do so wittingly, which is what it does in fact by recognizing the type of uni- versality we are concerned with here as being no more than ut nunc. As we get closer to things in their concretion, the universals that a defect of much scholastic philosophy, especially in the manual form, has consisted in treating so many things as falling under dici de omni absolutely and as though subject to rigorous demonstration. The great scholastics, however, were never under such illusion. St. Albert, for instance, especially with respect to the sort of knowledge we have in the investigation of nature, says the following: " It is plain, then, from what has been pointedly considered in natural things, that every definition or notion of natural forms is conceived with matter, which is subject to motion or change or to both; and it must therefore be conceived with time inasmuch as time is in the temporal thing. Because of this, much opinion is involved in this sort of knowing, so that it cannot attain to the firm, constant and necessary habit of science, as Ptolemy says." After contrasting the " doctrinal sciences (mathematics) with such knowledge, St. Albert adds: ". . . the habits acquired by the speculative intellect have been given the name of true science, and are called doctrinal and teachable; and the reason is that they are taught from unchanging principles, which the disciple receives from the teacher by sheer notifi- cation of the terms, without need of experience, as Aristotle says in Book IV, but by the teacher's simple demonstration the intellect of the disciple comes to rest; hence it is that adolescents, without experience, can so often excel in these matters — something which is in no way possible in the natural sciences, where experience is of far greater account than doctrine by demonstration." In I Metaph., Tract. I, cap. 1, (Borgnet, VI) pp. 1-2. (Constat autem ex his quae subtiliter in naturis considerata sunt, omnem difRni- tionem aut rationem formarum phj-^sicarum conceptam esse cum materia, quae motui subjacet, aut mutationi, aut utrique; et ideo concipi oportet cam cum tempore secundum quod tempus est in re temporali. Propter quod etiam id quod scitur de hujusmodi, multum miscetur opinioni, et pertingere non potest ad confirmatum constantem et necessarium scientiae habitum, sicut dicit Ptolemaeus. . . . habitus per speculativum intellectum adepti verae scientiae nomen acceperunt, et doctrinales et disciplinales vocantur, ideo quia ex principiis non mutantibus quae discipulus a magistro non accepit nisi per terminorum notitias, docentur, experientia non indi- gentes, ut dicit Aristoteles libro quarto, sed simplici demonstratione doctoris constante intellectu discipuli: propter quod etiam juvenes inexperti ut plurimum magis excellunt in ipsis: quod nullo modo possible fuit in physicis speculabilibus, in quibus experientia multo plus confert quam doctrina per demonstrationem) . 34 JOHN A, OESTERLE are more and more provisional in the sense that we deliberately posit terms, vague and uncertain, which our mind is free to invest with intentions of universality, and thereupon seek to establish relations between those terms. Our mind has this power because it can bring together things which in nature are not 'per se connected, e. g., " man walks " or " man is white." In these examples we do attain a truth, however, since we do not mean that every man is walking or that every man is white. But what we learn from such examples is that what is accidentally one in nature can be brought together by the intellect to form a proposition that is per se one as a proposi- tion. Moreover, the mind can go further than that, and in fact must do so, positing terms and bringing them together for the purpose of getting behind the appearances upon which our posits are based.* Verisimilitude, either with respect to terms or with respect to composition or division, is the proper basis of universality ut nunc. By verisimilitude we mean that which may in fact have no more than a resemblance to truth, a mere appearance of it and recognized as being no more than that. This is enough for our mind to reach out beyond what we really know, beyond what is warranted. Actually, universality for the time being keeps us within the bounds of the mind, as any opinion does, so long as it is no more than opinion. But opinion, as dialectic in general, has the nature of a tool, an organon, with respect to truth. Constructed universals of the type v*^e are concerned with (as distinguished from the relation of universality we may tentatively invest them with) are logical organa. For dialectics as logica utens does not go beyond the stage of instrumentality. There is in all of this something of a paradox which we should notice. The mind goes beyond what it really knows, but in so doing it still remains within its own confines. How does this occur.'^ A situation analogous to this is the one already noted, of the mind's composing a proposition that is one per se about * Aristotle was certainly aware of this procedure. See, for example, De Caelo, III, chap. 7. SIGNIFICANCE OF THE UNIVERSAL " UT NUNC " 35 something that is one only -per accidens. The per se one remains within the mind, yet the mind is thereby enabled to say something that is true, namely " man is white." However, at best this is only an analogy, or perhaps only an example, of the main point we have in mind. How does this main point differ from the instance of the mind's composing as per se one which is one only per accidens? Let us try to bring out the difference by considering the status of opinion. Here we go beyond what is warranted, either by a proper reason (as in the case of an opinion concerning something in logica docens) or by what we know truly of reality (e. g., why ruminants need the type of digestive system they have; the reason assigned could be one that would apply to horses, who also eat and digest gi^ass) . In thus going beyond reality, we do not do so in the way one real thing goes beyond another, as cows beyond cabbage. The " going beyond " is in the order of knowing. It is not as if our mind casts out a net. The mind does cast out nets (as, indeed, we do so well and frequently in logical divisions) but they remain within the mind and are ordered to knowledge, not to the actual handling of things. Of course, there is, nonetheless, a kind of reaching out physically toward reality and even a meddling in it when we perform an experiment. But why do we perform so many experiments? Not to improve things in any practical sense, at least primarily, but to improve our understanding of what things are so far as possible. And so we are back in the mind, which we have really never left. The external operation is performed with a view, not to altering a given order in reality, but to improving the knowledge in our mind. Hence the paradox remains, but is intelligible. We go beyond our mind in order for the mind to understand what it otherwise could not, but this " going beyond " is a dialectical extension, remaining an instrument for the mind's ever increasing grasp of an obscure physical reality. In this order, experience and experimenting contribute more to our knowledge than strict demonstration. The evolution of scientific theories, based upon wider obser- 36 JOHN A. OESTERLE vations enhanced by physical instruments, suggesting new hypotheses that suggest further research and crucial experi- ments, shows that we may have to remain content with a knowledge that, ever progressive, remains nonetheless pro- visional. Now in the measure that this is true of most of our investigation of nature, it is clear that the domain of uni- versality ut nunc has far greater dimensions than that of true universals, and this is the point of emphasis in this paper, a point which seems to have been somewhat ignored in the scholastic tradition. There are two complementary reasons for the greater dimension of the universal ut nunc. First, there is the very nature of our mind, which is an experimental one, seeing that our knowledge must be derived from things them- selves. Second, there is the unexpected complexity of the things we seek to know, even of those which apparently are at close range, the sensible things. Even these are somehow fathomless in the experimental sense of the word. A simple example is enough to illustrate this point, our organs of external sensation. We agree that our skin is an organ of touch and that our eyes are organs of sight. This seems safe enough to say so long as we do not look too closely into the subject. We have initially recognized and understood these organs with reference to our sensations. But now we must delve into anatomy and physi- ology, and then into chemistry and physics. In this process we are wading toward a limit we shall never reach. Yet we know that the limit is somehow there though we have nothing more than an intimation of just what it is. And so it is that the whole interval between actual sensation along with the vaguely recognized organs, and the limit we are moving toward, is replete with provisionally contracted terms, with universals " for the time being," ever in need of reconstruction and implementation. Even a true universal such as " what a man is " does not settle all that man is, once for all.^ The example of sensation ° The definition of " man " as " rational animal " has often been criticized as inadequate and even ridiculed as being incomplete. But this definition, though an SIGNIFICANCE OF THE UNIVERSAL UT NUNC 37 and its organs shows that this true universal is quite incom- plete and must be implemented with a world of universals ut nunc. Man is a good enough example, for in one sense he is the being which we know best, while in another sense we know least of him. We know him best because of our internal experience; but in terms of external experience we know the lower forms of life far better even though these, from the former point of view, are by far the more obscure. Now the situation is such that while we may be definitely certain about some things we come to know from internal experience, as soon as we try to narrow down our knowledge of living things in terms of external experience, then even our simplest terms, such as " protoplasm " or " genes," though their related conceptions have some basis in experience, are in the main " logical fictions " in even Lord Bertrand Russell's sense of this term. Nevertheless, we should not wholly identify logical fictions with our universals ut nunc. The fictions are not intended to have that kind of resemblance to true universal natures. Logical fictions are symbolic constructions whereas the uni- versals ut nunc are names and bear a real verisimilitude to natures. When all is said and done, however, it still remains that the bulk of our knowledge remains provisional and in constant need of implementation. That such is the status of our knowl- edge is not itself mere theory. It is a well established fact. The history of science proves that we may be quite certain of our uncertainties, i. e., of the provisional nature of most of our knowing as regards things in their ultimate concretion, and therefore of the fact that most of our universals are ut nunc. We are definitely certain that two is an even number and even of what a circle is (no matter how little the calculator may care about this) ; and that if an even number is taken from an essential one and a good one in precisely this sense, was never intended to be a complete definition. From the standpoint of completion, much remains to be said about what man is, and much of what we know in seeking to determine more fully what man is will remain provisional. 38 JOHN A. OESTERLE even number, the remainder will be an even number — all this being a matter of strict demonstration. But we have nothing like this kind of certitude about dogs and cats, not to mention the less familiar objects of even ordinary experience. Recog- nizing, therefore, how provisional most of our knowledge is, let us, for the time being, make all possible use of universals ut nunc. John A. Oesterle University of Notre Dame, Notre Dame, Indiana. WILLIAM HARVEY, M.D.: MODERN OR ANCIENT SCIENTIST? WILLIAM HARVEY was born in England in 1578 and died in 1657. He received his grammar school education at the famous King's School in Canter- bury. In 1593 he entered Caius College, Cambridge, and re- ceived his B. A. degree in 1597. In this period, it was not unusual for English Protestants interested in a scientific edu- cation to seek it in a continental Catholic university. Harvey chose the Universitas Juristarum, the more influential of the two universities which constituted the University of Padua in Italy and which had been attended by Thomas Linacre and John Caius, and where, incidently, the Dominican priests were associated with University functions. Competency in the traditional studies of the day was char- acteristic of William Harvey's intellectual development. The degree of Doctor of Physic was awarded to Harvey in 1602 with the unusual testimonial that " he had conducted himself so wonderfully well in the examination, and had shown such skill, memory, and learning that he had far surpassed even the great hopes which his examiners had formed of him. They decided therefore that he was skilled, expert, and most effici- ently qualified both in arts and medicine, and to this they put their hands, unanimously, willingly, with complete agreement, and unhesitatingly." ^ In 1616 he gave his first Lumleian lectures in surgery at the Royal College of Physicians in London. The manuscript notes of his first course of lectures, the Prelectiones, are preserved and have been reproduced in facsimile and transcript." In these lectures he first enunciates the circulation of the blood. ^ D'Arcy Powers, William Harvey (London, 1897), pp. 26-27. ' William Harvey, Prelectiones Anatomiae Universalis (London: J. & A. Churchill, 1886). 39 40 HERBERT ALBERT RATNER He waited for 12 years, however, until 1628, before he pub- Hshed his great work entitled, An Anatomical Exercise on the Motion of the Heart and Blood in Animals. In this classic he foniially demonstrated the true nature of the heart and that the motion of the blood was circular. This work is relatively short and takes up 86 pages in the standard English edition of his collected works.^ In 1648 Harvey's demonstration was at- tacked in a treatise published by Dr. Jean Riolan of Paris. Harvey answered his critic in two lengthy letters published in Cambridge in 1649. Harvey's second famous work, Anatomical Exercises on the Generation of Animals, which is over five times the length of the first, appeared in publication in 1651 through the solicita- tion and under the direction of Dr. George Ent, a well-known physician of the period. In his personal life and professional career Harvey had a wide circle of acquaintances and friends. Though it is not certain whether he knew Galileo who was a fellow student at Padua, he knew most of the leading contemporaries of his day. This included Boyle, Hooke, Hobbes, Dryden, Cowley, Descartes, Gilbert, Wren, Bacon and others, in addition to prominent physicians and anatomists. Harvey was extremely well-read and made reference in his lectures and writings to the Greek philosophers and scientists of the fourth through the seventh centuries, B. C, to many Greek writers of the Christian era, to numerous Latin writers includ- ing many of the poets, to Albert the Great, and to numerous Renaissance men of the fifteenth and sixteenth centuries. In all, he made reference to approximately 100 authors in his ^ The Works of William Harvey, M. D. (London: Printed for the Sydenham Society, 1847): Translated from the Latin by Robert Willis, M. D. It includes An Anatomical Exercise on the Motion of the Heart and Blood in Animals; The First Anatomical Exercise on the Circulation of the Blood to John Riolan; A Second Exercise to John Riolan, in Which Many Objections to the Circulation of the Blood are Refuted; Anatomical Exercises on the Generation of Animals, to Which are Added, Essays on Parturition, On the Membranes and Fluids of the Uterus, and on Conception; and miscellaneous items (Harvey's will, autopsy of Thomas Parr and nine short letters) . WILLIAM HARVEY, M. D. 41 writings. In particular, he had a comprehensive working knowl- edge of Aristotle, as well as Aristotle's commentators, Avicenna and Averroes. According to one Harvian lecturer, Harvey refers to Aristotle 269 times.* References are made to Aristotle's logical, physical, biological and metaphysical works. It is clear that Harvey's superior intellectual formation through ancient authors — the Great Books of his day — proved no block to his momentous contribution to the future. Finally, it is pertinent to note his basic religious belief as it relates to his scientific work. On the title page of his Prelec- tiones he prefixes from his favorite poet, Virgil, the motto " Stat Jove principium, Musae, Jovis omnia plena." Over thirty years later he explicates this motto in Exercise 54 of the Generation of AniTnals: ... in the same way, as in the greater world, we are told that ' All things are full of Jove,' so in the slender body of the pullet, and in every one of its actions, does the finger of God or nature no less obviously appear . . . We acknowledge God, the supreme and omnipotent creator, to be present in the production of all animals, and to point, as it were, with a finger to his existence in his works, the parents being in every case but as instruments in his hand. In the generation of the pullet from the egg all things are indeed con- trived and ordered with singular providence, divine wisdom, and most admirable and incomprehensible skill. And to none can these attributes be referred save to the Almighty, first cause of all things, by whatever name this has been designated, — the Divine Mind by Aristotle; the Soul of the Universe by Plato; the Natura Naturans by others; Saturn and Jove by the ancient Greeks and Romans; by ourselves, and as is seeming in these days, the Creator and Father of all that is in heaven and earth, on whom animals depend for their being, and at whose will and pleasure all things are and were engendered.^ In his last will and testament he states, " I doe most humbly render my soule to Him that gave it and to my blessed Lord * D. F. Fraser-Harris, " William Harvey's Knowledge of Literature Classical, Mediaeval, Renaissance and Contemporary." Proceedings of the Royal Society of Medicine, XXVII (1934), 195-99. * Harvey, Works, ed. cit., pp. 401-402. 42 HERBERT ALBERT RATNER and Savior Christ Jesus and my bodie to the Earth to be buried at the discretion of my executor . . ," " Before we can determine whether Harvev was a modem or an ancient scientist, we must first know him as the great scientist he was. The twentieth century scientist, more nar- rowly educated for the most part, pays only lip service to Harvey's greatness. We can say about most contemporary sci- entists concerning Harvey, what Galen said about his contem- poraries concerning Hippocrates: they admire him, but do not read him; when they read him, they do not understand him; when they understand him, they fail to put into practice what he has taught.^ Characterizing the lip service of contemporary biologists and physicians is the unexpressed and hidden belief — a reflection of our current pride and prejudice — that what Harvey enunciated was so obvious, so easily discoverable, so easily observable by all beginning students, that the uniqueness of his discovery was principally his ability to liberate himself from the yoke of ancient traditions, thought and terminology — from dark ages, sterile scholasticism, authoritarianism and philosophical en- croachments — sufliciently to see what in itself was so patently observable. Even then, Harvey's liberation was incomplete according to many historians. Part of the modem difficulty stems from not reading him. Typical of the difficulty is the belief that Harvey's discovery of the circulation of the blood was a sense observation rather than a conclusion resulting from reason utilizing inductions from sense observations, as principles or propositions in a demonstration. Part of the modem difficulty also stems from those who have read him, but not well. Many such readers have failed to ap- preciate the complexity of obtaining a new and true conclusion within a context in which the old conclusion was a plausible part of an integrated body of knowledge. The modern reader, ' Ibid., p. Ixxxix. '' Galen, Si quis optimus medicus est, eundem esse philosophum,, among Isagogici libri, in Opera omnia, 9th ed. (Venetiis, apud Juntas: 1625), fol. 6r-v. WILLIAM HARVEY, M. D. 43 by reading Harvey retrospectively as if his work were merely the beginning of what came afterwards, tends to miss what is more basic: that Harvey's discovery like most scientific dis- coveries results from a scientific methodology which is related to one's education, philosophy, habits, and experience as a scientist. Rather than relate Harvey's discovery to the past out of which it emerged, the modem reader acts as if it sprang de 710V0 from a pair of eyes newly able to observe through the Renaissance liberation from the medieval blinders that enveloped this age. The following comments are characteristic of those made by critics who dissociate Harvey's demonstration from the tradi- tion of his predecessors. Harvey " with one blow demolished the structure, compounded of metaphysics, far-fetched analogy, and mysterious ' principles ' and ' spirits,' which constitute the method of medieval biology." Harvey's method was char- acterized " by the rigid exclusion of mysterious forces and agencies." ^ " Harvey . . . never entirely emerged from the mystifying language of his contemporaries, and even regarded himself as a loyal Aristotelian, but he builded better than he knew." ^ The contemporary translator of the most widely read version of Harvey's classic on The Motions of the Heart and the Blood — an outstanding scientist in his own right — has this to say: In his more scientific passages, Harvey is remarkably terse and ' snappy,' in the current style. In his philosophical discussions he becomes vague and his sentences grow beyond control ... At the same time, he tried to complete his demonstrations by metaphysical arguments based on the traditional teleology. This was the anti- thesis of the method by which he had achieved such brilliant success in the preceding chapters . . . There is a good discussion of the comparative and embryological aspects of the subject, and then a peculiar use of the traditional authority of Galen as evidence. One may find almost all kinds of logic in Harvey." * Franklin Fearing, Reflex Action (Baltimore: William & Wilkins, 1930), p. 29. ® A. Wolf, A History of Science, Technology and Philosophy in the 16th and 17th Centuries (London, 1935) , p. 415. ^° Chauncey D. Leake, An English Translation with Annotations of De Motu Cordis (Springfield: Charles C. Thomas, 1931), Translator's Preface. 44 HERBERT ALBERT RATNER If these comments truly delineate Harvey's contribution, we are faced with the following paradox: Harvey, who was edu- cated superbly in the traditional education of his time, who considered himself a loyal traditionalist in science and philoso- phy, and who utilized philosophical arguments based on the established teleology of the day, all of which are alleged to be antithetical to scientific advance, was also the same Harvey who produced a brilliant, original and revolutionary work of science which laid the groundwork for modern physiology and medicine. To explicate this paradox, it seems incumbent upon us to keep open the possibility that the fruit of his labors bears a direct relationship to the tree that bore it and the intellectual soil that nourished it. That Harvey was well educated, and respected and utilized his learning heightens this possibility. Furthermore, Harvey was one of the few successful investiga- tors in the history of science who actually thought about and wrote on scientific methodology, and whose thinking on this permits us to measure his reciprocal accomplishments. It is ironic, in contrast, that the modern scientist looks upon Harvey's contemporary, Francis Bacon, as the father of modern science, despite history's testimony that no scientific dis- covery can be attributed to the Baconian method. It is par- ticularly ironic since there is no indication that Bacon even recognized Harvey's striking contribution. A leading Bacon scholar writes, " The probability is that ... he regarded the theory as hardly worthy of serious discussion."" Contrari- wise, Harvey, who was Bacon's personal physician, said of him derogatorily that, although he enjoyed his wit and style, Bacon " writes philosophy like a Lord Chancellor." ^- The alternative of the hypothesis that Harvey's contribution flowed from his past is a dismal one. It forces one to conclude that Harvey was a schizophrenic, a duality — a sterile scholastic and a fertile scientist — rather than a unity; and that his " bril- ^^ Thomas Fowler, Bacon's Novum Organum, Edited with Introduction, Notes, etc., 2nd ed. (Oxford, 1889) p. 28. ^^ John Aubrey, Lives oj Eminent Men (London, 1813), vol. 2, p. 381. WILLIAM HARVEY, M. D. 45 liant success " was accomplished by " almost all kinds of logic." We can best seek to understand the paradox of Harvey by seeing whether Harvey, in his turn, merely paid lip service to Aristotle who dominated the medieval period or actually util- ized him the way one scientist utilizes another. To show that Harvey was a genuine disciple of Aristotle, four illustrations of how Harvey utilizes and follows Aristotle are presented below. The first summarizes Harvey's essay on sci- entific methodology and shows Harvey's adherence to Aris- totle's Organon. The second illustration deals with the great scientific controversy in embryology as to whether animals are preformed or epigenetically unfold themselves in development. It shows Harvey decisively siding with Aristotle. The third reviews the actual references Harvey makes to Aristotle in The Motion of the Heart and Blood and shows that Aristotle abets rather than hinders Harvey's ultimate demonstration. One of these references points up the need for a modern reader to have a knowledge of Aristotle's works if he is to have an adequate understanding of Aristotle's contribution to Harvey's discovery and demonstration. The final analysis shows that Harvey's demonstration of the true motion of the heart and blood is a classic Aristotelian demonstration, and illustrates that Harvey follows in practice what he adheres to in theory, AN ESSAY ON THE SCIENTIFIC METHOD Harvey's essay on the scientific method is the preface to his work. Anatomical Exercises on the Generation of Animals, wliich was published 23 years after the publication of his classic, The Motion of the Heart and Blood, when Harvey was 73 years old. It is a product of his later years and reflects the permanency of the position he held. It is not intended as a complete exposition of the scientific method but only as a preface to his work on generation. The preface " consists of 27 paragraphs and has three headings: ' Of the Mode and Order of Acquiring KJnowledge '; ' Of the Former, Calling to Mind " Harvey, Works, ed. cit., pp. 151-167. 46 HERBERT ALBERT RATNER Aristotle '; and ' Of the Method to be Turned to in the Knowl- edge of Generation.' The following is a paragraph analysis of this essay. Preface Anatomical Exercises on the Generation of Animals A. Introduction 1. Causes of writing (par. 1) 2. Present opinions concerning generation a. Of Galen and physicians (par. 2) b. Of Aristotle and philosophers (par. 3) 3. Concerning the falsity of these opinions (par. 4) 4. Further exposition of final causes of writing (par. 5) 5. Concerning the method employed a. That it is difiicult (par. 6) b. That its difficulty should not be a deterrent (par. 7) B. Of the Mode and Order of Acquiring Knowledge {cognitio) 1. That there can be only one road to science (scientia) (par. 8) 2. Explication of the road a. Relation of sense to universals (par. 9) b. As expressed by Seneca and expounded by Harvey (par. 10) 3. The importance of sense for judgment (par. 11) 4. Why it was thought fit to present this by way of intro- duction (par. 12) C. Of the Former, Calling to Mind Aristotle 1. That knowledge (cognitio) is not innate but acquired (par. 13) 2. Whence and how we come to know (par. 14) WILLIAM HARVEY, M. D. 47 3. Resolution by Aristotle of the difficulty involved (par. 15) 4. The order of knowledge in any art or science (par. 16) 5. Conclusions as to the relation of perfect knowledge to sense (par. 17) 6. Conclusions as restated by Aristotle (par. 18) 7. Explication of preceding passage from Aristotle (par. 19) 8. Concluding advice to the reader concerning testimony of the senses (par. 20) D. Of the Method to be Turned to in the Knowledge {cog- nitio) of Generation 1. The method proposed (par. 21) 2. This method compared to that of Fabricius (par. 22) 3. What will be set forth according to the method a. in respect to formal content (par. 23) b. in respect to material content (par. 24 and 25) 4. What will be inferred from that set forth and the diffi- culties involved (par. 26) 5. Conclusion (par. 27) Under * Of the Mode and Order of Acquiring Knowledge ' (Section B) Harvey rests his scientific method solidly on Aristotle. Harvey juxtaposes two key Aristotelian texts which " at first blush may seem contradictory." The one text emphasizes that there is but one road to scientific knowledge, i. e., to the rea- soned fact, namely, a syllogistic process by which we move from universals to particulars. He states that we " start from the thinsrs which are more knowable and clearer to us and proceed towards those which are clearer and more knowable by nature " {Physics, Bk. I, Ch. 1, 184 a 16-18) . The second text stresses the inductive and prior knowledge obtained from sense data for " that is more perspicuous to us which is based 48 HERBERT ALBERT RATNER on induction . . . whence it is advisable from singulars to pass to universals " {Post. Anal., Bk. II, Ch. 13) . In the following section entitled " Of the same matters, according to Aristotle," Harvey elaborates Bk. I, Ch. 1, of the Posterior Analytics, which states that all doctrine and intel- lectual discipline, including the two forms of reasoning, the syl- logistic and the inductive, is acquired from antecedent knowl- edge, none of which is innate. He then uses a passage from Aristotle to explicate this antecedent knowledge, which arises in sense, is retained by memory, and which, when repeated, results in experience, from which in turn is derived the beginnings of art and science. He again quotes a more " elegant " passage of Aristotle to the same effect {Metaphysics, Bk. I, Ch. 1) . Harvey goes on to say that "By this Aristotle plainly tells us that no one can truly be entitled prudent or truly knowl- edgeable {scientem vere) , who does not of his own proper ex- perience, i.e., from repeated memory, frequent perception by sense, and diligent observation, know that a thing is so in fact. Without these, indeed, we only imagine or believe, and such knowledge {scientia) is rather to be accounted as belonging to others than to us." Harvey concludes this section with a pas- sage from one of Aristotle's research works: That the generation of bees takes place in this Avay appears both from reason and from those things that are seen to occur in their kind. Still all the incidents have not yet been sufficiently examined. And when the investigation shall be complete, then will sense be rather to be trusted than reason; reason, however, will also deserve credit, if the things demonstrated accord with the things that are perceived by sense {Gen. An., Bk. Ill, Ch. 10, 760 b 28-33) . EPIGENESIS VS. PREFORMATION A textbook in a required biological course in a leading uni- versity in the United States makes reference to the " pre- formationists " of approximately 300 years ago who thought that the " embryo was preformed in miniature in the micro- scopic spermatozoon and had but to unfold as the rosebud into the rose " and to the " ovicists," who " postulated a pre- WILLIAM HARVEY, M. D. 49 formed embryo in the egg that needed only a slight stimulus to make it grow and develop." In contrast the authors cite the modern scientist who through " the employment of the scien- tific method of repeated and careful observations and deduc- tions has made it clear to us that the embryo is not preformed in its final form. . ." but that " the various parts of the new individual are gradually formed and undergo a tremendous modification from their first appearance up to their final state." " These same authors could have equally and more accurately written: Over 2300 years ago, Aristotle, by employing the scientific method of repeated careful observation as his basis for inference, made it clear to anybody and everybody who would read, that the preformationist account of embryological development was impossible and the epigenetic account neces- sary. He asked, " How, then, does it [the embryo] make the other parts.f^ "; he answered, " Either all the parts, as heart, lung, liver, eyes and all the rest, come into being together or in succession . . ." " That the former is not the fact is plain even to the sense, for some of the parts are clearly visible as already existing in the embryo while others are not; that it is not be- cause of their being too small that they are not visible is clear, for the lung is of greater size than the heart, and yet appears later than the heart in the original development " (734 a 17 ff .) . William Harvey, 2000 years later, who did read, came out with experimental confirmation and enrichment of the same view. He states in his Generation of Animals: Now it appears clearly from my research that the generation of the chick from the egg is the result of epigenesis (Exercise 45) . And first, since it is certain that the chick is produced by epigenesis, i. e. the addition of parts successively, we shall investigate what part may be observed before any of the rest are erected, and what may be observed in this mode of generation. What Aristotle says of generation ... is confirmed and made manifest by all that passes in the egg, viz. that all the parts are not made simultaneously, but ^* S]jllabus, Introductory General Course in the Biological Sciences, edited by Merle C. Coulter. Seventh edition. (University of Chicago, 1937), p. 104. 50 HERBERT ALBERT RATNER ordered one after the other, and that there first exists a genital particle, by the power of which as from a principle, all the other parts proceed (Exercise 51) . Curiously enough, however, the preformationist theory came into prominence again — curiously, because it did so just follow- ing the discovery of the microscope and the aberrations that passed for facts that resulted thereof. But the epigenetic theory has since been restored and given great richness of detail in support. It can be seen that Harvey in following Aristotle reaffirmed a truth that was lost during the late Renaissance, but redis- covered in modem times. That it was one of Harvey's prime objects in writing The Generation of Animals to defend and establish the opinion already held by Aristotle has been ex- pressed by Thomas H. Huxley.^ 15 REFERENCES TO ARISTOTLE In The Motion of the Heart and Blood, which is more a demonstrative work than a descriptive one, 22 references to Aristotle are made. In only one instance does Harvey clearly disagree with Aristotle. In this instance Harvey writes, " Hence, since the veins are the conduits and vessels that transport the blood, they are of two kinds, the vasa and the aorta; and this not by reason of sides (as in Aristotle) , but office (officio) , and not, as is commonly said, by constitution, for in many animals, as I have said, the vein does not differ from the artery in the thickness of its tunic, but is distinct by duties (munere) and use (usu) ." ^® It should be noted that the disagreement is not based on Aristotle's anatomical obser- vations, which D'Arcy W. Thompson states to be " remarkable ^^ Thomas H. Huxley, " Evolution in Biology," in Darwiniana Essays (New York, 1898), p. 193. ^^ Harvey, Works, ed. cit., cli. 8, p. 47. The English translations of Harvey appearing in this article are mostly adapted from the Willis translation following consultation with the original Latin. Where possible key Latin terms which have English equivalents are substituted. The Latin text consulted is the edition of Bernardus Albinus (Johannes van Kercjhem, 1737) . WILLIAM HARVEY, INI. D. 51 for its wealth of detail [and] for its great accuracy in many particulars . . . ," but rather on physiological considerations, viz. on its ojfifice, duty and use." In another reference Harvey discusses an anatomical obser- vation which " probably led Aristotle to consider this ventricle double, divided transversely." ^^ Other than these, the remain- ing references to Aristotle are utilized to help Harvey make or confirm a particular point. Of particular interest is the reference to Aristotle where Harvey enunciates the possibility of " a motion, as it were, in a circle . . . which motion we may be allowed to call circular, in the same way as Aristotle says that the air and the rain emulate the circular motion of the superior bodies; for the moist earth, warmed by the sun, evaporates; the vapors drawn upwards are condensed, and descending in the form of rain, moisten the earth again; and by this arrangement are genera- tions of living things produced; and in like manner too are tempests and meteors engendered by the circular motion, and by the approach and recession of the sun." ^^ In connection with this passage, a recent translator and a scientist of renown, who is now President of the American Association for the Advancement of Science, is able to observe only that " Harvey seems never to have heard of [the] studies [of] Copernicus, J. Kepler, and G. Galilei [which] had over- thrown the Ptolemical theory of the circular motion of the stars in the heavenly spheres . . ." ~° But to think of this reference as a poetic metaphor to which scientific error can be attached rather than as a striking evo- cation of Aristotle's analysis of locomotion misses the precision for the poetry in the analogy. Here one has to know certain passages from Aristotle's works, Post. Anal, Bk. II, Ch. 12, Physics, Bk. VIII, Ch. 8 & 9, ^^ Aristotle, History of Animals, Translated by D'Arcy W. Thompson (Oxford, 1910). 513 a 35, fn. 3. "Harvey, Works, ed. cit., ch. 17, p. 79. '" Ibid., ch. 8, p. 46. ^° Chauncey D. Leake, op. cit., ch. 8, p. 70, fn. 1. 52 HERBERT ALBERT RATNER Gen. and Cor., Bk. II, Ch. 11, Meteorology, Bk. II, Ch. 4, among others. Aristotle divides natural locomotion into circu- lar and rectilinear. Only circular motion can be single and continuous. When Harvey concludes in Ch. 14 that " it is absolutely necessary to conclude that the blood in the animal body is impelled in a circle, and is in a state of ceaseless (perpetuo) motion . . ." he is talking in a strict Aristotelian framework. Harvey, in the development of this conclusion, had to combat in his own mind the prevailing physiological concept that blood was produced from nutriment in a central organ, and was moved peripherally to be totally consumed by the body. That Harvey refers to Aristotle's concept of circular motion in his exposition, which is in the order of demonstration, suggests the critical role that Aristotle's concept had in the order of discovery. THE DEMONSTRATION OF THE MOTION OF THE HEART AND BLOOD Harvey makes it clear throughout his work that his " new views of the motion and use of the heart and the circulation of the blood " "^ are the result of the application of both sense and reason. In his dedication to the learned physicians he states that " for nine years or more [he has] confirmed these views by ocular demonstrations [and] manifested them by reasons and arguments, freed from the objections of the most learned and skillful anatomists." In Ch. 14 entitled ' The Conclusion of the Demonstration of the Circulation of the Blood ' where he concludes that the blood is impelled to the whole body by the pulse of the ventricles, he states that this is " confirmed by reason and ocular experiment," and that one must " necessarily conclude " that the motion of the blood is circular. In the final words of the concluding chapter of his book, the chapter which confirms the motion and the circula- tion of the blood through an anatomical analysis of the heart, '^ Harvey, Works, ed. cit., Dedication to Learned Physicians, p. 5. WILLIAM HARVEY, M. D. 53 Harvey concludes that " All these phenomenon and many others observed in dissecting, if rightly weighed, seem clearly to illumine and fully confirm the truth contended throughout these pages ... it would be difficult to explain in any other way for what cause all is constructed and arranged as we have seen it to be." Notwithstanding, the modern scientist with his dispropor- tionate worship of observation manages for the most part to ignore the role played by reason, thereby missing what is so magnificent in this classic work. The carefully organized nature of Harvey's demonstration can be detected by scrutinizing Harvey's table of contents, which, because it is a contraction, mirrors the logical structure of the masterpiece in bold outline. The following represents a structural analysis of the table: Analysis of Harvey's Table of Contents " of an Ana- tomical Exercise on the Motion of the Heart and Blood Part 1. Prefatory A. Dedicatory: extrinsic to work, 1. To the King: to civil authority, 2. To Learned Physicians: to peers who respect truth. B. Introductory: intrinsic to work, 1 . ' Introduction ': establishes the need for the work; dated to the belief of scientists of that period. 2. ' The Causes Moving the Author to Write ' (Ch. 1) : establishes the difficulty of the work; timeless, as the truths obtained from nature are permanent and belong to posterity. Part 2. Motion of the Cardiovascular System (Ch. 2-7) A. Motion of the Containing Parts 1. 'Motion of the heart through dissection of living ani- mals.' (Ch. 2) ^^ Words enclosed in single quotation marks are those used by Harvey as chapter headings. Other quotations have individual reference numbers. 54 HERBERT ALBERT RATNER 2. 'Motion of the arteries through dissection of Hving animals.' (Ch. 3) 3. ' Motion of the heart and auricles through dissection of Hving animals.' (Ch. 4) 4. ' Motion, action and function of the heart.' (Ch. 5) B. Motion of the Contained Parts from Right to Left Ventricle 1 . ' Ways by which blood passes from right ventricle to left.' (Ch. 6) 2. 'That the blood pass through the lung from right ventricle to left.' (Ch. 7) Part 3. Circular Motion of the Contained Part (Ch. 8-17) A. The Thesis and Demonstration (Ch. 8-14) 1. Preliminary statement of the thesis: " Of the abun- dance of blood passing through the heart out of the veins into the arteries and of the circular motion of the blood." (Ch. 8) 2. The three suppositions necessary for the demon- stration. a. ' The first supposition ': " the blood is incessantly transmitted by the pulse of the heart out of the vena cava into the arteries in such abundance that it cannot be supplied from the ingesta, and in such wise that the whole mass must very quickly pass through the heart." "^ (1) ' circulation of blood confirmed from it.' (Ch. 9) (2) ' is freed from objections and further confirmed by experiments.' (Ch. 10) b. ' The second supposition ': " the blood under the influence of the arterial pulse enters and is im- pelled in a continuous, equable, and incessant " Harvey, Works, ed. cit., ch. 9, p. 48. WILLIAM HARVEY, M. D. 55 stream through every part and member of the body, in much greater abundance than were suffi- cient for nutrition, or than the whole mass of in- gesta could supply " "^ (1) 'is confirmed/ (Ch. 11) (2) * circulation of blood confirmed from it.' (Ch. 12) c. * The third supposition ': " the veins in like manner return this blood perpetually to the heart from all members of the body " ^^ (1) ' confirmed and that there is a circulation of blood from it.' (Ch. 13) 3. ' The conclusion of the demonstration concerning the circulation of the blood.' (Ch. 14) B. Confirmation of Conclusion that the Blood Circulates (Ch. 15-17) 1. 'The circulation of the blood is confirmed by likely reasons.' (Ch. 15) 2. ' The circulation of the blood is proved from conse- quences.' (Ch. 16) 3. ' Motion and circulation of the blood is confirmed by those things that appear in the heart and which are clear from anatomical dissections.' (Ch. 17) In the Introduction (Part 1, B, 1) Harvey paves the way for his new theory by showing that the existing theory is un- satisfactory. He states in the opening paragraph that " In dis- cussing the motion, pulse, action, use and utility of the heart and arteries, we should first consider what others have said on these matters, and what the common and traditional viewpoint is. Then by anatomical dissection, multiplied experience, dili- gent and accurate observation, we may confirm what is rightly stated, but what is false make right." Harvey then carefully examines the beliefs of his contemporaries in a series of seven- " Ibid. " Ibid. 56 HERBERT ALBERT RATNER teen dialectical propositions and replies. He concludes, " From these and many other considerations it is plain that what has been said on the motion and use of the heart and arteries must seem obscure, inconsistent, or impossible to the thoughtful student. It will therefore be proper to investigate the matter more closely, to study the motion of the heart and arteries not only in man but in all animals possessing a heart, and to search out and find the truth by frequent vivisections and by constant ocular inspection." This doxographic approach is distinctly Aristotelian,'^ and establishes that one should not lean on man as the final author- ity.^^ In Ch. 1, he indicates that nature, despite the difficulty of extracting answers from her, is the final authority. 