The Metaphysical Foundations of Modern Physical Science

"How curious, after all, is the way in which we moderns think about our world ! And it is all so novel, too. The cosmology underlying our mental processes is but three centuries old—a mere infant in the history of thought—and yet we cling to it with the same embarrassed zeal with which a young father fondles his new-born baby."

"Philosophers never succeed in getting quite outside the ideas of their time so as to look at them objectively-this would, indeed, be too much to expect. ...But philosophers do succeed in glimpsing some of the problems involved in the metaphysical notions of their day and take harmless pleasure in speculating at them in more or less futile fashion."

"The central place of epistemology in modern philosophy is no accident... Knowledge was not a problem for the ruling philosophy of the Middle Ages ; that the whole world which man's mind seeks to understand is intelligible to it was explicitly taken for granted. That people subsequently came to consider knowledge a problem implies that they had been led to accept certain different beliefs about the nature of man and about the things which he tries to understand."

"It may very well be that the truly constructive ideas of modern philosophy are not cosmological ideas at all, but such ethico-social concepts as 'progress,' control,' and the like."

"In the last analysis it is the ultimate picture which an age forms of the nature of its world that is its most fundamental possession. It is the final controlling factor in all thinking whatever."

"All of us tend easily to be caught in the point of view of our age and to accept unquestioningly its main presuppositions."

"For the dominant trend in medieval thought, man occupied a more significant and determinative place in the universe than the realm of physical nature, while for the main current of modern thought, nature holds a more independent, more determinative, and more permanent place than man."

"For the Middle Ages man was in every sense the centre of the universe. The whole world of nature was believed to be teleologically subordinate to him and his eternal destiny. Toward this conviction the two great movements which had become united in the medieval synthesis, Greek philosophy and Judeo-Christian theology, had irresistibly led."

"This view underlay medieval physics. The entire world of nature was held not only to exist for man's sake, but to be likewise immediately present and fully intelligible to his mind. Hence the categories in terms of which it was interpreted were not those of time, space, mass, energy, and the like ; but substance, essence, matter, form, quality, quantity... the facts and relations observed in man's unaided sense-experience of the world and the main uses which he made it serve."

"Man was believed to be active in his acquisition of knowledge—nature passive. When he observed a distant object, something proceeded from his eye to that object rather than from the object to his eye. And, of course, that which was real about objects was that which could be immediately perceived about them by human senses."

"What more natural than to hold that these regular, shining lights were made to circle round man's dwelling-place, existed in short for his enjoyment, instruction, and use? The whole universe was a small, finite place, and it was man's place. He occupied the centre ; his good was the controlling end of the natural creation."

"The visible universe itself was infinitely smaller than the realm of man. The medieval thinker never forgot that his philosophy was a religious philosophy, with a firm persuasion of man's immortal destiny. The Unmoved Mover of Aristotle and the personal Father of the Christian had become one. There was an eternal Reason and Love, at once Creator and End of the whole cosmic scheme, with whom man as a reasoning and loving being was essentially akin. ...the religious experience to the medieval philosopher was the crowning scientific fact. Reason had become married to mystic inwardness and entrancement..."

"The world of nature existed that it might be known and enjoyed by man. Man in turn existed that he might "know God and enjoy him forever.""

"The whole natural world in its present form was but a moment in a great divine drama..."

"What a contrast between the audacious philosophy of Dante reposeful, contemplative, infinitely confident and this view! To Russell, man is but the chance and temporary product of a blind and purposeless nature, an irrelevant spectator of her doings, almost an alien intruder on her domain."

"Just as it was thoroughly natural for medieval thinkers to view nature as subservient to mans knowledge, purpose, and destiny ; so now it has become natural to view her as existing and operating in her own self-contained independence, and so far as mans ultimate relation to her is clear at all, to consider his knowledge and purpose somehow produced by her, and his destiny wholly dependent on her."

"Berkeley, Hume, Kant, Fichte, Hegel, James, Bergson all are united in one earnest attempt, the attempt to reinstate man with his high spiritual claims in a place of importance in the cosmic scheme. The constant renewal of these attempts and their constant failure widely and thoroughly to convince men, reveals how powerful a grip the view they were attacking was winning over people's minds, and now, perhaps even more than in any previous generation, we find philosophers who are eager above all things to be intellectually honest, ready to give up the struggle as settled and surrender the field."

"That the scientific philosophy of the Greeks, with all its sublime passion for the very truth of things, arrived in its turn at an exalted philosophy of man, might be due to the circumstances insisted upon by some historians of thought, that the zenith of Greek metaphysics was attained quite consciously through the extension, to the physical realm, of concepts and methods already found helpful in dealing with personal and social situations. ...the misapplication being based in the last analysis on the unwarranted assumption that because man, while here, can know and use portions of his world, some ultimate and permanent difference is thereby made in that world."