28 '" It is part of Aristotle's methodology to examine dialectically existing opinion before proceeding to the scientific investigation of things. Examples of this pro- cedure are found in Physics, Bk. 1, ch. 2; Generation and Corruption, Bk. 1, ch. 1; The Soul., Bk. 1, ch. 2, and elsewhere. The following passage from On the Heavens states some of the reasons for the procedure: " Let us start with a review of the theories of other thinkers; for the proofs of a theory are difficulties for the contrary theory. Besides, those who have fu-st heard the pleas of our adversaries will be more likely to credit the assertions which we are going to make. We shall be less open to the charge of procuring judgment by default" (Bk. 1, ch. 10, 279 b 6-11). " We may convince ourselves not only by the arguments already set forth but also by a consideration of the views of those who differ from us ... If our view is a possible one . . . and [what] they assert is impossible, this fact will be a great weight in convincing us . . ." (Bk. 2, ch. 1, 283 b 30-a) . All translations from Aristotle are from the Oxford edition of his works. ^' The true Aristotelian tradition may be gathered from the following statements: " We had perhaps better consider the universal good and discuss thoroughly what is meant by it, although such an inquiry is made an uphUl one by the fact that the Forms have been introduced by friends of our own. Yet it would perhaps be thought to be better, indeed to be our duty, for the sake of maintaining the truth even to destroy what touches us closely, especially as we are philosophers or lovers of wisdom; for, while both are dear, piety requires us to honour truth above our friends." (Aristotle, Nicomachean Ethics, Bk. 1, ch. 6, 1096a 11-16). " He who believes Aristotle to be a god ought to believe that he never made a mistake. But whoever thinks him to have been a man must admit that he was as liable to make mistakes as the rest of us." (St. Albert the Great, Physicorum lib. VIII, tr. I, cap. 14, ed. Borgnet, III, p. 553). " Unless a man holds truth dearer than friends, he will be ready to pronounce false judgments and to bear false witness for the sake of friends. But that is immoral. All men ought to hold truth dearer than friends, because all men have the use of reason. But this duty is particularly binding on all philosophers, be- WILLIAM HARVEY, M. D. 57 In subsequent chapterS^ Harvey begins to record his reading of the book of nature. In Chapters 2-5, he reports what she says about the heart and arteries. By obtaining the true attri- butes of these critical components of the cardiovascular system, their motion, pulse and action, he will be in a position subse- quently to elucidate their use and utility. " For if none of the true attributes of things have been omitted in the historical survey " states Harvey's mentor Aristotle, " we should be able to discover the proof and demonstrate everything which ad- mitted of proof, and to make that clear, whose nature does not admit of truth." Aristotle emphasizes in this same passage that " in each science the principles which are peculiar are the most numerous. Consequently it is the business of experi- ence to give the principles which belong to each subject. I cause they profess to teach wisdom, and wisdom is nothing else than the knowl- edge of truth . . . Truth is, indeed, divine for it is found fundamentally and primarily in God. That is why Aristotle insists on the sacredness of the duty of holding truth dearer than friends . . . Plato is of the same opinion. For, once, when setting aside a theory of his master, Socrates, he declares that truth must be our supreme concern. And elsewhere, he declares: Socrates is, indeed, a friend of mine, but truth is a greater friend. And in a third text, he declares that one may make little of Socrates, but one must make much of truth." (St. Thomas Aquinas, In I Ethic, lect. 6, nn. 76, 78) . ^* This is another expression of the true Aristotelian position. " God, like a good teacher, has taken care to compose most excellent writings that we may be in- structed in all perfection. ' All that is written,' says the Apostle, ' is wi'itten for our instruction.' And these writings are in two books: the book of the creation and the book of the Holy Scriptures. In the former are so many creatures, so many excellent writings that deliver the truth without falsehood. Wherefore Aristotle, when asked whence it was that he had his admirable learning, replied: ' From things, which do not know how to lie.' " (St. Thomas, Sermo 5 in Dom. II de adventu, ed. Vives, Opera Omnia, XXIX, p. 194). William Harvey, who, on the one hand, makes clear that " the authority of Aristotle has always such weight with me that I never think of differing from him inconsiderately " (Harvey, Anatomical Exercises on the Generation of Animals, Ex. 11, ed. cit., p. 207), also states that " 'Wlioever, therefore, sets himself to opposition to the circulation, because [he] regards it as in some sort criminal to call in question disciplines that have descended through a long succession of ages, and carry the authority of the ancients; to all these I reply: that the facts manifest by the senses wait upon no opinions, and that the works of nature bow to no antiquity; for indeed there is nothing either more ancient or of higher authority than nature." (Second Exercise to John Riolan, ed. cit., p. 123) . 58 HERBERT ALBERT RATNER mean for example that astronomical experience supplies the principles of astronomical science: for once the phenomena were adequately apprehended, the demonstrations of astron- omy were discovered. Similarly with any other art or science. Consequently, if the attributes of the things are apprehended, our business will then be to exhibit readily the demonstrations."^® Again Aristotle emphasizes that " each set of principles we must try to investigate in the natural way, and we must take pains to state them definitely, since they have a great influ- ence on what follows. For the beginning is thought to be more than half of the whole, and many of the questions we ask are cleared up by it." ^'^ Harvey, of course, as an Aristotelian, does not limit himself to man. To get at the heart of the matter and of man he must be interested in the hearts of other animals. His aim is to get at the true nature of the heart. His interest is not descriptive. He is not interested in this heart or that with the variations in numbers of chambers or differing associations with lung or gills, but in the heart universally considered, prescinding from the variations that are found in nature. He refers to cold blooded animals as well as to warm blooded: toads, snakes, frogs, snails, shellfish and fish. In all it has been estimated that he worked with about 80 species of animals .^^ That this is a methodological approach and not simply the insatiable curiosity of a field biologist is made clear from the quote from Aristotle that appears on the title page of Prelec- tiones, from the fifth of the canons which Harvey lists for his own guidance at the beginning of his lectures, and from a passage from Harvey that appears in De Motu. The Aristotle quotation states, " The fact is that the inner parts of man are to a very great extent uncertain and unknown, and the consequence is that we must have recourse to a con- ''^ Prior Analytics, Bk. 1, ch. 30, 46 a 18-27. ^^ Nico-machean Ethics, Bk. 1, ch. 7, 1098 b 4-9. '^ William Harvey, Prelectiones, ed. cit.. Introduction by a Committee of the Royal College of Physicians of London, p. vi. WILLIAM HARVEY, M. D. 59 sideration of the inner parts of other animals which in any- way resembles that of man." ^- The fifth canon emphasizes that one should systematically study other animals " according to the Socratic rule " for this will permit one to refute and correct errors in natural phi- losophy, and to discover the use, action and dignity of things, and thereby obtain for anatomy knowledge of the causes of the parts, the ends, their necessity and use. The Harvey passage is as follows: Since the intimate connection of the heart with the lungs, which is apparent in the human subject, has been the probable occasion of the errors that have been committed on this point, they plainly do amiss who speak and demonstrate the parts of animals generally (as all anatomists commonly do) from the dissections of man alone, and at that dead. They obviously act no otherwise than he, who, having studied the form of a single republic, should set about a general discipline of polity; or who, having taken cognizance of a single farm, should imagine that he has scientific knowledge of agriculture; or who, on one particular proposition attempts to syllogize the universal. Had anatomists only been as conversant with the dissection of the lower animals as they are with that of the human body, the matters that have hitherto kept them in a perplexity of doubt would in my opinion, have met them freed from every kind of difficulty.^^ It should be seen here that in his dedication to comparative anatomy, to Socrates' and Aristotle's rule, Harvey differs from the modern scientist. The latter directs this branch of biology primarily to taxonomy or to the elucidation of evolutionary his- tory. The Socratic rule, on the contrary, is directed at eliciting an essential definition through the use of the inductive method. Socrates, according to Aristotle, was interested in what a thing is, its essence, as the starting point for syllogizing. " Two things may be fairly ascribed to Socrates," says Aristotle, " in- ductive arguments and universal definitions, both of which are concerned with the starting point of science." 34 '''Aristotle, The History of Animals, Bk. 1, ch. 16, 494 b 21-24. *^ Harvey, Works, op. cit., ch. 6, p. 35. ** Aristotle, Metaphysics, Bk. M, ch. 4, 1078 b 18-30. 60 HERBERT ALBERT RATNER To understand the use and the goal of Grecian and Har- vian comparative biology, two things should be understood. First, that one has to seek out and know the many. Secondly, that knowledge of the many which one has to seek out is the " one in the many " — that which is common to the many, that commonality which most fully accounts for why the thing is as it is. To know the many, however, does not automatically result in an answer. Modern science suffers from a plethora of the many, because of the variety and the high output of sense observations from our laboratories. The modern scientist is in the position of Meno, who, in answer to Socrates' question. What is virtue?, responds that " Every age, every condition of life, young or old, male or female, bond or free, has a different virtue: there are virtues numberless, and no lack of definitions for them . . ." ^^ The modern scientist in the absence of the Harvian answer would respond similarly to the question, What is a heart .f*, that every species of animal has a different heart: there are numberless hearts and numberless definitions. But Harvey, following Socrates, prescinds from the many and seeks what the heart is " in the universal . . . whole and sound, and not broken into a number of pieces." ^® Harvey also follows Aristotle, who formally discusses the method of obtaining defi- nitions in his Posterior Analytics which, as part of the Org anon, was part of Harvey's formal training in logic and scientific methodology. Unlike the modern whose notion of causality is limited pri- marily to the material and efficient causes, Harvey further follows Socrates and Aristotle in seeking the fuller explanation that comes with the additional knowledge of the formal and final causes. Socrates in his last days recollects his rejection of this ancient error of modem scientists when, as a young man, he, " with a prodigious desire to know that department of philosophy which ^^ Plato, Meno, 71 E-72 A (Jowett translation.) "'Ibid., 77 A. WILLIAM HARVEY, M. D. 61 is called the investigation of nature: to know the causes of things, and why a thing is " " registers his disappointment after being directed to Anaxagoras who, forsaking any principle of order, tried to explain everything by " having recourse to air, ether, and water and other eccentricities." ^^ Aristotle as a scientist's scientist ^^ and philosopher's philoso- pher fully and formally develops this Socratic position in Book I of the Parts of Animals. He, too, as if writing against the enthusiastic follower of Harvey, who reads but does not under- stand him, talks about " the ancient writers, who first philoso- phized about Nature as having busied themselves " with " the material principle and material cause." *° Aristotle explains, on the contrary, that if men and animals and their several parts are natural phenomena, then the natural philosopher must take into consideration not merely the ultimate substances of which they are made but also . . . the homogeneous and heterogeneous parts; and must examine how each of these comes to be what it is, and in virtue of what force. For to say what are the ultimate substances out of which an animal is formed, to state, for instance, that it is made of fire or earth, is no more sufficient than would be a similar account in the case of a couch or the like . . . For a couch is . . . such and such a matter with this or that form; so that its shape and structure must be included in our description. For the formal nature is of greater importance than the material nature.*^ Aristotle finally concludes that It is plain, then, that the teaching of the old physiologists is inadequate, and that the true method is to state what the definitive characters are that distinguish the animal as a whole; to explain what it is both in substance and in form, and to deal after the same " Plato, Phaedo, 96 B. "' Ibid., 98 C. '' Charles Darwin, Life and Letters, Letter to Ogle, 1882, vol. 3, p. 252: " From quotations I had seen I had a high notion of Aristotle's merits, but I had not the most remote notion what a wonderful man he was. Linnaeus and Cuvier have been my two gods, though in very different ways, but they were mere schoolboys to old Aristotle." *° Aristotle, Parts of Animals, Bk. I, ch. 1, 640 b 5. " Ibid., 640 b 15-29. 62 HERBERT ALBERT RATNER fashion with its several organs; in fact, to proceed in exactly the same way as we should do, were we giving a complete description of a couch."*- We can see then that Harvey as an Aristotelian is interested in function as well as action, in ends as well as means — the teleological as well as the mechanical. We shall also see that Harvey respects the differentiation as well as the interrelation- ship of what has to be known for a full understanding of the causes. Part of the modern difficulty in understanding Harvey stems from a failure to appreciate Harvey's sensitivity to lan- guage, and our insensitivity to the sharply delineated concepts w^hich his terminology precisely communicates — concepts and terms which are the culmination of a long logical and biological tradition. The conceptual difficulty can best be seen from the Leake translation. In the table of contents: the Latin words dis- sectione, in three instances, and ex-perimentis are both trans- lated into experiment', dissectio, in another instance, is trans- lated into investigation; confirmato is translated into both established and proved; probatur is translated into supported; and suppositio is translated into consideration and proposition. The first sentence of the Introduction of this translation begins, " In discussing the movements and functions of the heart and arteries, we should first consider . . .". The original Latin, however, instead of movement and junctions, has motu, pulsu, actione, usu, utilitatibus. We can now return more specifically to the manner in which Harvey arrived at his revolutionary conclusions concerning the motion of the heart and blood. If one turns to the table of con- tents above, he will note that whereas the word dissection is characteristically found in the chapter headings on the motion of the heart and arteries (part 2 A) , the word supposition is characteristically found in the section on the circulation of the blood (part 3 A) . Dissection, of course, pertains to sense; supposition, to reason. One may correctly infer from this that, "/62d., 641 a 14-18. WILLIAM HARVEY, M. D. 63 when it comes to the circulation of the blood, the demonstra- tion is logical, not ocular. The absence of magnifying instru- ments of sufficient strength at the time made it impossible to observe either the circulation of the blood or the continuity of the cardiovascular system. It is not implied here, however, that the ocular, even if possible, could approach or match the certi- tude of the logical demonstration.^^ Circulation, as such, is not mentioned in the body of the work until Chapter 8, where it is introduced in the form of a short review of the argument developed subsequently. Since the conclusion that the circulation of the blood is the end result of a long reasoning process, the chief function of Harvey's pre- ceding chapters is to contribute premises which are ti*ue, primary, immediate, better known than, prior to, and the cause of the conclusions which follow from them.** In other words, it is necessary to establish the motion, pulse, and action of the heart and arteries, and the relationship of the lungs to the heart and the blood to the lungs first. This calls for the most exacting type of sense observations, their verification by col- lated findings, and care in the inferences drawn from them. It is through such knowledge that Harvey is in a position to ask questions leading to the initial idea and final demonstration that the blood circulates. The first part of Harvey's treatise establishes, contrary to the beliefs at the time, that the heart and the arteries in the living animal always contain blood: that the proper motion of the heart is contraction, not expansion; that its action is pump- like, not bellow-like, and that it forcibly expels blood in one direction; that contraction, not expansion — systole, not diastole — corresponds to the pulse on the chest wall; that the arterial ** It should not be forgotten that the observations of Swammerdam of the per- fectly formed butterfly in the cocoon in 1669, and those of Leeuwenhoek of the com- plete outline of both maternal and paternal individuals in the microscopic sperma- tozoa in 1677, led to the complete replacement of Harvey's theory of epigenesis by the preformation theory, which lent itself to a mechanical explanation of nature, and which was to dominate biological thinking through the first half of the eight- eenth century. "Aristotle, Posterior Analytics, Bk. 1, ch. 1, 71 b 16-22. 64 HERBERT ALBERT RATNER pulse, which in arterial diastole corresponds to carliac systole, not cardiac diastole; that cardiac systole is the cause of the arterial pulse via the motion it transmits through the blood; and that blood from the right ventricle gets to the left ventricle through the lungs. Since " the one action of the heart is the transfusion and pro- pulsion of the blood by mediation of the arteries to the extremi- ties of the body," ^^ the question arises as to where the heart gets the blood which is the subject of its action. The genesis of the belief and the hypothesis that blood circulates is as follows: And sooth to say, when I surveyed in various disquisitions by how much abundance blood might be lost from cutting arteries, in dissections and induced experiments in the living; then the sym- metry and magnitude of the vessels that enter and leave the ven- tricles of the heart (for nature doing nothing groundlessly, would never have given them such proportionate magnitudes ground- lessly) , then the ingenious and attentive fitting together of the valves and fibers, and the rest of the heart's fabric and many other things besides, I frequently and seriously bethought me, and long revolved in my mind, by how much abundance blood was trans- mitted, and the like, in how short a time its transmission might be effected, and not finding it possible that this could be supplied by the juices of the ingested aliment without the veins on the one hand becoming drained, and the arteries on the other hand getting ruptured through the excessive charge of blood, unless the blood should somehow find its way from the arteries into the veins, and so return to the right ventricle of the heart; I began to think whether there might not be a motion as it were, in a circle.^® Chapter 9 contains the principal demonstration of the cir- culation: A fluid of limited quantity kept in perpetual motion in one direction is moved circularly. And the blood is such a fluid. Therefore the blood is moved circularly. In this syllogism according to the Aristotelian logic em- " Harvey, Works, op. cit., ch. 5, p. 32. ** Ibid., ch. 8, pp. 45-46. WILLIAM HARVEY, M. D. 65 ployed by Harvey the middle term is the material cause (i. e. limited quantity of fluid) , and the demonstration is " one through the material cause." The major premise is a general physical theorem proved by Aristotle in Books VII and VIII of the Physics, where he shows that perpetual motion of any system must be circular in character. The minor premise is a definition of the blood derived from Harvey's careful studies recorded in his earlier chapters. Harvey's conclusion is, as he admonishes a critic on a later occasion, " demonstrative and true, and follows of necessity, if the premises be true." *^ Therefore he adds that any criti- cism of his conclusion cannot be in the area of argument and logic, but in the area of observation and experiment which supplies the premises. Harvey insists here that " our senses ought to assure us whether such things be false or true and not our reason, ocular testimony and not contemplation." ^^ That Harvey has learned well from Aristotle, who was the father both of biology and logic, is evident from Harvey's recognition of and respect for the proper spheres of sense and reason. The degree to which Harvey's demonstration is Aristotelian should be noted further. First, it is an example of the relation- ship of a less general science, biology, to a more general and fundamental science, physics, to which it is subalternate: a par- ticular biological fact is illuminated by a universal physical theorem to yield a new biological fact. Secondly, it is an ex- ample of the dictum that demonstrations in science are made through a definition expressing an essential characteristic. Thirdly, contrary to modem thinking, Harvey's demonstration does not depend on mathematical measurements but on physical proportions, i. e., the proportion of one quantity to another on the basis of physical comparison rather than on mathematical principles. In stating that Chapter 9 is " the first instance of the quantitative method in physiology " and that it " introduced the most important method of reasoning in *^ Harvey, Second Exercise to John Riolan, ed. cit., p. 133. " Ibid. 66 HERBERT ALBERT RATNER science," *° Leake misses Harvey's fidelity to Aristotle's method and its reward. Kilgour, in a recent and careful analy- sis of Harvey's use of the quantitative method, concludes that certainly " Harvey was not concerned with accurate measure- ment " and that his estimations were consciously indifferent to precision, the essence of the mathematical procedure. He adds, " Apparently, quantitative evidence was not important in lead- ing Harvey to develop the idea of the circulation because there is no quantitation in his Lumleian Lecture notes of 1616." '" The computations Harvey supplies, therefore, may be better viewed as communicating to the reader — in the manner in which a sensible model makes a theory vivid to the reader — the physical reality of the disproportion between the amount of ingesta and the flow of blood through the heart.^^ Finally, it would be amiss not to recogTiize that the demon- stration of the circulation of the blood is just an Aristotelian step in the elucidation of the nature of the heart, the prime component of the cardiovascular system. The ultimate purpose of Harvey's treatise is to define the heart upon which the motion of the blood is dependent. One of the most remarkable chapters in this work of Harvey's is the 17th and final chapter. From all the fields opened up by the establishment of circulation — physiology, pathology, symp- tomatology and therapeutics — he selects his topic: to relate the various particulars that present themselves in the ana- tomical study of the fabric of the heart and arteries to their several uses and causes, " for I shall meet with many things *" Chauncey D. Leake, op. cit., ch. 9, p. 74, fn. 1. ^° Frederick C. Kilgour, " William Harvey's Use of the Quantitative Method," Yale Journal of Biology and Medicine, XXVI (1954) , 417-18. ^^ Some of the thoughts appearing in this article were first presented and in part developed at a summer institute for scientists and philosophers conducted by The Albert Magnus Lyceum for Natural Science at River Forest, Illinois, July 1952. A report of this institute is to be found in the publication, entitled, Science in Synthesis: A dialectical approach to the integration of the physical and natural sciences, by W. Kane, O. P.; J. D. Corcoran, O. P.; B. M. AsUey, O. P.; and R. H. Nogar, O. P. (The Aquinas Library, Dominican College of St. Thomas Aquinas: River Forest, Illinois. 1953). See pp. 93-108. WILLIAM HARVEY, M. D. 67 which receive light from the truth I have been contending for, and which, in turn, render it more obvious. And indeed I would have it confirmed {firmatain) and beautified {exorriatam) by anatomical arguments above all others." °" This chapter is primarily an elaboration of the formal cause of the heart through the re-examination of the heart and the vessels — structurally, comparatively, embryologically and func- tionally — in the light of the final cause, viz. the circulation of the blood. His final statement which closes his treatise is: " it would be difficult to explain in any other way for what cause all is constructed and arranged as we have seen it to be." He establishes what a heart is in his characterization of the heart per se as the left ventricle, viz. that ventricle " distin- guished by use not position, the one namely that distributes blood to the body at large, not the lungs alone." In doing so he establishes the connection of the final and formal causes. This chapter completes the definition of the heart for Harvey, which definition may be expressed in syllogistic form as follows: An organ which must supply an organ which is so con- the body with a steady flow structed as to be able to of a fluid whose quantity is produce a circular motion proportionately small is of that fluid. And the heart has this very function. Therefore the heart is: 1 . An organ which has a pulsating " left " ventricle mth a non-regurgitating valvular inlet and outlet and whatever addi- tional cardiac parts that conform to the needs of the species (the formal cause: the anatomical structure described teleo- logically and in detail, i.e., in its relationship to its motion, pulse, action, use and utilities, e. g., the arrangement of the fibres in the walls, the valves, the braces of the heart; " the actions and uses of the heart may be understood from the con- ^^ Harvey, Works, op. cit., ch. 16, p. 74. 68 HERBERT ALBERT RATNER stitution of its muscular fibers and the fabric of its moveable parts " '') , 2. and is composed of muscular tissue and other tissue com- ponents necessary to the parts (the Tnaterial caiise) , 3. for the sake of circulating the blood (the final cause or function) 4. by contraction (the efficient cause of circulation) .^* ^* Ibid., ch. 17, p. 82. ^* That the last chapter is an integral and important part of Harvey's classic is not the common position. Leake presents a typical viewpoint when he states that " The last three chapters add little to the significance of the demonstration " (Chauncey D. Leake, op. cit., Translator's Preface, p. x) . But here it seems that Leake has a limited appreciation of the purpose of the work as explicitly stated by Harvey, and of the true scientific nature of the anatomical exercise employed by Harvey. As to the purpose of the work it should first be recalled that the title of this classic makes clear that it is an anatomical exercise, and that it concerns the motion of the heart as well as the motion of the blood. Secondly, that the opening statement of the Introduction states that Harvey is discussing " the motion, pulse, action, use and utility of the heart and arteries," and of Chapter 1 that his purpose is to discover " the motions, use and utility of the heart." That Leake does not appreciate the comprehensiveness of the anatomical exercise is reflected in his translation, in which he reduces action, use and utility to junction in the Intro- duction, and M5e and utility to junction in Chapter 1. If we turn to the anatomical works of Fabricius, who was Harvey's teacher, we find the following exposition of the anatomical exercise: "to treat first the dissection or description of each organ, then its action, and finally its utilities, and in this way present our entire knowledge of the organs as comprised in these three divisions." He adds that he has followed " this path the more willingly because those distinguished pioneers, Aristotle and Galen, have blazed the trail and, so to speak, carried the torch before me on the way." (Fabricius, De Visione, voce, auditu, Preface, translated by Howard B. Adelmann, The Embryological Treatises oj Hieronymus Fabricius oj Aquapendente, Cornell University Press, 1942, p. 82). Fabricius classifies the biological works of Aristotle and Galen in these three divisions and states that " The third part, indeed, which discusses the utilities of the whole, as well as of the parts of an organ, corresponds to the four books of Aristotle's De partibus animalium [and] to that great work of Galen's, De usu partium . . ." (ibid., p. 83) . When we turn to Aristotle's explication of the third part of the anatomical exercise he states that " In the first place we must look at the constituent parts of animals. For it is in a way relative to these parts, first and foremost, that animals in their entirety differ from one another: either in the fact that some have this or that, while they have not that or this; or by peculiarities of position or arrangement; or by the differences that have been previously mentioned, depending upon diversity of form, or excess or defect in this or that particular, or analogy, or WILLIAM HARVEY, M. D, 69 NatuFcally, the final and efficient causes are proximate causes and are not intended as complete in any sense. In this context Harvey's Aristotelian answer to his critic Riolan is pertinent: " To those who repudiate the circulation because they neither see the efficient nor final cause of it, and who exclaim, Cui bono? I have yet to reply, having hitherto taken no note of the ground of objection which they take up. And first I own I am of opinion that our first duty is to inquire whether the thing be or not, before asking wherefore it is (propter quid) ? for from the facts and circumstances which meet us in the on contrasts of the accidental qualities." For, according to Aristotle " to do this [pass on to the discussion of the causes] when the investigation of the details is complete is the proper and natural method, and that whereby the subjects and the premises of our argument will afterwards be rendered plain." (Aristotle, The History of Animals, Bk. 1, ch. 6, 491 b 10-19). Galen's position is quoted by Fabricius: "A practical knowledge of the nature of each of the members is gained from dissection together with a thorough under- standing of its actions and utilities." Galen further adds, in the quotation from Fabricius: " Moreover, lest anyone unwisely neglects these aspects or be thought- less enough to say that they are not of great consequence, I can truly say this: They are of so much importance, that whoever has learned them thoroughly must unhesitatingly confess that he has learned and comprehended the whole subject of anatomy, which, in my opinion, is nothing but the true and solid foundation of all medicine and the absolute and perfect end of natural philosophy." (Fabricius, op. dt., p. 83) . Galen's statement is clearly in anticipation of criticisms such as Leake's. That Leake has this position is in great part explained by the fact that contemporary physicians and doctorates of anatomy have been raised on Gray's AnatoTny which is entitled Anatomy, Descriptive and Surgical and which is intended for " Students of Surgery rather than for the Scientific Anatomist." (Henry Gray, Anatomy, Descriptive and Surgical, A New Edition Thoroughly Revised by American Authori- ties from tlie Thirteenth English Edition (Lea Brothers, 1896) Preface to the Thirteenth English Edition, p. 8) . It can be seen that Gray's Anatomy is a practical work ordered to surgery and which only relates the first division of the traditional notion of anatomy, namely description, to surgery. An understanding of Harvey's procedure then, may be summarized in the words of Fabricius: " Now in the second part of this treatise, I must discuss action, since, as Galen everywhere testifies, it is not permissible to arrive at the third section, which describes the usefulness (utilitates) of the parts, before the actions of the organs are understood. For the utilities of an organ always have reference to action, and depend upon the action which proceeds from the homogeneous parts of it. For this reason, in every organ there is always provided one part which is the prin- cipal instrument of its action, that is, a part from which the action proceeds, while the other parts of the organ are related to the action as useful assistants." Fabri- 70 HERBERT ALBERT RATNER circulation admitted, established, the use and utilities of its institution are especially to be sought." ^^ Notwithstanding, Harvey makes clear " the principal use and end of the circulation: it is that for which the blood is sent on its perpetual course, and to exert its influence continually in its circuit, to wit, that all parts dependent on the primary innate heat may be retained alive, in their state of vital and vegetative being, and apt to perform their duties; whilst to use the language of physiologists, they are sustained and actu- ated by the inflowing heat and vital spirits." ^® The modem reader, of course, will have to understand that it would take some time, and the modem development of the science of chemistry, before this point could have been made in terms of oxygen instead of vital spirits, or amino acids, glucose, and fatty acids instead of natural spirits. In the mean- time he can have the reassurance from Harvey that " There is, in fact, no occasion for searching after spirits foreign to, or cius then exemplifies the above distinctions with the eye, in which the crystalline lens has the principal utility, and the other parts of the eye, the cornea, the iris and the rest, are structures useful for the eye's action through the secondary utilities they have for either improving or protecting vision, and concludes: " It is now clear from the foregoing that utility is always related to activity, whether the usefulness of the organ is sought from its action or from other things either consequential or accidental; nor can you inquire into the usefulness of any organ unless its action is first known." (Fabricius, The Formed Fetus, Part 2, The Action and Usefulness (utilitas) of the parts of the fetus, ch. 1, Adelmann trans- lation, ed. cit., p. 276) . Harvey's last chapter, which is entitled " The motion and circulation of the blood is confirmed by those things that appear in the heart and are clear from anatomical dissections," can now be seen as an integral part of the anatomical exercise. In the preceding chapters Harvey has established the proper action of the heart, as well as its use, the circulation of the blood. This now permits him to look at the heart so as to determine formally its utilities, i. e., its abilities to serve, in the light of its actions and use. By determining that the formal cause of the heart — its utilities — has a one to one correspondence with its action — the efficient cause of blood circulation — and with its use, the final cause, namely, the circulation of the blood, Harvey can now reflectively confirm the circulation. In this remarkable chapter Harvey identifies the principal utility with the muscular left ventricle and the secondary utilities with valves, braces, etc. ^® Harvey, Second Exercise to John Riolan, ed. cit., pp. 122-123. ^^ Harvey, First Exercise to John Riolan, ed. cit., p. 98. WILLIAM HARVEY, M. D. 71 distinct from, the blood ": " for " the blood and spirits con- stitute one body (like — whey and butter in milk, or heat in hot water . . .) ." ^^ It should be stressed that Harvey in elucidating the formal cause of the heart, as well as the formal cause of the arteries and veins, has obtained the efficient cause of circulation and the basis for a propter quid demonstration. This is the import of his last chapter and his concluding statement quoted above. Conclusion Although Harvey's discovery of the circulation of the blood was truly revolutionary, its establishment was strictly tradi- tional. Ironically, the greatest opposition to his work came from the traditionalists. What accounts for the paradox? Most scholastics of the fifteenth and sixteenth centuries so admired Aristotle that they ended up slaves to his conclusions and caricaturists, rather than disciples, of the methods by which he arrived at them. As a result they were very unpro- ductive in the natural sciences. Modern biologists trace their lineage back to three seven- teenth century scientists who revolted from these Aristotelians: Francis Bacon, Rene Descartes ^^ and William Harvey. What ^^ Harvey, Anatotnical Exercises on the Generation oj Animals, Ex. 51, ed. cit., p. 502. ^^ Harvey, The Motion of the Heart and Blood, Introduction, ed. cit., p. 12. ^^ Descartes was one contemporary who had no difficulty accepting Harvey's conclusion. " I need only mention in reply what has been written by a physician in England, who has the honour of having broken the ice on the subject (that the blood's) course amounts precisely to a perpetual motion." (Rene Descartes, A Discourse on Method of Rightly Conducting the Reason and Seeking Truth in the Sciences, Everyman's Library, p. 41). He accepted Harvey's conclusion without difficulty because it fit in with his mechanistic and mathematized method. His method, however, did not protect him from misunderstanding Harvey's demon- stration and almost everything that Descartes further said about the motions of the heart and blood was in error. (Ibid., pp. 37-43) . Harvey, of course, was fully cognizant of Descarte's failure and makes this clear in the following passage: ". . . the ingenious and acute Descartes (whose honourable mention of my name demands acknowledgments,) and others ... in my opinion do not observe correctly . . . Descartes does not perceive how much the relaxation and subsidence of the heart and arteries differ from their distention or 72 HERBERT ALBERT RATNER each of these three did was to free himself from the short- comings of his contemporaries by a daring innovation. The innovation of Descartes was philosophical. He allowed his philosophical genius to carry him to the extreme of founding a completely new philosophy. The innovation of Bacon was pseudo-philosophical. His lack of philosophical genius carried him to the extreme of founding a new methodology of investi- gation. Descartes paved the way for a whole series of modern errors; and Bacon caused the disappearance of methodology in those who became his followers. But the innovation of Harvey lay in the diligence of his investigation of the Aristotelian prem- ises and the profundity of his penetration of Aristotle's method. From this novelty — fidelity to the tradition — has come his permanent contribution to modern science. It made him both an authentic representative of the past and an authentic repre- sentative for the future, and establishes him as a model for an age that slights sense, as well as for an age that slights reason. Herbert Albert Ratner, M. D. Loyola University Chicago, Illinois diastole; and that the cause of the distention, relaxation, and constriction, is not one and the same; as contrary effects so they must have contrary causes; as different movements they must have different motors; just as all anatomists know that flexion and extension of an extremity are accomplished by opposite antagonistic muscles, and contrary or diverse motions are necessarily performed by contrary and diverse organs instituted by nature for the purpose " (Harvey, Second Exercise to John Riolan, ed. cit., pp. 139-140) . Part Two HISTORY OF SCIENCE MEDICINE AND PHILOSOPHY IN THE ELEV- ENTH AND TWELFTH CENTURIES: THE PROBLEM OF ELEMENTS THE cultivation of the liberal arts and the sciences during the twelfth century developed new methods and inves- tigated new subject-matters. What was achieved in theory and interpretation is obscured by the further trans- formation of problems and enlargement of data during the succeeding period, the hundred years between the middle of the twelfth and the middle of the thirteenth centuries, when the scientific and philosophical works of Aristotle and a vast body of accompanying commentary, elaboration, and specu- lation were translated for the first time. The problem of uni- versals and the problem of elements are two highly ambiguous signs of the intellectual activity of a period of distinguished cultural and scientific renaissance. The grammarian, rhetorician, and dialectician of the early twelfth century studied texts that had long been available more constructively and imaginatively — Latin grammars and rhetorics, translations of Aristotle's Categories and On Inter- pretation, Porphyry's Introduction, and Boethius' logical trea- tises and commentaries — and the twelfth century Book of Six Principles attributed to Gilbert de la Porree was assimilated with Porphyry's Introduction to the canon of Aristotle's Or- ganon. Even the problem of universals was familiar in the widely known three questions of Porphyry, After the trans- lation of the last four books of Aristotle's Org anon the work of twelfth century logicians like Abailard had little pertinence to the continuing problems; and, in general, the liberal arts of the trivium were turned from interpretative applications and constructive theories to demonstrative and speculative systematizations. 75 70 RICHARD MCKEON The encyclopaedist and the cosmologist of the twelfth cen- tury likewise worked on texts long available but neglected — Chalcidius' translation of Plato's Timaeus and his commentary on it, the works of the Platonists Apuleius and Macrobius or of Martianus Cappella who furnished bits of the theories of Hermes Trismegistus, and finally the eleventh century trans- lations of works on medicine or on the nature of man, like those of Constantine the African or Alfanus of Salerno in which the problem of elements is stated. Thierry of Chartres, Peter Abailard, William of Conches (one of whose works is sometimes called On the Ele77ients of Philosophy) , and their critic William of St. Thierry as well as many other philosophers of the early twelfth century used the elements as beginning points and ordering principles in their expositions of composites as man, the universe, and the sciences; and elements were continued in that function in the encyclopaedias of the later twelfth and early thirteenth centuries, such as Alexander Neck- ham's On the Natures of Things, Thomas of Cantimpre's On the Nature of Things, and Bartholomew of Glanville's On the Properties of Things. After the translation of Aristotle's scien- tific work and of commentaries which put varying interpre- tations on his conception of things, neither the data nor the theories of these organizations of knowledge were useful in the continuing investigations; and, in general, encyclopaedic organi- zations of the sciences were turned from the classification of the nature and properties of things to the ordering of motions and functions according to principles. The problem of elements is the counterpart of the problem of universals. (1) Science is of the universal; (2) it is derived from and applied to particulars; (3) examination of universal predicates is therefore involved in questions of existence and being, of experience and reason. Conversely, (1) wholes or complexes are composed of parts and ultimately parts are Composed of simple parts; (2) the nature of parts depends on how the whole is conceived; (3) determination of simples is therefore involved in a complex of related questions concerning MEDICINE AND PHILOSOPHY IITH AND 12TH CENTURIES 77 the indivisibility of the element, such as, whether the compound is divided actually or intellectually; whether the elements so produced are corporeal or incorporeal; whether they are indi- viduals or classes; and whether they are infinite or finite; whether they are characterized only by properties like size, shape, weight, and motion or also by other qualities. Questions about universals arise from the opposition of different con- ceptions of logical and scientific method. Questions about elements arise in the opposition of different interpretations of data. The problem of universals and the problem of elements are important in periods like the twelfth and the fourteenth centuries and they are subject to similar resolutions, but the differences of disciplines and of information in two such periods change the implications of the problems and the considerations relevant to their treatment. The history of the treatment of elements in the Middle Ages reflects the indirect influence of earlier theories of elements and repeats in ironic fashion the customary history of Greek phi- losophy. Aristotle taught us that the Ionian and Italian philoso- phers used the " elements " as principles in their philosophies in " lisping anticipations " of his own use of " causes " as prin- ciples. We fill in or modify this version of the development of thought by giving the elements interpretations suggested by the ways in which they are used in cosmological or medical accounts of the origin of the universe or the development and functions of organisms. Thales' conception of water as a prin- ciple is given meaning in application to the structure and origin of the universe, and Hippocrates' theory that all natural objects are characterized by four qualities — hot, cold, dry, and moist — has its obvious applications in physiology and therapy. The theories of elements propounded in the medical works of the eleventh century and the cosmologies of the twelfth century likewise provide the principles of the relevant sciences and prepare for the more diversified treatment, in the thirteenth century, of principles and sciences devised from the interpre- tation of Aristotle's works. 78 RICHARD MCKEON Aristotle's version of intellectual history depends on his dis- tinction of principles, causes, and elements, yet his meaning of " elements " is seldom used even when his history is repeated. A principle is a " beginning "; all causes and all elements are principles, but not all principles are causes or elements, and not all causes are elements. Elements are one variety of one of the four causes, the material cause. Aristotle defines element as the first component part of a thing, indivisible in kind into other kinds. The Aristotelian conceptions of " matter " and of " kind " have prevented the wide acceptance of this definition, for incorporeal as well as corporeal things have matter and a thing indivisible " in kind " may be divisible in many ways. Aristotle gives three examples to clarify his definition; elements of speech, of bodies, and of geometrical or logical proof. The Greek word stoicheion means both " element " and " letter." The elements of speech or letters are the parts into which speech is ultimately divided and which cannot be divided into forms of speech different in kind from them: a syllable can be divided into parts different in kind, but if letters can be divided their parts are likewise letters. The elements of bodies are simple parts like water, whose parts in turn are water. The elements of geometrical and logical proof are the primary demonstrations and the primary syllogisms, which are each implied in many demonstrations and which have no parts different in kind from them. The elements of demonstrations are demonstrations, not propositions or terms. Some people use " element " in the broader transferred sense of the small and simple and indivisible; the most universal things and genera are then thought to be elements, and unity and the point to be first principles.^ The first philosophers sought the principles of things among the material causes, including the four elements; - Leucippus and Democritus said the full and the empty, the atoms and the void, are elements; ^ the physicists ^ Metaphysics, V, 3, 1014a26-bl5. * IhH., I. 3, 983b6-984b8. * Ihid., 985b3-19. MEDICINE AND PHILOSOPHY 1 ITH AND 12TH CENTURIES 79 posited elements of bodies^ and neglected elements of incorporeal things, while the Pythagoreans treated the principles and ele- ments even more strangely, for they derived their principles from non-sensible mathematical objects and applied them to perceptible bodies.* Physical elements have an important place in Aristotle's organization of the physical sciences. The principles and causes of motion are treated in his Physics; elements become important in discriminating the kinds of bodies according to their motions in his De Caelo; elements are not fixed and changeless, and the effects of changes or transmutations of the elements are treated in his On Generation and Corruption; the remaining problems of phenomena caused by the operation of elements above the earth's surface and by the formation of mixtures, compounds, and functionally organized wholes are considered in his Meteor- ology.^ The division of bodies in the De Caelo is into simples (haplon) , which have simple motions, and compounds {sun- theton) of those simples, which have composite motions. The circular motion of the first body, aither, and of the heavenly bodies, is treated in the first two books of the De Caelo; ® the straight line motions of the simple bodies, fire and earth, which are respectively light and heavy, and of the bodies compounded of them, are investigated in the last two books. ^ The definition of a bodily element is that into which other bodies can be analyzed but which cannot itself be analyzed into parts differing in kind.^ The On Generation and Corruption is concerned with substantial change rather than with local motion, and the transformation of the four elements or simple bodies, fire, air, water and earth, is explained by combinations of the primary qualities, hot, cold, dry and moist, rather than by the qualities light and heavy. * Ibid., I, 8, 988b23-990al8. ^ Aristotle reviews this course of inquiry at the beginniiifj of the Meteorologica, I, 1, 338a20-339a9. « De Caelo, I, 2, 268b26-269bl7. ''Ibid., m, 1, 298a24-bl2. » Ibid., in, 3, 302al5-19. 80 RICHARD MCKEON The Meteorology finally turns to phenomena less regular than the motions of the primary body, aither, below the region of the motion of the stars. These include, in addition to meteor- ological phenomena in the strict sense, the composition of elements into homogeneous bodies and of homogeneous bodies into structured or organic bodies. Two of the primary qualities, hot and cold, are active, and two, dry and moist, are passive. The combinations of elements may be mechanical mixtures (sunthesis) or chemical compounds (mixis) . The latter are " homoeomerous " bodies, inorganic (gold, silver, stone) , vege- table (bark, wood) , or animal (bone, flesh, sinew) , Homoeo- merous bodies are distinguished by qualities which act on the senses (white, fragrant, resonant, sweet, hot or cold) and more intrinsic qualities which, like moist and dry, are passive, such as solubility, solidifiability, flexibility, frangibility, plasticity, duc- tility, malleability, combustibility, compressibility.^ Homoeo- merous bodies are composed of elements, and are in turn the material for more complex " non-homoeomerous " bodies. Aris- totle's examples of inorganic structured complex bodies are artificial objects, like flutes and saws, which have specific functions, while his examples of organic complex bodies are leaf and root, hands, feet, and eyes." The bodies composed, in turn, of non-homoeomerous bodies are men and plants and the like. In the course of discussing homoeomerous bodies Aristotle makes use of the distinction between masses or cor- puscles (onkos) and pores (poros) , which is used later in the history of elements and is thought to derive from Democritus' distinctions between atoms and void; it is to be observed, however, that these particles would have the status of molecules relative to simpler atoms or elements. Philosophers continued to form theories concerning elements after Aristotle, and Aristotle's history of elements as the prin- ciples of the early philosophers was usually combined with a Stoic or Neoplatonic conception of elements. These were the » Meteorologica, IV, 8, 384b24-385al8. " Ibid., IV, 10, 388al0-29; 12, 389b23-390b22. MEDICINE AND PHILOSOPHY IITH AND 12TH CENTURIES 81 versions in which the history influenced early Christian thought. The Stoics held that the universe, like other wholes, had two principles, an active and a passive principle, or an efficient and a material principle, and that the universe is ordered by reason and providence/^ Plato distinguished and related the operation of reason and of necessity in the formation of the universe by placing reason in the composition of the world soul and neces- sity in the operation of elements. The pattern of later dis- cussions of elements as the material parts of a universe brought into existence by the efficient or rational causality of God is established in pagan and Christian accounts of the history of philosophy during the early centuries of the Christian era. Almost the same doctrines are given in three related accounts — one by Sextus Empiricus, a physician and skeptical philosopher, the other two ascribed respectively to the physician Galen and to the Christian Clement the Roman — and they are adaptable to the Mosaic account of creation.^" The Recognitions of the pseudo-Clement were translated into Latin, with modifications, by Rufinus and are well-known in various versions during the early Middle Ages; the Historia Philosopha of the pseudo-Galen is in accord with the treatment of elements in Galen's medical works which were translated in the eleventh century. Sextus and the pseudo-Galen follow the Stoic division of philosophy into three parts, logic, physics, and ethics; and they organize their treatment of physics by distinguishing an efficient and a material principle .^^ The pseudo-Clement distinguishes simples from composites and argues that corporeal wholes cannot be accounted for by the elements of which they are composed without recourse to a simple cause, rational and providential, of the invisible universe which contains the visible " Diogenes Laertius, VII, 134 and 138-139. ^^ Herman Diels (Doxographi Graeci, Berlin, 1889, pp. 251-2) argues that the three are so closely related that they must have been derived from a common Stoic source composed between the times of Seneca and the Antonines. ^' Sextus Empiricus, Pyrrhoneiai Hypotyposeis, III, 1, Adversus Mathematicos, IX, 4; Galen, Historia Philosopha, 16 (Diels, pp. 608-9) . 82 RICHARD MCKEON universe/* Sextus undertakes to show that dogmatic views of God and of elements are alike untenable; the pseudo-Galen enumerates the various philosophic views of elements and of God; the pseudo-Clement refutes Epicurus with the aid of Plato and sketches the various doctrines of elements before treating the problems of their use in explaining the phenomena of the universe. The enumerations of theories of elements in the three accounts have striking points of similarity/" Similar problems are treated — whether the " material " elements are " corporeal " or " incorporeal," perceptible by sense or by reason, or imperceptible, free of qualities or characterized by qualities, finite or infinite. The character of the elements reflects the mode of composition used as a model and is sometimes indi- cated by use of other terms instead of " element," such as " atom," " seed," " root," " minimum," or " molecule." The place of elements in the discussion of problems of parts and wholes is apparent in each of these accounts. The author of The Recognitions, thus, presents himself as one who had frequented the schools of the philosophers before he became a Christian, and in the dialogue in which elements are discussed, the chief speaker, Niceta, acknowledges that he attended the Epicurean schools, while one of his brothers studied with the Pyrrhonians and the other with the Platonists and Aristotelians. He begins his treatment of the origin of the universe by differ- entiating all things {omne quod est) into the simple and the composite. The simple " lacks number, division, color, differ- ence, roughness, smoothness, heaviness, lightness, quality, quantity, and, therefore, even limitation." The composite is made up of two, three, four, or more components. The simple is incomprehensible and immense, without beginning and end, ^^ Recognitiones, VIII, 9-12, Patrologia Graeca 1, 1375A-6C. ^^ Sextus Empiricus, Pyrrhoneiai Hypotyposeis, 111,30-32, Adversus Mathematicos, IX, 359-64; Galen, Historia Philosopha, 18, pp. 610-11; Clement, Recognitiones, VIII, 15, 1378. Sextus goes on to other problems of physical philosophy in Adversus MathcTnaticos, Book X — problems of place, motion, time, number, generation and corruption — which also involve elements, and a similar enumeration of theories is made in connection with generation and destruction, ibid., IX, 310-18. MEDICINE AND PHILOSOPHY IITH AND 12TH CENTURIES 83 without cause, but himself father and creator. Man is able, however, to come to awareness of intellectual and invisible things from things seen and touched, as is apparent in arithmetic. The problem of the origin of the world raises two questions: whether it was made or ungenerated; and, if it was made, whether it was made of itself or by another. Only the last position would provide a place for providence. Niceta argues that the world was made by God, and the argument turns therefore to the characteristics of the visible world. Bodies have two differentiae: either they are connected and solid or divided and separate. If the world was made from a solid body, it would have to be divided into parts; if it was made from diverse parts, they would have to be brought into relation and composition. He argues that the universe could not have been made from a single body or matter, and that a creator is necessary to compound it from two or more bodies. The Greek philosophers formed different theories of the principles of the universe. Pythagoras said the " elements of principles " are numbers; Strato qualities; Alcmaeon contrarieties; Anaxi- mander immensity; Anaxagoras equalities of parts; Epicurus atoms; Diodorus the incomposite (amere) ; Asclepiades masses (onkos) which can be called tumors or swellings; the geometers limits; Democritus ideas; Thales water; Heraclitus fire; Diogenes air; Parmenides earth; Zeno, Empedocles, and Plato, fire, water, air, earth; Aristotle introduced a fifth element, called aka- tonomaston or the incompellable, no doubt to indicate him who made the universe one by conjoining the elements. The " machine of the universe " could not have been set up without a maker and director.^® Niceta then refutes the position of ^^ Recognitiones, VIII, 15, PG 1, 1378A-9A. The enumerations of Sextus and Galen are somewhat longer and follow a different order from the pseudo-Clement's account, proceeding through the single elements, two, three, four, five, and finally other varieties of elements. The list in Sextus' Pyrrhoneiai Hypotyposeis, III, 30-32 runs: Pherecydes earth; Thales water; Anaximander the infinite; Anaximenes and Diogenes of Apollonia air; Hippasus of Metapontum fire; Xenophanes earth and water; Oenopides of Chios fire and air; Hippo of Rhegium fire and water; Onama- 84 RICHARD MCKEON Epicurus, reports the arguments of Plato, and finds support in the phenomena of the world — the courses of the stars, meteorological occurrences, vegetable, animal, and human struc- tures and functions. critus fire, water, and earth; the school of Empedocles and the Stoics fire, air, water, and earth; the school of Aristotle fire, air, water, earth, and the revolving {kyklo- phoretikon) body; Democritus and Epicurus atoms; Anaxagoras homeomeries; Diodorus Cronos minima (elachista) and incomposite (amere) bodies; Heracleides Ponticus and Asclepiades the Bithynian irregular masses or molecules (anarmoi onkoi) ; the school of Pythagoras numbers; Strato qualities. Some of the compexities of the problem of elements become apparent in the interpretation of these lists. Thus, Sextus elaborates the Pythagorean doctrine that numbers are the principles and elements of all things by observing that the Pythagoreans held that the method of philosophizing was the same as the m.ethod of linguistic analysis. Language is composed of words, words of syllables, syllables of letters or elements (stoicheia) ; in the same fashion the true physicist investigates the universe by seeking the elements (stoicheia) into which it can be resolved. The advocates of numbers (arithmos) as principles (stoicheion) of all things agree with the advocates of atoms (atomos) , homoeomeries (homoiomereia) , molecules (onkos) , minima (elachiston) , and incomposites {amere) , recognizing that principles must be non-phenomenal, non-sensible, intelligible bodies. YAdversus Mathematicos, X, 248-57; cf. Pyrr. Hyp., Ill, 151-55, where numbers in turn are generated from the monad (monas) and the indeterminate dyad (aoristos duas)]. In the same fashion, Galen emphasizes, in his medical writings, the affinity of the atoms of Democritus and Epicurus and the molecular masses (onkos) of Heracleides and Asclepiades, even to the extent of reducing the differences in the case of Asclepiades to a difference of terms, the sub- stitution of onkos for atomos and of poros for kenon. (De Theriaca ad Pisonem, cap. 11, Claudii Galeni Opera Omnia, ed. C. G. Kiihn [Leipzig, 1827], vol. XIV, p. 250.) Yet the molecules of Heracleides and Asclepiades were frangible or divisible, and possessed qualities, and the terms " molecules " and " pore " have an Aristotelian derivation which is clearer than their Democritean analogy, for they are terms used in the discussion of homogeneous bodies in the Meteorology. Or again, Strato of Lampsacus, the successor of Theophrastus as head of the Lyceum, is said to have shown tendencies to atomism, yet he is also said to have treated elements as " qualities "; this seems to be another case of the assimilation of a philosophy of of elements to a philosophy of atoms, for it is clear that in his opposition to Platonism, Strato based his analysis on " ultimate components " which he treated quantitatively and qualitatively. Doctrines of elements tended to be likened to atomism if the operations ascribed to the elements are naturalistic and mechanical; elements may be incorporeal and qualitative and still be presented as atomic; if they undergo qualitative changes and transmutations, exhibit purposive or teleologicaJ orderings, or show effects attributable to God or the world-soul, they are not atomic. It is relevant to this transformation of the characterization of elements that Galen claimed to have added a fifth instrumental cause (di'hou) to the formal, final, efficient and material causes of Aristotle. MEDICINE AND PHILOSOPHY IITH AND 12TH CENTURIES 85 The treatise On the Nature of Man by Nemesius, Bishop of Emesa, probably written toward the end of the fourth century A. D., was strongly influenced by the medical theories of Galen. Nemesius presents man as a conjunction of natures or functions, ranging from the inanimate and the irrational to the rational, combining the visible and the invisible, and giving evidence both of the elements of which he is composed and of the con- junctive union in man and in the universe, in both the lesser and the greater world, from which the Creator can be inferred. Man shares properties with inanimate things, life with animate beings, and knowledge with rational beings. He shares with inanimate things body and the conjunction of the four elements; he shares with plants the nutritive and generative powers; with irrational animals he shares, in addition to these powers, volun- tary motion, appetite and anger, and the sensitive and respira- tory powers; with intellectual natures he shares rationality, applying reason, understanding, and judgment, and following virtues. He is midway between intellectual and sensible essences, conjoined by body and corporeal powers with other animals and with inanimate things and by reason with incor- poreal substances. The Creator conjoined step by step the diverse natures in order to make the universe one and of one kind, and this is the best proof that there is one creator of all existences.^' God adapted and conjoined all things to all things harmoniously, and united into one, through the creation of man, invisible and visible things.^^ Nemesius finds the Mosaic account of creation bears out this analysis, and he organizes his treatment of the nature of man in accordance with it, presenting in turn the soul, the union of soul and body, and the faculties of man, ranging from imagination and sense through intellect, memory, thought, expression, passion, nutrition, pulse, respiration, voluntary action, free-will, and providence. The body is presented as a conjunction of elements in humors, ^^ Nemesii, Premnon Physicon a N. Alfano Achiepiscopo Salerni in Latinum trans- latus, I, 8-11, ed. C. Burkhard (Leipzig, 1917), pp. 6-7. '' Ibid., I, 23, pp. 9-10. 86 RICHARD MCKEON homogeneous parts, and members.^^ Nemesius defines the cor- poreal element {elementum rriundanuin) as the least part in the composition of bodies. The mundane elements are four: earth, water, air and fire. " They are the first and simple bodies relative to other bodies. For every element is of the same kind as the bodies of which it is an element. A principle is not of the same kind as the things of which it is a principle, but an element is wholly of one kind." -" He analyzes the four elements by means of the four qualities hot and cold, wet and dry, but he argues that these qualities are not elements because bodies cannot be constituted of incorporeal things, and he treats the problem of the order of elements in the organization of the universe by interposition of elements to mediate between con- trary qualities. He also expounds the Platonic analysis of elements, distinguishing two ways in which he classifies ele- ments: (1) by the regular solids, (2) by assigning three qualities to each element — fire having sharpness, rarity, motion, and earth, at the other extreme, having dullness, density, rest. To these he added a third way used by some philosophers, who distinguish the heavy elements, earth and water, from the light elements, air and fire."^ The elements and the body enter into the analysis of the functions of the soul, and Nemesius expounds the Galenic theory of the localization of functions: imagination in the anterior lobe of the brain," understanding in the intermediate lobe,"" and memory in the posterior lobe,"* adding that evidence for the localization of these functions was derived from observation of brain lesions and diseases affecting the brain." Nemesius' On the Nature of Man was translated into Latin in the eleventh century by Archbishop Nicholaus Alfanus under the title Premnon Physicon or Key to Natural Things but with- out mention of the name of the author or of the title he gave "/6i(Z., IV, pp. 59-61. '" Ibid., V, 1-2, p. 62. '" Ihid., XII, 3, p. 87. " Ihid., V, 24-25, pp. 67-69. ^* Ibid., XIU, 7, p. 89. " Ibid., VI, 4, p. 73. ^^ Ibid., 8-13, pp. 89-90. MEDICINE AND PHILOSOPHY IITH AND 12TH CENTURIES 87 his work. It was translated again in the twelfth century by Richard Burgundio of Pisa, who was under the impression that it was written by Gregory of Nyssa. Alfanus's version was used by Albertus Magnus, and Burgundio's is quoted by Peter Lombard and Thomas Aquinas. Some remnants of these distinctions are transmitted to the Middle Ages by Isidore of Seville. Cassiodorus (490-583) had recommended the reading of Latin translations of Hippocrates and Galen,"*' but manuscripts of these early translations have not been found. He does not treat elements in his Institutiones, but a section on the four elements is added in a later inter- polation.^^ It deals with the order of elements familiar in meteorology from the heavenly bodies to earth, and explains the sequence of fire, air, water, and earth, by combinations of the properties incorporeal, corporeal, immobile, mobile, sharp, blunt (fire is sharp, incorporeal, mobile, as well as hot and dry; earth is blunt, corporeal, immobile, as well as cold and dry) which are caused by the influence of proximate elements. The elements are also equated with regular solids and numbers: fire with the pyramid and 12; air with the sphere and 24; water with the icosahedron and 48; earth with the cube and 96. In a diagram, the four elements, the upper three and the lower three are connected by three sets of lines drawn in groups of four to points numbered 576 (12 X 48) , 1152 (24 X 48) , and 2304 (48 X 48) . The text says that the lines indicate ways in which the elements by their obvious contacts with each other both prepare substances of different species from them- selves and are combined because of the diversities in themselves. This is the bond binding the union of the world, the relation assembling the elements. The interpretation may be based on "'Cassiodorus, Institutiones Divinarum et Humanarum Lectionum, I, 31, PL 70, 1146. He also recommends the reading of Caelius Aurelianus' On Medicine which treats the problems of elements. " Cassiodori Senatoris Institutiones, ed. R. A. B. Mynors (Oxford, 1937), pp. 167-8. 88 RICHARD MCKEON Plato or Macrobius or on St. Ambrose's statement that the Greek word stoicheia means joining with each other.^® Isidore of Seville (560-636) takes up the elements in his encyclopaedic Etymologies, briefly in his treatment of medicine, and more fully as ordering principles in his treatment of the universe. In medicine the four humors are explained by the four elements; blood refers to air, choler to fire, melancholy to earth, and phlegm to water."^ Man is composed of soul and body; and his living flesh is compacted of the four elements .*° The treatment of meteorology and geography opens with suc- cessive chapters on the world, on atoms, on elements, on heaven, and on the parts of heaven. Atoms are defined as " certain parts of the bodies in the world so extremely minute that they can neither be seen nor undergo tonne, that is, cutting, for which reason they are called atoms." ^^ Isidore adds that there are atoms in body, in time, in number, or in language. The list recalls Aristotle's list of kinds of elements, but Isidore's criterion for atoms is indivisibility: the atom of body is the indivisible particle, of time the point or indivisible moment of time, of number the unit, of language the letter. The chapter on elements begins with a definition of the Greek word hyle as a kind of first matter in no way formed but capable of all bodily forms. The Greek word for elements, stoicheia, means those things which agree with each other in a kind of concord of society and communion, since they are said to be joined to each other in a kind of natural proportion, and therefore the sequence from fire, through air and water, to earth, and the sequence back, are causal. All elements are present in all things, but a thing is named from the preponderant element. Animate beings are distributed among the elements by divine provi- "* Ambrose, Hexaemeron, III, 4. PL 14, 176: "... atque ita sibi per hunc cir- cuitum et chorum quendam concordiae societatisque conveniunt. Unde et Graece stoicheia dicuntur, quae Latine elementuvi dicimus, quod sibi conveniant et concinnant." -* Isidore of Seville, Etymologiae, IV, 5.3; PL 82, 184C. '"' Etymologiae, XI, 1; PL 82, 398-9. " Ibid., XIII, 2, 472D-3B. MEDICINE AND PHILOSOPHY IITH AND 12TH CENTURIES 89 dence: heaven filled with angels, air with birds, water with fish, and land with men and animals. Chapter 5 begins the treat- ment of the heavens with the element aether or fire; Chapter 7 proceeds to meteorology by way of air; Chapter 12 begins the treatment of waters with the element water; and Book XIV, which is devoted to the earth and its parts, has an opening chapter on the element earth. The Venerable Bede (672-735) follows a similar order in his On the Nature of Things. A fourfold distinction concerning the divine creation is made in the first chapter; one phase of creation is that the elements of the world were made together in unformed matter. In the formation of the world it is specified, in the second chapter, that heaven, earth, angels, air, and water were made from nothing in the beginning, and the elements are used to differentiate the six days of creation. Elements enter into the definition of the world in the third chapter. The fourth chapter is on the elements and their influence on each other and the mixtures they form are stated in terms of the qualities heavy and light, hot and cold, moist and dry.^" Astronomical questions are introduced by considera- tion of the element fire in Chapter 5; the transition to meteor- ological questions is made in Chapter 25, on air; waters are treated after Chapter 38 on the differentiation of salt and fresh waters; geographic questions are introduced by Chapter 45, on earth. Bede makes use of the idea of atoms in his treatment of time. In Chapter 3 of the De Temporum Ratione, on " the most minute spaces of times," he calls the minimum indivisible part of time atoms. Days are divided into 12 hours, and hours into 12 points, 10 minutes, 15 parts, 40 moments — points and minutes being measured on clocks, parts on the circle of the Zodiac, moments by the swiftest motion of the stars. The least of all divisions of time which can in no way be divided further is called the atoTn in Greek, that is, the indivisible. Because of its smallness it is preceptible by grammarians rather than *^ Venerable Bede, De Natura Rerum, I-IV, PL 90, 187-96. 90 RICHARD MCKEON calculators, for grammarians divide verses into words, words into syllables, syllables into feet, and feet into long and short, and since it is impossible to divide further, the short foot is the atom. Bede rejects the divisions of time proposed by the astrologer, and concludes his treatment of atoms by quoting Paul on the speed of resurrection: " We shall not all sleep, but we shall all be changed, in a moment, in the twinkling of an eye, at the last trumpet." ^^ Bede's text, however, reads " atom " instead of " moment," and he therefore defines the atom of time by the flash of an eye which cannot be divided or cut, and which is sometimes called " moment," sometimes " point," and sometimes " atom." ^* Bede's interpretation of Paul could have been derived from Augustine, and one of the continuing sources of information concerning the meaning of atom during the Middle Ages was interpretations of the New Testament. ^^ The elements of the world, the seasons of the year, and the humors of man are distinguished by the same qualities and for this reason man is a microcosm or lesser world. Air, spring, and blood which grows in spring, are damp and warm; fire, summer, and red choler, which develops in summer, are hot and dry; earth, winter, and black choler are dry and cold; water, autumn and phlegm are cold and damp. Moreover the succes- sive ages of man and the different temperaments of men are determined by the predominance of one or another of the humors.^® Rhabanus Maurus (748-856) treats the world in Book IX of his De Universo in the manner of Isidore of Seville, even to the ^^ I Corinthians, 15: 51-52. " De Temporum Ratione, iii. PL 90, 302-7A. 35 I St. Augustine, Sermo, CCCLXII, 16, 19-18, 20. PL. 29, 1623-25. Augustine explains the atom in time by the atom in body. He remarks that many do not know what an atom is, and then defines atom from tom,e or cutting, so that atomos means what cannot be cut. He uses the division of a stone into indivisible parts to clarify the division of a year into like parts. Moreover, he argues that the ictus oculi by which Paul explains atomus, does not mean the opening or shutting of the eye, but the emission of rays from the eye to what is to be seen, including distant objects, such as heavenly bodies. *^ De Temporum Ratione, XXXV, 457C-9A. MEDICINE AND PHILOSOPHY IITH AND 1-TH CENTURIES 91 extent of repeating in the first two chapters Isidore's treatment of atoms and of elements.^' He follows Bede in his treatment of time, but his edition of the Epistle to the Corinthians has " momentum " instead of " atomum." He therefore adapts Bede's definition of " moment," and treats the moment as the minimum and smallest time measured by the motion of the stars. But he also remarks that another edition of the text of Paul has in atomo et in ictu oculi, gives the etymology of atomos, and explains that atoms of time are perceptible to grammarians rather than to calculators.^^ The marks and remnants of older distinctions concerning elements are plentiful, but the medical writings which were translated during the eleventh century used elements more systematically to explain the phenomena of nature and pro- vided greater precision of statement and more diversified data of application in the use of elements as principles. Constantine the African (c. 1015-1087) translated from the Arabic, or adapted, several books attributed to Galen, in which elements are treated in detail, as well as Isaac Israeli's Book of Elements, but the analysis of elements in the Pantegni, an adaptation of a portion of the Royal Book of Medicine of Haly Abbas, which is the tradition of Galen concerning elements, had a clearly marked influence.^" The Pantegni begins, in medieval fashion, by reciting the six things which should be known about a book: the intention of the book, its utility, its title, what part of learning it deals with, the name of its author, the division of the book. The author's name is given as Constantine the African, who brought the materials together from writings of many authors. It was Constantine's ambition to write a book covering the whole of theoretical and practical medicine, which "Rhabanus Maurus, De Universo, IX, 1 and 2, PL 111, 262A-3A. " Ibid., X, 2, 286A-B. " Constantini Africani, Opera, Basel, 1536 and 1539. Several of Constantine's translations are published among the works of Isaac Israeli, Opera Omnia Ysaac, Lyons, 1515. Thus, only the portion of the Pantegni devoted to theory is published in the 1539 volume of Constantine's works; both parts. Theory and Practice, are in the edition of Isaac. ()2 lUCIIARD MCKEON would make unnecessary the reading of any other book for preparation or supplementation. Medicine, he argues, is more necessary and of greater dignity than all the other arts, since without health of body rationality is impossible, and \vithout rationality science is impossible. But to understand this art, dialectic and the arts of the quadrivium must first have been mastered. Moreover, medicine covers the whole scope of science, for science is divided into logic, ethics, and physics, and medicine deals with all three of these parts, but falls entirely under none. The Pantegni is divided into two parts, Theory and Practice, and each in turn is divided into ten parts. Theory is per- fect knowledge of things to be seized by intellect alone and stored in memory for the control of those things; practice is the manifestation of theory in things of sense and in manual operations in accordance with understanding of the preexisting theory. Theory is divided into three parts — the sciences of natural things, of non-natural things, and of things outside nature. Practice is the science of caring for the healthy and curing the sick with diet, potion, and surgery. Natural things are those necessary to the subsistence of bodies and pertaining to their contruction or destruction. Natural things have seven kinds of parts, three of which are common to sensible and insensible things, that is, elements, complexions, and actions, and four of which are proper to sensible things alone, that is, humors, members, virtues, and spirits. There are six non- natural causes — the air about the human body, motion and rest, food and drink, sleep and waking, inanition and continence, and the accidents of the soul. There are three things outside nature — disease, the causes and signs of disease, and the accidents of disease. The theoretic portion of the treatise proceeds syste- matically from elements to complexions of elements to members and virtues of members; then non-natural things and things beyond nature are treated. The element, as philosophers define it, is a simple and mini- mum particle of composite bodies. The elements include fire, MEDICINE AND PHILOSOPHY IITH AND 12TH CENTURIES 93 air, water, earth, but not rocks and metals which, though simple to sight are composite to understanding. The elements are themselves indestructible, and the destruction of all other things consists in their return to the elements of which they were composed. Constantine scouts the idea of a single element, whether atoms or any one of the ordinary four elements, with arguments, ascribed sometimes to Hippocrates, designed to show that it is impossible for a single thing to generate things diverse from itself without commixture with other things. The four elements are the hot, the cold, the dry, and the moist — not the qualities simply, rather heat actually perfect is fire; actual and perfect cold is water; naturally perfect moistness is air; and the perfectly dry is earth. Each element acquires a second quality from the element contiguous to it: from the motion of the circle of the moon which is next to it, fire acquires dryness; air acquires heat from its contiguity to fire; water has dampness from the propinquity of air, and earth coldness from water. The qualities light and heavy are likewise divided among the elements, fire being most light, earth most gross and heavy, air and water falling between the two. The compounds of elements from which bodies are formed are called complexions. They may be of varying degrees, and the quality and function of the whole is determined by the preponderant element. Sensation is explained by the temper- ateness of the complexion of the organs. Thus, nothing would be perceived by touch if the organ were not changed into the quality perceived; if the organ of touch were not temperate it would not distinguish between hot and cold, soft and hard, smooth and rough. Man is the most temperate of all animals. Unlike the brute which is possessed of a single function, he can do all things, and he is rational and intellectual because he can understand and distinguish by reason whatever he does. The complexions are instruments of nature or of the soul or of both. Each animal has instruments of the body in agreement with the virtues of the soul, for the government of all bodies is either by the soul and nature or by nature alone, that is, nature rules 04, RICHARD MCKEON in both animate and inanimate bodies, the soul only in animate bodies. Certain virtues must be present if the body is to com- plete its operations. Constantine lists three general virtues: one pertains only to nature and is therefore called natural; a second, pertaining to the soul, only vivifies and is called spiritual; a third, also per- taining to the soul, gives understanding, sense, and voluntary motion, and is called animate. The action of natural virtue, which consists in generation, nutrition, and growth, is universal in animals and plants. Spiritual virtue is common to rational and irrational animals, but not to plants; it consists in the vivification which is accomplished by the action of the heart and the dilation and contraction of the arteries for the con- servation of natural bodily heat. The animate virtue is partly common to rational and irrational animals, for both participate in sense and voluntary motion, and partly not, for only rational animals have fantasy, reason, and memory. This analysis per- mits the reduction of all actions to kinds of motion, and Constantine elaborates the enumeration of six kinds of motion, two simple and four complex, all depending ultimately on the simple contraries. The details of medical theory and practice, for which this analytic structure was prepared, are organized relative to the means of recognizing and controlling the mixtures of these qualities, Constantine is credited with a translation of The Book of Degrees (Liber de Gradibus) ascribed to Isaac Israeli but of unknown origin, in which medicinal simples are con- sidered in terms of their varying degrees of hot and cold, dry and moist. Constantine reports four principal grades: a food or medicine is in the first degree of heat if it is below that of the human body; in the second degree if it is of the same tempera- ture; in the third degree if it is somewhat hotter; in the fourth if it is extremely hot. The consideration of the contraries is an analytical device for the unification of physiology, pathology, and therapy. The doctrines of the four elements and the four qualities, whose development can be traced from Hippocrates MEDICINE AND PHILOSOPHY IITH AND 12TH CENTURIES 95 through Aristotle to Galen, were at times used for discovery or systematization of knowledge and at times as repetitive formulae for easy analogies or empty classifications. Their use in the twelfth century was as principles employed over a broadening scope in intellectual curiosity and on a diversifying body of empirical and rational data. The framework within which the analysis of elements was fitted in the twelfth century was a Platonic conception of the universe derived from Plato's Timaeus and Latin Platonists, like Apuleius and Macrobius, with echoes of Hermes Tris- megistus and the pseudo-Dionysius the Areopagite, a human- istic study of the liberal arts in which rhetoric and dialectic colored an Aristotelian scheme of categories, syllogisms, and topics, and a tradition of interpretation of the Mosaic account of creation which used Platonic conceptions and methods derived, by way of Augustine and Ambrose, from the Greek Hexaemerons and Philo. The medical conception of elements lent concreteness, specificity, and empirical detail to the con- sideration of the nature of things, but it also accentuated the tendency to use a variety of structures or organisms as models for the universe or to use the structure of the universe as a model for other lesser wholes, and therefore to analogize man and universe (microcosm and macrocosm) , human soul and world-soul, deliberate action and physical motion, in the treat- ment of cosmology, psychology, physiology, geography, and history. This merging of Platonism, the liberal arts, and the new sciences was one of the distinguishing marks of the school of Chartres in the twelfth century. William of Conches (c. 1080-1145) , whom John of Salisbury calls the most richly endowed grammarian (John's epithet opulentissimus has also been interpreted as a reference to the high fees of grammarians) , was a grammarian and wrote treatises of science and ethics. He was influenced by Thierry of Chartres and Peter Abailard in cosmology and theology, and he quotes Constantine the African about elements. William divides science into two species in his Gloss on Boethius' Con- 96 RICHARD MCKEON solation of Philosophy: eloquence and wisdom. Eloquence is the science of presenting what is known with the proper orna- ments of words and sentences; it is a species of science because all science consists of only these two parts, knowing things and presenting what is known well. Eloquence is not philosophy, nor any part of philosophy, but without philosophy, eloquence is a hindrance rather than an aid. William's division of phi- losophy is Aristotelian rather than Stoic: practical and theo- retical, each in turn divided into three parts, practical into ethics, economics, and politics, and theoretical into theology (the study of incorporeal things) , mathematics (the quad- rivium) , and physics (the study of the properties and qualities of bodies) . The proper order of learning is from the study of eloquence (from grammar through dialectic to rhetoric) to the study of practical problems to the study of theoretic problems, beginning with bodies in physics and proceeding through mathe- matics — arithmetic, music, geometry, astronomy — to the con- templation of incorporeal things and to the Creator in theology. The Philosophy of the World was written, according to William's Preface,*" because he saw so many men arrogating to themselves the name of Master, who have dissolved the union between eloquence and wisdom, who spend their time sharp- ening a sword they never use in battle, and who know nothing of philosophy, yet blush to confess themselves ignorant of anything and, seeking solace for their lack of learning, proclaim to less cautious men that the things they do not know are of little utility. The use of elements to organize bodies of knowledge and empirical data continues to employ two philosophical assump- tions: that the invisible things of the world are understood by the things that are made,*^ and that the existence of causes *° The De Philosophia Mundi or the Peri Didaxeon sive Elementorum Philosophiae Libri IV has been ascribed to several philosophers and has been published as the work of William of Hirschau, the friend of St. Anselm (Basel, 1531), of the Venerable Bede (PL 90, 1127-78) and Honorius of Autun (PL 172, 39-102). The reference is to Book I, Praefatio (in the Honorius of Autun edition) PL 172, 41-43. *^ The inference from visible to invisible, which is used by the pseudo-Clement MEDICINE AND PHILOSOPHY llTH AND 12TH CENTURIES 97 is proved from consideration of the characteristic of effects/^ WiUiam opens his treatise with the definition of philosophy as " the true comprehension of things which are and are not seen and of things which are and are seen," and specifies that the first are incorporeal things, and the second corporeal things, whether they are possessed of divine or perishable bodies.*^ He treats incorporeal things first — God, the soul of the world, demons, and the souls of men. Since God can be known in this life, William undertakes to prove his existence to the incredulous by arguments from the creation of the world and from its daily disposition. The first argument begins with the fact that the world is compounded from contrary elements, hot and cold, wet and dry. This composition of the world might have been effected by nature, or chance, or some artificer. Not by nature, since nature flees contraries and seeks similars. Not by chance, since simpler constructions, like houses, are not made by chance, and, moreover, chance is the unexpected occurrence of a thing from a confluence of causes, but nothing preceded the world except the Creator. But the artificer was not man, since the world was made before man; nor an angel, since the angels were made with the world; therefore the artificer was God. The second argument, from the daily dis- position of things proceeds similarly. Whatever is disposed is disposed in accordance with some wisdom, and in the case of the world it is not human or angelic but divine wisdom. From the daily disposition of things one attains to the divine wis- dom, and from the divine wisdom to the divine substance. and many of the Church Fathers, finds support in Paul (Rom. 1: 20, "For the invisible things of him from the creation of the world are clearly seen, being under- stood by the things that are made ") and elaboration in Platonic philosophies. *^ The dependence of phenomena perceived by sense or reason on a transcendent cause, equally well established in the Christian tradition, finds like support in Paul (Col. 1: 16, "For by him were all things created, that are in heaven, and that are in earth, visible and invisible ") and its elaboration may have an a ])riori Platonic turn, in which man and the world are image, likeness, or imprint and reasoning about them proceeds by models, or an a ■posteriori Aristotelian or Stoic turn in which phenomena are effects and reasoning about first causes proceeds from effects. " De Philosopkia Mundi, I, 1-3, PL 172, 43B-C. 98 RICHARD MCKEON Philosophers say that in this Divinity, which is maker and governor of all things, power, wisdom, and will are present, corresponding to the persons of the Trinity, power to the Father, wisdom to the Son, and will to the Holy Spirit. In this work William only touches on the world soul, enu- merating three opinions about it. Some think the world Soul is the Holy Spirit, for all things which live in the world live by the divine goodness and will which is the Holy Spirit. Some think that it is a natural vigor placed by God in the world by which some beings only live and others live and perceive and think; some, finally, think that it is a kind of incorporeal substance which is whole in each body although it does not perform the same functions or operations in all because of the comparative slowness of some bodies. In his Gloss on Boethius, however, William states his own doctrine, characteristically combining aspects of the three: the world soul is a natural vigor by which all things have their being, their motion, their growth, perception, life, reason; its effects differ in different subjects; and the natural vigor is the Holy Spirit. William's discussion of the third kind of incorporeals, demons, is based, as his critics were quick to point out, on Plato as well as on Scripture and the Fathers. William argues that even Plato's division of good demons (kalodaimones) into two genera is not inconsistent with the Scriptural division of angels into nine orders, since Plato divides them according to the places they occupy and the Bible according to the functions they perform. The treatment of the fourth kind of incorporeals, souls of men, is postponed to the consideration of man in Book IV. When William makes the transition from things which are and are not seen to things which are and are seen, he warns the reader that his manner of presentation must change since his exposition will use either statements that are probable and not necessary or statements that are necessary and not prob- able, " for as philosophers we posit the necessary even if it is not probable, and as physicists we add the probable even if MEDICINE AND PHILOSOPHY 11TH AND 12TH CENTURIES 99 it is not necessary." ** His claim for his treatment is that nothing more probable will be found in the works of " modern physicists." Since things which are and are seen are bodies, and since all bodies are composed of elements, his starting point is with elements as Constantine defines them. " An element, therefore, as Constantine says in the Pantechne, is a simple and minimum part of any body, simple with respect to quality, minimum with respect to quantity." *^ William interprets this to mean that an element is " a simple part, which has no contrary qualities," which Constantine expands, in order to exclude homogeneous wholes, like bones, by adding " a mini- mum part, which is a part of something in such wise that nothing of the same sort is part of it." Letters are elements in like fashion because they are parts of syllables in a way in which nothing is part of them. Constantine undertook to derive humors from the composition of the four elements, then homo- eomeries or " consimilar parts," like flesh and bone, as well as organic or " instrumental parts," like hands and feet, from humors, and finally, the human body from these two kinds of parts. Consequently, the elements are not " things which are seen," the earth, water, air, and fire, which are commonly called elements, for those are not simple in quality or minimum in quantity, but each is seen to contain all the qualities, as there is in earth, for example, something of hot, of cold, of dry, and of moist. William argues therefore that the elements of corporeal things or things which are seen are incorporeal or things which are not seen. Division is of two sorts: the human body can be divided into members and homoeomeries actually, but only the understanding divides homoeomeries into humors and into elements. The power of the understanding, as Boethius points out, is to disjoin the conjunct and to conjoin the disjunct. If it is asked where the elements are, the answer is that they are in composition of bodies as the letter is in the composition of syllables but not in itself {per se) . Some thinkers, like simple "■'Ibid., I, 20, PL 172, 48C-D. "/6«Z., 21, 48D-9A. 100 RICHARD MCKEON minds, know nothing unless they can comprehend it by sense, but the investigations of the wise man must be concerned more with insensible than with sensible things. The elements are simple and minimum parts determined by simple, non-contra- dictory qualities, as earth is by cold and dry. The parts which are seen are composites in which one of the elementary particles dominates, as the composite in which cold and dry particles predominate is called earth. If one wishes to apply separate names to the two, William says, the particles which are not seen may be called the elements, elementa, and the particles which are seen may be called the elemented, elevientata, prod- ucts or mixtures of elements.'