"It is difficult for the modern mind, accustomed to think so largely in terms of space and time, to realize how unimportant these entities were for scholastic science. Spatial and temporal relations were accidental, not essential characteristics. Instead of spatial connexions of things, men were seeking their logical connexions ; instead of the onward march of time, men thought of the eternal passage of potentiality into actuality."

"The big puzzles of modern philosophers are all concerned with space and time. Hume wonders how it is possible to know the future, Kant resolves by a coup de force the antinomies of space and time, Hegel invents a new logic in order to make the adventures of being a developing romance, James proclaims an empiricism of the 'flux,' Bergson bids us intuitively plunge into that stream of duration which is itself the essence of reality, and Alexander writes a metaphysical treatise on space, time, and deity."

"It might be that the reason for the failure of philosophy to assure man something more of that place in the universe which he once so confidently assumed is due to an inability to rethink a correct philosophy of man in the medium of this altered terminology. It might be that... modern philosophy had accepted uncritically certain important presuppositions, either in the form of meanings carried by these new terms or in the form of doctrines about man and his knowledge subtly insinuated with them..."

"During the last generation these ideas of science have been subjected to vigorous analysis and criticism by a group of keen thinkers, who have asked themselves what modifications in the traditional conceptions would be demanded if we sought to overhaul them in the light of a broader and more consistently interpreted experience. At present this critical investigation has culminated in a rather extensive transformation of the major concepts of scientific thinking, furthered on the one hand by radical physical hypotheses of a gifted student of nature like Einstein, and on the other by the attempted reshaping of scientific methods and points of view by philosophers of science such as Whitehead, Broad, Cassirer."

"Just how did it come about that men began to think about the universe in terms of atoms of matter in space and time instead of the scholastic categories? Just when did teleological explanations, accounts in terms of use and the Good, become definitely abandoned in favour of the notion that true explanations, of man and his mind as well as of other things, must be in terms of their simplest parts? What was happening between the years 1500 and 1700 to accomplish this revolution? And then, what ultimate metaphysical implications were carried over into general philosophy in the course of the transformation? Who stated these implications in the form which gave them currency and conviction? How did they lead men to undertake such inquiries as that of modern epistemology? What effects did they have upon the intelligent modern man's ideas about his world?"

"Professor Cassirer himself has done work on modern epistemology which will long remain a monumental achievement in its field. But a much more radical historical analysis needs to be made."

"We must grasp the essential contrast between the whole modern world-view and that of previous thought, and use that clearly conceived contrast as a guiding clue to pick out for criticism and evaluation, in the light of their historical development, every one of our significant modern presuppositions."

"The whole magnificent movement of modern science is essentially of a piece ; the later biological and sociological branches took over their basic postulates from the earlier victorious mechanics, especially the all-important postulate that valid explanations must always be in terms of small, elementary units in regularly changing relations. To this has likewise been added, in all but the rarest cases, the postulate that ultimate causality is to be found in the motion of the physical atoms."

"As for pre-Newtonian science, it is one and the same movement with pre-Newtonian philosophy, both in England and on the continent; science was simply natural philosophy, and the influential figures of the period were both the greatest philosophers and the greatest scientists. It is largely due to Newton himself that a real distinction came to be made between the two; philosophy came to take science, in the main, for granted, and another way to put our central theme is, did not the problems to which philosophers now devoted themselves arise directly out of that uncritical acceptance?"

"A student of the history of physical science will assign to Newton a further importance which the average man can hardly appreciate. ...the separation ...of positive scientific inquiries from questions of ultimate causation."

"The history of mathematics and mechanics for a hundred years subsequent to Newton appears primarily as a period devoted to the assimilation of his work and the application of his laws to more varied types of phenomena. So far as objects were masses, moving in space and time under the impress of forces as he had defined them, their behaviour was now, as a result of his labours, fully explicable in terms of exact mathematics."

"Newton... not only found a precise mathematical use for concepts like force, mass, inertia ; he gave new meanings to the old terms space, time, and motion, which had hitherto been unimportant but were now becoming the fundamental categories of men's thinking."

"In his treatment of such ultimate concepts, together with his doctrine of primary and secondary qualities, his notion of the nature of the physical universe and of its relation to human knowledge (in all of which he carried to a more influential position a movement already well advanced) in a word, in his decisive portrayal of the ultimate postulates of the new science and its successful method as they appeared to him, Newton was constituting himself a philosopher rather than a scientist as we now distinguish them."

"Imbedded directly and prominently in the Principia... these metaphysical notions were carried wherever his [Newton's] scientific influence penetrated, and borrowed a possibly unjustified certainty from the clear demonstrability of the gravitational theorems to which they are appended as Scholia."

"The fact that his [Newton's] treatment of these great themes... was covered over by this cloak of positivism, may have become itself a danger."