*^ Some philosophers who have read neither the writings of Constantine nor those of any other physicist say that the elements are the properties or qualities of things which are seen, that is, dryness, coldness, dampness, and heat. William uses quotations from Plato, Johannitius, and Macrobius to prove that the qualities are in the elements, and therefore, the elements are not the qualities. Other philosophers say that things which are seen are elements, and William argues that there is no contradiction between this position and that of Constantine, although they treat two different kinds of elements. Constantine treats the natures of bodies as a physi- cist, and he calls the simple and minimum particles of bodies " elements " in the sense of first principles. Philosophers who investigate the creation of the world rather than the natures of individual bodies call the four parts which are seen " elements " because the world is composed of them and they were created first. If it is said that these are not elements, because they are made of the four elements, and earth, for example, contains some water, and that Plato asks how one is to decide during the transmutation of elements whether to call it earth or water,*' William's reply is that the earth in question is some- thing porous and saturated with water, and even if it is dis- "Cf. Tlieodore Silverstein, " Elementatum: its appearance among the Twelfth century Cosmogonists," Medieval Studies, XVI (1954) , pp. 156-162. *■' Plato, Timaeus 49B-C. MEDICINE AND PHILOSOPHY llTH AND 12TH CENTURIES 101 solved in water, it is' not the element " earth " but the " earthly," which is " part of the element," which is dissolved. Therefore the elements of bodies are the particles and the elements of the world are accounted for by their conjunctions and mixtures. William raises two more questions which have the same characteristic of relating the problem of how wholes are com- pounded of parts and how intelligible principles are used to structure sensible data, that is, how the incorporeal things of understanding are related to the corporeal things of sensible experience. They are the questions (1) of the composition of the universe or of the bonds by which elements are joined together in compounds and organisms and (2) of the origin of the universe or whether the elements were formed from a preexistent chaos or were present in the chaos. Both questions raise issues which are philosophic in character about the defining properties of elements which are qualitatively simple and quantitatively minimum in kind, and about how they " are " (corporeal or incorporeal) and " are understood " (sen- sible or intellectual) . William's treatment of the structure of the universe is based on Plato's demonstration that between extreme elements fire and earth, two and not more than two elements, air and water, are needed to establish the unity and cohesiveness of a uni- verse.^* Plato's argument is that that which comes to be must be corporeal and therefore visible and tangible, for the basic proportion underlying his account of creation is that being is to becoming as thought and reason are to opinion and sensa- tion. William interprets Plato's statement that Divine Reason ordained that the universe be so constructed as to be percep- tible to sight and to touch as a consequence of the purpose in creation that man should see even with his eyes in the creation and government of things the divine power and wisdom and goodness, should fear the power, venerate the wisdom, and imitate the goodness. But sight is impossible without fire and ''/?>irf., 31B-32C. 102 RICHARD MCKEON touch is impossible without earth, and the conjunction of fire and earth, which are opposed by contraries (since fire is subtle, mobile, and acute and earth is corporeal, obtuse, and immobile) required the interposition of one or more middle terms. William distinguishes mixture {commistid) , in which neither of the contraries remains what it was before, from conjunction (con- junctio) , in which both the contraries remain what they were before. Conjunction is impossible in the case of active qualities (like hot and cold) unless they are separated by a middle term to prevent one from dissolving the other. Wishing to conjoin, not mix, fire and earth that both would remain what it is, God created between the two elements, not one, but two more elements, water and air. For if he had placed only water between them it would be conjoined to earth more than to fire, for it shares corporality and obtuseness with earth and only mobility with fire, and that conjunction would not endure; similarly, if only air were placed between, it would have subtlety and mobility in common with fire and only obtuseness with earth. To the objection that if one did not suffice, God could make it suffice, William says that he does not put a limit on God's power, but he says concerning things which are that none could suffice nor could there be anything, according to the nature of things, that would suffice. Having shown that one would not suffice, he demonstrates why there could not be anything that would suffice. Elements may be separated by two contrary qualities or by three. Between some binary pairs, one element would suffice as a middle term; thus, in the case of earth, which is cold and dry, and air, which is hot and damp, water (which shares coldness with earth and dampness with air) is a term of separation and connection. Between ternary terms there is no middle, since any element would share one quality with one of the extremes and two with the other. Moreover, even if fire and air are treated in terms of two rather than three qualities no middle could be found since fire is hot and dry, earth, cold and dry, and any combination of the two qualities would be identical MEDICINE AND PHILOSOPHY 11 TH AND 12TH CENTURIES 103 with one of the two elements or the impossible combination, hot and cold.*^ Of the six combinations of the four qualities, four are possible and determine the four elements; and the remaining two combinations, hot and cold, dry and wet, are impossible. ** The demonstration of the harmony or unbreakable chain of elements binding the universe together, dependent on the interposition between fire and earth of two and only two elements, goes back to Plato, but the changes in the properties of the elements on which the demonstration depends mark changes in the doctrine of elements. Plato's argument depends on the nature of proportion and of numbers: if the universe had been a plane surface, one middle would have sufficed; since it is solid two middle terms are required. Macrobius gives a rough translation of this passage, omitting the references to proportions and square and cubic numbers; instead he discusses hot and cold, dry and moist. (Commentarii in Somnium Scipionis, VI, 23-33) . The Medieval tradition, finally, presents the Platonic analysis of elements as permutation of sets of three qualities, elaborated and systematized from his account of the properties of elements resulting from the geometric forms assigned to them (Timaeus, 55C-56B) . The systematic account of the six qualities of the elements is known as early as Nemesius, and scholars have argued that his source is a lost commentary of Posidonius on the Timaeus or a lost commentary of Porphyry. If the problem is treated in terms of three qualities, the two extreme elements of the universe are opposed by sets of contrary qualities — subtle, mobile, acute (fire) vs. corporeal, immobile, obtuse (earth) , whereas if it is treated in terms of two qualities, the contraries separate the elements in groups of threes, but the two extreme elements are not opposed by contrary qualities — hot, dry (fire) vs. cold, dry (earth) — and therefore, according to Nemesius (V, 11, p. 64). the sequence of elements is not merely an ascent and a descent but a circle, since fire shares with earth the quality dry. ^Miatever the origin of the analysis in which each element is characterized by three qualities, the Latin writers of the Middle Ages learned the distinctions it employs from the Commentary of Chalcidius on the Timaeus. The sequence of elements between the two extremes, fire and earth, as set forth by Chalcidius, may be schematized as follows — Ignis — acutus subtilis mobilis Aer — obtunsus subtilis mobilis Aqua — obtunsa corpulenta mobilis Terra — obtunsa corpulenta immobilis The two extreme pairs — fire-air and water-earth — share two qualities and are opposed in one; the sequence consists in the change of one quality at each step; the two extremes are opposed in all three contrary qualities. Chalcidius' translation and commentary (in the manuscripts that have come to us) are incomplete. The translation breaks off at 53C, immediately before the analysis of the mathematical forms which constitute the elements and of the sequence of the elements relative to each other. The Commentary is also incomplete: the list of topics enumerated is not completed; nonetheless the treatment of the elements is complete and it runs through all three forms of analysis. The theory of the elements as mathematical 104 RICHARD MCKEON Finally, the sequence of the elements from fire to earth is shown to involve an order of lightness and heaviness.^" The resolution of the second question, that of the place of the elements in the creation of the universe, according to William, is also worked out in opposition to a widely held position. Almost all philosophers say that the elements did not occupy fixed places in the first creation but were mixed in one mass and therefore moved up or down together. This position is derived from Ovid and Hesiod, but its proponents add a reason for it (that the Creator might show how great the confusion of things would be if they were not ordered by his power and wisdom and goodness) , and they add the authority of Plato who said that God reduced the elements from an unordered scattering to order.^^ William argues that the position is false, the argument invalid, and the authority incorrectly interpreted. The position is false because elements must be bodies, or spirits, or properties of bodies or of spirits; he shows that they cannot be any of these except bodies, and bodies occupy place. The argument is invalid because before the creation there were neither angels nor men to show how great the confusion of things would be. The quotation from forms is expounded and elaborated. The theory of the three quahties constituting the elements is developed (Platonis Timaeus, Interprete Chalcidio cum eiusdem Commentaria, XXI-XXII, ed. J. Wrobel, Leipzig, 1876, pp. 87-8) as commentary on Plato's argument that the elements are required to explain how the world is sensible (Timaeus 31C; it makes use, however, of distinctions from 55C-56C) , since what comes into being must be material and capable of being seen and touched. The treatment of the two qualities (hot or cold and dry or moist) constituting the elements is part of the analysis of matter (silva or hyle) , which is without qualities, and the transmutation of the elements (ibid., CCCXVII-CCCXXIX, pp. 341 fE.) . The excerpt on the four elements which appears in Cassiodorus' Institutiones is given without derivation (Mynor's note [p. 167] is " Quod unde dictum sit pudet me nescire ") . The analysis set forth in the interpolated passage is clearly derived from Chalcidius' Commentary on the Timaeus. ^° William's analysis combines the three modes of treatment of the elements that were observed in Nemesius — (1) two qualities, heavy and light, assigned to the elements in pairs of elements, (2) four qualties, hot, cold, dry, wet, assigned two to each element, and (3) six qualities, obtuse, acute, mobile, immobile, subtle, coropreal, assigned three to each element. "^ Timaeus, 53B. MEDICINE AND PHILOSOPHY IITH AND lliTH CENTURIES 105 Plato is incorrectly interpreted because Plato did not hold that the elements were actually in an unordered scattering, but that they could be, and in the first creation they were where they now are, but they were thicker, in so far as they were mingled, and obscurer in as much as there were no sun, moon, or stars to light them. The stars, thus, were made from all four ele- ments, the upper elements which are \Tisible and mobile, and the lower elements which are obscure and immobile. The stars, which are visible, shining, and mobile, have their qualities from the interplay of the properties of the elements, and in that interplay each of the four qualities is found in the visible forms in which the elements appear. According to Constantine each of the elements has two qualities, one proper to itself, the other from another element; fire hot of itself, dry from earth; air damp of itself, hot from fire; water cold of itself, damp from air; earth dry of itself, cold from water. The stars, being fiery in nature, began to move immediately on their generation and to heat adjacent air and, through it as intermediary, the further removed water. The various genera of animals were created from heated water, birds in the air, fish in the water, and other animals and man on the earth. The theory of elements gives organization to William's encyclo- paedic examination of the world and of its parts. At the beginning of Book II, he describes Book I as a summary exposition, within the limits of his small powers, " concerning the particles of things which are and are not seen and con- cerning elements which some teachers present as visible things," and he proposes now to take up in turn each element and its embellishment (ornatus, i. e., kosmos) . The opening chapter of Book II is on ether and its ornatus. Fire is the space above the moon, and it is also called ether; its ornatus is whatever is seen above the moon, that is, the stars, both fixed and wandering. The book presents information concerning the planets and astronomical phenomena. The opening chapter of Book III is on air which extends from the moon to the earth and is damper and thicker nearer to earth. 106 RICHARD MCKEON The early chapters take up the zones of the air and the effect of the heat of the sun raising water to form clouds, and the transition from air to water is made in Chapter 14 on the tides of the Ocean. The book presents information concerning meteorological phenomena, snow, thunder, lightning, tides, fountains, and wells. Book IV is devoted to the remaining element, and begins with a chapter on earth and the world. After sketching some geogi-aphical questions — the qualities of earth, its inhabitants, the continents Asia, Africa, and Europe, a translation is made to man in Chapter 7. Since the creation of the first man, male and female, from dust was treated in Book I, William undertakes now to treat " of the everyday creation, formation, birth, ages, members of man, and of the functions and uses of his members." He begins with the sperm, traces man from the womb through infancy, examines his organs, digestion, sleep, senses, soul, virtues, and youth and old age largely in terms of the fundamental contraries. The book ends with five chapters on teaching and the order of learning. William argues that man is by nature hot and cold and is tempered by the interplay of the four qualities, so that dif- ferences of virtue and temperament result from the intensifica- tion and remission of the contrary qualities. ^^ He follows Constantine's localization of the functions of the mind in the three cells of the brain. The anterior cell is called fantastic, that is, visual or imaginative, because it is the seat of the power of seeing and understanding; it is hot and dry to attract the forms of things and colors. The middle cell is called logistic, that is rational, because it is the seat of the power of distinguishing; it is hot and moist that it may conform to the properties of things and distinguish better. The posterior cell is called memorial, because it is the seat of the power of retaining; it is cold and dry in order to retain better. This localization was determined, according to William, by observa- tion of wounds of the head in which it was noted that injuries " De PhUosophia Mundi, IV, 20; PL 172, 93B-C. MEDICINE AND PHILOSOPHY IITH AND 12TH CENTURIES 107 to one of the cells resulted in the loss of the function associated with it without affecting the other functions.^^ Sensation is a function of the body which man shares with other animals; distinguishing and understanding are functions of the soul, peculiar to man. There are three powers of the soul: under- standing {intelligentia) by which man perceives incorporeal things with the certain reason why they are thus; reason by which man perceives in what respects things agree with other things and in what they differ; memory by which man firmly retains what was known before. The doctrine of elements provided William of Conches with more than the simple parts from which to construct things, organisms, and a universe; they were also principles for the examination of the relation of corporeal things perceived in sense experience to the incorporeal structures conceived by the mind and used to explain the nature of corporeal things. The processes of composition and resolution which related elements as qualitatively and quantitatively simple parts to composite wholes also crossed the line which separates seen from unseen and corporeal from incorporeal. William's analyses therefore have philosophic interest (since he explores the problems involved in these relations) and empirical content (since the structures w^hich he abstracts are found embodied in things which are and are known) . The elements serve similar func- tions in other twelfth century cosmologies, scientific treatises, and encyclopaedias, and they provide common principles for the work of William of Conches and the work of men like Thierry of Chartres and Peter Abailard who influenced him and of William of St. Thierry who criticized him. Thierry of Chartres was Chancellor of the School of Chartres from about 1141 to about 1150. John of Salisbury calls him " the most zealous investigator of the arts," and another disciple says he was " preeminent among the philosophers of all Europe " {totius Europae philosophorum precipuus) . Bernard Sylvestris dedicated the De Universitate Mundi to him, and two of his " Ibid., IV, 24, PL 172, 95. 108 RICHARD MCKEON pupils, Herman the Dalmatian (or Carinthian) and Robert of Chester (or Katene) , in the dedication of their translation of Ptolemy's Planisphere to him, address him as the first anchor and sovereign of the second philosophy (the mathematical arts of the quadrivium) , the immovable support of studies tossed by every tempest, in whom relives the soul of Plato descended from the heavens for the blessing of mortals, the true father of Latin Studies. Thierry says that his method of commenting on the first part of Genesis is by distinctions which are literal and according to physics. There are four causes of earthly subsistences: an efiicient cause, God the Father; a formal cause, the wisdom of God, or the Son; a final cause, the benignity of God, or the Holy Spirit; and a material cause, the four elements. To say In the beginning God created the heaven and the earth is to say that he created matter in the first moment of time. Once created, heaven could not remain immobile: in the revolution which constituted the first day, the highest element, fire, illumi- nated the lower element air. In the revolution of the second day, fire through the medium of air, heated the lower element water, vaporizing it into minute drops which can be suspended in air; the firmament was thus placed in the midst of the water, air being suspended between a layer of vaporized and a layer of condensed water. Since the condensed water below was diminished in that process, dry land appeared in the third revolution; the action of the heat of the superior air and the dampness of the earth produced herbs and trees. In the fourth day, the bodies of the stars were created by contraction, caused by heat, of the waters above the firmament. Heat was increased in the revolution of the fifth day by the motion of the stars, became vital, and produced fish in the waters and birds in the air. On the sixth day, the vital heat proceeded to earth, and the animals of the earth were created, including man made in the image and likeness of God. After the sixth day no new mode of creation was used, but new creatures were produced from the seminal causes inserted in the elements in those first MEDICINE AND PHILOSOPHY IITH AND 12TH CENTURIES 109 stages of creation. Among the elements, fire is an active and efficient cause, earth a passive and material cause, while air and water are both active and passive, instruments and vehicles of causation. Among the seminal causes which determine pro- cesses and developments after the formation of the world are gravity and lightness which bring the elements into inter- relations in local motion.^* Thierry proceeds from the creation of the world to an exposi- tion according to the analysis of physicists (secunduvi rationem physicoruTn) of the motions of heaven and earth as determined by the properties and relations of elements. He argues that when Moses said that the earth was without form and void, and when he used other similar expressions, he was referring to the " informity," or rather the " uniformity," of the four elements. This " confusion " of elements, which the ancient philosophers called matter (hyle) or chaos, is what Moses signified by " heaven and earth." The informity of those elements then consisted in the fact that each of them was almost of the same sort as the others and that the differences between them were minimum or almost nothing. There- fore that difference was held by the philosophers to be nothing, and they called the elements thus confused one unformed matter. Plato, however, considering the minimum which separates the elements, and knowing that the difference, although minimum, is present in the confusion, concluded consequently that matter, that is, the con- fusion of elements, underlies the four elements themselves, not in the sense that that confusion preceded the four elements in time or creation, but in the sense that confusion naturally precedes differentiation, as sound precedes word, or genus precedes species.^^ When Moses went on to say that the spirit of the Lord moved upon the waters (Gen. 1: 2) , he distinguished the operative cause from the material cause. The power of the artificer, whom he calls the spirit of the Lord, excels and dominates '^^ Thierry of Chartres, De Sex Dierum Operibus, ed. M. Haureau, in Notices et Extraits des Manuscrits de la Bibliotheque Rationale, Paris, 1888, vol. XXII, Part 2, pp. 172-7. " Ihid., p. 179. no RICHARD MCKEON matter in order to inform and order it, in a relation similar to that which Plato, Hermes Trismegistus, and Virgil found between God or spirit or world-soul and matter or hyle or world. Having presented the two primordial causes of the creation, matter and operative power (inateria et virtus opera- trix) , Moses went on to demonstrate how and in what order the spirit of the Lord operated on matter, but Thierry pauses to examine the knowledge that man can have of the Creator from creation. He distinguishes four kinds of demonstrations {genera rationum) which lead from things to their creative cause — arithmetical, musical, geometrical, and astronomical proofs, but our manuscripts break off after an arithmetical analysis of unity and equality and their bearing on the existence of things. Peter Abailard (1079-1142) developed a theory concerning the nature of universals in his treatises on logic and dialectic, and he drew conclusions concerning the nature of the artificer and the elements of the world in the treatises in which he used rhetoric or dialectic to interpret statements of Scripture and facts of history or to interpret doctrines of prophets and phi- losophers. He opens his Commejitary on the Epistle of S. Paul to the Romans by observing that all Sacred Scripture has the objective of teaching and moving like a rhetorical oration,^® and that the two Testaments are therefore divided into three parts: the law, to teach what should be done and avoided; the Prophets or the Epistles, to dissuade from evils or persuade to goods; and the histories, to provide examples. He interprets Paul's statement that the invisible things of God are understood by the things that are made, to mean that knowledge of the universe as a vast fabrication or as effects may lead to knowl- edge of its artificer as power, wisdom, and goodness. In his interpretation of the passage from Paul, Abailard finds a similar treatment of creation in Plato and Cicero; he argues that the perception of the power, wisdom, and goodness of the Creator ^* Comvientariorum super S. Pauli ad Romanos Libri Quinque, Prologus PL 178, 783B. MEDICINE AND PHILOSOPHY 11TH AND 12TH CENTURIES 111 is the discovery of the marks of the Trinity; and he analogizes that knowledge to the perception, when a bronze statue is set before the eyes, that the bronze and the bronze statue are the same thing essentially and numerically and yet are diverse in their properties.^^ His rhetorical method is apparent in his Expositio in Hexaemeroji, in which he undertakes a threefold interpretation — historical, moral, and mystic — " of the abyss of profundity " of Genesis. As first step in the historical inter- pretation, one must take into account the fact that Moses addressed a carnal and uneducated people and sought to raise them to a consideration of divine things. Moses therefore began his exposition with the creation and disposition of the world, for " God, who is invisible and incomprehensible in himself, conveyed to us the first knowledge of himself from the mag- nitude of his works, since all human knowledge arises from the senses." ^^ To begin with creation is to follow the natural order in addressing a carnal people, committed to the corporeal senses, and not far advanced in spiritual understanding. Christian philosophers had learned from Platonic and Stoic philosophers to treat problems of wholes and parts by distin- guishing the artificer or the efficient principle causing the unity and the material principles compounded into wholes. Abailard's exposition of the creation marks off the stages of formation by means of the four elements and finds in the structure and embellishments of the world evidence for the unity and trinity of the Creator. The opening statement of Genesis, " In the beginning God created the heaven and the earth," means that the four elements were created first, " heaven " signifying the light elements, fire and air, " earth " signifjang the heavy " Ibid., I, PL 178, 802D-5A. The doctrine of the Trmity is developed in detail in Abailard's Theologia Christiana, I, 2 and £f. (PL 178, 1124 fl.) . Abailard says at the beginning of the second book of the Theologia Christiana that he has assembled in the previous book quotations from the prophets and the philosophers concerning the Trinity; in the second book he examines the relation between the philosophical disciplines and religion. (Ibid., 1165 ff.) Cf. Introdiictio ad Theo- logiam, I, 8-10 and 11. (Ibid., 989C-95B, and 1035 ff.) ^* Expositio in Hexaemeron, PL 178, 733A. 112 RICHARD MCKEON elements, water and earth; and they were created " in the beginning," because the first confusion or congeries of elements constituted the matter for the formation of other bodies. Fire and earth marked off the limits within which the other elements provided connecting bonds and limiting differentiations, and the whole constitution of the world consisted in the four elments/® The Trinity is expressed in the beginning of Genesis, and is developed more fully in the creation of man in the image of God on the sixth day, for it is in power, wisdom, and love that the likeness of the human soul to God is apparent.^" The moral interpretation is based on the same distinctions as the historical interpretation. Much as the confused congeries of elements is later ordered, so too man, composed of soul and body, but in the beginning unformed and incomposite in moral character, is transformed from the initial confusion (symbolized by the fluid element water) first by the light of faith, then by hope, and finally by charity.®^ The mystical interpretation is an allegory of cultural history proceeding through six ages, in which the first age of primitive culture without law or art is symbolized by the confused congeries of elements, and sub- sequent ages follow like analogies to the days of creation, until in the sixth age the future is extrapolated from the history of the past.®^ It is apparent that the problem of elements is a problem of parts and wholes, not in the simple sense that a whole is compounded of parts, but in the more complex sense that a whole persists through changes of parts and that a whole is identifiable although characterized by different properties. When changing wholes or inclusive wholes are under considera- tion, the problem of part and whole becomes a problem of same and other. Abailard distinguishes three senses of same and other {idem et diversum) : as likeness, as essential sameness but not same in number, and as sameness in property,^^ for the " Ibid., 733C-7B. " Ibid., 770C-1D. •° Ibid., 739B, 760B-1D. " Ibid., 771D-3A. " Introductio ad Theologiam, 11, 12, PL 178, 1065. MEDICINE AND PHILOSOPHY IITH AND 12TH CENTURIES 113 examination of data in a universe, which is a whole charac- terized by properties of dynamism, wisdom, and goodness, requires an analytic device by which to identify the wholes which remain the same essentially although characterized by different properties. One analogy runs through his works, the comparison of the distinction of Persons in the unity of God to the distinction of properties in a physical object: in his Covimentary on S. Paul he uses the analogy of a bronze statue; in his Introductio ad Theologiam, a bronze seal; in his Theo- logia Christiana, a wax image. In the later two works he adds a third analogy, the characterization of man, to these two.^^ Bronze is the " matter " on which an artificer works to form a seal; the seal, thus " mattered " (materiatum) and formed (formatum) , is " scalable " (sigillabile) , that is, adapted to impress an image on a soft substance like wax; when it is actually used, it is " sealing " (sigillans) , that is, its act is the transfer of the form to another matter. When the wax is being sealed, the single bronze substance has three diverse predi- cates: bronze, scalable, and sealing; bronze is matter, scalable and sealings are " mattered." Abailard argues that the relation of the persons of the Trinity is similar: wisdom is a kind of power, as the bronze seal is a kind of bronze; benignity reforms the image of God in us that we may conform to the image of the Son of God, as sealing comes to be from bronze and the scalable. In the same way the genus, animal, is the matter of the species, man, for man is a kind of animal as the bronze seal is a kind of bronze.®^ " Matter " and " mattered " in a given image are the same, essentially, yet the matter precedes the mattered; and a like precedence is found in each of the related pairs of terms — constituent and constituted, cause and effect, generating and generated.*^® The distinction and the terms in which it is expressed are found in the eleventh century ** Expositio in Epistolam ad Romanos, PL 178, 804B-5A; Introductio ad Theo- logiam, II, 13-14, PL 178, 1068C-70B, 1073A-5A; Theologia Christiana, III, IV, PL 178, 1248B-9A, 1288A-90C. «^ Introductio ad Theologiam, II, 13-14, 1068C-70B, 1073A-5A. *» Theologia Christiana, IV, 1288A-90C. 114 RICHARD MCKEON translations of Salerno. Alfanus, Archbishop of Salerno, dis- tinguished materia from matenatum in his translation of Nemesius. After pointing out that some philosophers held that the soul is corporeal, while others held it was incorporeal, he gives a Neoplatonic refutation of the corporeity of the soul: the body needs a principle to hold it together; the principle is either incorporeal or corporeal; if it is corporeal, it in turn needs a principle to bind its constituents together. If the Stoics say that the principle is a motion, one asks what is the power or virtue (virtus) which causes this motion. If it is matter, the previous arguments are repeated; if it is not matter, it is " mattered " (materiatiim) , and the mattered will be different from matter, for " what participates in matter is called mattered." But if it is not matter, it is " immattered " and all body is " mattered." "^ The Stoic distinction of an operative and a material cause may, however, be joined to the distinction between " matter " and " mattered " without becoming involved in the Stoic materialism: " matter " is potentiality and the " mattered " is potentiality restricted by a form which confers a specific function or potentiality and from which a specific act follows, but the distinction does not entail the consequence that all things are corporeal. William of St. Thierry (1085-1148) made elaborate use of the doctrine of elements, but was critical of the use of physical arguments to specify properties of God or the Trinity inferred from creation. He was the adversary of Peter Abailard and William of Conches and called their errors to the attention of St. Bernard. In his Disputation against Peter Abailard, his criticism of Abailard is that " he loves to think about all things '■^ Nemesii, Premnon Physicon, pp. 25-26. The distinction of materia and materia- tum used by Abailard, of elementum and dementatum used by William of Conches, and of natura naturans and natura naturata, which came into use about the same time or a little later, have common origins in translations from Greek or from languages which preserve verbal forms of materia, elementum, or natura from which passive (and sometimes also active) particles can be formed and recognized. In the other languages the relation between matter, mattering, and mattered is lost in the circumlocutions of translation of a work which examines that relation and is inconspicuous in original inquiries into like problems employing the same data. MEDICINE AND PHILOSOPHY llTH AND 12TH CENTURIES ll5 and wishes to dispute about all things, about divine things and about secular things equally." '^^ He criticizes Abailard's use of power, wisdom, and benignity to differentiate the persons of the Trinity. In particular, he criticizes his use of the analogy of the bronze seal and the distinction between materia and materiatum to explain the relation of the Father and the Son.**^ He expresses the wish that Abailard would read the Evangel of God with the same simplicity as he reads Plato and that he would imitate his beloved Plato, who proceeds cautiously and prudently from the creation to the incomprehensibilities of the Creator.^" He criticizes William of Conches for adding a new philosophy to the theology of Abailard, confirming and multiplying whatever Abailard said and adding more that he did not say.'^ He says that William of Conches describes the creation of the first man philosophically, or rather physically, and holds that his body was not made by God, but by nature, and that his soul was given to him by God, after his body had been made by spirits, whom he calls demons, and by the stars. William of Conches seems to him to follow the opinion of certain stupid philosophers who say that nothing exists except bodies and corporeal things, that God in the world is nothing else than the concourse of elements and the harmony or tem- perature of nature, and that he is himself a soul in body." ** Guillelmus Abbas S. Theodorici, Disputatio adversus Petrum Abaelardum ad Gaufridum Carnotensem et Bernardum, 1, PL 180, 250A. "* Ibid., 3, PL 180, 254C-7C. The analogy is also criticized by St. Bernard. '" Ibid., 7, PL 180, 270C-D. '^^ De Erroribus Guillelmi de Conchis ad Sanctum Bernardum, PL 180, 333 A. " Ibid., PL 180, 339A-40A. Walter of Saint Victor says that " William of Conches held that all things are made from the concourse of atoms, that is, of the most minute bodies," and that Peter of Poitiers used atoms to prove that the flesh of Christ was not in Abraham or Adam. (Contra Quatuor Labyrinthos Franciae, IV, 25, ed. P. Glorieux, Archives d'Histoire Doctrinale et Litteraire du Moyen Age, XIX (1953) , 289.) In the Dragmaticon which is in dialogue form, William of Conches replies to his interlocutor's question about Epicureanism, denying that he is an Epicurean, but adding that there is no philosophic sect so false that it has no truth mixed with its falsehood; the Epicureans are correct in saying that the world is composed of atoms, wTong in supposing that the atoms were without beginning and that the four bodies of the world were composed by the bombardment of large IIG RICHARD MCKEON William of St. Thierry is not opposed to the use of the doctrine of elements. His treatise On the Nature of the Body and the Soul treats its subject physically: Book I is entitled " The Physics of the Human Body " and Book II " The Physics of the Soul." All animal bodies are formed of earth, that is they are composites of the four elements; for the earth, from which they are formed, and what they consist of must be distinguished. William follows Constantine's analysis, defining each element by one quality to which a second quality is added from an element adjacent to it, and he quotes the argument of Hippo- crates that the animal body would feel no pain if it were composed of one element. The elements are transformed into one another; they form the humors and nourish them; and the " children of the elements " follow the ways of their fathers, for the elements operate in the greater world as the four elements operate in the lesser world or microcosm, man.^^ William differentiates three virtues in the regimen of the body: the natural virtue localized in the liver, the spiritual virtue in the heart, and the animal virtue in the brain. His analysis of these three virtues follows Constantine's position in detail, and he shares his conclusions also on the localization of the functions of imagination, reason, and memory in the three cellules of the brain.'* The five senses correspond to the four humours: sight is fiery; hearing, aerial; odor, smoky; taste, watery; and touch, earthly. William characterizes the method of his treatment of the exterior man as one in which he has considered not only the exterior man but also certain things within human bodies which are not subject wholly to the senses of man but are discerned by philosophers and physicists through reason and experience." particles. Peter of Poitiers uses the word " atom " in his argument that the flesh of Christ was not in Abraham, because there were not in Abraham as many atoms as there have been men descended from him by concupiscence. (Sententiae, IV, 7, 11, PL 211, 1164C). "" De Natura Corporis et Animae, I, PL 180, 695-8C. '* Ibid., I, 700A-D and 702A-C. " Ibid., I, 707B-708A. MEDICINE AND PHILOSOPHY — IITH AND 12TH CENTURIES 117 In his treatment of the soul, William of St. Thierry distin- guishes the definition of the philosophers of this world, who say that the soul is a simple substance, a natural species, dis- tinct from the matter of its body, and possessed of the power of life, from the definition of the ecclesiastical doctors, who say that the soul is a proper substance created by God, vivifying, rational, immortal, but convertible toward good and evil. The soul vivifies the body in three manners — for the purpose of living only, for the purpose of living well, and to provide opportunity for the succession of future goods.^^ God made man in his image and likeness, as a sculptor makes a statue, combining in him virtues of inanimate things, plants, animals, and angels. Moreover, since man is made in the image of God, his soul is related to his body as God is related to the world: it is everywhere and everywhere whole, whole in natural, in spiritual, and in animal operations; ^^ and the image of the Trinity is found in man's body and in his soul, for the soul, which is one, is also memory, counsel, and will, and the body, which is one, is also measurable, numerable, and weighable.'* The works translated from Arabic and Greek, the epitomes of the translators, and the treatises of Western philosophers learned in the new sciences introduced further modifications in the doctrine of elements. Avicebron (whose Fons Vitae, in Latin translation, uses both elementatum and materiatura) , Gundissalinus, Herman of Carinthia, and Adelard of Bath discuss the problems of determining simple parts and they use them in the classification and analysis of a wide range of data. The theoretic aspects of the problem become clear again in the exploration of the consequences of alternative approaches to elements; but the materials on which the schematisms are employed, once the new materials treated in the translations have become familiar, tend to fall into reiterative repetitions. There is some indication that the distinctions based on elements stimulated new observation in some fields, but the evidence is ambiguous because the task of assimilating the new materials '* Ihid., II, 707-9. " Ihid., I, 702C. " Ibid., II, 722A-23A. 118 RICHARD MCKEON of the sciences was so great that what seems new is often the interpretation of an old text newly acquired. It is ambiguous also because the focus of inquiry was turning from the elements or natures of things to the principles of motions or functions. In that transition, the physical sciences of Aristotle are them- selves interpreted in terms of elements rather than of principles. Gundissalinus distinguishes natural bodies into simple and com- posite and then divides natural science into eight large parts: the investigation (1) of what is common to natural bodies, simple and composite, as in Aristotle's Physics; (2) of simple bodies in heaven and earth, as in the De Caelo et Mundo; (3) of the mixture and corruption of natural bodies and the generation and corruption of elements, as in the De Generatione et Corruptione; (4) of the principles of the accidents and passions of elements and composites, as in the De hnpres- sionihus Siiperioiibus; (5) of bodies compounded of elements and of bodies of similar or of dissimilar parts, as in the De hnpressionibus Supeiiorum; (6) of bodies compounded of simi- lar parts which are not parts of a body compounded of diverse parts, as in the De Mineris; (7) of what is common to the species of vegetables and what is proper to each of them, as in the De Vegetabilibus; and (8) of what is common to the species of animals and what is proper to each of them, as in the De Ajiimalibus, the De Anima, and the books included up to the De NaturalibusJ^ It is worth observing that the fact that the title by which Aristotle's De Caelo was known during the Middle Ages was De Caelo et Mundo suggested analogies to the opening lines of Genesis concerning the creation of the heaven (caelum) and the earth (terra) . Aristotle con- ceived the history of natural philosophy to be an evolution from elements as principles used by early philosophers to his own methodical use of causes as principles. This history is repeated in the transition from the eleventh to the twelfth century, but ironically Aristotle's natural philosophy enters into that transition as a philosophy of elements. " Domingo Gundisalvo, De Scientiis, ed. P. Manuel Alonso Alonso (Madrid, 1954), pp. 120-6. MEDICINE AND PHILOSOPHY 11 TH AND 12TH CENTURIES 119 After the first systematic commentaries on the newly trans- lated scientific writings of Aristotle had appeared in the latter half of the thirteenth century, the problem of elements began to emerge again, and all the opposed conceptions were formu- lated in terminology borrowed from the Aristotelian writings. The discussion of least parts and simples in terms of kinds of motion led into theories of minima and viaxima, and of simples and composites; the discussion of numbers and mathematical bodies as least parts and organizing principles of composites and organisms went from Platonic beginnings to mathematical elaborations; the Stoic elements and their efficient principles and the arbitrary models which used methods familiar to the skeptics were known in the Renaissance; the Epicurean atoms moving in a void were set forth by Gassendi in the seventeenth century. With the progress of medicine, astronomy, and me- chanics in the Renaissance attention concentrated on the ele- ments as principles again, and Boyle was able to assemble in the dialogue of the Sceptical Chymist a Corpuscularian, a Peripatetic, and a Spagyrist or modern Chemist, to discuss a large variety of theories of elements (including van Helmot's theory that all things are water fructified by seeds) . The transition from the Renaissance to the seventeenth cen- tury is similar in what happened to the treatment of elements to the transition from the twelfth to the thirteenth century: more was known and the data were richer, but the opposed theories followed a similar pattern, and the discussion of elements again yielded to the discussion of laws and principles of motion — the issue in the seventeenth century was not pri- marily between Descartes' vortices, Leibniz' monads, and Newton's atoms but between their conceptions of mass and motion and their elaborations and applications of laws of motion. The Newtonian principles were used to organize a system of the world and a system of physical science in the eighteenth and early nineteenth centuries, but in the twentieth century our attention has turned again to elements and par- ticles and to more subtle and better grounded forms of anti- 120 RICHARD MCKEON nomles and paradoxes of matter and energy, matter and antimatter, machine and organism, simple and composite, motion and rest. We have nothing to learn concerning the substance of the twentieth century problem from what was known about elements in the twelfth century or in the Renais- sance, but the theoretic characteristics and consequences of the opposed positions were thoroughly elaborated in the earlier periods in statements which have echoes in contemporary problems, and the ironical turn of history which transformed rather than solved the problems of the earlier periods is prepara- tion which might be useful for like transformations in the problems faced today. Richard McKeon University of Chicago, Chicago, Illinois. THE ORIGINS OF THE PROBLEM OF THE UNITY OF FORM THE philosophical problem with which we are here con- cerned may briefly be formulated thus: Whether in one and the same individual, remaining essentially one, there are many substantial forms or only one. A concrete thing of matter and form, the crwoXov, is one essence and one nature, but it possesses several perfections and activities. It is, in fact, a body, corpus, and it is such and such a body, a stone or a tree or a horse. A tree is a body, but it is a determinate body, quite different from a stone or a horse; besides being a corporeal thing, it is also a living thing. Now, as Boethius has it, it is the form that confers on matter the actual being: ovme esse ex jorma est.^ A substantial form imparts an essential perfection, and an accidental form a rela- tive or qualified perfection. Assuming that substantial form is the determining principle of a composite being, the difficulty arises of how to account for the various essential perfections of an individual. Does one substantial form give one perfection only, so that we have to look for as many substantial forms as there are perfections and activities; or does a single form suffice to determine the thing in its own nature, thus endowing it with all its perfections and activities. f^ A stone is a corporeal thing as much as a piece of iron, and man is as much a living being as a tree or a horse; but as a horse possesses some per- fections which a tree has not, for example, sensitive life, so man, besides having nutritive and sense powers, is also endowed with an intellective soul. The whole point of the discussion, therefore, comes to this: Is a man — let us say rnan, for it was in connection with the human soul that the vexed question was first stated — a living ^Boethius, De trinitate, c. 2 (The Theological Tractates, ed. H. F. Stewart and E. K. Rand. London, 1926, p. 8; PL 64, 1250 B). 121 122 DANIEL A. CALLUS being by virtue of a distinct nutritive soul, an animal through a distinct sensitive soul, and finally rational by an intellective soul; or does he owe to one single substantial form, the intel- lective soul, not only his being a man, or rational, but also his being an animal, a living thing, and a corporal substance? If with Aristotle one holds (i) that prime matter is a com- pletely passive potency without any actuality of its own what- ever; (ii) that privation is the disappearance of the previous form, and, consequently, has no part at all in the composition of the substance; and (iii) that substantial form is absolutely the first determining principle, which makes the thing to be what it is, the only root of actuality, unity and perfection of the thing; then, consistent with his stated principles, the conclusion forced upon us is that in one and the same individual there can be but one single substantial form: other forms, that come after the first, are simply accidental and not substantial forms. Since the thing is already constituted in its own being, they cannot give substantial being, but exclusively accidental or qualified being; they do not confer upon the concrete thing its own definite and specific kind of being, e. g., man, but only a qualified or relative state of being, for example, of being fair or dark, big or small, and the like. On the other hand, if one contends (i) that primary matter is not absolutely passive and potential, but possesses in itself some actuality, no matter how incomplete or imperfect it may be: an incohatio farmae, or any active power; (ii) that priva- tion does not mean the complete disappearance of the previous form, so that matter is not stripped of all precedent forais in the process of becoming; or (iii) that substantial form either meets with some actuality in prime matter or does not determine the composite wholly and entirely, but only partially; from all this it will necessarily follow that there are in one and the same individual plurality of forms. Briefly, the utimate philosophical issue resolves itself as follows: (a) Do the various substantial forms, as imparting different ORIGINS OF THE PROBLEM OF UNITY OF FORM 123 essential perfections and virtues, remain actually and simul- taneously in a composite, which is essentially one, whether in juxtaposition, in co-ordination, disposed hierarchically, or in any other way implying actual persistence? (b) Or must all previous forms pass away with the coming in of the more perfect substantial form, in such a wise that they are in the crvvoXov only virtually as implied, synthetized, and comprised in the higher form, each essential perfection being gathered up into the unity of a single form, which alone gives to the individual its ultimate and specific determination? The problem may be, and in fact had been, approached from two angles: the psychological and the metaphysical. Regarded psychologically, the problem was restricted to living beings, especially to man. Considered metaphysically, it was raised from as many aspects as there are things composed of matter and form, whether living or lifeless bodies (mixta) , or simply from simple logical relations, such as genus and species viewed as matter and form, and their mutual predication. The question was not fully elaborated all at once, but slowly and by degrees. The starting-point was whether the nutritive, the sensitive and the rational principles in man are one soul, one substance, or three distinct souls or substances. To avoid confusion, it is important to bear in mind that the problem of the unity or plurality of the human soul is a dif- ferent question from that of the unity or plurality of substan- tial form, whether in man or in any composite. Naturally enough, if there is plurality of souls, a jortiori there must be plurality of substances or forms. Substance, philosophically speaking, is equivalent to form. But the latter question is a more complex one; that is, assuming that there is in man one soul only, and even that the soul is the form of the body so as to constitute one essence, it still remains undecided whether the determining principle is one only or whether there are required as many principles, or forms, as there are perfections and powers. There is a general consensus among scholars that it was St. l!24 DANIEL A. CALLUS Thomas Aquinas who gave to the problem of the unity of sub- stantial form its full significance. It is equally agreed that the question cannot have originated with him, since it was current in the schools as early as the first decades of the thirteenth century, though, it is true, it then turned on a single instance, namely whether the nutritive, the sensitive and the rational are in man one soul, one substance, or three distinct souls or sub- stances. (We have already observed that to say substance is the same as saying form) . Further, it should be admitted that many of the masters, who held that the three principles are in man not only one soul, but also one substance, did not fully grasp all its implications. Albert the Great was, perhaps, the first to see the general and wider principles involved; yet he too neither stressed the point nor deduced all the logical con- clusions. With Aquinas, on the contrary, the debate entered a new phase. Refusing to regard it merely as a psychological theory, he considered it as fundamentally metaphysical, based on the principle of contradiction; he thus gave it stability, uni- versality and full value. Since it is essentially metaphysical, it concerns the total range of matter-form composites, without exception, holding good not only in psychology, but also in logic, in the philosophy of nature and by inference in theology as well. It is precisely here that Aquinas' original contribution to the problem lies. Still, granted that St. Thomas' predecessors and contemporaries, chiefly because of their somewhat imper- fect grasping of metaphysical principles, did not clearly per- ceive all the issues involved, the fact remains that the problem itself, in its psychological aspect, had already been discussed and propounded in the schools of Paris and Oxford for at least half a century before St. Thomas' time. And if in reality there were two contrary opinions, one must have been in sup- port of plurality of substances, or forms, and the other in sup- port of the unity of substance, or form. There is no alternative position. The aim of this paper is not to discuss in detail the philo- sophical issues of the problem, but to attempt to trace its ORIGINS OF THE PROBLEM OF UNITY OF FORM 125 origins and to consider its impact on the early masters in Paris and Oxford. * * The origin of the problem under discussion is obscure. On the assumption that it could arise only on the basis of Aristo- telian principles, it would serve no purpose to search for its beginning before the rediscovery of the libri naturales and the Metaphysics. The twelfth-century thinkers, failing to under- stand the problem of change and becoming, could not perceive the value of the question of forms. They posited primary mat- ter, not as the potential principle of which things are essentially constituted, but rather as a chaotic mass of the four elements, as something actual, and therefore already informed.- Simi- larly, they had no clear notion of the distinction between sub- stantial and accidental forms. The substantial form was, for them, not the constitutive principle by which things are what they are, but more truly the collection of all the attributes by which a thing is discriminated from other things.^ With a con- fused notion of matter and form, the question of the unity or of the plurality of substantial forms does not even arise. The times were not yet ripe for so refined a discussion. To trace, then, the origin of the dispute and to investigate how and when the Schoolmen came for the first time into contact with it, we must turn to another field of inquiry. In the height of the conflict against Aristotelianism in the last decades of the thirteenth century, there appeared a list entitled Errores philosophorum, written, in all probability, by * See, for example, Alanus de Insulis, Distinctiones dictionum theologicalium, s. v. silva (PL 210,944 C); see also s. v. aqua (704 A); and Regulae de sacra theologia, reg. 5 (626 A). ^ " Forma dicitur proprietas rei, unde Boetius: ' Considerat enim corporum formas,' id est proprietates." Alan de Insulis, Distinctiones, s. v. forma (796 D) . " Forma est quae ex concursu proprietatum adveniens a qualibet alia substantia facit suum subiectum aliud." Nicholas of Amiens, De arte seu articulis catholicae fidei, Prologus (PL 210,597-8). Cf. among others, M. Baumgartner, Die Philosophie des Alanus de Insulis itn Zusammenhange mit den Anschauungen des 12. Jahr- hunderts (B.G.P.M., II. 4). Miinster i. W., 1896, particularly pp. 47-60. 126 DANIEL A. CALLUS Giles of Rome,* in which Aristotle and Avicenna are made re- sponsible for the thesis: Quod in quolihet composito sit una forma substantialis tantum. The author, who is on the whole familiar with the facts, argues that the unity thesis is a logical inference of the Aristotelian doctrine on change and movement. For, since the coming-to-be of a thing never takes place without the passing-away of another, and one substantial form is never introduced unless the one which preceded it is expelled — seeing that the matter of all things material is the same — it follows that there are no more substantial forms in one composite than there are in another. Nay if one stresses this point rightly, it seems necessary to maintain that there is in all compounds one substantial form only: and indeed this appears to be the Phi- losopher's position. In fact, in the Metaphysics, Book VII, in the chapter ' On the unity of definition,' he states that the attributes in the definition are one, not because they are present in one thing, but because they constitute one nature, one thing. If he means one thing composed of many forms, this view may be tolerated, but if he means one simple nature and that in the concrete thing there is one form only, then it is false .^ Doubtless in the Aristotelian system there can be no room for the theory of plurality of forms. St. Thomas more than once pointed out that haec positio (plurality of forms) secundum vera philosophiae principia quae consideravit Aristoteles est * Giles of Rome Errores Philosophorum, ed. J. Koch (Milwaukee: Marquette Univ., 1944). ^ Among Aristotle's errors: "11. Ulterius, quia per viam motus nunquam est generatio unius, nisi sit corruptio alterius, et nunquam introducitur una forma substantialis, nisi expellatur alia, cum eadem sit materia omnium habentium earn (De gen. et corrup., I. 3, 319 a 33-b 5; c. 5, 320 b 12-14), sequitur ex hoc quod non sint plures formae substantiales in uno composito quam in alio. Immo qui bene pro- sequitur viam istam, videtur esse ponendum in omni composito unam formam sub- stantialem tantum; et ista videtur via Philosophi. Unde VII° Metapliysicae, capitulo ' De unitate diffinitionis,' vult partes diffinitionis non esse unum (Z. 12, 1037 b 22-27) , ' quia sunt in uno,' sed quia dicunt unam naturam. — Quod si intel- ligit unam naturam compositam ex pluribus formis, posset tolerari; sed si intelligit unam naturam simplicem, et quod sit in composito una forma tantum, falsum est." Ibid., p. 8. And in the summa errorum: "11. Quod in quolibet composito sit una forma substantialis tantum." p. 12. ORIGINS OF THE PROBLEM OF UNITY OF FORM 127 imposdbilis.^ Yet, since at the earliest stage the question was not discussed under this aspect, we are still far from knowing how and when the Schoolmen became aware of the problem. We get nearer with Avicenna, who, according to the Errores 'philoso'phorum, explicitly maintained that est una tantum forma suhstantialis in coinpodto. As a matter of fact, this thesis stands at the head in the enumeration of Avicenna's errors. Indeed, in his Metaphysics, section II, in the chapter ' On the division of corporeal substance,' Avicenna holds that the form of the genus is not made specific through anything extrinsic. By this he implies that the form of the species is not some essence besides the essence of the form of the genus. ^ This is a clear statement of the unity thesis. Elsewhere too, as for instance, in the Sufficieiitia, Avicenna firmly expresses the same view: one and the same substantial form makes matter a definite kind of body and a body: Non est alia jorma qua ignis est ignis et qua est corpus.^ None the less, the weight of these arguments was felt only at a later and more developed period of the debate. At all events, we can trace its very beginning to Avicenna's Liher sextus naturaliuTn, or De anima, translated into Latin at Toledo in the second half of the twelfth century by Dominic Gundissalinus and his associates, who also rendered into Latin Algazel and Ibn Gebirol's Pons vitae. Avicenna argues from the unity of the human soul to its substantiality. Since it is the soul that makes man what he is and constitutes him in his species, if there were in man diverse souls, man would be in diverse species.^ Moreover, he posits unequivocally that the ' Cf. among others, St. Thomas Aquinas, De s'piritualihus creaturis, a. 3 (ed. L. W. Keeler, Romae: Gregorianum, 1938, p. 42) . ' " 1 . Avicenna autem similiter videtur errasse ponens unam formam in com- posite, ut patet in Il° tractatu Metaphysicae suae, capitulo * De divisione sub- stantiae corporeae ' (ed. Venetiis, 1508, fol. 76ra) , ubi vult quod forma generis non specificetur per aliquod extrinsecum. Per quod innuitur quod forma speciei non sit aliqua essentia praeter essentiam formae generis." Ibid., pp. 24-26. Summa: "1. Quod est tantum una forma substantialis in composito." p. 34. ^ Avicenna, Sufficientia, II, c. 3. ' " Anima ergo perfectio est subiecti quod est constitutus ab ea. Est etiam 128 DANIEL A. CALLUS human soul, while possessing a multiplicity of powers, namely vegetative, sensitive and rational, is essentially one; for it is one and the same principle that gives life and movement, and governs and acts in man/° Gundissalinus is known to us not only as a translator, but also as an author. His treatises, in which he made full use of his own translations, chiefly of Avicenna and Gebirol, are important not so much for his personal contribution to medieval thought — for he is rather a compiler than an original thinker — as for his being the first to utilize and attempt a systematic exposition of the new learning, thus opening up fresh subjects constituens speciem et perficiens earn. Res enim habentes animas diversas fiunf propter eas diversarum specierum, et fit earum alteritas specie non singularitate; ergo anima non est de accidentibus quibus non specificantur species, nee recipiuntur in constitutione subiecti. Anima enim est perfectio substantiae, non ut accidens." De anima, I, c. 3 ( ed. cit., fol. 4ra) . I have collated Avicenna's text with Bodleian Library, Oxford, MS Bodl. 463 (S. C. 2456). ^° " Postea autem declarabitur tibi quod anima una est ex qua defluunt hae vires in membra, sed praecedit actio aliquarum, et consequitur actio aliarum secundum aptitudinem instrumenti. Ergo anima quae est in omni animali ipsa est congregans principia sive materias sui corporis, et coniungens et componens eas eo modo quo mereantur fieri corpus eius; et ipsa est conservans hoc corpus secundum ordinem quo decet, et propter eam non dissolvunt illud extrinseca permanentia, quamdiu anima fuerit in illo, alioquin non remaneret in propria sanitate." Ibid., fol. 3vb. Cf. P. V, cap. 7, fol. 27r S. — Deviating, however, from his own principles, Avicenna held that the substantial forms of the elements remain entire in the mixed bodies, an inconsistency which cannot be explained save by assuming that he did not foresee all the consequences implied in his premises. See Sufficientia, I, c. 10, fol. 19rb; Metaph., VIII, c. 2, fol. 97vb-98ra; De anima, IV, c. 5. Cf. St. Thomas, Summa tkeologiae, I, q. 76, a. 4 ad 4. It has also been urged that Avicenna's theory on the forma corporeitatis is in support of the pluralist view. That it may be inter- preted as advocating pluralism is beyond doubt. In this sense it was understood and criticized by Averroes. The phrase itself is ambiguous, and because of its ambiguitj' it was avoided by Aquinas. Nevertheless, it seems to have a different meaning in Avicenna, as M.-D. Roland-Gosselin (Le " De Ente et Essentia " de s. Thomas d'Aquin [Bibliotheque Thomiste, VIII; Kain, 1926] pp. 104 fl.) , A. Forest (La structure metaphysique du concret selon saint Thomas d'Aquin [Etudes de Philosophic medievale, XIV; Paris, 1931] pp. 189 ff.) and others maintain. At any rate, Avicenna himself did not use it, it seems, in the sense assumed by the pluralists, namely as meaning the first substantial form that makes matter to be a body apart from, and previous to, its specific form. His teaching, that it is one and the same substantial form which makes matter a definite kind of body and a body, remained unaltered. ORIGINS OF THE PROBLEM OF UNITY OF FORM 129 of inquiry and new approaches to old problems. It was through his treatise De anima, together with Avicenna's Liher sextus naturalium, that the question concerning unity of form reached the schools. Gundissalinus deals with the question in Chapter IV: Anima an una vel multae, a faithful echo of Avicenna's An sit una an multae. Following Avicenna closely, Gundissalinus discusses two dis- tinct questions. The first is whether in all living beings there is one single soul which, though in itself one substance, in virtue of its manifold powers performs the function of vegetative life in plants, of sensation in animals, of intellect and reason in man. Thus, a single rational soul produces, according to its various powers, vegetation alone in the bones, hair and nails, in other parts of the body sensation and movement, and in the brain intellect and reason. Or again, to use a simile, just as one and the same solar ray causes different effects in different things, hardening the clay and melting the wax, so one and the same soul, according to diversity of bodies, operates diversely, bestowing upon some mere existence, upon others sensation, and making others rational beings.^^ The other question propounded here is whether in man the vegetative, the sensitive and the rational are three distinct souls and substances, or one soul and one substance only. It is obvious that the former topic is not to be confused with the latter; they are two distinct problems. The first opinion, qualified as erroneous, is rejected (hunc er- rorejn ita destruunt philosophi) . Gundissalinus argues against it that these three are in reality not only three powers, but three souls specifically distinct from each other, the vegetative which is in plants alone, the sensitive which is in brute animals, and the rational which is in man. The evidence that they are distinct from each other is that each one possesses a separate existence; hence one cannot be the other. The vegetative is like ^^ " The Treatise De Anima of Dom'micus Gundissalinus," ed. J. T. Muclde, Mediaeval Studies, II (1940), 44. 130 DANIEL A. CALLUS the genus to its species; it is therefore in plants as well as in animals; but plants and animals are specifically diversified. Nevertheless, from the fact that each taken separately is speci- fically distinct, it does not follow that they are also distinct subsances when they are united. For instance, a palm tree and a vine are both a tree, that is, they are endowed with vegetative soul, a power of self-nurishment and growth. Yet for a palm or a vine there is not required another soul in addition to the vegetative soul, namely, the soul of a palm or of a vine. It is one and the same soul that makes the living, growing tree a palm or a vine.^" Likewise the three vital powers, vegetative, sensitive and ra- tional, exist in man. Taken separately, each one is a substance distinct from the other, but this is not the case when they are jointly existing in man. As the sensitive includes the vegetative and has something else besides, that is, sensitivity, so the human soul is one single substance {cum sit una simjjlex sub- stantia) , implying in itself, not only the rational but also the vegetative and the sensitive, not however as distinct substances {nan tamen tres substantiae sunt in homine) , but simply as dis- tinct powers. Moisture and heat, taken separately, are dif- ferent, but conjoined in vapor they make one single thing,^^ The higher soul presupposes the lower, without which it can- not exist. Neither can the sensitive exist without the vegeta- tive, nor the rational, in its turn, exist without the vegetative and the sensitive. But the lower form, when conjoined with the higher, has not a separate existence, but is implied in the higher, " Ibid., pp. 44-45. ^' " Quamvis autem omnis anima sit substantia et hae tres simul sint in unoquo- que homine, quoniam in homine est anima vegetabilis, et sensibilis, et rationalis, non tamen tres substantiae sunt in homine; humana enim anima, cum sit una simplex substantia, habet vires animae vegetabilis et vires animae sensibilis et vires animae rationalis; similiter et anima sensibilis habet vires animae vegetabilis. Et quamvis hae vires diversae sint inter se, ita ut una earum non praedicetur de altera, quippe cum unaquaeque earum sit species per se, tamen nihil prohibet eas simul haberi ab anima rationali. Quemadmodum, quia invenimus humorem in aere non separatum a calore, non tamen idcirco necesse est ut humorem et calorem qui sunt in aere non habeat aliqua una forma vel aliqua una materia. Sic et de viribus animarum." Ibid., p. 45. ORIGINS OF THE PROBLEM OF UNITY OF FORM 131 since the higher possesses all that the lower has and something more besides: the higher the soul, the greater the power, the more comprehensive its virtue. The power which supervenes, being stronger, becomes the principle of that which preceded and remains the only principle and cause of all the powers and virtues operating there. Similarly with regard to the sen- sitive and rational souls, just as when the sensitive soul super- venes, the vegetative is superseded, so with the appearance of the rational soul all the operations both of the vegetative and of the sensitive are effected by the rational. The latter vir- tually includes the former, not in the sense that we can dis- tinguish in the sensitive two souls or substances, and in the rational three, but in the sense that one single soul, the highest, has the power to produce all the operations performed by the vegetative and the sensitive souls.^* Gundissalinus reaches the same conclusion in Chapter II, when he is discussing the substantiality of the soul. The soul is a substance and not an accident, since there is one soul only in a living composite, whether it be a tree, an animal or a man. To prove, in turn, the unity of the soul, he argues that it is the soul that makes man what he is and imparts to him his specific nature, for it is the self-same principle that bestows life and movement, and governs and acts in man. It is not by reason of two or more principles, but by virtue of the self-same prin- ^* " Quaedam non recipiunt nisi animam vegetabilem tantum, quaedam vero amplius quia animalem; quaedam vero multo amplius quia rationalem. Quemad- modura si corpus unum ponatur ad solem cuius situs talis esse potest ut non recipiat a sole nisi calorem tantum; si vero talis fuerit eius situs ut recipiat ab eo calorem et illuminationem, tunc simul calefiet et illuminabitur, et lux cadens in illud erit principium calefaciendi illud: sol enim non calefacit nisi radio. Deinde si maior fuerit eius aptitudo ut etiam possit accendi, accendetur et fiet flamma, quae flamma erit etiam causa calefaciendi et illuminandi simul ita ut quamvis sola esset, tamen perficeretur calefactio et illuminatio, et praeter hoc calefactio poterat invenire per se sola, vel calefactio et illuminatio sola per se, quorum posterius non esset principium a quo emanaret prius. Cum autem omnia simul concurrunt, tunc id quod fuerat posterius fit principium etiam prioris et emanat ab eo id quod erat prius. Sic ergo dispositionem virium animarum facile intelligere poteris, si per corpus calefieri intelligas illud tantum vegetari, et per illuminari illud ab anima sensificari, per accendi vero animam rationalem sibi infundi." Ibid., p. 46. 132 DANIEL A. CALLUS ciple, namely the soul, that an organic body is a body and a definite kind of body, that is, an animal or human body, since whatever perfection is superadded to an already constituted being does not impart a specific being, but merely an acci- dental being, or a mode of being. Unless we admit the patent contradiction that one and the same being could belong to two different species, we must agree that the soul confers on the organic composite a complete substantial being, and conse- quently that the soul is only one. In fact, as soon as the soul departs from the body, the body is no longer an animal or human body, but becomes something else, with an utterly dif- ferent nature. ^^ Professor E. Gilson has correctly remarked that there is complete agreement between Avicenna and Gundis- salinus on the concept of the unity of the soul in a composite. ^*^ I have dwelt at some length on this point, for it is of no mean importance in determining the exact source of the unity thesis. It is true that, strictly speaking, the discussion turned primarily on the unity of the soul; obviously, as we have already noted, a different question from that of the unity of substantial form. Nonetheless, Gundissalinus, presenting ^^ " Nam corpus proprium, in quo existit unaquaeque animarum, scilicet tarn vegetabilis quam sensibilis quam etiam rationalis, non est id quod est ex com- plexione propria sed ex anima. Anima enim est quae facit illud esse illius com- plexionis, nee permanet in complexione propria in actu nisi quamdiu fuerit anima in illo. Anima enim sine dubio est causa per quam vegetabile et animal sunt illius complexionis; ipsa enim anima est principium generationis et vegetationis. Unde impossibile est ut proprium subiectum animae sit id quod est in actu nisi per animam. Non enim verum est ut proprium subiectum animae prius constituatur ab alio, cui postea adveniat anima quasi non habens partem in eius constitutione vel definitione, sicut accidentia quae consequuntur esse rei consecutione necessaria, non constituentia illud in actu. Immo ipsa anima constituit ipsum proprium subiectum et dat ei esse in actu. Cum vero anima separatur ab eo, succedit necessario cum separatione eius alia forma, quae est sicut opposita formae complexionali. Haec enim forma et haec materia, quam habebat dum aderat anima, non remanet post animam in sua specie, quoniam destruitur eius species et eius substantia quae erat subiectum animae." Ibid., chap. 2, p. 41. " Les deux philosophes se trouvent done avoir du meme coup une conception identique de I'unite de I'ame dans le compose." E. Gilson, " Les sources greco- arabes de I'Augustinisme avicennisant," Archives d'hist. doctr. et litt. du M-A., IV (1929), 84. ORIGINS OF THE PROBLEM OF UNITY OF FORM 133 Avicenna's treatment more systematically, provided the School- men with the main elements of the problem by asserting un- ambiguously (i) that the vegetative, the sensitive and the rational, though three distinct substances when taken sepa- rately, are one simple substance when united; (ii) that the higher principle includes the lower, which is only virtually present when the higher supervenes; (iii) that whatever per- fection is superadded to an already constituted being does not impart specific being, but merely accidental being; and conse- quently (iv) that the vegetative, the sensitive and the rational are in man not three distinct substances, but powers. The formulation, the arguments and similies set forth by Gundis- salinus will become a common patrimony and will be continu- ally used in more or less refined fashion by successive genera- tions of masters. Some confusion as to the unity of soul or sub- stance will linger for a time, but soon philosophers and theo- logians will accurately distinguish between the question of the unity of soul and the unity of substance or form. Turning our attention now to the pluralist theory, Aquinas ^^ traced its source remotely to Plato and proximately to Avice- bron (Ibn Gebirol) . Both systems issue from the same root, both present as reality what is a mere distinction of the mind, and one is the sequel of the other.^^ The pluralist theory, in fact, follows logically from Platonic presuppositions. Plato holds that there are several souls in a body, distinct according to different organs and their various vital actions, such as the nutritive in the liver, the concupiscible in the heart, and the knowing in the brain. ^^ Furthermore, he maintains that the human soul is united to the body not as form to matter, but merely as mover to the moved, just like a sailor in a boat; and again, that man is not composed of soul and body, but that ^' St. Thomas, De spiritualihus creaturis, a. 3 (ed. Keeler, pp. 40-41) . ^^ St. Thomas, Summa theoL, I, q. 76, aa. 3-4. " Et haec positio [Avicebron's], quamvis videatur discordare a prima [Plato's], tamen secundum veritatem rei cum ea concordat, et est sequela eius." De spirit, creat., loc. cit. ^" Cf. St. Thomas, QQ. dis-p. de anima, a. 11: " Plato posuit diversas animas esse in corpore; et hoc quidem consequens erat suis principiis." Also Summa theoL, I, q. 76, a. 3. 134 DANIEL A. CALLUS man is a soul using a body. In all these cases the resultant union would not be essential but accidental. Now in things accidentally united there may be plurality of forms without any incongruity. Nevertheless, the main true source from which the pluralist theory has come down to the Schoolmen is undoubtedly Avice- bron.-° The keystone of his system is his doctrine of the ' uni- versal matter ' (materia universalis) and ' universal form ' (fonna universalis) : the two roots from which every thing, save God, comes forth and into which it is ultimately resolved. ^^ Universal matter is one and the same, and is necessarily devoid of every form; it becomes substance by its composition with universal form. Substances are essentially different because they have diverse forms; each form conferring a special degree of being corresponding to its own nature, independently of the other. Since every thing possesses its special matter and its special form of which it is never stripped, and, at the same time, the new added form remains with the previous form or forms, it logically follows that in one and the same individual we must posit as many substantial forms as there are perfections or degrees of being," " It must be taken for granted," he says, " that man owes his humanity to the human form, his animality to the animal form, his life to the vegetative form, his body to the form of corporeity, and his substance to the universal form." '' ^° " Circa ordinem formarum est duplex opinio: una est Avicebron et quorumdam sequacium eius." St. Thomas, Quodl. XI, a. 5. Cf. Comm. in 11 De anima, lect. 1 (ed. Pirotta, n. 225); In 1 Dc gen. et corrup., lect. 10 (ed. Leonina, n. 8); De spirit, creat., a. 1 ad 9; a. 3, etc. See M. Wittmann, Die Stellung des hi. Thomas von Aquin zu Avencebrol (Ibn Gebirol) , (B. G.P.M., III, 3) Miinster i. Westf., 1900. Materia universalis et forma universalis . . . haec duo sunt radix omnium et ex his generatum est quicquid est, . . . haec natura praecedunt omnia, et in ea etiam resolvuntur omnia." Avencebrolis, Fans Vitae ex Arabico in Latinum trans- latus ab lohanne llispano et Dominico Gundissalino, primum edidit C. Baeumker (B.G.P.M., I, 2-4) Munster i. Westf., 1892-95. I, 5, p. 7. '"' Fons vitae, II, 2 (ed. cit., pp. 26-27) . Tanquam certum . . . quod forma naturae est aliud a forma animae vege- tabilis, et quod forma animae vegetabilis alia est a forma animae sensibilis, et ORIGINS OF THE PROBLEM OF UNITY OF FORM 1S5 As Gimdissalinus in his De anima made known the unity thesis of Avicenna, so it was he too who in his other treatises popularized Avicebron's theory. In the De processiojie mundi -* we meet with the same description of matter and form as in Avicebron, whereas in the De imitate ^^ (wrongly attributed to Boethius "") he reproduced almost verbatim Avicebron's teach- ing on the various degrees of forms. By bringing these theories to the fore, Gundissalinus contributed considerably to the spread of an utterly un-Aristotelian notion of matter and form which is at the base of all pluralism. Again, by proclaiming that other Avicebronian tenet, that quicquid iritellectus dividit et resolvit in aliquid, com'positmn est ex his in quae resolvitur, he provided the pluralists with the fundamental principle on which their thesis stands.^^ All things considered, we may unhesitatingly conclude that the main sources from which medieval speculation drew the philosophical problem with which we are concerned were Avi- quod forma animae sensibilis alia est a forma animae rationalis, et quod forma animae rationalis alia est a forma intelligentiae." Ibid., IV, 3 (pp. 215-216). Cf. Ill, 46 (pp. 181-2); V, 34 (p. 320). ^* Dcs Dominicus Gundissalinus Schrift ' Von detn Hervorgange der Welt ' (De processione mundi), ed. G. Biilow (B. G. P. M., XXIV, 3) Miinster, 1925, p. 30: " Materia est prima substantia per se existens, substentatrix diversitatis, una numero. Item, materia prima est substantia receptibilis omnium formarum." Cf. Fo-ns vitae, V, 22 (p. 298) . Also loc. cit.: " Forma vero prima est substantia con- stituens essentiam omnium formarum." Cf. Fans vitae, ibid. ^^ Die dent Boethius fdlschlich zugeschriebene Abhandlung des Dominicus Gundi- salvi De Unitate, ed. P. Correns (E.G. P. M., I, 1) Munster, 1891, p. 8: "Quia igitur materia in supremis formata est forma intelligentiae, deinde forma rationalis animae, postea vero forma sensibilis animae, deinde inferius forma animae vege- tabilis, deinde forma naturae, ad ultimum autem in infimis forma corporis: hoc non accidit ex diversitate virtutis agentis, sed ex aptitudine materiae suscipentis." Cf. Pons vitae, V, 20 (p. 295) . ** St. Thomas has remarked that the De unitate was wrongly attributed to Boethuis: " Dicedum quod liber De unitate et uno non est Boethii, ut ipse stilus indicat." De spirit, creat., a. 1 ad 21 (ed. cit., p. 18) . ^' De processione mundi, ed. cit., p. 4; cf. Fans vitae, II, 16: " Quicquid com- positorum intelligentia dividit et resolvit in aliud, est compositum ex illo in quod resolvitur" (p. 51). See St. Thomas, loc. cit. Cf. Wittmann, op. cit., pp. 17-18; M. de Wulf, Le traite ' De Unitate Formae ' de Gilles de Lessines (Les Philosophes Beiges, I), Louvain, 1901, p. 35. 136 DANIEL A. CALLUS cenna for the unity thesis and Avicebron for the pluralist theory, Gundissalinus being the immediate channel through which the same problem reached the schools. In thirteenth-century writings A\acebron is expressly men- tioned less than Avicenna (the Schoolmen, it seems, were some- what shy of referring to him by name) ; yet his influence is not to be underrated, chiefly among the so-called Augustinians and in the Franciscan school, particularly at Oxford. There were, however, other factors which helped to strengthen the pluralist theory. Not least among these was the De differ- entia spiritus et animae of Costa-ben-Luca,"** the Constabulinus of the schools. This short treatise exerted no little influence on medieval physiological and psychological thought. From it Gundissalinus in his De anima borrowed Plato's and Aristotle's definitions of the soul.^^ It helped to sanction the difference between ' spirit ' and ' soul ' ^° and to posit an intermediary uniting the soul to the body. The soul is united to the body by means of a corporeal ' spirit,' which, inasmuch as it comes forth from the heart, produces life, breath and beating of the pulse; as proceeding from the brain, it causes sensation and movement."^ Further, Costa-ben-Luca holds that the three powers of the soul, the vegetative, the sensitive and the ra- tional, are forms and genera of soul, and may at choice be called animae.^- Thus, by introducing an ambiguous teraiinology, he rendered an already involved theory even more confused. The Liber de causis, springing from the same Neo-Platonic ^* Excerpta e libra Aljredi Anglici De mofu cordis. Item Costae-ben-Lucae De diferentia animae et spiritus liber translatus a Johanne Hispalensi, ed. C. S. Barach (Bibl. Phil. Med. Aetatis, II), Innsbruck, 1878. ^* Cf. Gundissalinus, De anima, chap. 2 (ed. Muckle, pp. 37-41) . ^° The difference between spiritus and anima is also clearly stated by Isaac Israeli in his Liber de definitionibus, translated by Gerard of Cremona, ed. by J. T. Muckle in Archives d'hist. doctr. et litt. du M.-A., XI (1937-38), 318-19. *^ Costa-ben-Luca, De differentia animae et spiritus, cap. 4 (ed. cit., p. 138) ; cf. cap. 1, pp. 121, 124, and cap. 2, pp. 124, 130. " Nunc loquarum de virtutibus animae, et dicamus, quod primae virtutes animae, quae sunt ei formae et genera, sunt tres: prima, scilicet vegetativa, secunda sensibilis, tertia rationalis, et hae virtutes vocantur ad placltum animae." op. cit., cap. 3, p. 137. ORIGINS OF THE PROBLEM OF UNITY OF FORM 137 source as Avicebron's Fons vitae, supplied a fresh argument in support of the pluralist view. We have it from Roland of Cremona, that some, to prove that there are three souls in man, based their contention on the authority of the book De pura honitate, proposition I."" (It is well known that in some ancient manuscripts the Liber de causis is entitled De pura honitate.) On the other hand, Albertus Magnus adduces this very same first proposition to demonstrate that such an assumption is untenable. " To admit three souls in man," he argues, " would destroy the order of formal causes, which is against the Phi- losopher's ^* teaching in the De causis, that the causes are dis- posed in a certain order: being, living, sentient, intelligent. For in that case the second cause would in no way be influenced by the first cause, whereas it is by virtue of that influence that a cause is and is a cause." ^^ These are the main sources from which the Schoolmen de- rived their knowledge of the problem under consideration and drew their arguments in favor of or against either opinion. Secondary channels, however, concurred to feed the stream. We may mention, for instance, the pseudo-Augustinian De spiritu et anima,^^ utilized by John de la Rochelle,^' St. x41bert *^ '' Et probant illud idem per primam propositionem quae est in libro De pura honitate." Text edited by Dom Odon Lottin, 0. S. B., " L'Unite de I'ame humaine avant saint Thomas d'Aquin," Psychologic et Morale aux XIP et XIIP siecles, 2nd edition (Gembloux, 1957) , I, p. 465. ^* The Liber de causis was attributed to Aristotle in the thirteenth century until Aquinas discovered its true origin when William of Moerbeke translated the Elementatio theologica of Proclus from the Greek (Viterbo, 18 March 1268) . ^^ " Hoc autem dato (quod vegetativum, sensitivum, intellectivum sint per sub- stantiam separata) , sequuntur duo inconvenientia, quorum unum est. . . . Aliud autem est, quod destruitur ordo causarum formalium: quia secunda causa non habebit a primaria quod est, et quod causa est. Sunt enim ordinatae causae for- males, esse, vivum, sensitivum, intellectivum, ut dicit Philosophus in libro De causis." De anima. III, tr. V, c. 4 (ed. Borgnet, V, 418 b) . ^^ De spiritu et anima, PL 40, 779-832. It was attributed to St. Augustine by many in the thirteenth century, but not by St. Thomas. See G. Thery, " L'authen- ticite du ' De spiritu et anima ' dans saint Tlaomas et Albert le Grand," Revue des Sciences philosophiques et theologiques, X (1921) , 373-377. *^ " Dicamus ergo secundum Augustinum in libro De anima et spiritu: ' Una et eadem est animae substantia vegetabilis, sensibilis et rationalis, secundum diversas 138 DANIEL A. CALLUS and others '« in support of the unity thesis, and by the plural- ists for their embryo-genesis theory.^** Medieval thinkers would make their approach from various standpoints. Arguments were drawn from the most disparate sources; a simile, an obiter dictum frequently offered ample matter for speculation. What might seem to us quite an insignificant, tentative suggestion sometimes gave rise to long and important controversies. It is, therefore, not surprising that there were indeed other factors which mingled with these to strengthen the development and growth of the problem. The next question with which we are confronted is when did the problem itself reach the Universities of Paris and Oxford.^ Although it is beyond doubt that the problem was discussed in the schools in the first decades of the thirteenth century, at the latest, it would surely be rash, in our fragmentary knowl- edge of this period, to assert definitely who were the first masters to introduce it. It is rather disappointing that Daniel of Morley makes no allusion to it in his Pliilosophia.'^° In one so familiar with Avicenna and Arabic learning, we should expect to find an echo of the discussions held at Toledo on psychological mat- potentias diversa vocabula sortitur ' [c. 13, PL 40, 788-9]." La Summa De Anima di Frate Giovanni della Rochelle, ed. T. Domenichelli (Prato, 1882) , p. 138. Cf. also Richard Rufus of Cornwall, for whom see D. A. Callus, " Two early Oxford Masters on the Problem of Plurality of Forms: Adam of Buckfield — Richard Rufus of Cornwall," Revue neoscolastique de Philosophic, XLII (1939), 439. "* Albertus Magnus, Summa de creaturis, II, q. ,7 a. 1 : " Ex his omnibus accipi- tur, quod sententia omnium philosophorum est, quod vegetabile, sensible, et rationale in homine sunt una substantia. Et hoc expresse dicit Augustinus in libro De spiritu et anima." (ed. Borgnet, XXXV, 90 b) . *° De spiritu et anima, cap. 9: " Vegetatur tamen (humanum corpus) et movetur et crescit et humanam formam in utero recipit, priusquam animam rationalem recipiat. Sicut etiam virgulta et herbas sine anima moveri et incrementum habere videmus." (PL 40, 784-5) Daniels von Morley Liber de naturis inferiorum et superiorum," ed. K. SudhofT, Archiv fiir die Geschichte der Naturioissenschajten und der Technik, VIII (1918). See A. Birkenmajer's remarks on this edition, ibid., IX (1920), 45-51. ORIGINS OF THE PROBLEM OF UNITY OF FORM 139 ters; but he has purposely, it seems, avoided the subject to devote himself entirely to cosmology and astronomy: ostenso itaque ex quihus diversitatihus homo constet, turn in anima tuiii in cor pore, quoniam ad praesens non spectat negotium in huiusmodi diutius jnorari, ad constitutionem mundi, unde sermo venit, prius stilum iiiclino.'^^ Alexander Nequam taught in Paris at the school of Petit Pont in the last quarter of the twelfth century, and about 1190 was lecturing in theology at Oxford. Seemingly he was in a position to know the main questions of the day. Yet in the De naturis rerum and in the De laudihus divinae sapientiae summing up the problems concerning man, which were then current in the schools,*" he has not a word on our topic, though he was familiar with the connected question, whether the soul and the body are united by means of a medium.*^ Moreover, in Books III and IV of his theological work, the Speculum speculatio?ium,** he has a short treatise on the soul, which would have offered him a good opportunity of introducing the point at issue, considering especially his acquaintance with Avicenna's De anima. Again, in Chapter XC, De viribus animae, he has a long discourse on the powers of the soul, and in Chapter XCIV, De sensualitate, under which heading theo- logians generally discussed our question, he makes no allusion *' Ibid., p. 9. *■ Alexandri Neckam De naturis rerum lihri duo, with the -poem of the same author, De laudibus divinae sapientiae, ed. T. Wright (R. S.) , London, 1863, cap. 173, p. 299. Another set of similar questions is found in De laud. div. sap., dist. X, p. 499. M.-D. Chenu (" Grammaire et theologie aux XII^ et XIII^ siecles," Archives d'hist. doctr. et litt. du M.-A., X (1935-36), 5-28; and " Disciplina. Notes de lexicographie philosophique medievale," Rev. So. phil. et thiol., XXV (1936) , 686-92) has shown the great profit that can be derived from these topics in order to trace the origin and development of much medieval speculation. ** " Nonne maior est contrarietas inter animam et corpus, quae tamen sine aliquo medio coniuncta sunt? " De naturis rerum, cap. 16, ed. cit., p. 55. ^* The Speculum speculationum, written between 1204 and 1213, is extant in one manuscript, British Museum, MS Royal 7 F. I. On Alexander Nequam and other early masters, see R. W. Hunt, " English Learnmg in the late twelfth century," Transactions of the Royal Historical Society, 4th ser., XIX (1936), 19-42; D. A. Callus, Introduction of Aristotelian Learning to Oxford (Proceedings of the British Academy, XXIX, 1943). 140 DANIEL A. CALLUS to it, as though he had never heard of the AristoteHan distinc- tion of the vegetative, the sensitive and the rational. Alfredus Anglicus, or Alfred of Sareshel, well versed in medi- cine and in the natural sciences, was one of the very first to make extensive use of the new Aristotelian learning. His De motu cordis, dedicated to Alexander Nequam (d. 1217) , was introduced in the university curriculum of studies as pars in- ferior fhilosophiae naturalis. It contains in a curious mixture a large body of doctrine common to Neo-Platonic metaphysics and Aristotelian biological and natural philosophy. The re- peated assertion that the soul is one only in every living being, seems to suggest that Alfred had some inkling of the question. He teaches with Aristotle that no living being is without the vegetative soul, since nutrition is indispensable for every thing that grows and decays: a living being must therefore have within itself a principle by which it acquires growth and under- goes decay, that is, soul. Animals are not only living but also sentient beings. But since one and the same principle, not a distinct one, produces life and sensibility, in every living being there must be one soul only. Consequently animals have not two distinct souls, one vegetative and the other sensitive, for from the same soul the operations of life and sensibility arise. By one single principle an animal is a living and a sentient being .■'^ Obviously, this is not an ordered exposition or a thorough treatment of the question, which is rather touched upon occa- sionally and only in passing; it is more presupposed than ex- plicitly and directly stated. The principles upon which the structure of the doctrine is built are laid down, the conclusion inferred is there; but it is referred to only incidentally insofar as it is raised in connection with the general subject matter. *^ Des Alfred von Sareshel (Alfredus Anglicus) Schrift De Motu Cordis, ed. C. Baeumker (B. G. P. M., XXIII, 1-2), Munster i. Westf.. 1923. " Hanc (animam) in quolibet animate unam esse constans est " cap. 13, p. 65; " unius autem una est anima " cap. 8, p. 31; " aninia enim animalis simplex et una est; ex ea autem tantum vivit et sentit animal; ex una igitur causa. Ex ea igitur animal est. A causa igitur uniformi vivit et sentit " cap. 10, p. 43. ORIGINS OF THE PROBLEM OF UNITY OF FORM 14«1 None the less, it is noteworthy that in establishing his point, namely, the unity of the soul in every living being, Alfred urges the same argument advocated before him by Avicenna, and which later will be more elaborately used by Aquinas. Turning our attention now to the Paris theologians of the period, we meet with no explicit mention of the problem in Peter of Poitiers (d. 1205) , in Simon of Toumai (d. 1203) , Praepositinus of Cremona (d. 1210) , Robert Curzon, William de Montibus (d. 1213) , or Stephen Langton. William of Aux- erre (d. 1231) , so keen to turn to profit in his Summa aurea (c. 1220) every new topic, and perhaps the first theologian to make wide use of the new learning, is equally silent. The earliest, to my knowledge, clear and unmistakable ac- count is found in the faculty of Arts, in the treatise On the Soul of John Blund, written not later than 1210.