"The old set of categories, involving, as it appeared, the now discredited medieval physics, was no longer an alternative to any competent thinker. In these circumstances it is easy to understand how modern philosophy might have been led into certain puzzles which were due to the unchallenged presence of these new categories and presuppositions."

"Post-Newtonian philosophers... were philosophizing quite definitely in the light of his [Newton's] achievements, and with his metaphysics especially in mind. ...Of course, these men do not accept Newton as gospel truth they all criticize some of his conceptions, especially force and space—but none of them subjects the whole system of categories which had come to its clearest expression in the great Principia to a critical analysis."

"At the time of his death Leibniz was engaged in a heated debate on the nature of time and space with Newton's theological champion, Samuel Clarke. Berkeley's Commonplace Book and Principles, still more his lesser works such as The Analyst, A Defence of Free Thinking in Mathematics, and De Motu, show clearly enough whom he conceived to be his deadly foe. Hume's Enquiry Concerning Human Understanding and Enquiry Concerning the Principles of Morals contain frequent references to Newton. The French Encyclopaedists and materialists of the middle of the eighteenth century felt themselves one and all to be more consistent Newtonians than Newton himself. In his early years Kant was an eager student of Newton, and his first works aim mainly at a synthesis of continental philosophy and Newtonian science. Hegel wrote an extended and trenchant criticism of Newton."

"The only way to bring this issue to the bar of truth is to plunge into the philosophy of early modern science, locating its key assumptions as they appear, and following them out to their classic formulation in the metaphysical paragraphs of Sir Isaac Newton. The present is a brief historical study which aims to meet this need. ...At its close the reader will understand more clearly the nature of modern thinking and judge more accurately the validity of the contemporary scientific world-view."

"There were no known celestial phenomena which were not accounted for by the Ptolemaic method with as great accuracy as could be expected without more modern instruments. Predictions of astronomical events were made which varied no more from the actual occurrence than did predictions made by a Copernican."

"The motions of the heavenly bodies could be charted according to Ptolemy just as correctly as according to Copernicus."

"To the senses it must have appeared incontestable that the earth was a solid, immovable substance, while the light ether and the bits of starry flame at its not too distant limit floated easily around it day by day."

"The earth is to the senses the massive, stable thing; the heavens are by comparison, as revealed in every passing breeze and every flickering fire, the tenuous, the unresisting, the mobile thing."

"There had been built up on the basis of... supposedly unshakeable testimony of the senses a natural philosophy of the universe which furnished a fairly complete and satisfactory background for man's thinking."

"The assertion that a body projected vertically in the air must fall considerably to the west of its starting-point if the Copernican theory be correct, had to wait for its refutation till Galileo laid the foundations of modern dynamics."

"The objection that according to Copernicus the fixed stars ought to reveal an annual parallax, due to the 186,000,000-mile difference in the position of the earth every six months, were not answered till Bessel's discovery of such a parallax in 1838."

"In Copernicus' day the non-appearance to the senses of any stellar parallax implied, if his theory be sound, the necessity of attributing to the fixed stars a distance so immense that it would have been dismissed by all but a few as ridiculously incredible."

"Even had there been no religious scruples whatever against the Copernican astronomy, sensible men all over Europe, especially the most empirically minded, would have pronounced it a wild appeal to accept the premature fruits of an uncontrolled imagination, in preference to the solid inductions, built up gradually through the ages, of men's confirmed sense experience."

"Contemporary empiricists, had they lived in the sixteenth century, would have been first to scoff out of court the new philosophy of the universe."

"Copernicus... could plead only that his conception threw the facts of astronomy into a simpler and more harmonious mathematical order."

"Both ancient and medieval observers had noted that in many respects nature appeared to be governed by the principle of simplicity, and they had recorded the substance of their observations to this effect in the form of proverbial axioms which had become currently accepted bits of man's conception of the world. That falling bodies moved perpendicularly towards the earth, that light travelled in straight lines, that projectiles did not vary from the direction in which they were impelled, and countless other familiar facts of experience, had given rise to such common proverbs as: 'Natura semper agit per vias brevissimas'; 'natura nihil facit frustra'; 'natura neque redundat in superfluis neque deficit in necessariis' [Nature always acts by the shortest path; nature does nothing in vain; nature never overflows into the unnecessary, nor is she deficient in what is necessary]. This notion, that nature performs her duties in the most commodious fashion, without extra labour, would have tended to decrease somewhat the repulsion which most minds must have felt at Copernicus; the cumbrous epicycles had been decreased in number, various irregularities in the Ptolemaic scheme were eliminated..."

"An intensive study of the classic English thinkers early taught me that no one could hope to appreciate the motives underlying their work till he had mastered the philosophy of the one Englishman whose authority and influence in modern times has rivalled that of Aristotle over the late medieval epoch—Sir Isaac Newton."