*" Its main source is undoubtedly Avicenna. This treatise, representative of both Paris and Oxford, is a striking example of the deep penetration in the schools of Avicennian theories, under the cloak of Aristotle, at the beginning of the thirteenth century. Like Gundissalinus and Alfredus Anglicus, John Blund belongs to a period of transition, and joins in the attempt to utilize Eastern philosophy in Western thought, linking up the Arabian world with Scholasticism, The elementary way in which the question is treated points unmistakably to its early stage. Its very title, utruvi anhna vegetabilis. sensibilis et rationalis sint in homine eadem anima an diversae, bears the impress of Avicenna. In the table of contents it is described quomodo anima vegetabilis se habeat ad animam sensibilem et rationalem. The chief point of the discussion, in fact, appears to be more logical than psycho- logical, though this is not excluded, namely, whether ' anima ' or ' animatum,' the vegetative soul is a genus or a species; and if a genus, how it is predicated of its species, namely the nutritive soul of animal soul and of rational soul. *'See D. A. Callus, "The treatise of John Blund On the Soul," in Autour d' Aristotle. RecueU d' etudes ofert a Mons. A. Mansion (Louvam, 1955), pp. 471- 495. This treatise will be published shortly. 142 DANIEL A. CALLUS The debate opens by setting forth the evidence in support of the unity view. Three arguments are brought forward: the first two are drawn from the univocal predication of ' animatum ' and ' substance.' (1) Animatum is univocally predicated of a living body, of animal and of man. Now a thing is said to be animated inas- much as it possesses a soul. Since, therefore, animatum, is predi- cated according to the same formal notion signified by the name ' animated,' similarly the soul pertains to each thing possessing a soul according to the same formal notion. Conse- quently, one and the same is the soul of a living body, of animal and of man. (2) Again, ' substance ' is univocally predicated of body, of living body, and of each of its inferiors; and it is specified by the addition of gradual differences, such as corporeal, living, sentient, and so on. Likewise the soul is specified by the addi- tion of vegetative, sensitive, and rational. Now as ' substance ' is a genus with respect to its species, so ' soul ' is a genus with respect to its species. But it cannot be said that there are many substances in one species of substance. For the same reason it should not be said that there are three souls in man, but one soul only. Accordingly, the vegetative, the sensitive and the rational are not three souls, but one soul only. (3) ]\Ioreover, if these were three diverse souls, there would be in reality three souls in man, which is contrary to Avicenna, who teaches that in man it is from the same rational soul that the vegetative life, the sensitive life and the rational life are derived.*^ That they are diverse souls might be argued as follows: (1) If the vegetative, the sensitive and the rational were one soul, then as the rational is incorruptible, so also the vege- tative and the sensitive souls would be incorruptible; and as *' " Si sint diversae aiaimae, contingit hominem habere tres animas in effectu, quod est contra Avicennam, qui dicit quod ab anima rationaJi est in homine vegetatio, sensibilitas, rationalitas." Cambridge, St. John's College, MS 120, fol. 125rb. ORIGINS OF THE PROBLEM OF UNITY OF FORM 14& the rational soul can be separated from the body, enjoying per- petual life, likewise the souls of a tree or of an ass would live forever. (2) The second argument aims at proving that ' soul ' is not a genus; for, since the genus contains something more than each of its species, no genus is equal to its species. Consequently, the vegetative, the sensitive and the rational are three distinct species, not a genus. Blund's answer is that this word soul {hoc nomen * anima ') means the genus of the vegetative, of the sensitive and of the rational souls. Sensitive soul is a subaltern genus, inasmuch as it is a genus with respect to the rational soul, and a species of the vegetative soul. But in man there is only one single soul which imparts vegetative life, sensitivity and reason.*® Doubtless, John Blund's treatment is still quite embryonic, and the real issue is more implied than expressed. Nevertheless, Blund is a definite witness, not only to the fact that the ques- tion was discussed in the schools by the masters of Arts in the first decade of the thirteenth century, but also to the fact that its first solution was in favor of the unity thesis. Its significance lies in this, that we have in this account, however inarticulate it may be, some of the same arguments which were later ad- vanced in the heyday of the conflict by both opponents and defenders: that of the corruptibility or incorruptibility of the soul was adduced by all the pluralists, whereas the supporters of the unity thesis insisted that it is one and the same prin- ciple that gives life, sense and reason to one individual. A few years later Roland of Cremona, the first Dominican master in the University of Paris (1229-1230) , attests that the question had reached the faculty of theology. His statement bears considerable weight for its accuracy and conciseness. There are, he says, three species of souls: the vegetative soul, *^ " Solutio. Dicimus quod hoc nomen ' anima ' significat genus animae vegeta- bilis et animae sensibilis et rationalis. Et in homine est una sola anima a qua est vegetatio, sensus et ratio. Et anima sensibilis est genus subalternum, quia anima sensibilis est genus animae rationalis et species animae vegetabilis." Ibid., fol. 125va. 144 DANIEL A. CALLUS which is in phmts; the sensitive soul, which is in dumb animals; and the rational soul, which is in man alone. Yet there are not three souls in man, as some think. According to these thinkers, there are really three souls in man: the vegetative, the sensitive and the rational. But this is untenable, for of one and the same thing there cannot be but one first perfection, since one and the same thing can have but one existence {unicum esse) . Now all agree that the soul is the perfection of an organized body holding life in potentiality. The vegetative soul, therefore, is the perfection of this body, and likewise the sensitive and the rational soul. It follows, then, that if there were three souls, this body would be perfected in virtue of the first perfection, which is impossible. Again, if the first endows the body with its perfection, the second or the third would serve no purpose.*^ Those who claim that there are three souls in man are per- suaded by this reason: they see that the embryo, even before it is perfected by the sensitive and the rational soul, grows. But growth is exclusively caused by the vegetative soul. Con- sequently, it seems that the vegetative soul is in the embryo before the sensitive and the rational soul. They prove this from the first proposition of the book De pwa bonitate. However, they labor in vain {frustra nituntur) . The embryo is not self- growing or vegetating, but grows in virtue of the mother, inas- much as, previous to the infusion of the rational soul, it is in a certain manner a part of the mother, since the embryo is united to the matrix by cotyledons.^" Accordingly, it remains that the ** " Neque sunt tres animae in homine, quemadmodum quidam putant. Dicunt quod in homine est anima vegetabilis, et anima sensibilis, et anima rationalis. Sed hoc non potest stare, quia unius rei unica est perfectio prima, quia unius rei unicum est esse. Constat autem quod anima est perfectio corporis organici potentia vitam habentis. Ergo haec anima vegetabilis est perfectio huius corporis, et haec anima sensibilis, et haec anima rationalis. Ergo habet hoc unicum corpus vi per- fectionis primae, quod esse non potest. Iterum, si prima perficit, pro nihilo venit secunda vel tertia." Text edited by Dom O. Lottin, Psychologie et Morale aux XW et XIW siecles, 2nd edition (Gembloux: Duculot, 1957) , p. 465. ^^ See, e. g., Alexander Nequam, De naturis reruTn: " Cum enim cotilidonum nexu familiari foetus adhaerens matrici quodammodo pars sit ipsius matris " (ed. cit., p. 240) ; Albertus Magnus, De animalibus, XVI, tr. II, c. 7: " Qualiter per cottilidi- ones fit incrementum embrionis " (ed. Stadler, 1131-3) ; and tr. I, c. 2. ORIGINS OF THE PROBLEM OF UNITY OF FORM 145 vegetative and the sensitive in man are not distinct souls, but powers of the rational soul.^^ Assuredly the development of the problem is as yet at its first stage. The discussion turns on the unity or plurality of souls in man. The solution gives the impression that it is merely outlined and unfinished; it is none the less clear and categorical, and the treatment of the whole question is extremely instruc- tive, Roland based his reasoning on the Aristotelian definition of the soul, regarded as axiomatic. Constat autem quod anima est perfectio corporis organici potentia vitarn habentis. The argument brought forward is the same one that Aquinas will urge and develop to its utmost value in upholding the unity of form not only in man, but in all composites: unius rei unica est perfectio prima, unius rei urdcum est esse, si prima perficit, pro nihilo venit secunda vel tertia. There can be no doubt that the first reaction of the Schoolmen in both faculties of Theology and of Arts was in favor of the unity thesis: the vegetative and the sensitive are not distinct souls in man, but powers of the rational soul. On the other hand, the same argument from the vital opera- tions of the embryo was constantly adduced by the pluralists as the most cogent in stressing their view. It is found wherever the problem is discussed, often with the biblical text. Exodus, 21:22, and always with the same physiological reflection. It was later corroborated with the authority of Aristotle, De generatione animalium, II. 3 {De animalibus XVT. 3, 736 b 1 ff.) .^" To refute this argument William of Auvergne dedi- cated a full chapter to it in his De anima,^^ and in St. Thomas' Quaestio disputata De anima, a. 11, to cite one more instance, no less than nine objections out of twenty are drawn from the embryo-genesis theory. When, however, Roland, trying to argue against this view contends that the embryo grows vege- ^^ " Sensibilis et vegetabilis sunt vires animae rationalis in homine." Ibid. On Roland of Cremona, see E. Filthaut, Roland von Cremona O.P. und die Anfange der Scholastik in Predigerorden (Vechta i. 0., 1936) . ^' See the discussion of this point in Albertus Magnus, De animalibus, ad locum. " De anima, cap. 4, P. II (ed. Orleans, 1674) , fol. 105 b-106 b. 146 DANIEL A. CALLUS tatione matris suae, he is assuming an erroneous fact, though it was taught by many physicians in his day.^* In conclusion: (i) The immediate and main sources of the problem of the unity or plurality of souls and substances in man are Avicenna and Avicebron. The former stood for the unity thesis in every living being; the latter advocated plurality of forms in all compounds. (ii) The problem was formulated by Dominic Gundissalinus, and it reached the schools through him. Under the influence of Avicenna he transmitted the unity thesis in his De anima, but he popularized the opposite view through his other writings drawn chiefly from Avicebron. (iii) Various elements of diverse kind mingled with the main sources: the Platonic-Galenic teaching on the tripartite dis- tinction of the soul and on embryo-genesis; the theory of Costa- ben-Luca and of Isaac Israelita on the vital spiritus as distinct from the soul and as a medium of union with the body; the Liber de causis. All these secondary sources contributed to reinforce the pluralist stream. (iv) The first reaction of the Schoolmen was in support of the unity thesis, both in the faculty of Arts and in the faculty of Theology. Theologians in general held the thesis of one soul, one substance in man; they held that the vegetative, the sensi- tive and the rational in man are not three souls and three substances, or one soul and three substances, but one soul and one substance. St. Albert the Great voicing their view main- tained that " error pessiinus est dicere unius subiecti plures esse substantias, cmn illae substantiae non possunt esse nisi jormae." ^^ And again: " Hunc errorem hucusque in diem sequuntur quidam Latinorum philosophorum, praecipue in sen- ^* Cf . Albertus Magnus, De animalibus, XVI, tr. I, c. 2, where he ascribes such a view to some " de medicorum imperito populo "; St. Thomas, Contra gentiles, II, cap. 89. "^ De unitate intellectus contra Averroem, cap. 13 (ed. Borgnet, IX, 455 b) . ORIGINS OF THE PROBLEM OF UNITY OF FORM 147 sibili, vegetabili et raiionabili, qui dicunt esse diversas sub- stantias et unain animam in corpore haminis." ^^ (v) With Philip the Chancellor (c. 1230) the problem en- tered into its second stage of development. The discussion turned, then, not on the unity or plurality of souls, but defi- nitely on the unity or plurality of substances, whether the vege- tative, the sensitive and the rational are one or three substances in man. Theologians discussed it in their commentaries on Book II, dist. 17, of the Sentences, and also in their quaestiones disputatae and quodlibetales, and later in special treatises. (vi) The masters of Arts generally raised the question in their commentaries on Aristotle's De anima, at the close of Book I or at the beginning of Book II. We have an illuminating clue in Adam of Buckfield (c. 1250) as to their procedure in setting the question. In this passage (411 a 26-411 b 11), he tells us, Aristotle deals with two questions. The first is whether the attributes of the soul, namely understanding, opinion, de- sire and the like, appertain to the soul as a whole, or whether each particular operation is dependent on a particular part; that is, whether the soul as a whole thinks, desires, perceives, or whether one part thinks, another perceives, another desires. The second question is this: Does life reside in one single part of the soul, or in more than one, or in all parts.? According to some, however, Aristotle's intention is to investigate a different problem, namely whether the vegetative, the sensitive and the rational are distinct with respect to their operations, or with respect to a diversity of substance. Buckfield believes that this interpretation is based neither on our translation {jiostram, i. e., the Greek-Latin version) nor on the other {aliam, i. e., from the Arabic) . Aristotle simply meant to maintain against Plato that the soul is not divided into various parts which in turn are located in different organs. Since, therefore, the problem concerning one or more substances in man was left unsolved by the Philosopher, there is room for further inquiry. "De anima, I, tr. II, c. 15 (ed. Borgnet, V, 184 a); III. tr. V, c. 4 (417 b ff.) et alibi passim. 148 DANIEL A. CALLUS Et est hie quaestio: utrum in anima hominis sit eadem sub- stantia intellectivae , sensitivae et vegetativae, an sint sub- stantiae diversae.^' (vii) The question was also raised in the commentaries on Aristotle's Metaphysics, particularly in connection with the " unity of definition " (Z. 12, 1037 b 22-27) , as quoted in the Errores philosophorum {see supra, p. 263) . For instance, we find it discussed at great length in an anonymous commentary by a secular Oxford master of Arts in the first half of the thirteenth century .^^ (viii) Finally, the Aristotelian distinction of the soul into rational and irrational in the Nicomachean Ethics (I. 13) offered another opportunity to theologians and masters of Arts to discuss the question. St. Albert was well aware that this °' " In hac parte intendit [Aristoteles] de opinionibus aliorum, et sistit sua determinatio in prosecutione cuiusdam quaestionis. . . . Cum ita sit, quaestio est, utrum omnes istae actiones attribuantur animae secumdum se totam, ita scilicet quod secundum se totam intelligat, et secundum se totam sentiat, et sic de aliis, an secundum diversas partes sui in diversis membris existentes diversas faciat operationes, ut, scilicet, secundum unam partem sui in uno membro existentem intelligat, et secundum aliam in alio membro existentem sentiat, et sic de aliis. — Adhuc quaerit ulterius, si secundum diversas partes sui in diversis membris existens diversas faciat operationes. Tunc est quaestio adhuc, utrum ab una illarum partium tantum insit vita animali, aut a pluribus, aut ab omnibus; hoc est quaerere, utrum quaelibet pars animae vivificet suum membrum in quo est, aut non. Ista tamen quaestio principalis secundum quosdam aliter intelligitur, ita scilicet, ut intendat Aristoteles quaerere, utrum anima, cum sit una et eadem secundum substantiam et radicem, habeat operationes diversas, an diversificetur substantia ita, scilicet, quod substantia vegetativae sit alia a substantia sensitivae, et sub- stantia sensitivae alia a substantia intellectivae, sicut et operationes diversae sunt. Ista tamen quaestio nee per nostram translationem nee per aliam videtur prae- tendi. . . . Cum iam manifestum sit secundum intentionem Aristotelis in hac liltima parte quod anima est indivisa secxmdum situm et subiectum, et non videtur esse determinatum ab ipso utrum, cum sit indivisa secundum situm et subiectum, simi- liter sit indivisa secundum substantiam, propter hoc circa hoc est dubitandum. Et est hie quaestio: utrum in anima hominis sit eadem substantia intellectivae, sensi- tivae, vegetativae, an sint substantiae diversae." See D. A. Callus, "Two early Oxford Masters," ed. cit., pp. 434-5. "Although in this commentary the question is discussed in Book IX, it refers to the unity of definition. Cf. G. Gal, " Commentarius in Metaphysicam Aristotelis cod. Vat. lat. 4538 fons doctrinae Richardi Rufi," Archivum Franciscanum Histori- cum, XLIII (1950), 216: " Sed modo quaeri potest: si diffinitum . . ." cf. p. 237. ORIGINS OF THE PROBLEM OF UNITY OF FORM 149 topic, strictly speaking, was unrelated to the text. Neverthe- less, because there were various opinions, Albert thought it fitting to inquire into the question, together with the kindred question about whether the powers of the soul are distinct or identical with the essence of the soul.^^ We meet with similar questions in an anonymous commentary on the Ethica nova by a master of iVrts of the first half of the thirteenth century ."^^ But by this time, mid-thirteenth century, the debate was well advanced, and the treatment of the problem was greatly developed. A few years later, the genius of St. Thomas Aquinas will bring its solution to full maturity. Daniel A. Callus, O. P. Blackfriars Oxford, England ^^ " Quamvis considerare horum differentiam [rationabilis et irrationabilis] non pertineat ad banc scientiam, sicut ipse [Aristoteles] dicit, tamen quia de hoc sunt opiniones, quaeritur, utrum. . . . See G. Meersseman, " Die Einheit der mensch- licheii Seele nach Albertus Magnus," Divus Thomas (Frib.), X (1932) 86 ff. "" These questions have been published by Dom O. Lottin, Psychologic et Morale, ed. cit., I, pp. 511-12. THE CELESTIAL MOVERS IN MEDIEVAL PHYSICS IN the spring of 1271 John of Vercelli, Master General of the Order of Preachers, sent a list of forty-three questions to three Dominican Masters in Theology for their considera- tion. Independently of each other, the three theologians were to consider each question carefully and reply promptly keeping in mind the directive of the Master General: (i) Do accepted authorities, the Sancti, maintain the doctrine or opinion con- tained in the articles listed? (ii) Apart from the weight of authorities, does the consultor maintain the aforesaid doctrine or opinion? (iii) Apart from the consultor 's personal views, could the aforesaid doctrine or opinion be tolerated without prejudice to the faith? ^ Clearly the purpose of this question- naire was to safeguard the truths of faith, even where the question raised was one of philosophical opinion or strictly natural science, St, Thomas Aquinas had previously given his decision on most of these questions in two private communiques to the lector of Venice, Bassiano of Lodi,- The official questionnaire of the Master General contained nothing of importance which had not already been considered by St. Thomas in his two private replies. The questions are for the most part idle curiosities and useless fantasies, as the consultors themselves realized. However, the official questionnaire was sent to three outstanding Masters in the Order, and not all the questions are without interest to the modern reader. St. Thomas' reply to the official questionnaire has always been known to Thomists, even though little studied. The reply of the second consultor, * St. Thomas, Responsio ad jr. Joannem Vercdlcnsem de articulis XLII, prooem., ed. R. A. Verardo, O. P., Opuscula Theologica (Turin: Marietti, 1954), I, p. 211. In this list the original q. 8 is missing. * Responsio ad Lcctorem Venetum de articulis XXX and Responsio ad eundem de articulis XXXVI, ed. R. A. Verardo in Opuscula Theologica^ pp. 193-208. 150 CELESTIAL MOVERS IN MEDIEVAL PHYSICS 151 Robert Kilwardby, later archbishop of Canterbury, was dis- covered and published by Fr. M.-D. Chenu, O. P., about thirty years ago.^ Now with the discovery and publication of the reply of the third consultor, the great St. Albert himself,* we are in a position to compare the views of the three Dominican Masters point by point. Among the relatively few interesting questions in the list of forty-three, the first five stand out as particularly important for the historian and philosopher of science. They have to do with the cause or causes of celestial motion. In the order of appear- ance they are as follows: 1) Does God move any physical body immediately.? 2) Are all things which are moved naturally, moved under the angels' ministry moving the celestial bodies.? 3) Are angels the movers of celestial bodies.? 4) Is it infallibly demonstrated according to anyone that angels are the movers of celestial bodies? 5) Assuming that God is not the immediate mover of those bodies, is it infallibly demonstrated that angels are the movers of celestial bodies.? To the casual reader these questions, too, might appear to be useless in this age of scientific progress. Angels, it is frequently thought, have no place in a discussion of scientific questions. Some Catholic scientists, and even some Thomistic philosophers feel considerable embarassment at the mention of angels; they would rather not mention them at all, or at least not mention them as having anything to do with the real world in which we live. In medieval literature the problem of celestial movers was not created by theologians, nor did it take its origin in any point of Catholic faith, although St. Thomas was keenly ' M.-D. Chenu, O. P., " Les Reponses de s. Thomas et de Kilwardby a la con- sultation de Jean de Verceil (1271)," in Melanges Mandonnet (Bibl. Thomiste XIII: Paris 1930), vol. I, pp. 191-222. * James A. Weisheipl, O. P., " The Problemata Determinata XLIII Ascribed to Albertus Magnus (1271)," in Mediaeval Studies, XXII (1960), 303-354. 152 JAMES A. WEISHEIPL aware of the guiding role of faith in this matter. The problem of celestial movers was entirely a scientific one having many ramifications. But here, as in other problems of medieval science, it is not sufficient to know what a particular author maintained. It is far more important to understand the scien- tific problem in its philosophical context and to evaluate the arguments leading to the solution proposed. After all, the best of medieval science is not to be found in the lapidaries, herbals or bestiaries of the Middle Ages; least of all is it to be found in pious legends, sermons or morality plays. Rather it is to be found in the speculative commentaries, treatises and disputa- tions of the schoolmen. These writings, emanating largely from various faculties of the university, are not readily intelli- gible to modern readers, as anyone who has tried to read them can testify. To understand the writings of medieval authors one needs a considerable background in the sources, a specu- lative competence to follow the argumentation, and a famili- arity with medieval practice. Neither the questionnaire of the Master General nor the replies of Albertus Magnus, Thomas Aquinas or Robert Kilwardby can be evaluated correctly with- out reference to the sources, the argumentation and medieval practice. In a review of Chenu's edition of Kilwardby 's reply to the questionnaire, Fr. Mandonnet noted the similarity between the view of Robert Kilwardby and that of John Buridan, the fourteenth century proponent of " impetus " to explain violent motion. Inspired by the thesis of Duhem's J^tudes sur Leonard de Vinci (3™^ serie) , Mandonnet was quick to point out the modernity of Kilwardby 's universal mechanics.^ This sug- gestion was developed at some length by Fr. Chenu in a special study devoted to the origins of " modern science." ® Whatever may be said of the validity of Duhem's well-known thesis, one may perhaps doubt the utility of isolating a particular medieval thesis — in this case one of dubious modernity — to extol the ^P. Mandonnet, O. P., Bulletin Thomiste, III (1930), 137-9. ' M.-D. Chenu, O. P., "Aux origines de la ' Science Moderne,' " in Revue des Sc. Phil, et Theol., XXIX (1940), 206-217. CELESTIAL MOVERS IN MEDIEVAL PHYSICS 153 modernity of medieval science. Even if there should happen to be considerable similarity between some aspect of medieval science and a current scientific view, this would be no more than an interesting curiosity, unless we come to grip with an objective philosophical problem and analyze the issues his- torically and scientifically. A short paper such as this cannot sketch even in broad out- lines a picture of medieval astronomy or the history of its development.' All that can be attempted here is an examina- tion of the problem as seen by each of the three Dominican Masters consulted by the Master General, and an explanation of the views proposed, especially in their response to the oflficial questionnaire. Since our purpose here is to understand the medieval view, we need not be concerned about the true his- torical intent of ancient sources, but only about how the medieval schoolmen interpreted them. That is to say, it is not essential here to understand what Plato, Aristotle, Ptolemy or Al-Bitruji really meant; it is essential only that we understand what St. Albert, St. Thomas and Kilwardby thought them to mean. There is always the possibility that these great school- men misunderstood or misinterpreted their sources, but this makes little, if any, difference to the medieval view of the scientific problem. Preliminary Observations In the traditional division of the speculative sciences derived from Plato and Aristotle, astronomy occupied a peculiar posi- tion. By astronomy we do not mean the elementary calculation of movable feast days, the Epact or the Golden Number; nor do we mean identification of the signs of the zodiac or prognosti- cations from conjunctions. By astronomy is meant the theo- retical sciences which attempts to make celestial phenomena intelligible by means of mathematical principles. The peculiar position of this theoretical science can be recognized clearly in the writings of the three consultors. '' An outline can be found in P. Duhem, Le Systeme du Monde (Paris: Hermann, 1954). vol. III. 154 JAMES A. WEISHEIPL In the first place, astronomy was classified with optics, mechanics, harmonics and other scientiae mediae between the sciences of pure mathematics and natural science.^ As a sci- ence intermediate between mathematics and physics, astronomy was considered from three points of view. First, it was con- sidered in relation to the higher science of mathematics, to which it is subalternated and on which it depends for its scien- tific validity. Astronomy, it was said, accepts as established all the conclusions of geometry and applies them to the known measurements of celestial phenomena. In this consideration, astronomy and the other scientiae mediae " have a closer affinity to mathematics, because what is physical in their con- sideration functions as something material, while what is mathematical functions as something formal." ^ Intelligibility in every science was taken as derived from the principles, the formal element, as contrasted to the material element which is the conclusion, or fact now understood scientifically.^" We know that mathematical astronomy did not begin until Eu- doxus of Cnidos accepted the challenge from Plato " to find out what are the uniform and ordered movements by the assump- tion of which the phenomena in relation to the movements of the planets can be saved." ^^ The obviously irregular motions in the heavens, tabulated for centuries before Plato, could not be made intelligible except by reducing them, at least in theory, to perfectly regular movements of geometric spheres. In other words, astronomy was taken formally to be a mathematical type of knowledge, extending to measurable quantities of celestial phenomena, such as size, distance, shape, position and velocity. Considered in its own right, astronomy was presented as a true speculative science, demonstrative within its own limits. Unless there be some true demonstrations in astronomy, true * St. Thomas, In I Post. Anal, lect. 1, n. 3; In II Phys., lect. 3, n. 8; In Boeth. de Trin., q. 5, a. 3 ad 5-7; Sum. theol., I-II, q. 35, a. 8; II-II, q. 9, a. 2 ad 3. * In Boeth. de Trin., q. 5, a. 3 ad 6; Sum. theol, II-II, q. 9, a. 2 ad 3. "/n / Post. And., lect. 41, n. 11; Sum. theol, II-II, q. 1, a. 1; q. 9, a. 2 ad 3. " Simplicius, De caclo, ed. Heiberg (Comm. in Arist. Graeca, VII) , p. 488, 18-24. CELESTIAL ]\IOVERS IN MEDIEVAL PHYSICS 155 causal dependencies between principle and conclusion, this knowledge would not deserve the name of science. The mathe- matical principles of astronomy are themselves demonstrated in one of the purely mathematical sciences. Moreover, in theory " mathematical principles can be applied to motion," ^~ and sometimes the application is clear. But very often geometrical figures and principles must be assumed as applicable to the celestial phenomenon under consideration, as in the case of Eudoxus' four spheres to explain the motions of Jupiter, Cal- lippus' seven spheres and Ptolemy's epicycle. Nevertheless, the relationship between the principles assumed, even assumed as applicable, and the celestial phenomenon to be saved can be one of necessity. This connection of necessary dependency of the conclusion on the assumed principles is sufficient to estab- lish astronomy as a demonstrative science. It was in this sense that St. Thomas and St. Albert interpreted Aristotle's state- ment that, " It is the business of the empirical observers to know the fact, of the mathematicians to know the reasoned fact." ^^ Between the mathematical principle and the quantified aspect of the fact, there may well be a propter quid relationship, that is, the immediate, proper and convertible middle term of the measured facts of the conclusion may be the mathematical principle invoked. To this extent astronomy should be called, and was called a true science subalternated to mathematics. To be sure, astronomical science fell far short of the ideal of scientific knowledge described by Aristotle in the Posterior Analytics. It did not demonstrate through the immediate, physical cause of celestial phenomena; at best, it demonstrated through a kind of extrinsic formal cause (secundum causam formalem remotam) of the natural phenomena." Even this, as has already been suggested, is most often in a tentative, dia- lectical and hypothetical manner. Considered in relation to the physically real celestial bodies ^^ St. Thomas, In Boeth. de Trin., q. 5, a. 3 ad 5. "^^Post. Anal., 1, c. 13, 79a2-3. St. Thomas, In I Post. And., lect. 25, n. 4; St. Albert, Lib. I Post. Anal, tr. Ill, c. 7. " St. Thomas, In I Post. Anal., lect. 25, nn. 4 & 6. 150 JAMES A. WEISHEIPL and their movements, astronomy was recognized fully as hypo- thetical. The true causes of celestial motion are extremely difficult for any science to discover. " These matters into which we inquire are difficult since we are able to perceive little of their causes, and the properties of these bodies are more remote from our understanding than the bodies themselves are spatially distant from our eyes." ^^ Simplicius, and possibly Plato before him, was aware that the aim of astronomy is to give 3ome rational account of celestial phenomena, saving all the known facts {'X(i)(,eLv ra ^aivoixeva) .^"^ But as it turns out, all the known facts of astronomy can be explained by a variety of hypotheses. Of course, when a new fact is discovered which cannot be accomodated by the existing hypothesis, then some new hypothesis must be devised to account for the new fact. St. Thomas, commenting on the homocentric spheres of Plato and Eudoxus, observes: The hypotheses which they devised (adinvenerunt) are not neces- sarily true, for although the appearances are saved on the assump- tion of those hypotheses, one does not have to say that they are true, because the phenomena of celestial bodies may perhaps be saved in some other way not yet known to man.^'^ An astronomical hypothesis which accounts for all the known facts is indeed worthy of provisional credence. But every astronomical hypothesis by its very nature was considered by St. Thomas to be provisional and indemonstrative. Speaking of this type of reasoning, St. Thomas notes: Reasoning is employed in another way, not as furnishing an adequate proof of a principle, but as showing how the existing facts are in harmony with a principle already posited; as in astron- omy the theory of eccentrics and epicycles is considered as estab- lished, because thereby the sensible appearances of celestial move- ments can be explained; it is not, however, as if this proof were " St. Thomas, In II De caelo, lect. 17, n. 8. Cf. P. Duhem, " Sc^fetj/ ra ^aLPo/Meva. Essai sur la notion de theorie physique de Platon a Galilee," Annales de philosophie chretienne (Paris), 4 serie, VI (1908), 113 ff., 277 flf., 352 ff, 482 ff., 561 ff. ^' St. Thomas, In II De caelo, lect. 17, n. 2. CELESTIAL MOVERS IN MEDIEVAL PHYSICS 157 [demonstratively] adequate, since some other theory might explain them.^* The tentative and hypothetical character of astronomical theories was commonly recognized from the thirteenth century onward, that is, after the acceptance of both Aristotle and Ptolemy in Latin translation. The homocentric hypotheses of Eudoxus and Callippus were taught in the faculty of arts together with the Ptolemaic hypotheses of epicycles and eccen- trics. The schoolmen frequently discussed the preferability of one over the other in their commentaries on Aristotle. This brings us to the second peculiar characteristic of astron- omy recognized in the Middle Ages, namely that mathematical astronomy was ordained to the discovery of true physical causes in nature. The mathematical character of astronomy was clearly evident to the schoolmen. But as mathematical, it abstracted from all questions of efficient, final and material causality; its concern was with the quantitative formalities of celestial phenomena related functionally to assumed mathe- matical principles. [Astronomi] non considerant motum caeles- tium secundum principia Tnotus, sed potius secundam numerum et mensuram quantitatis suae.^^ This being the case, one might have expected such an abstract science to be an end in itself, a purely speculative science sought for its own sake. In actual fact, however, this was not the view of Albertus Magnus, Thomas Aquinas or Robert Kilwardby. These three men, it is true, did not consider the functional use of astronomy in the same way, but they did consider astronomy to have a func- tional use in discovering real physical causes beyond quantity. In the Second Book of the Physics Aristotle had raised the problem concerning the relation between the mathematical sciences and natural science.-" Taking the case of astronomy, Aristotle posed the dialectic: astronomy is obviously a part of mathematics, but it is also a part of natural science since it ^* St. Thomas, Sum. theoL, I, q. 32, a. I ad 2. " St. Albert, Lib. XI Metaph., tr. 11, cap. 10, ed. Borgnet (Paris: Vives, 1890- 1899), VI, 628a. '" Arist., Phys. II, c. 2, 193b22-194al2. 158 JAMES A. WEISHEIPL considers the sun, moon and stars; therefore mathematics also is a part of natural science. In reply Aristotle distinguished purely mathematical definitions from those of natural science; this is sufficient to establish the sciences as distinct. In confir- mation Aristotle pointed to the quasi-physical character of optics, harmonics and astronomy, which he called to, ^vo-tKajxepa Twv fiadrjixaTcov (Phys., II, 2, 194a7) . Modern translators give the more probable rendering of this phrase as " the more physical of the branches of mathematics." It was in this sense that Averroes (text. comm. 20) and St. Albert (ibidem) had understood the text, William of Moerbeke, however, rendered this phrase with equal grammatical correctness as magis physica quam matheviatica. This translation presented St. Thomas with the opportunity of explaining how astronomy, harmonics and optics pertain, in a certain sense, rather to natural science than to mathematics: Sciences of this kind, although they are intermediate between natural science and mathematics, are here described by the Philoso- pher as more natural than mathematical, because each thing is denominated and specified by its ultimate term; hence since investi- gation in these sciences terminates in natural matter, though by means of mathematical principles, they are more natural than mathematical. . . . Hence astronomy is more natural than mathe- matical.-^ Both St. Albert and St. Thomas recognized two tj^es of astronomy: mathematical astronomy, such as was studied by Eudoxus, Ptolemy and others, and physical astronomy, such as Aristotle discussed in the Physics and De caelo et mundo. This latter astronomy was considered an integral part of natural philosophy. Unlike mathematical astronomy, physical astrono- my attempts to discover all the physical causes of celestial phenomena, the ultimate efficient and final cause as well as the material and intrinsic formal cause. For Albert and Thomas physical astronomy alone indicates the real system of the uni- verse. The difficulties involved in discovering the real system " In 11 Phys., lect. 3, nn. 8-9. See also Sum. theol., II-II, q. 9, a. 2 ad 3. CELESTIAL MOVERS IN MEDIEVAL PHYSICS 159 of the universe, the moving causes of celestial motion, their number and order, are obvious. Consequently this part of natural philosophy abounds with tentative views and argu- ments, having need of mathematical astronomy to suggest possibilities. Discussing the number of celestial movements, Aristotle himself realized the need of " that one of the mathe- matical sciences which is most akin to philosophy, namely of astronomy." ^" He was unable to determine the exact number of distinct celestial motions, but he tentatively adopted the astronomical hypotheses of Callippus minus eight uncertain motions, taking the number of spheres to be forty-seven. From this he argued that " the unmovable substances and principles also may probably be taken as just so many; the assertion of necessity must be left to more powerful thinkers." "^ That there must be many movements and movers was accepted by St. Albert and St. Thomas as certain, but their exact number was hypothetical and not essential to the argument pursued.^* In other words, for St. Albert and St. Thomas mathematical astronomy and the other physical parts of mathematics are considered as ordained to the discovery of physical causes in natural philosophy. The mathematical sciences are, as it were, the dialectical preparation for the real demonstrations in na- tural philosophy. Since all mathematics, even the more physi- cal parts of mathematics, prescind from motion and sensible matter,-^ they are that much removed from reality and need to be evaluated by that science which studies nature as it really exists, in Tuotu et inabstracta. That is to say, the mathe- matical sciences are subordinated to and ordained to the phi- losophy of nature. Consequently, " if there were no substance other than those which are formed by nature, natural science would be the first science." ^^ " Metaph., XII, c. 8, 1073b4-5. "/fete?., 1074al5-17. " St. Albert, Lib. XI Metaph., tr. II, c. 17 & c. 27; St. Thomas, In XII Metaph., lect. 9, n. 2565; lect. 10, n. 2586. "Boethius, De Trinitate, c. 2. ''"Metaph., VI, c. 1, 1026a28-29, and XI, c. 7, 1064b9-10. 160 JAMES A. WEISHEIPL Robert Kilwardby, on the other hand, represents a different tradition in medieval thought.-" His is the Platonic tradition of Robert Grosseteste, Pseudo-Grosseteste and Roger Bacon, which considered natural science ordained to the mathematical, and mathematics ordained to metaphysics. The Platonic hier- archy of the sciences was seen to correspond to a real priority of forms in nature, not, of course, existing apart from sensible reality, but within physical bodies. Thus motion and sensible qualities, the object of natural science, are radicated in the prior forms of pure quantity, the object of mathematics; the forms of quantity, in turn, are radicated in the prior form of nude substance, the concern of metaphysics. Kilwardby, discussing the four mathematical sciences, sees a perfect hierarchy of priority and dignity among the mathematical forms. The lowest of all the mathematical sciences is astronomy, for it con- siders celestial motion through the principles of geometry; hence astronomy is prior to and more abstract than natural science. ^^ Since discrete quantity is simpler and prior to extension, all the sciences which deal with number are prior to geometry. Among these the lower is the ideal harmony of numerical proportions; the science of numerical harmony, therefore, is prior to geometry.-'' The highest and most abstract of all the mathematical sciences is arithmetic, or algebra, quia ipsa ut sic, nulla aliarum indiget.^° Thus arithmetic, the sciences of pure number, is quasi mater aliarum [scientiarum].^^ But as Kilwardby failed to distinguish the numerical " unity " dis- cussed in mathematics from the entitative " unity " convertible with being, he said that it belongs to the metaphysician to explain the cause of plurality in mathematics.^" It may perhaps be a fair interpretation of Kilwardby 's mind "'' See my " Albertus Magnus and the Oxford Platonists," in Proceedings Am. Cath. Phil. Assoc, XXXII (1958), 124-139. ^** Kilwardby, De ortu scientiarum, cap. 16 ad 1. Meiton College, Oxford, MS 261, fol. 25v. ^* Ibid., cap. 24 ad 4, fol. 32ra. *Ubid., cap. 19, fol. 27va. '^Ibid., cap. 22, fol. 28vb. ^'^Ibid., cap. 24 ad 1, fol. 29rb; also cap. 14 ad 2, fol. 24vb. CELESTIAL MOVERS IN MEDIEVAL PHYSICS IGl to say that if there wefe no metaphysics, arithmetic would be the supreme universal science. This contrast, however, with the view of St. Albert and St. Thomas is not perfectly symetri- cal, since Kilwardby did not consider metaphysics to rest on the real existence of " substance other than those which are formed by nature." Nevertheless a clear contrast can be seen between the Platonic orientation upward from nature to mathe- matics and the Aristotelian orientation subordinating mathe- matics to natural philosophy. St. Albert and St. Thomas both defended the autonomy of natural science within the limits of its own piincipia propria illuininantia, distinct from meta- physics and superior to mathematics.^^ The third peculiar characteristic of astronomy recognized in the Middle Ages was the special role it had in the discovery of God's existence. This characteristic was not entirely new. In pagan mythology the celestial bodies were themselves con- sidered gods or at least the inhabitation of the gods. Pagan philosophers such as Plato and Aristotle did not hesitate to call celestial bodies divine. Ptolemy himself saw in astronomy the only secure path to theology: For that special mathematical theory would most readily prepare the way to the theological, since it alone could take good aim at that unchangeable and separate act [God], so close to that act are the properties having to do with translations and arrangements of movements, belonging to those heavenly beings which are sensible and both moving and moved, but eternal and impassible.^ 34 Al-Bitruji, St. Albert frequently points out, had this advantage over the complicated system of Ptolemy that he considered all celestial motions to be derived from a single first mover, who is God.^^ For Kilwardby the path to God rose more tortuously ''^Cf. J. A. Weisheipl, " Albertus Magnus and the Oxford Platonists," ed. cit., pp. 136-139. ^* Ptolemy, Almagest, Bk. I, chap. 1, trans, by R. C. Tahaferro (Great Books of the Western World, 16; Chicago, 1952), p. 6. ^^ Al-Bitruji, De motibus celorum, III, 10-14, trans, by Michael Scot, ed. Francis J. Carmody (Berkeley: Univ. of California, 1952), pp. 79-80; St. Albert, Prob- Jeviata Determinata, q. 1, ed. cit., p. 321; Liber de causis, I, tr. IV, c. 7, ed. Borgnet X, 426b-427b; lib. II, tr. II, c. 1, ed. Borgnet X, 479b-480a et alibi. 162 JAMES A. WEISHEIPL from nature through astronomy, geometry, harmonics, arith- metic to the One of metaphysics; for him the proper subject of metaphysics is God precisely as the first cause of all plurality, material and immaterial .^^ St. Albert's view of the matter is most interesting. Through- out the Metaphysics and Liber de causis St. Albert repeatedly rejected the " Platonic view " which would admit into philoso- phy certain separated substances totally unrelated to celestial movement. " The statement of certain Platonists that there exist separated substances not related to movable bodies, is entirely outside the realm of philosophical discourse, since this cannot be proved by reason." ^^ The separated substances called angels by Avicenna, Algazel, Isaac and Moses Maimoni- des have nothing to do with celestial movement or with celestial bodies; they are independent intermediaries between God and man. For Albert the only demonstrative way to separated sub- stances and to God is through the study of celestial motions. Consequently not only are angels, as revealed in Sacred Scrip- ture, outside philosophical discussion, but the intellectus uni- versaliter agens of celestial motions can be none other than God. That is to say, the first cause of the primum mobile and its diurnal motion is God, and not an intermediary. That God is " the immediate natural mover " of the universe in its diurnal motion is taken by St. Albert as true and demonstrated among those who know anything about philosophy .^^ Whatever modern Thomists may have to say about the famous quinque viae of St. Thomas, it cannot be denied that for Thomas all the proofs progress from terrestrial phenomena through celestial phenomena eventually to God. The question of angels in St. Thomas' philosophy will be considered later. For the present it is important to establish only that in St. Thomas' proofs celestial phenomena do have an important part to play. This is not to say that the validity of those proofs Cf. Kilwardby, De ortu scientiarum, cap. 26, fol. 32rb-va. ''' St. Albert, Liber XI Metaph., tr. II, c. 17, ed. Borgnet VI, 638a; cf. Proble- mata determmata, q. 2, ed. cit., pp. 323-327 ** St. Albert, Problemata determinata, q. 5, ed. cit., p. 328. CELESTIAL ZMOVERS IN IMEDIEVAL PHYSICS 163 depend upon the antiquated astronomy of the Middle Ages. The principle of each proof has universal validity and the line of argumentation transcends all astronomy, ancient, medieval and modem. Nevertheless to see the proofs as St. Thomas saw them, it is necessary to accept, at least historically, the system of the universe as he understood it. There can scarcely be any doubt that St. Thomas' first proof is derived historically from Aristotle's Physics and Meta- physics. This is clearly evident in the detailed analysis pre- sented in Summa contra gentiles, I, c. 13, where Aristotle is explicitly cited as intending to prove the existence of God ex parte motus duabus viis. The first way is a paraphrase of Phys. VII, c. 1 to VIII, c. 5, text. 35; the second corresponds to Phys. VIII, c. 5, text. 36, to the end. The first starts mth the example of solar movement and ends disjunctively with Plato's self-mover of the first sphere or Aristotle's separated mover of the whole. The second starts with various types of self-movents, showing how all must be reduced to some primum movens se quod sit sempiternum, and ends with God as a self-movent. " But since God is not a part of any self-movent, Aristotle in his Metaphysics further discovers from this mover which is a part of a self-movent, another mover entirely distinct, who is God." Two objections to the Aristotelian argument are easily handled. The first, that it assumes the eternity of motion con- trary to the Catholic faith, is shown to be irrelevant, for it makes no difference whether or not motion is eternal; there is still need of an adequate mover. The second, that Aristotle assumes the animation of celestial bodies contrary to the view of many, is likewise shown to be irrelevant, for even if the celes- tial bodies are animated, one must still conclude according to Aristotle's principles to an unmoved mover entirely separated from bodies. A simplified form of this manifestior via is the only one presented by St. Thomas in his Compendium theo- logiae for Brother Reginald of Pipemo. The involvement of celestial bodies in the other proofs for God's existence is not so patent in the text of St. Thomas. However, it ought to be obvious that the argument from effi- 164 JAMES A. WEISHEIPL cient causality includes the universal agency of celestial bodies operating in elementary bodies and in animal reproduction: Even among naturalists it is admitted that above those contrary agencies in nature there is a single first agent, namely the heaven, which is the cause of the diverse motions in those lower bodies. But since in the very heaven there is observed a diversity of posi- tion to which the contrariety of lower bodies is reduced as to a cause, [this diversitj^] must further be reduced to a first mover who is moved neither 'per se nor per accidens.^^ Similarly the argument from possible and necessary beings includes not only terrestrial necessities and contingencies, but also the sempiternal celestial bodies and spiritual substances, which are radically necessary beings. Their necessity for being can, indeed, be seen as derived; therefore beyond them there must exist an absolutely necessary being whose necessity is in no way derived. *° The Platonic, or more specifically, the Avi- cennian *^ argument concerning perfections clearly includes the immutable celestial bodies in the participated inequality of being and goodness, an inequality which needs to be derived from a single source which is essentially being, goodness and supreme perfection. The fifth argument likewise includes the influence of celestial bodies and separated intelligences on natural operations.*" Natural terrestrial operations, influenced by celestial motions, the light and heat of the sun, are appar- ently purposeful operations of nature; all such operations of nature require the direction of intelligence {cypus naturae est opus intelligentiae) . Historically, then, the five proofs of St. Thomas for the exist- ence of God involve celestial bodies and their movement as he understood them. Therefore a careful consideration of celes- tial phenomena in the physics of St. Thomas is not without ^* St. Thomas, De pot., q. 3, a. 6. *° St. Thomas, De pot., q. 5, a. 3. *^ De pot., q. 3, a. 5. *'' De verit., q. 5, a. 2; Sum. contra gentiles, I, cap. 13. Cf. Averroes, In II Phys., comm. 75. CELESTIAL MOVERS IN MEDIEVAL PHYSICS 165 value to the modern Thomist, however much the modern Thomist may wish to adapt the traditional arguments. To understand the problem of celestial movers in medieval physics, it is necessary to present the views of Albertus Magnus and then those of Robert Kilwardby before examining the cru- cial problem in the doctrine of St. Thomas. St. Albert the Great For St. Albert both physics and metaphysics attain the existence of God, but under different formalities and in different ways. Physics, although it demonstrates through all the real causes in nature, is primarily concerned with the efficient and material cause: " if we have said anything about the form or about the end [in physics], this was only of form insofar as it is mobile and of end only insofar as it is the termination of the motion of a mover." " But metaphysics deals with substantial being and its causes; therefore in metaphysics " we directly show that the first efficient cause is the universal end, that from him flow all mobile substances, and that he is like a leader of an army with respect to the universe." ** This task is proper to metaphysics, and in this respect nothing is borrowed from natural science. It is true that natural science proved by way of motion the absolute immobility of the first mover, but it did not reveal him prout ipsum est causa universi esse et forma et finis. This is proper to metaphysics. Hence, Albert concludes, it is evident that metaphysics is a loftier contemplation by far than physics. The task of physics is to explain all changes in nature, both terrestrial and celestial. Terrestrial movements, alteration, generation and corruption can be explained in large measure by the celestial bodies, but since these celestial bodies them- selves are moved, the ultimate source of this movement must itself be immovable. This ultimate unmoved mover, proved in the Physics, is considered by St. Albert to be God, the " St. Albert, Lib. XI Metaph., tr. I, c. 3, ed. cit., VI, 584b. " Ibid. 166 JAMES A. WEISHEIPL Christian God. But the approach is different in metaphysics. Since the term of terrestrial movement and alteration is 'per se the generation of a substantial being/^ and since the substantial being of the very heavens must be produced, beyond the physi- cal universe there must exist a pmicipium universi esse, who is the efficient source of being, the formal principle of all being, and the universal end of all things.*'' Hence it belongs to both physics and metaphysics to consider celestial phenomena and God, but physics considers these through the principles of motion {secundum pnncipia motus) , while metaphysics con- siders these through the principles of being (essendi) . In other words, the natural philosopher arrives at the existence of God as the first mover, but the metaphysician arrives at His exist- ence as the efficient cause, the formal principle and the ultimate end of all being. This does not mean, Albert points out, that the metaphysi- cian gives the propter quid reason for changeable substance, and the physicist the quia, as some would have it. " For if the physicist borrowed from the metaphysician, it would follow that physics is subalternated to first philosophy, which from the opening pages of this science we have shown to be false." *'' Thus physics and metaphysics are each autonomous sciences with special principles of investigation proper to each. How- ever, unless it is first demonstrated in physics that there exists some real separated substance, there is no need for the sub- sequent investigation called metaphysics. The Platonists, Albert repeatedly points out, postulated ideas and mathe- matical entities separate from matter in order to explain sensible being; but these cannot exist apart from matter, and if they did, they could not be responsible for motion in the universe.*^ Therefore if some separated substance exists to be studied in metaphysics, this substance can be demonstrated is 46 St. Albert, Lib. VIII Pkys., tr. II, c. 4, ed. cit.. Ill, 572a. St. Albert, Lib. XI Metaph., tr. I, c. 3, ed. cit., VI, 584b-585a. " Ibid. " St. Albert, Lib. XI Metaph., tr. I, cc. 4 & 8; lib. 1, tr. V, cc. 8, 12 & 14; lib. VII, tr. II, c. 3, et alibi. CELESTIAL MOVERS IN MEDIEVAL PHYSICS 167 only as the cause of motion, specifically as the cause of celestial motion. St. Albert accepted the order of celestial spheres commonly taught by the Arabian astronomers. The spheres were con- sidered generically to be ten in number: the primum mobile causing diurnal movement of the whole universe, the sphere of fixed stars, the spheres of Saturn, Jupiter, Mars, the Sun, Venus, Mercury, the Moon, and the terrestrial sphere of active and passive elements.*^ It was well understood by all that each so-called sphere was subject to many distinct motions, each of which required some kind of mover. But it was simpler to talk in terms of the clearly visible planets, the fixed stars and the unseen cause of diurnal motion, than in terms of the precise number of celestial motions postulated to save the appearances of each planet. Similarly, it was understood among the better informed that the notion of " sphere " was postulated to regularize the errant motions of the planets and to give intel- ligibility to their complicated movements. Those spheres were no more " solid," contrary to some modern interpretations, than the familiar sphere of terrestrial change. In the view of Avicenna each sphere was moved and ruled by a separated substance, whatever may have been the number of distinct movements required for each planet. It is within this context that St. Albert discusses the problem of celestial movers. But Avicenna further identified those intelligences and the proximate mover {anima nobilis) with angels .°° St. Albert, as has already been noted, was unwilling to identify the sepa- rated substances of the philosophers with the angels of Sacred Scripture. Further, the tenth intelligence for Avicenna was the intellectus agens hominum, which ruled the terrestrial realm of mutable substances by infusing forms from without. This dator formarum was invoked by Avicenna to explain the apparent generation of new substances in the world of nature. St. Albert *' St. Albert, Problemata determinata, q. 2, ed. cit., p. 324; see ibid., note 9. '° An excellent discussion of this has been given by Henry Corbin in his Avicenna and the Visionary Recital, trans, by W. R. Trask (New York: Pan- theon, Bollingen Series 66, 1960), pp. 46-122. 168 JAMES A. WEISHEIPL repeatedly rejected the Avicennian innovation with sound Aristotelian arguments, which need not concern us here. The real problem for St. Albert was the obvious difference between terrestrial changes arising from nature and celestial motions which could not arise from nature. The term " nature " is a technical one and it designates that " principle of motion and rest in those things to which it belongs properly {per se) and not as a concomitant attribute (per accidens) ," " Tech- nically it was contrasted with soul {anima, ^vxr]) and with intelligence (intelligentia, vov<;) , particularly in Platonic and neo-Platonic writings; and it was also contrasted with art {ars, Texvy]) and with chance (casus, avroixaTov) by Aristotle. Nature as an intrinsic principle always acts in a determined manner for a predetermined end.^^ This nature must always be efficiently produced by some generator of the form. Once this natural form has been generated by an efficient cause, that nature spontaneously moves toward the unique end propor- tioned to it and rests in the possession of the end. " Hence place and motion are given by the generator just as the form is, but the form is given principally, while place and motion are given per consequens, just as proper accidents are given to the form by generation." °^ Moreover, strictly speaking, " nature " designates the internal power of inanimate substances {natura non est nisi virtus inanimatae suhstantiae) .^* Finally, nature is a source of individual attainment, and not of transient ac- tivity. Hence " locomotion is never derived [efficiently] from nature as ' the principle of motion and rest in those things to which it belongs properly and not concomitantly,' as defined by Aristotle in Physics II; for which reason, as we have said, locomotion must be derived either from the generator or from one removing an impediment or from a soul." ^^ In other words, "Aristotle, Phijs., II, c. 1, 1921b21-23. Cf. James A. Welsheipl, "The Concept of Nature," in The New Scholasticism, XXXVIII (1954), 377-408. " Cf. Albert, Lib. VIII Phys., tr. II, c. 4, et passim. ^^ Ibid., ed. cit.. Ill, 572a-b. " St. Albert, Lib. XI Metaph., tr. I, c. 13, ed. cit., VI, 604. ^° St. Albert, Problemata determinata, q. 2, ed. cit., p. 325. CELESTIAL MOVERS IN MEDIEVAL PHYSICS 169 since celestial motions do not attain any end, these motions cannot arise spontaneously from the nature of celestial bodies. For St. Albert, as for Plato and Aristotle before him, celestial motions must be derived immediately from some kind of soul, or self-mover. Comparing the views of Plato and Aristotle,^® Albert notes that both agree on three points: (i) that all natural motions must be reduced to some self-movent; (ii) that a celestial body cannot move itself, but must be moved by a spiritual substance which is either a soul or an intellect; (iii) that the spiritual mover of the body must itself be indivisible, without magni- tude, possessing adequate power to move the celestial body. However, Albert notes, Plato and Aristotle differ on two essen- tial points: (i) Plato considered the conjoined mover to be the ultimate mover, while Aristotle considered this soul to be the instrument of a higher intellect entirely separated from all mat- ter; (ii) Plato considered the celestial soul to be perpetual and descendent from the stars, while Aristotle conceived the con- joined mover to be produced by the separated intellect and moved by it. In other words, Aristotle, according to St. Albert's understanding, admitted a conjoined mover for each celestial motion, a mover which was somewhat similar to a spiritual, intellectual soul, but without sense faculties. This conjoined mover explained how a celestial body like the primum caelum could be moved perpetually without attaining any end or finality intrinsic to itself. However, the conjoined mover itself was moved by reason of the celestial body; that is, the anima caeli moved concomitantly {per accidens) with the celestial body, much as the human soul is moved by the movement of the body. Therefore, the anima caeli is a moved mover, needing to be moved by another, a substance entirely separated from matter not only in definition, but also in existence. The spirit- ual anima caeli can be moved only by intellection and desire. The initial intellectual light emanating from the subsisting act- ^» St. Albert, Lib. VIII Phys., tr. U, c. 8. 170 JAMES A. WEISHEIPL ing intellect, giving the soul the idea and the desire to move, is the true immediate mover of the universe. As St. Albert understands it, when Aristotle speaks of the heavens or the celestial bodies, he usually means the composite of soul and body, mover and moved; the heavens are for Aris- totle animated substances {substantiae animatae) . While it is easier to talk of the sun as though it were a simple substance, the movement of the sun is complex and due to many animated substances. For Aristotle at least the diurnal, longitudinal and latitudinal motions are distinct; each of these is caused by an animated celestial body. Ultimately these motions of the sun and all other planetary motions are due to the diurnal motion of the entire universe, the primum caelum, the first animated cause of the universe. Now the animated substance is the cause not only of inanimate substances, but also of their order and motion. According to the teaching of the Peripatetics, this animated substance is the corpus caeli. Moreover, it was shown in Book VIII of the Physics that the first mover, which is a composite of mover and moved, or pushed, is the first heaven (primum caelum.) . In this manner it was there- fore shown that the animate precedes the inanimate. We have likewise shown in that same place at the end of Book VIII of the Physics, first that the first mover is absolutely simple, and that this, since it is related to the first body as its mover, unquestionably will have the character of soul, and not nature (pro certo habebit rationem animae et non naturae) , because nature never moves that body whose nature it is according to local motion.^^ Plato, according to St. Albert, stopped here with the anima mundi as God, but Aristotle realized that each soul, since it is moved along with the body, must be moved by the desire for some absolutely separated intelligence. Thus for Aristotle the separated intelligence known and desired by the first animated mover is the actual source of all physical movement and the ultimate end of every celestial motion. There is, in other words, a hierarchy of intelligences proportioned to the various orders of animated substances. There is, for example, at least one illu- ■*' St. Albert, Lib. XI Metaph., tr. I, c. 13, ed. cit., VI, 604b. CELESTIAL MOVERS IN MEDIEVAL PHYSICS 171 minating intellect for all the animated movers of Venus, another for Jupiter, and so forth. The highest separated intelligence is the true immediate mover of the entire universe, the primum caelum. The mind and will of God are obediently accepted and executed by the animated substances, who consequently move as moved movers. When discussing this matter on his own terms, St. Albert prefers to keep three elements distinct: the celestial body, the soul-like mover, and the separated intelligence. The reason for this is that Albert could not accept Aristotle's concept of celestial " souls " as the substantial form of the body. For Albert these " souls " could not be the substantial form of an inorganic, insensitive body, such as the moon and sun; this kind of body would be entirely useless for intellectual processes. Consequently these " souls " move the body only as an efficient cause, not as a formal cause.^^ In his early work, the Summa Parisiensis, Albert was willing to reconcile Aristotle's " souls " with the Catholic doctrine of angels."^ Later, however, Albert became most insistent that the angels of revelation should not be identified with celestial souls or intelligences. According to Giles of Lessines, a disciple of St. Albert, Haec est 'positio multorum viagnorum et praecise domini Alberti quondam Ratisponensis episcopi, oh cuius reverentiam rationes prae- dictam positionem confirmantes addidimus.^° Albert's strong views distinguishing angels from intelligences and souls were shared by Theodoric of Freiberg, another disciple of his.®^ The ^^ " Nos cum Sanctis confitemur caelos non habere animas, nee esse animalia, si anima secundum propriam rationem sumatur. . . . Operatur autem ad corpus ut nauta ad navem, hoc est, secundum rationem movendi ipsum et regendi." Summa de creaturis, tr. Ill, q. 16, a. 2, ed. Borgnet XXXIV, 443a. In this edition " natura " is erroneously printed for " nauta." ^' " Ita non est contrarium fidei quosdam angelos iuvare naturam in movendo et gubernando sphaeras caelorum, quos Angelos moventes sive intelligentias Phi- losophi dicunt animus." Ibid., ad 6, p. 445b. *° Giles de Lessines, De unitate formae, P. II, c. 5, ed. M. de "Wulf in Les Philosophes Beiges, I (Louvain, 1902), p. 38. ®^ " Est autem et hoc circa iam dicta tenendum, quod dicti philosophi, loquentes de mtelligentiis, non loquebantur de angelis, de quibus scriptura sacra loquitur, quae loquitur mysteria abscondita a sapientibus et prudentibus et revelat ea par- 172 JAMES A. WEISHEIPL reason for Albert's view is clearly stated in the reply to John of Vercelli's questionnaire: the separated intelligence known to philosophers is entirely immobile locally, nee mittitur nee venit nee reeedit^- This is entirely contrary to what we know of Gabriel, Raphael and Michael according to the Scriptures. Further, the separated intelligence is known to philosophers solely as the cause of celestial motion and of inferior forms, while the angels of Scripture are the messengers of God, a function which cannot be proved by natural reason.*^' To understand St. Albert better, we must consider celestial motion itself and its three distinct causes, namely the body, the soul-like mover, and the separated intelligence. St. Albert clearly insists throughout all his writings that celestial motion cannot be accounted for by the nature of the celestial body. That is to say, perpetual motion of the spheres cannot originate spontaneously from " nature " as from a formal principle. Scholastic philosophy, following Aristotle, distinguished two uses of the technical term " nature." ®* The primary and principal use of the term was to designate an intrinsic active source of regular, teleological activity and at- tainment; nature in this sense was called a formal principle, since form is the ultimate source of these activities. In a secondary and analogical sense the innate, passive receptivity for the form could also be called " nature," since potency is a true principle of change; nature in this sense was called a material or passive principle. For St. Albert none of the char- acteristics of nature as a formal principle could be verified in vulis." Theodoric of Freiberg, De intellectu et intelligibili, P. I,cap. 12, ed. E. Krebs in Beitrdge z. Gesch. d. Phil. d. M.-A., Bd. V, heft 5-6 (Miinster, 1906), pp. 132*- 133*. Cf. ibid., P. II, cap. 34, pp. 164-165*. I am grateful to Fr. William A. Wallace, O. P., for allowing me to utilize his transcription of Theodoric's De intelli- genciis et motoribus celorum and De corporibus celestibus quoad naturam eorum corporalem from MS Vat. lat. 2183. ^'^ St. Albert, Problemata determinata, q. 2, ed. cit., p. 323. "^ Ibid., q. 5, ed. cit., p. 328. '* Cf. J. A. Weisheipl, " The Concept of Nature," loc. cit. above in note 51 and reprinted in Nature and Gravitation (River Forest: Albertus Magnus Lyceum, 1955), pp. 1-32. CELESTIAL MOVERS IN MEDIEVAL PHYSICS 173 celestial motions. Nature as a formal principle always moves toward a determined end, and when it has attained it, rests in that attainment. " The reason for this is that nature does not cause local motion except 'per consequens, for in moving toward the form it consequently moves to the place which belongs to its form." In the celestial motions there is never any attain- ment and possession. " The mover of the heaven never moves to any position, but to move out of it again. But to move into a position and to move out of it again is not from nature, but from soul." ^^ For this reason Albert frequently insisted that celestial motions are not from nature, but from intelligence (caeli motus non dicitur naturae motus, sed intelligentiae) .^^ Albert undoubtedly would have admitted that celestial motions are " natural " in the sense of coming from a passive principle, the celestial body. But invariably he prefers to deny the natural character of celestial motions, insisting always that they are not from nature, but from soul or intelligence. Precisely because the body itself is not the source of its perpetual movement, it is said to be moved. " Everything which is moved has a mover conjoined to itself, as was proved in the Seventh Book of the Physicsr " The nature of the conjoined mover is difficult to determine in the wi'itings of St. Albert, largely, no doubt, because Albert retained the Aristotelian terminology while denying the sub- stantial union of the two " parts " of the sphere. The con- joined mover is clearly a spiritual substance, indivisible, and separated from all matter, at least in definition .^^ It moves the body by its knowledge and desire of something higher.®^ " Since *^ " Adhuc autem natura non movet nisi ad unum, et cum pervenerit, quiescit in illo. Cuius causa est, quia natura non est causa motus localis nisi per consequens: movendo enim ad formam, per consequens movet ad locum qui est illius formae. Motor autem caeli non movet unquam ad aliquem situm, nisi moveat etiam ex illo. In aliquid igitur movere et ex iUo non est naturae, sed animae." St. Albert, Lib. XI Metaph., tr. I, c. 13, ed. cit., p. 605b. ** St. Albert, Lib. II Phys., tr. I, c. 2, ed. cit., p. 95b. " St. Albert, Lib. XI Metaph., tr. II, c. 3, ed. cit, p. 614a; see Lib. VII Phys., text et comm. 10. «' St. Albert, Lib. XI Metaph., tr. II, cc. 12-13. '"Ibid., c. 13, ed. cit., p. 605a. 174 JAMES A. WEISHEIPL every motion of the heaven is according to the form which is in the intellect, as the artistic idea is in the mind of the artist, so in the intellect of the mover there is the image to be effected by its motion; otherwise its motion would be unintentional, a chance result and an accident." ^'^ At times St. Albert does call this conjoined mover a " soul," particularly the anima nohilis of the Liher de causis (prop. 3) . But more frequently he con- ceives the mover as a luminous form of intelligence and desire, produced by the separated intelligence. " Since the intelligence by its light produces every form in its sphere and order, and since those forms are its light {lumen) and this light desires to produce beings in existence {luTuen desiderans ad esse de- ducere) , the proximate mover of the orb moves the orb and by moving produces forms in existence." ^^ The conjoined mover, therefore, is an intelligent form, but not the " soul " of the sphere. " Thus it is evident that the intelligence is not an angel; and if it were, it would still not be the proximate mover of any celestial sphere." ^^ It is important to note that for St. Albert the luminous forms, the conjoined movers of celestial bodies, are the true causes of everything which is produced within that sphere. That is to say, the luminous form, obedient to a higher intelli- gence, is the active principle of such mysterious phenomena as animal reproduction, and the spontaneous generation of living things from inanimate matter." " Every lower motion which is in the matter of generable things is reduced to the motion of the heavens, which is the cause and measure of lower motion by means of (i) the form of the moving intelligence, (ii) the form of the celestial orb, and (iii) stellar rays." '* The active powers of light, heat, conjunctions of the planets and stars are, for St. Albert, instrumental causes of the celestial forms whereby the natural powers of the elements can be pro- '» Ihid. '^ St. Albert, Problemata determinata, q. 2, ed. cit., p. 327. " Ibid. " St. Albert, Lib. XI Metaph., tr. I, cc. 6 & 8. Ibid., c. 8, ed. cit., p. 594a; cf. Problemata determinata, qq. 7-15 and qq. 34-36. CELESTIAL MOVERS IN MEDIEVAL PHYSICS 175 ductive of higher forms. One can say that these higher forms produced preexist in the elements virtually insofar as these elements are instruments of celestial movers. Of course, the celestial mover is itself a voluntary, intellectual instrument of the absolutely first intelligence, which is God. Similarly the male sperm virtually and actively contains the living and sen- tient souls of the embryo, but only as the instrument of celes- tial forces and intelligences. In other words, the natural heat, density, mobility and structure of the male sperm are used instrument ally by celestial agents to produce an effect higher than their own active powers. ^^ It was in this way that St. Albert understood and explained the famous Aristotelian phrase. Homo ex materia generat hominem et sol. (Phys. II, 2, 194bl3) .''^ The only qualification which Albert, the phi- losopher and theologian, makes to this phrase is the direct creation of the human soul.'^ Finally, for Albert, the separated movers of celestial bodies are the active intelligences {intellectus agens) . Each intelli- gence is like a practical intellect of an artist who conceives the image to be produced and implants this in his instruments as he uses them. The instruments of the active intelligence are three-fold, namely the conjoined spiritual mover, the celestial body itself, and the inherent powers of terrestrial nature. Con- sequently the ultimate mover of each celestial body is, in fact, the separated active intelligence proportioned to the spheres. Since, however, all celestial spheres depend upon the diurnal motion of the first heaven, the absolutely first mover of all the celestial bodies is the separated, active intelligence command- ing the primum caelum. This absolutely first mover is the primum principium universi esse, the cause not only of all 75 7« " ' St. Albert, Problemata determinata, q. 34; De animalibiis XVI, tr. I, cc. 11-13. ' Quod enim impressiones separatorum a materia generabilium sint in materia patet per hoc quod ex materia hominis homo generat hominem, et sol et motor solis; et ideo oportet considerare separata in quantum impressiones earum per motum caelestium sunt in generabilibus et corruptibilibus." St. Albert, Lib. 11 Phys., tr. I, c. 11, ed. cit., pp. 113-4. See Averroes, ibid., comm. 26. ''"' Problemata determinata, q. 33; De nat. et orig. animae, tr. I, c. 5; De animxi- libus, lib. XVI, tr. I, cc. 11-12; Summa de creaturis, P. II, q. 5, a. 4. 176 JAMES A. WEISHEIPL motion, but also the absolute efficient cause, formal principle and ultimate end of all being. He produces not only the hier- archy of conjoined celestial movers, their bodies and motion, but he is also the first efficient cause, formal principle and final end of each intelligence. The first principle of universal being is commonly designated by St. Albert as the intellectus univer- saliter agens, who, as has already been noted, is God Himself. As first mover of the heavens He is attained in natural science; as first cause of being He is attained in metaphysics. Once Albert has established in his reply to the Master General that angels are not the same as intelligences discovered by the philosophers, he can easily dismiss the first five ques- tions as fatuous. The existence of angels, the messengers of God, cannot be proved in philosophy; they have nothing to do with problems of natural science; and even if God were not the first mover of the heavens — which He really is — the exist- ence of angels would still not be demonstrated. God, for St. Albert, is the first cause of celestial motions, not as a form conjoined to the universe, but as a separated active intelligence commanding the motions of all, " since Aristotle says that the first cause moves the first heaven, to the motion of which all motions of celestial bodies are referred, as all movements of organic members are referred to the movement of the heart." ^^ The only body which God moves immediately as conjoined to Himself is the body of Christ, joined hypostatically to the Word. Robert Kilv^ardby The approach of Kilwardby is very different from that of St. Albert. Kilwardby, in fact, reflects much more the schools of Oxford than those of Paris, despite his own regency in arts at Paris (c. 1237-c. 1245) . He had been a Master in Theology of Oxford about fifteen years when he was asked to reply to the questionnaire of John of Vercelli. We cannot be certain that Kilwardby always maintained the views presented in the reply of 1271, but we can be certain of his views at that date. ''^ Problemata determinata, q. 1, ed. cit., p. 321; cf. Aristotle, De caelo et mundo, II, c. 2, 284b6-286a2. CELESTIAL MOVERS IN MEDIEVAL PHYSICS 177 Replying to the first question, Kilwardby explicitly denies that God is the immediate mover of the heavens moving either eternally or temporally in place: certissime tenendum est et asserenduTn quod Deus non movet "priraum caeluTn nee aliquod corpus immediate motu localiJ^ He admits that Aristotle seems to consider God as the first mover of the eternal spheres, " but the truth is that God does not move any body immedi- ately " by continual locomotion. If God did move any body in this way, He would be either the substantial act of that body and a part of the whole or a simple mover like a man on a horse. The first alternative is obviously erroneous. The second is awkward and unreasonable for it implies that the first heaven is moved by violence: secundo modo caelum primuTn videre- tur moveri violenter. Kilwardby, however, does admit that God can and does move bodies immediately by a certain supernatural change, as in creation, the production of light, the formation of Eve and similar events. In such events God operates without the assistance of nature or angels. Concluding his reply to the first query, Kilwardby categorically states: From these considerations, therefore, the reply to the question must be that God moves no body immediately by continuous motion, but only by His word when a body is changed instan- taneously so that something supernaturally begins to exist. The second question has to do with natural motions and their dependence on angelic movers of the celestial bodies. Kil- wardby first distinguishes between natural and violent motions. Nature is an intrinsic principle of motion; only bodies which have such a principle per se are said to move naturally. Mo- tions are called violent when their moving force is extraneous, the subject contributing nothing to the motion (quando prin- cipiwm motivum est extraneum, passo non conjerente) . Among natural motions Kilwardby enumerates continuous movement of bodies, instantaneous transmission of light, the irascible and concupiscible emotions of spiritual beings, and intellectual ac- tivity. Clearly, intellectual and appetitive activities of spiritual ''^ Kilwardby, Responsio, q. 1, ed. Chenu, loc. cit., p. 194. 178 JAMES A. WEISHEIPL beings are not affected by celestial movement; rather, such spiritual activities are productive of celestial motion. There are for Kilwardby two types of celestial motion. The first emanates from celestial bodies in the form of energy and light rays affecting all the active and passive powers of ter- restrial bodies, both elementary and composite. This cosmic influence is produced by the celestial bodies, but the influence is subjectively located in terrestrial bodies. " And perhaps if this influence of light and energy were withdrawn from elements and composites, all active and passive powers of bodies would cease to act or react; hence this influence seems to be the 'per se cause of natural activity and movement in the elements." ^'^ There is, however, another motion located in the celestial body itself; this is the continual rotation of the sphere. Kilwardby does not consider this rotational movement of the spheres to have any direct or proper bearing on natural terrestrial motion. Such motions do provide variations of temperature, humidity and the like, but this is secondary to the direct cosmic influence affecting natural changes. Finally Kilwardby proceeds to discuss the crucial question of celestial movers. He notes that there are three opinions concerning the motion of celestial bodies. The first is that of Aristotle and certain other philosophers. Kilwardby 's inter- pretation of Aristotle's view is essentially that of St. Albert: " celestial bodies are animated, having animal life and intelli- gence by which they perceive the will of the first cause, and motion in place by which they fulfill the known will of God; by this motion of theirs they conserve things and preserve generation and the limited being of generable natures." ^^ In this view celestial bodies are moved by spirits which are their " souls " just as man is moved by his spirit, or soul. It is inter- esting to note in passing that the author of Errores philoso- phorum does not attribute animation of the heavens to Aristotle or Averroes, but exclusively to Avicenna: 80 Ibid., q. 2, ed. dt., p. 196. *^ Responsio, q. 2 § De tertio. For this part of the reply we rely on the emended edition published by Chenu in Revue des Sc. Phil, et Theol. XXIX (1940), 211. CELESTIAL MOVERS IN MEDIEVAL PHYSICS 179 Again [Avicenna] erred' on the subject of the animation of the heavens. For he held that the heavens were animated. He said that the soul of the heavens is not only a suitable moving power, as the Philosopher and the Commentator were intent upon saying, but that a single being is produced by the union of the soul of the heavens with the heavens, just as by the union of our soul and our body.^' Concerning this presumed view of Aristotle, Kilwardby notes that it is philosophically sound and supported by reason: " since those bodies seem to be more noble than living bodies, they ought to have a higher form of life." Nevertheless in 1277 the Bishop of Paris condemned the proposition " that celestial bodies are moved by an intrinsic principle, which is a soul." ^^ And St. Albert, as we have seen, clearly rejected celestial ani- mation as alien to the Catholic faith. The second opinion listed by Kilwardby is in reality that of St. Thomas: " others hold that those bodies are moved by angelic spirits who govern and move them in such a way that they are not their act, or form." Kilwardby dismisses this view as unphilosophical, and he remarks, " Nor do I recall it being approved by any of the Sancti as true and certain." However, Kilwardby does admit in passing that it could be held absque error e by Catholics.^* Kilwardby 's own view of celestial motion is presented suc- cinctly as the third opinion: Just as heavy and light bodies are moved to a place in which they rest by their own inclinations and tendencies, so celestial bodies are moved circularly in place by their own natural inclinations similar to weight {quasi ponderibus) in order to conserve corrup- tible things lest they suddenly perish and fail. Some spheres rotate naturally from West to East, others from ®° Giles of Rome, Errores phUosophorum, VI: Avicenna, 10, ed. Josef Koch, trans, by J. O. Riedl (Milwaukee: Marquette, 1944), p. 31. ** Chartularium Univ. Paris., ed. H. Denifle, 0. P., I, n. 473, p. 548, prop. 92; see also prop. 213. Cf. E. Krebs, Meister Dietrich, in Beitrdge z. Gesch. d. PhU. d. M.-A., Bd. V, heft 5-6 (Miinster, 1906), pp. 75-76. ** Cf. J. A. "Weisheipl, " The Problemata Determinata Ascribed to Albertus Magnus," loc. cit., p. 304, note 8. 180 JAMES A. WEISHEIPL East to West, and still others move naturally as epicycles, and others on the eccentric. To each planet and orb God gave an innate natural inclination to move in a particular way in rota- tional motion; to each He accorded an innate order, regularity and direction without the need of a distinct agency like a soul, an angel or Himself here and now producing the motion. " Just as the forces (pondera) of heavy and light move bodies con- sistently, not permitting them to stray outside a determined path, so it is with the forces of each and every celestial body." Consequently rotational motion is as natural to celestial bodies as gravitational motion is to heavy bodies. Both arise spon- taneously from nature as an intrinsic active principle, instinctu proprioruTn ponderum (q. 3) . It was commonly recognized among the schoolmen that heavy bodies need nothing more than their own generated nature to account for gravitational motion; heavy bodies need no conjoined mover to account for the continued downward fall.®^ Kilwardby wished to explain celestial motions by a similar intrinsic formal principle. Ter- restrial bodies are unattached and hence move rectilinearly to a place of relative rest. But for Kilwardby the heavens are spherical; stars and planets are attached to their proper orbs within a sphere. Consequently the only " natural " motion the heavens could have is rotational, a continual rotation of each orb on its axis. The combination of various rotations on suit- able axes together with the required uniform velocity of each rotation produced the apparent motion of the planet. Kil- wardby thus dispenses with the need of any conjoined or separated mover, whether that mover be called a soul, an angel, intelligence or God. It is clear from this that Kilwardby could not prove the existence of God through physical motion. He cannot even prove the existence of a separated substance. Because of the great diversity of opinion concerning celestial movers, Kilwardby maintained that it is impossible to prove that angels move the spheres (q. 4) . Philosophers think that they have infallibly demonstrated the existence of spiritual *^ Cf. J. A. Weisheipl, Nature and Gravitation, ed. cit., pp. 19-21, 25-28. CELESTIAL MOVERS IN MEDIEVAL PHYSICS 181 movers for the heavens', but these are certainly not the angels discussed by Catholics. Even assuming that God is not the immediate mover of the heavens — which according to Kil- wardby He is not — it is in no way proved that angels have to be celestial movers (q. 5) . Unlike St. Albert, Kilwardby con- ceives the physical universe as perfectly self-contained, per- fectly " natural," having no need of immaterial agencies direct- ing and moving the heavens. His is the closed world created by God in the beginning with sufficient innate tendencies to move rectilinearly and rotationally. This view was not original with Robert Kilwardby. Fr. Daniel A. Callus has pointed out that this idea can be traced to the earliest days of Aristotelianism in Oxford. Some sixty years before Kilwardby's reply, John Blund gave as his con- sidered opinion that the heavenly bodies are not moved by souls, nor by intelligences, but by their own active nature moving orbiculariter.^^ As is commonly known, this opinion found favor among many in the fourteenth and fifteenth century. Fr. Chenu saw in Kilwardby's view an anticipation of John Buridan's famous suggestion about celestial motions, that an impetus (given by God) is also found in the celestial spheres, but one which cannot be diminished by resistance, since celes- tial matter offers no resistance.®'^ In all terrestrial projectiles impetus is diminished and overcome by nature resisting the violent force. But in Aristotelian theory celestial bodies could offer no resistance, since they had no weight or gravity; they were considered completely passive, having " nature " only as a passive principle of motion. Consequently Buridan's sug- gestion of an initial impetus for celestial motion was a perfectly obvious one; it presupposes Aristotle's doctrine of the pure passivity of those bodies. In other words, it is precisely because ** " Dicimus quod firmamentum movetur a natura, non ab anima, et alia super- celestia." The full passage is published by Daniel A. Callus, O. P., " The Treatise of John Blund On the Soul," in Autour d'Aristote (Louvain, 1955) , pp. 487-9. " Cf. Pierre Duhem, tltudes sur Leonard de Vind, III (Paris: Nobele, 1955) , p. 42. 182 JAMES A. WEISHEIPL such bodies have no active " nature " that they can, in the scheme of Buridan, receive a perpetual impetus for continued motion. This is quite different from Kilwardby's conception of celestial spheres actively inclined to circular motion, for here the " nature " of celestial bodies is an active principle. The final result of both views may be similar or even identical, but the theoretical foundation of Buridan's theory of impetus for the heavens is profoundly dissimilar to the views of Kilwardby. Kilwardby's view, however, was common enough in later centuries. It was favored particularly by Platonists and semi- Platonists. Notably Nicholas of Cusa attempted to explain the circular motion of the heavens by an appeal to their orbicular shape; their matter, being different from terrestrial matter, naturally tended to move orbicularly, that is, by rotating.^^ Copernicus himself explained the circular motion of the heav- enly bodies by their spherical nature: Now we note that the motion of the heavenly bodies is circular. Rotation is natural to a sphere and by that very act is its shape expressed. For here we deal with the simplest kind of body, where- in neither beginning nor end may be discerned, nor, if it rotates ever in the same place, may the one be distinguished from the other.^^ For Copernicus, as for Kilwardby before him, the substantial form of a spherical body naturally tends to move spherically. Surprisingly, for Copernicus the outermost sphere of the fixed stars, though spherical by nature, was said to be at rest.^° It must be admitted, however, that Copernicus was not concerned with explaining the physical causes of celestial motion, as this is beyond the scope of mathematical astronomy. We may seriously doubt that Kilwardby's reply influenced later writers; it certainly did not influence John Buridan. Nevertheless it does represent an important medieval view concerning celestial motion. ** Nicholas of Cusa, De ludo globi, lib. I (Basel, 1565), pp. 210-214. ** N. Copernicus, De revolutionihus orbium caelestium, lib. I, c. 4 (Thorn, 1873) , p. 14; also c. 8, pp. 21-24. »" Ibid., c. 10, pp. 28-29. celestial movers in medieval physics 183 St. Thomas Aquinas The reply of St. Thomas is the shortest and most succinct of the three. He adheres strictly to the forma expected, appeal- ing to the Sancti (Scripture, Augustine, Pseudo-Dionysius, Gregory, Jerome) and evaluating all questions in the light of Catholic faith. " It seems to me safer," he says in the prooem- ium, " that doctrines commonly held by philosophers which are not contrary to the faith be neither asserted as dogmas of faith (although they may sometimes be introduced as philosophical arguments) nor denied as contrary to the faith, lest occasion be offered to men learned in human wisdom to ridicule the doc- trine of faith." In his important theological treatise, De suhstantiis separatis, St. Thomas considers the relative merits of Plato and Aristotle on the question of angels.^^ Plato — really Proclus — is under- stood by St. Thomas to have postulated various orders of spiritual substances between the human soul and God. Under God, the supreme unity and goodness, there is the order of secondary gods who are the Forms or Ideas eternally radiant. Inferior to these is the order of separated intellects, " which participate in the above-mentioned Forms in order to have actual understanding." Next come the various orders of soul, each one inhabiting a certain kind of body. Celestial souls animate celestial bodies and move them, in such a manner that " the highest of the bodies, namely the first heaven, which is moved by its own motion, receives motion from the highest soul, and so on to the very lowest of the heavenly bodies." Below celestial souls are the demons who inhabit unearthly bodies. The lowest intellectual soul is man, who although he inhabits a visible body " as a sailor in a ship," also has another nobler body belonging to the soul, incorruptible and everlast- ing, even as the soul itself is incorruptible. Souls below man, such as plant and animal souls, lack intelligence and immor- tality. If all these views of Plato were true, notes St. Thomas, Cap. 1-4. For the treatise De suhstantiis separatis we rely on the excellent English version of Fr. Francis J. Lescoe (West Hartford: St. Joseph College, 1959) . 184 JAMES A. WEISHEIPL then all orders between God and man would be called ' angels ' by Catholics. The fundamental weakness of Plato's position, as St. Thomas sees it, is that it is without proof, for his separated intelligences are merely postulated, not demonstrated. " That is why Aris- totle proceeded by a more manifest and surer way, namely, by way of motion, to investigate substances that are separate from matter." St. Thomas' interpretation of Aristotle is substanti- ally that of St. Albert and Kilwardby. Since all generable and celestial bodies are moved, they must be moved ultimately by a substance which is not material. The immaterial soul con- joined to celestial bodies is moved concomitantly with the body, therefore it is moved by knowledge and desire of abso- lutely separated intelligences. " Therefore each of the heavenly bodies is animated by its own soul and each has its own sepa- rate appetible object which is the proper end of its motion." For Aristotle, then, there are as many intelligences as there are celestial souls, and as many celestial souls as there are motions. It was Avicenna, according to St. Thomas, who er- roneously limited the number of separated intelligences to ten, thinking that the multiple motions of a planet could be " or- dered to the motion of one star." In any case, according to the position of Aristotle, between man and God " there exists only a two-fold order of intellectual substances, namely the sepa- rated substances which are the ends of the heavenly motions, and the souls of the spheres, which move through appetite and desire." ^^ Aristotle and Plato both agree that all immaterial substances have their entire being from God, that they are entirely immaterial, and that they are ruled by divine provi- dence. They differ, however, with respect to the number and precise character of separated substances as well as to their relevance to the physical order. For St. Thomas the theologian, Aristotle made three serious errors concerning angels. First, he erroneously limited their number to what could be ascertained by celestial motion; there t2 Ibid., c. 2, n. 10; cf. In II De caelo, lect. 18, n. 16. CELESTIAL MOVERS IN MEDIEVAL PHYSICS 185 is no demonstrative reason why they cannot be more numerous, as Catholic theology teaches .^^ Second, he erred by considering some to be substantially united to celestial bodies as their soul; such a union is unreasonable and contrary to Catholic teach- ing.^* Finally, Aristotle erred in considering angels and the universe to have existed from all eternity; such eternity cannot be demonstrated by reason. ^^ St. Thomas himself never doubted that Plato and Aristotle admitted another mode of " coming- into-being " besides physical generation for immaterial sub- stances and the universe. " Over and above the mode of be- coming by which something comes to be through change or motion, there must be a mode of becoming or origin of things, without any mutation or motion through the influx of being {'per iiifluentiam essendi) ." ^^ St. Thomas goes on to say that, although Plato and Aristotle did posit that immaterial sub- stances and even heavenly bodies always existed, " we must not suppose on that account that they denied to them a cause of their being." ^^ On this point they did not depart from the position of the Catholic faith. We can now return to St. Thomas' reply to the official ques- tionnaire. His reply to the first three questions simply states that God normally rules His creation through intermediaries, the lower and more gross bodies being ruled by the higher and more subtle. The divine power, however, is in no way limited to the order it has established. Assuming that angels are the °^ Ibid., c. 2, nn. 12-13; cf. Sum. contra gent., 11, c. 92. ^* Ibid., c. 18, nn. 100-101; cf. De spirit, creat., a. 5; Sum. contra gent., 11, c. 91; SuTn. theol., I, q. 51, a. 1; De pot., q. 6, a. 6. ^^ Ibid., c. 2, n. 14; cf. Sum. theol., I, q. 46, a. 1; Sum. contra gent., II, cc. 31-38; De pot., q. 3, a. 17; De aetemitate mundi. ** Ibid., c. 9, n. 49. *^ Ibid., n. 52. For this reason St. Thomas frequently insists that those who interpret Aristotle's God as a mere physical mover or a mere final cause are in complete error. For St. Thomas Aristotle's God is a causa essendi ipsi mundo, a causa quantum ad suum esse, a factor caelestium carporum. " Ex hoc autem apparet manifeste falsitas opinionis illorum, qui posuerunt Aristotelem sensisse, quod Deus non sit causa substantiae caeli, sed solum motus eius." In VI Metaph., lect. 1, n. 1164. Also In VIII Phys., lect. 3, n. 6; In I De caelo, lect. 8, n. 14; In II Metaph., lect. 2, n. 295. 186 JAMES A. WEISHEIPL celestial movers, then no learned man can doubt that all natural motions of lower bodies are caused by the motion of celestial bodies (q. 3) . Dionysius himself notes that the sun's rays induce the generation of sensible bodies, generate life itself, nurture, strengthen and perfect it. All of this is within the power of angels. For some reason St. Thomas omitted to answer the fourth question directly. It asks whether it is infallibly demonstrated according to anyone that angels are the movers of celestial bodies. In two earlier replies to the lector of Venice, St. Thomas answered this very question in clear terms: The books of the philosophers abound with proofs for this, proofs, which they consider demonstrations. It seems to me therefore that it can be demonstrated that celestial bodies are moved by some intellect, either by God immediately or by means of angels moving them.®^ Consequently his reply to the fifth question comes as no sur- prise. He categorically insists that if God does not move those bodies immediately, then some other spiritual substance is demonstrated as mover, either a celestial soul or a separated angel. The fundamental reason for this assertion is stated clearly: Quod autem corpora caelestia a sola natura sua move- antur, sicut gravia et levia, est omnino impossibile.^^ In other words, for St. Thomas it is absolutely impossible that circular motion be explained by nature as an active (formal) principle within celestial bodies. This view is directly opposed to the position represented by Kilwardby. Throughout all his writings St. Thomas insisted on the essen- tial difference between rectilinear motion and rotational motion. Rectilinear motions, such as those of heavy and light bodies, arise spontaneously from within bodies, from nature as an active (formal) principle. Nature in this sense is predeter- mined to a certain end and to the means of attaining it. The ** St. Thomas, Resp. de art. XXXVI, a. 2; also Resp. de art. XXX, ad 4. *' St. Thomas, Resp. ad Joan. Vercel., q. 5; cf. Sum. contra gent.. Ill, c. 23 per totum. CELESTIAL MOVERS IN MEDIEVAL PHYSICS 187 end, therefore, is already within the intentionality of nature as form. Once nature has attained the end, it must rest in its acquisition, since it is its good. Physically there is no need for any " conjoined mover " to account for this motion downward or upward. Nature itself spontaneously moves toward the end which is its goal. " There is in heavy and light bodies a formal principle of its motion, because, just as other accidents pro- ceed from the substantial form, so does place and, consequently, movement toward place; not however that the natural form is a mover {motor) , but the mover is the generator which begot such a form upon which this motion follows." "° Therefore nature as an active principle is always ordained to rest in the possession of some good proper to itself. For St. Thomas the profound difference between celestial and terrestrial phenomena lay in the motions. The heavens move continuously in time, aiming at no rest or possession of a goal. Whether the heavens are eternal or created in time is not relevant to the question. Likewise it makes no difference whether the celestial bodies in motion are real spheres or inde- pendent planets; in either case the motion is always ordered to further motion. Clearly these motions cannot be striving for a rest as yet unattained, since such a rest would be disastrous for the celestial body and no nature can desire its own destruc- tion as a good. Nor can it be said that the purpose of such motion is motion itself. Motion by its very nature is a tending, a continual otherness; it has within its very nature a deformity which is incapable of being the final cause of any natural agent. " Therefore it is impossible that nature intend motion for the sake of motion." "^ Now for St. Thomas, if there is no intrinsic end attainable by a body in motion, then that motion cannot have sprung spontaneously from nature as form. Like the 100 g(. Thomas, In II Phys., led. 1, n. 4. Also In I De caelo, lect. 18, n. 1; II, lect. 2, n. 6; III, lect. 7, nn. 5-9; In II Phys., lect. 5, n. 5; IV, lect. 12, n. 9; VIII, lect. 8, nn. 5-7; Sum. cont. gent.. Ill, cc. 82, 84; De pot., q. 5, a. 5. ^"^ " Impossible est igitur quod natura intendat motum propter seipsum." Sum. cont. gent., Ill, c. 23, § 6. Also De pot., q. 5, a. 5: " impossible est quod aliqua natura inclinet ad motum secundum se ipsum." 188 JAMES A. WEISHEIPL matter in generable substances, the celestial body must be moved by another, by one in continual contact with it. Conse- quently celestial bodies have " nature " only in the sense of a passive (material) principle, which means the natural aptitude to be moved by another. Hence "the motion of a celestial body, as far as its active principle is concerned, is not natural, but voluntary and intellectual; however, in relation to its pas- sive principle, the motion is natural, for a celestial body has a natural aptitude for such motion." ^°- In this matter, notes St. Thomas, it makes no difference whether we conceive the celes- tial bodies to be moved by intellectual substances conjoined to the body after the manner of a soul or by one entirely dis- tinct like an angel. Non auteTn esset via solvendi, si moverentur -per solum naturae impetuTn, sicut corpora gravia et levia^°^ It is true that for St. Thomas celestial bodies can have only a passive nature whether the mover be a conjoined soul as Aristotle wished or a separated angel, as he himself believed. Nevertheless in establishing the existence of God along Aris- totle's lines, it does make a difference. St. Thomas, as St. Albert before him, was well aware that the First Mover of the Physics was for Aristotle identical with the First Being of Metaphysics XII. That is to say, St. Thomas knew St. Albert's interpretation to be correct. However, there is a serious diffi- culty. If the celestial movers are not souls, but angels, as St. Thomas himself held with the Sancti, then Aristotle's argument is not conclusive. A soul conjoined to the sphere is necessarily moved per accidens, that is, concomitantly with the sphere. Since this kind of mover is insufficient to account for the pri- mary source of physical motion, one can validly conclude to the existence of an intelligence which is entirely separated from matter. And if one erroneously limits the number of spiritual substances to the number of celestial movements, then the sepa- rated intelligence moving the first animated sphere (primum caelum) must be God. On the other hand, if the immediate ^°'^ Sum. cont. gent., Ill, c. 23, § 8. Also In II Phys., lect. 1, n. 4; in II De caelo, lect. 3, n. 2, and lect. 18, n. 1; De pot., q. 5, a. 5 ad 12. ^°'' St. Thomas In II De caelo, lect. 18, n. 1. CELESTIAL MOVERS IN MEDIEVAL PHYSICS 189 mover of the celestial bodies is not a soul, then it is in no way moved per accidens. This immediate mover could be God Him- self or an angel. And if the number of angels is greater than Aristotle conceded, then it is impossible to demonstrate that God is the immediate mover of the heavens. This is precisely the difficulty envisaged in St. Thomas' reply to the fifth ques- tion: assuming that God is not the immediate mover, then it is indeed demonstrated that an angel is the mover. This as- sumption, however, cannot be made on philosophical, much less on physical grounds. This is not to say that Aristotle failed to prove the existence of God in Meta^physics XII. Quite the contrary. St. Thomas was convinced that Aristotle perceived that other mode of becoming yer influentiam essendi, whereby every spiritual substance is necessarily dependent on the first cause of being. It is this other mode of " being moved " that St. Thomas sees in Aristotle's conception of the conjoined mover of the first heaven."^ It is the totality of movers which are in some true sense moved that validates the Aristotelian argument for St. Thomas. " Hence, unless the celestial bodies are moved immediately by God, they must either be animated and moved by their proper souls or be moved by angels, quod melius dicitur." Concluding his reply to the fifth question, St. Thomas notes that there are some philosophers who would have God move the first heaven by means of its anima propria, and the other heavens by means of intelligences and souls. St. Thomas' own view is that God directs the universe through a hierarchy of angels, only the lower of which directly move the celestial bodies. The view of St. Thomas is openly defended in the anonymous Quaestio de viotoribus corporum caelestium, a work formerly attributed to St. Thomas and still published among his works .^°' "*For example, In XII Metaph., lect. 7, nn. 2519-2522; lect. 8, nn. 2539-2543; In II De caelo, lect. 18, n. 6. "^ Opera Omnia (Parma: Fiaccadori, 1869) , XXIV, pp. 217a-219b. This treatise was first published by Thomas Boninsegnius, O. P., in his edition of the Summa with Cajetan's commentary (Venice: apud Juntas) in 1588. The first folio an- 190 JAMES A. WEISHEIPL Strangely, there is no known manuscript of this work extant, but it seems to be of English origin, written, as Grabmann has pointed out, some time after June 1271/°" In it the author rejects at length the tradition represented by Robert Kilwardby as well as the animation theory presented by Simplicius. The author defends vigorously the Thomistic view that celestial movers are two-fold: the passive nature of the celestial body and the active power of angels ministering to the will of God. The medieval views of celestial movers which we have out- lined in this paper are rarely considered today. Yet they are important for an understanding of St. Thomas, and they do have serious implications which deserve the attention of modern Thomists, implications of interest to theologians as well as to philosophers of nature. James A. Weisheipl, 0. P. Alhertus Magnus Lyceum Dominican Hou^e of Studies River Forest, Illinois nounced: " Quaestiones duae S. Thomae de Aquino nuper repertae ac in lucem editae, una de principio individuationis, altera vero de motoribus coelestium cor- porum, quae nuper repertae fuerunt Florentiae in bibliotheca S. Marci." This new manuscript was copied for San Marco by order of Cosmo de Medici and notarized on June 5, 1587; this document is published on fol. 2r of the edition. Boninsegnio rests his argument for the authenticity of the treatise (fol. 2v S.) on the Thomistic character of the doctrine and on the credibility of the manuscript, which also contained St. Thomas' De potentia. The same scribe had written the two new questions on folios 287-290 of the original manuscript, which is now lost. "*M. Grabmann, Die Werke des hi. Thomas von Aquin. 3rd ed. (Miinster, 1949). Beitrdge z. Gesch. d. PhU. u. Theol. d. M.-A., Bd. XXU, heft 1-2, p. 415. GRAVITATIONAL MOTION ACCORDING TO THEODORIC OF FREIBERG THE recent appearance of Marshall Clagett's The Science of Mechanics in the Middle Ages ^ has focussed atten- tion once again on the wealth of material made avail- able by scholars in the " Dark Ages " for the development of science as we now know it. Concentrating on " the mechanical doctrines of the medieval period which were framed in mathe- matical terms or had important consequences for a mathe- matical mechanics," ^ Clagett reproduces most of the important texts in this area and analyzes them for the conceptual content that contributed to the revolutionary seventeenth-century development. By intent he avoids the study of methodology, nor does he attempt to evaluate the complex relationships that existed between physics and natural philosophy during this period. Yet even these areas have not been without their share of attention in the recent literature. Three significant studies of medieval scientific methodology have appeared in succession,^ and Anneliese Maier has recently concluded the fifth volume of her monumental Stiidieji zur Naturphilosophie der Spdtscholastik * with some weighty observations on the transitional philosophical concepts that gave rise to the new * University of Wisconsin Press: Madison, 1959, xxix -\- 711 pp. " Ibid., p. xxii. 'A. C. Crombie's Robert Grosseteste and the Origins of Experimental Science, Oxford, 1953; my own The Scientific Methodology of Theodoric of Freiberg, Fri- bourg, 1959; and J. A. Weisheipl's The Development of Physical Theory in the Middle Ages, London, 1959. * Zwischen Philosophic und Mechanik, Rome, 1958, particularly pp. 373-382. The five volumes, which we shall henceforth refer to as Studien I, II . . . etc., are entitled respectively: I. Die Vorldufer Galileis im 14.. Jahrhundert (1949); II. Zivei Grundprobleme der scholastischen Naturphilosophie (1951); III. An der Grenze von Scholastik und Naturunssenschaft (1952); IV. Metaphysische Hintergriinde der spdtscholastischen Naturphilosophie (1955); and V. Zwischen Philosophic und Mechanik (1958). 191 192 W. A. WALLACE science. All of these works are fruitful sources of study for the Thomistic philosopher of science who would evaluate modern science in light of the traditional concepts of natural philosophy. It is to be hoped that the time will not be long before some penetrating studies in this area may help solve the stubborn problems that have frustrated and divided adherents to the philosophy of St. Thomas during the past several decades.^ Meanwhile these works have also signalized the importance of studying manuscript sources to fill the gaps in our knowledge of medieval science. Clagett's work, by his own admission, would have been quite impossible without the prior paleo- graphical efforts of Maier and Moody. It is in a spirit similar to that in which the latter research was undertaken that I should like to offer this brief study of gravitational motion according to Theodoric of Freiberg (c. 1250-c. 1310) . Theo- doric's contributions to medieval optics and scientific method- ology are sufficiently well known not to require further attention, but by some peculiar oversight the views of the German Dominican on the problem of gravitation have gen- erally not been recorded.® I shall attempt to fill this lacuna by a resume of the unedited opusculum De elementis corporum naturaliuTn ijiquantum sunt partes mundi,'' which contains ^ I have in mind the long-standing debate over a so-called " specific distinction " maintained by some to exist between Thomistic natural philosophy and modern science, which has impeded the study of a host of philosophical problems concerning the nature of matter, gravity, mass, energy, light, the elements, etc., all arising in modern science. * The literature on Theodoric is given in my Scientific Methodology of Theodoric of Freiberg (Studia Friburgensia, No. 26) , The University Press, Fribourg: Switzer- land, 1959. Miss Maier mentions him in several footnotes throughout her volumes, but otherwise has only a brief treatment of his doctrine on the elements in Studien III, pp. 58-69, without considering the relation of the latter to falling motion. ' This opusculum was probably written about the year 1300. Two complete manu- script versions are known: Cod. Maihingen (Fiirstliche Bibl. Schloss Harburg, II, 1 qu. 6), henceforth referred to as M, and Cod. Vat. Lat. 2183, henceforth referred to as U. In addition, some fragments of the opusculum are to be foimd in Cod. Vat. Lat. 1121, henceforth referred to as T. When a reading of the Latin text is given below, it is generally a composite text based on all available manuscripts, as indi- GRAVITATIONAL MOTION 193 Theodoric's complete doctrine on this subject. It is not my intention to enter into a detailed analysis of the doctrine presented, but rather to sketch the essential content of The- odoric's teaching, supporting this by substantial citation from the manuscript versions of the opusculum. In thus utilizing the space alloted to me, I also forego the opportunity to point out possible relationships between Theodoric's doctrine and more recent thought on gravitation. I trust, however, that the material presented will have some bearing on further analyses of the causes of gravitational motion that may be forthcoming from Thomistic philosophers. Gravity and the Elements The elements, for Theodoric, are material components of natural bodies, " principles according to the formality of matter," or, more explicitly, " whence a thing is materially composed." ^ As such, they can be studied by the meta- physician, who is interested in them " from the viewpoint of their substance, how they pertain to the genus of being pre- cisely as being," or they can be studied by the natural phi- losopher " insofar as they are natural bodies and accordingly related to motion and change." ^ The latter consideration again permits of a twofold division, for the natural philosopher may investigate them in a way similar to that of the modem physicist, insofar as they are " the first parts of the universe," or in a way similar to that of the modern chemist, insofar as they contain a " principle of transformation by which one element can be simply generated from another, or compounds formed from elements." " Gravity is of primary interest to the physicist, thus characterized, as Theodoric explains in the following passage: cated with the foliation. I have already furnished a critical Latin edition of the prologue and first eight chapters of this opusculum in my Scientific Methodology, pp. 324-331. ® Prologue, (ed. Wallace) pp. 324-325. * Cap. 7, p. 329. " Ibid. 194 W. A. WALLACE Certain accidents or qualities are in elements as they are parts of the universe, namely, gravity and levity, and, deriving from these, natural motions either to or from its center. . . , Through such motions bodies arc disposed in their proper places in the material universe, considering the latter quantitatively in its extensive and dimensional integrity as well as in its specific diversity. Such acci- dents are in elements as parts of the universe, making up the uni- verse precisely as actual, for actual parts are those which have a species. Thus it is that gravity and levity are first found in [elemental] bodies complete according to species, and that they are their very first accidents as parts of the universe. . . . Wherefore, if there be any bodies or natures simpler than these, of which the forementioned elements might in turn be composed, light and heavy would not be proper to such bodies or natures, nor would these be parts of the universe specifically and quantitatively, except possibly in an originative way.^^ Gravity, then, is one of the first qualities of bodies considered in relation to other bodies making up the universe, and is properly attributable to the elemental constituents of such bodies, themselves specifically complete, as the ultimate source of their natural or gravitational motions. This suggests for Theodoric some observations as to whether gravity is an abso- lute quality, or merely relative, and whether it is subject to intensification or not. Surprisingly enough, such questions were not commonly discussed at the turn of the fourteenth century; Ciagett has pointed out that the first evidence of the concept " specific weight " is only to be found in the pseudo-Archi- medean treatise De insidentibus in humidum, itself dating from the thirteenth.^- There is no direct use by Theodoric of the quantitative notions found in De insidentibus, but he does speak of an " intensity " of gravity, as is clear from the folio win 2: citation: *& There is a twofold modality of heavy and light. One is according to absolute quality, w^hose formality consists in this, that heavy and light are principles of a determinate tendency to some place in the universe. Under this formality heavy and light are distinguished in bodies in the following way, viz., some are heavy and light simply, " Ibid., pp. 329-330. " Op. dt., pp. 93-95, 674. GRAVITATIONAL MOTION 195 as fire and earth, which go to the extremities of straight-line motion; others are such comparatively, in the sense that they are heavy or light with reference to various boundaries, as air and water. But there is another modality of heavy and light which is noticed in the intensity of these qualities, whereby it happens that in the case of two bodies, even such as tend to the same terminus, one will be heavier or lighter than the other, in the sense that one will have more weight than the other. And this can result from one of two causes, viz., because of the aggregation of more parts of the same body, as a larger portion of earth has more weight than a small piece; or from the complexion and nature of the body itself, as lead or gold is heavier and has more weight than earth or stone of an equal size.^^ Thus there is in Theodoric's thought a recognition of specific weights, although he gives no mathematical treatment of them, and in fact is not interested in their effect on gravitational motion. His position is rather that the first modality men- tioned above, " according to absolute quality," is proper to bodies as they are parts of the universe, and this alone deter- mines the proper place or region to which a body tends, whether it be element or compound. If it is a compound, it will tend to a region determined by what is " predominant " in it, not by " proportional parts, even an exceeding one." What he means by this " predominant " is not too clear: he describes it as being " according to the property and nature of the com- plexion in which the species of the body is rooted, which itself is one and simple." Yet the practical consequence of his view is easily discerned, for he holds that " fiery bodies," i. e., " shooting stars and comets," tend to the proper place of fire, while " earthy bodies " such as " minerals and stones " tend to the place of earth." This is clearly in accord with Aristotle's doctrine in De caelo et mundo ^^ and itself adds little to the latter's development. Had Theodoric been discussing the " Cap. 8, p. 330. ^^ Ibid., p. 331. For the medieval understanding of the expression, "comets tend to the place of fire," see Lynn Thorndike's Latin Treatises on Comets Between 1238 and 1S6S A.D., Chicago, 1950, passim. ^^ Book IV, chap. 4, 311a30-b3. 196 W. A. WALLACE velocities of fall of such bodies, and not the places to which they tend, his elimination of specific weights as of incidental importance would have shown rare insight for his time. But there is no mention of velocities in this opusculum, and this discovery had still to await the researches of Galileo. It is by pursuing such a line of thought, however, that Theodoric comes to some interesting questions about composite motions and how these can be resolved into component parts, for which he proposes noteworthy answers. He maintains, in accordance with the teaching just proposed, that there are no " intermediary places . . . beyond the four places of the four primary bodies," although allowing that a particular compound might have a proper place to which it tends in " some one of these first regions," determined by its " relation to some part of the heavens or the horizon." ^^ Against this position he notes the objection, already in Aristotle, that simple bodies ought to have simple motions and composite bodies composite mo- tions. He replies to this by making precise the sense in which a motion is " composite " — not because its terminus is composite, but rather because " the manner in which it tends to that terminus is composite." This manner of tending, he points out, need not be composite, for we find that both simple and com- posite bodies undergo simple motions " according to the nature of the predominant." In fact, he notes, such simple motions are what manifest the natures of the simple bodies or elements, and it matters little whether the body undergoing motion be simple or composite when the motion itself is simple and mani- fests the simple nature that is its principle .^^ Yet it is a fact that some composite bodies have simple natural motions, while others have composite natural motions — ^* Cap. 10, M 14vb, U 141vb: Non est eciam aliquis locus medius, vel ut ita dicam mixtus, preter hec quatuor loca quatuor corporum primorum. Unde neces- sarium est omne corpus recti motus ferri ad aliquem istorum quatuor secundum predominans, et si fuerit aliquis locus proprius aJicui mixto secundum habitudinem ad aliquam partem celi vel orizontis, hie erit pars alicuius istorum primorum locorum et presupposita natura ipsius. "Cap. 11, M 15ra, U 142ra. GRAVITATIONAL MOTION 197 and this even when living things are excluded and one treats only of objects that move precisely as light or heavy. This leads Theodoric to a significant question: " Why do certain composite bodies move naturally with a simple motion, and certain others with a composite motion? " ^^ The answer he proposes, while hardly consonant with modern scientific thought on the subjects he treats, provides an insight into the way in which the medievals explained such divergent motions as those of currents, magnets, tides, and heavenly bodies, and may be suggestive of analogous approaches available to the natural philosopher of the twentieth century for evaluating modem theories dealing with these same topics. Composite Motions In summary form, the general answer that Theodoric gives to this question, which he then goes on to elaborate through twelve chapters of the opusculum, is contained in the following statement: It should be noted that there are many differences among bodies that are moved by nature either with composite or simple motions. Some are moved as parts of wholes, without being separate from such wholes. Others are moved somewhat as wholes themselves, and this in a twofold way, for some are moved by an intrinsic natural principle, while others are moved by an extrinsic principle, as will become apparent when we consider them singly .^^ To illustrate the meaning of this observation, we may note that for Theodoric the natural motions of fluids, such as those com- prising the atmosphere and the hydrosphere, are generally composite motions. Some of these are composite in the sense that they are motions of the parts of a fluid medium; the movement of such a part he resolves into two interacting "Cap. 12, M 15ra, U 142ra-b. ■^' Ibid.: Est sciendum quod corporum que moventur motu composite seu simplici per naturam multiplex est differencia. Quedam enim moventur ut partes in toto, non tamen separate a toto, quedam autem ut tota quedam, et hoc dupliclter, quia quedam moventur ab intrinseco principio naturali, quedam ab extrinseco, ut de singulis patebit. 198 W. A. WALLACE components, one impressed on it by adjoining parts, another arising intrinsically within the part itself. Other composite motions are those of clouds, vapors and winds, when these are considered as integi-al wholes apart from any internal move- ments that might characterize their parts; such motions he analyzes as deriving partly from the intrinsic elements of which such wholes are composed, and partly from the forces that generate them, which he sees as endowing them with added dispositions to fulfill special purposes intended by nature. Still other motions, such as those of rivers and whirlwinds, are com- posite because of the reaction of the fluid with its boundaries or because of the interaction that results when two natural motions converge from different directions. In practically all of these cases, as we shall see, the natural motion which is attributed by Theodoric to the elemental constituents of the fluid is a simple, straight-line motion towards the center of gravity, while the component that makes the total motion composite derives from an outside source and does not come directly from the fluid's intrinsic components. The case of the complex movement of parts of a fluid medium is not particularly noteworthy, except for the fact that Theo- doric there uses notions associated with Averroes' solution to the projectile problem,-" which may be indicative of his own ideas concerning impetus. Theodoric does not commit himself to any particular theory of impetus — in fact he explicitly refrains from discussing this matter " — but he does speak of the influence of the parts of a fluid on each other by which they continue to be in motion after the source of their initial dis- turbance has ceased." Since the cases of fluid and projectile ^°Cf. Commentarium in VIII Physicorum (ed. Venetiis, 1550), Tom. IV, 195va- 196ra. "For the Latin text, see Maier, Studien V, p. 290, fn. 1. Cap. 13, M 15rb, U 142rb: Tale enim corpus, cum receperit motum in aliqua suarum parcium, huiusmodi pars movet aliam vel alias, et sic deinceps, quod absque aliquali subinteraccione parcium ad partes fieri non potest, propter talium corporum spiritualitatem, ut dicit Commentator super octavum Physicorum. Partes autem sic mote et propulse, alias secum trahunt propter continuitatem. Cum autem per talem niocionem partes sursum vel alias extra locum suum actu fuerint, quasi per GRAVITATIONAL MOTION 199 motion are quite dissimilar, at least in the sense that the first is that of a continuous medium in direct contact with its dis- turbing force, while the second is that of an object obviously separated from its mover, one should not make too much of this argument, but there does seem to be a suggestion here of some motive power being communicated to parts of the fluid and thus accounting for its continued motion. In discussing the motions of fluids considered as wholes, such as winds, clouds, mists, rain, etc., Theodoric develops this notion further. He considers these as " incomplete entities not yet separated from their generator," and maintains that they have some motive principle, apart from the intrinsic gravi- tational principle associated with their elemental constituents, by which they fulfill a particular end intended by nature.-^ The gravitational principle, he notes, is analogous to the intrin- sic principle that might be induced into a body by the action of an altering agent, and here he gives the interesting example of a magnet's action on iron, which he observes causes the iron " to tend towards it in a straight line wherever it might be, whether through air, water, or a metallic container " 24 violentam alterius partis impulsionem vel aUractionem, motu suo natural! redeunt rursum ad locum suum proprium et ipse tales partes et impellentes. Et sic per talem impulsionem, tractionem parclum, subinteraccionem, fit quedam inundacio talis corporis humidi in suis partibus. Quo fit eciam ut non statim cesset huiusmodi motus ad cessacionem primi moventis primam partem, quia sicut dictum est huius- modi motus componitur ex naturali et violento, qui ex disposicione sibi, ex mutua disposicione seu alteracione vel influencia indita, sepius super seinvicem replicantur, cum in huiusmodi naturalis motus sequatur violentum, et violentus causetur a naturali. "■" Cap. 15, M 15rb, U 142rb. -* Cap. 16, M 15va, U 142va-b: Et huiusmodi motus per naturam non solum competit rebus que moventur ad aliquem naturalium locorum mundi secundum determinatam habitudinem ad centrum et circumferenciam mundi, et hoc secundum aliquod principium inexistens per mocionem generantis, sed ' eciam sic moventur secundum naturam principii inexistentis per approximacionem alicuius corporis alterantis seu aliquo modo afficientis ea. Cuiusmodi est motus ferri ad magnetem, quod non impeditum, secundum lineam rectam tendit ad ipsum ubicumque fuerit, sive per aerem, sive per aquam, sive per vasa metallina, ut patet ad sensum. Sic patet de quibusdam compositis qua racione moventur per naturam motu recto, quia scilicet moventur per principium intrinsecum. 200 W. A. WALLACE Unfortunately he does not discuss the character of the extrinsic principle in this context. However, when attempting later to account for the fact that mists arise naturally from ponds and move in determined directions, he explains that the generating agent " continually induces some natural disposition into such bodies," which is not gravity but " which presupposes and requires this qualitative principle," and is similarly related to a determinate place.^^ Such an added disposition, he observes, is the means by which "universal nature " provides for the needs of the various parts of the universe, as for example by moving rain clouds to particular areas where water is needed.^^ The added disposition he also calls a " generative principle," and notes that its action is not a violent one, even though attraction and propulsion characterize its operation. He would prefer to speak of the propulsion as arising from " whatever induces the form or disposition which is the principle of the motion," and to understand the attraction as being merely in the order of final causality.-^ Thus Theodoric analyzes certain composite motions found ^^ Cap. 17, M 15va, U 142vb: Sed si sunt alia aliqua corpora huius inferioris mundi que moveantur per naturam motu tortuoso vel composito vel circulari, huiusniodi eciam movebuntur ab exteriori principio, et hoc sive a generante, inquan- tum videlicet talibus corporibus continue influit aliquam disposicionem naturalem qua acquiratur eis continue locus post locum, non semper secundum habitudinem recte distancie que attenditur inter centrum et circumferenciam secimdum lineam rectam. Talis enim motus principium est generans, secundum quod ingenerat corporibus has simplices et absolutas qualitates que sunt gravitas et levitas. Pre- diotis autem corporibus aliquando acquiritur locus continue secundum habitudinem ad aliquam partem orizontis, ut si surgat aliquis vapor in parte australi et per naturam tendat versus septentrionem. Hoc autem fit secundum aliquam aliam disposicionem huiusmodi corporibus inditam, que nee est gravitas neque levitas. Presupponit tamen et preexigit hoc qualitativum principium, sic inditum per naturam, gravitatem et levitatem in corpore in quo est, sicut et locus in quo vel ad quem moventur huiusmodi corpora est pars alicuius locorum gravium et levium. ^"Cap. 18, M 15va, U 142vb-143ra. ^ Cap. 19, M 15va, U 143ra: Huic motui corporum que moventur per principium generativum commune assimilatur motus et nutrimenti per corpus. . . . Intelligenda est pulsio et tractio modo predicto proporcionaliter, sicut in predictis corporibus partibus mundi, ut scilicet dicatur pellens eo quod dat formam vel disposicionem que est principium motus, trahens autem intelligatur secundum racionem et inten- cionem finis. . . . GRAVITATIONAL MOTION 201 in nature and attributes their composite aspect to two com- ponent principles, one being the gravity or levity of the predominant elements of which the bodies are composed, accounting for the straight-line component of their motion to or from some center of gravity, the other being a natural form added to the gravitational principle by a generating force, and accounting for the non-linear component of their motion. This suggestion is pregnant with consequences if it could be under- stood as applying to the case of the heavenly bodies, and the question naturally arises if Theodoric, writing at the latest in the first decade of the fourteenth century, could have anticipated this seventeenth-century development of celestial mechanics. The answer is to be found in another unedited opusculum of Theodoric entitled De intelligenciis et motor ibus celorum.^^ Here he introduces the notion of composite motions once again, and precisely in the context where one might expect him to do so, namely, in connection with the astronomical theories of eccentrics and epicycles. Theodoric specifically rejects Aver- roes' adherence to the literal text of Aristotle, maintaining that Aristotle need not be understood as meaning that heavenly bodies must revolve in circular orbits exactly concentric with the midpoint of the universe, as Averroes interprets him, and suggesting that " perhaps he [Aristotle] wished ' center ' to be understood more generally, for the natural center of any natural circle whatsoever," as opposed to the center of the world. "^ His reason for urging a different interpretation of the Aris- totelian text is based on " the efficacy of the demonstrations " in Ptolemy's Ahnagest; here, as in other places, Theodoric is more convinced by the observational evidence " of the astrol- ogers " than he is by the authority of Aristotle.^" Granting the ^® This opusculum was probably written in the first decade of the fourteenth century. There are two manuscript copies extant: Cod. Vat. Lat. 2183, henceforth referred to as U; and Cod. Vindobon. (Dominikanerkloster) 138/108. Where readings of the Latin text are given below, they are based on U. "* Cap. 11, U o8va: Fortassis generalius voluit intelligi medium, videlicet, quod- cumque medium naturale cuiuscumque circuli naturalis. . . . ^° Capp. 11 et 14; De elementis, cap. 9 — cf. Scientific Methodology, p. 126. 202 W. A. WALLACE mathematical explanation of eccentrics and epicycles, however, he is still at a loss for a physical explanation as to why this peculiar motion of the heavenly bodies occurs, and in seeking such an explanation has recourse to his concept of " composite motion." In this treatment, as in De elementis, there is again a lack of quantitative analysis. Theodoric's argument is in fact very brief, and merely suggestive of an analogy that might obtain between straight-line motions and circular ones when both are considered as natural motions. He first notes that there is a certain relativity to be found in linear gravitational motions, when the principles of such motions are considered precisely as related to the surrounding environment.^^ If extrinsic factors introduce a type of composition into motions that should be simple when explained in terms of their intrinsic principles alone, he sees no reason why a similar type of composition might not also be found in circular motions: If this is the case in such straight-line motions, as has been said, it is not extraordinary or incomprehensible to interpret the Phi- losopher's [Aristotle's] treatment of circular motion, when he speaks of it as rotating about a center, as not to mean the exact center of the universe, but the natural center of any natural circle in which there is something having the nature of a terminus, as for example the mid-point of the revolution, insofar as a revolution includes in its very notion movement to a point and away from a point, both being vmderstood with reference to the center of the circle. ... If therefore different relations to various termini can introduce com- position into straight-line motions, so also different centers can '^ Cap. 16, U 59ra-b: Quia in talibus transformacionibus que sunt recti motus attenditur fercio aliquis terminus — nichil enini tali motu incipit moveri secundum naturam quod non potest perveiiire ad terminum secundum naturam intentum — hinc est quod in talibus motis secundum diversitatem talium terminorum invenitur nonnulla distraccio et aliquis recessus a pura et omnimoda simplicitate, ne talia corpora, quamvis habeantur per simplicibus, ad eosdem terminos vel secundum eosdem moveantur. Videmus enim alium esse terminum ad quem naturaliter movetur ignis in regione sua, quia ad superficiem infimam spere lune, alium autem terminum perpendimus ad quem movetur aer in spera sua, qui si esset in spera ignis ab ea recedet naturaliter. Et ita videmus diversitatem terminorum in aqua et in terra quoad proprias secundum naturam regiones eorum. GRAVITATIONAL MOTION 203 introduce plurality and composition into circular motions, and these too can be composed of many circular motions, of which each is itself simple and one.^- The composition which Theodoric here attempts to explain in terms of physical or natural causes is thus not the com- position that would result from a straight-line gravitational tendency to a center to which had been added a principle of tangential motion, as this was to be proposed by Newton in the seventeenth century, but rather a composition of rotary motions consistent with the geometrical picture of the universe already sketched by Ptolemy. What is interesting about Theo- doric's view, however, is his willingness to account for the deviations from perfect circularity detected by astronomers of his time in planetary, lunar and solar motions, by allowing for the possibility of different centers of gravity within the uni- verse, and this while viewing these centers not merely mathe- matically, but also as terms of proper natural motions from intrinsic principles. This represents a very definite break with the Averroist- Aristotelian tradition, and at the same time pro- vides the basis for accomodating Aristotelian thought to a plurality of gravitational centers, in the sense of universal gravitation as it was ultimately to be understood by Newton. Another interesting development of Theodoric's thought regarding composite motions is his attempt to explain the complex motion of the tides in terms of natural principles. This ^^ Cap. 17, U 59rb-va: Si inquam sic se habet in istis motibus rectis, ut dictum est, quid mirabile vel inconveniens si sic vult intelligi Philosophus illud quod tractat de motu circulari, dicens ipsum fieri circa medium, non sumendo medium omnino pro centro universi, sed pro quocumque naturali medio cuiuscumque circuli naturalis in quo invenitur eciam aliquis habens naturam termini, puta medium centrum circa quod volvitur, que circumvolucio includit in se et importat naturam motus ad terminum et a termino, quod utrumque intelligitur in respectum ad centrum talis circuli. Moveri enim circa centrum est moveri quodammodo ab ipso et ad ipsum; unde habet naturam et racionem termini motus. Si igitur habitudo diversa ad diversos terminos motus rectos, ut visum est, sic eciam quoad motum circularem secundum diversa media centralia, quorum quodlibet habet naturam et racionem termini, potest plurificari et componi motus, ut sit motus compositus ex pluribus circularibus motibus quorum quilibet in se simplex et unus est. . . . 204 W. A. WALLACE he undertakes to do in the opusculum De elementis, where he works out an explanation that is rather ingenious, even though quite implausible from the viewpoint of modern science. The motion of the tides, for Theodoric, is yet another case where " universal nature " provides for the needs of the universe by a composite motion, and this by inducing a motive principle that comes " effectively " from the heavenly bodies (particu- larly the moon) , and " passively " from sea water as being naturally adapted to receive this influx/^ The mode of trans- mission of the force deriving from the heavenly bodies is based on an interpretation of Proclus,^* whereby Theodoric conceives of some generic influence, originating with the separated sub- stances, as being more and more determined and composed as it works down through the heavenly spheres, finally receiving its ultimate determination from the moon.^^ Theodoric does not regard this influence as an attraction which exerts a pull on the sea, but rather conceives it as somehow effecting an alteration within the sea water, which makes it expand and thus extend its boundaries on land, thereby accounting for the rise (and fall) of the tides. Interestingly enough, Theodoric proposes a mechanistic type of explanation for this motion which is not without empirical foundation. As far as he can discern, tidal motions are restricted to bodies of sea water, and are not found in fresh water.^" Thus he proposes that sea water can be regarded as ^^ Cap. 22, M 15vb, U 143ra-b. ^* Cap. 23, M 16ra, U 143rb-va: Sicut dicit Proclus, 135 proposicione et 136 proposicione, dicit quod omnes illarum substanciarum separatarum potencie de- sursum inchoantes, et per proprias medietates procedentes usque ad extrema, perveniunt et ad loca circa terrain. . . . Sicut dicit Proclus 54 proposicione, sic: omne quod a secundis producitur, et a prioribus et a causalibus producitur eminen- cius. — The references are to the Elementatio theologica. Cf. Proclus, The Elements of Theology, A Revised Text with Translation, Introduction and Commentary, by E. R. Dodds (Oxford: Univ. Press, 1933), Props. 135-6, pp. 120-121, and Prop. 56 (cited as Prop. 54 by Theodoric), pp. 54-55. *^ Cap. 23, M 16ra, U 143rb. ^* Cap. 24, M 16va, U 144ra: Sufficiant ilia que dicta sunt nonnulla racione, cui racioni concordat hoc quod videmus in aquis dulcibus, sive sint fluentes sive sint stagna, scilicet, quod non videmus ibi notabiliter eas vaporare et moveri extra GRAVITATIONAL MOTION 205 a mixture of salt and fresh water, which is not strictly a new chemical compound, and whose components can therefore be separated " by the application of some force." ^' He conceives the action of the moon as being such a force, which effectively is able to " vaporize " the fresh (or " sweet ") component of sea water, thereby causing the whole body of the sea to expand and overflow its banks " as the moon approaches the meridian." ^^ Thus there are two natural causes of this com- consuetum modum suum, quia non est facilis separacio parcium talium aquarum, sicut dictum est de aquis que sunt in mari. ^' Ibid., M 16rb, U 143vb: Quando humida aliqua adinvicem confunduntur, et fuerint substancie diversarum naturarum, et fuerit unum eorum subtilius altero et passibilius et facilius obediens agenti, faciliter abinvicem separantur, maxima si fuerint valde distantis nature, vel si fuerit unum eorum in alio sic virtute, ut possit ex eo faciliter generari. Et sic se habent aqua et vinum, que ex hoc aliqua arte separantur. Sicut autem dictum est de aqua et vino, sic se habet et in aliis talibus, puta in aqua salsa et dulci. Dico autem aquam salsam cuius substancia est sal, ut putei salis. Et talis est aqua maris in sui substancia, et propter hoc coquitur sal ex eo. Constat autem quod substancia dulcis aque et aqua maris sunt valde diverse, et distantis nature in subtilitate et grossitudine multum differentes. Et propter hoc, permixta, possunt aliqua vi abinvicem separari. Manifestum est autem quod du