Quotations from the Border Wars between Philosophy and Physics
“Ideally the physicist should be allowed to elucidate his own universe up to a point, and then hand it over to the philosopher to ascertain its exact status in relation to a wider outlook. But in practice we have not sufficient confidence in one another, and we both make raids over the border to suggest all sorts of ways in which the other fellow may be deceiving himself and us.” – Sir Arthur Eddington, “Physics and Philosophy,” Philosophy 8.29 (1933): 30
Throughout the history of thought, no lack of observations, failed and successful attempts to explain the other side, and even barbs have been traded between metaphysicians (“philosophers”) and natural scientists or physicists (“philosophers of nature”). Indeed, the very array of overlapping names belies a long history of intramural strife (or, inter-mural, depending upon your view!). The following, for your enjoyment and edification, or both, is a list of some of the best examples that I have found. It is arranged in approximate chronological order by author.
If you have suggestions to send me for quotes to add to the list, please do so here!
A Brief Index of Authors Quoted (thus far; with links)
- The Pre-Socratics
- St. Thomas Aquinas
- Francis Bacon
- René Descartes
- Roger Cotes
- Hermann von Helmholtz
- Edmund Husserl
- James Jeans
- Bertrand Russell
- Albert Einstein
- Edward Milne
- C. P. Snow
- Richard Feynman
- John Barrow and Frank Tipler
- Stephen Hawking
- G. F. R. Ellis
- Jennifer Coopersmith
Fools. For they have no far reaching minds who think that what before was not comes to be or that anything dies and is destroyed utterly in every way. – Empedocles, DK B:11 (D. H. B. translation)
These thinkers, as we say, evidently got hold up to a certain point of two of the causes which we distinguished in our work on nature—the matter and the source of the movement,—vaguely, however, and with no clearness, but as untrained men behave in fights; for they go round their opponents and often strike fine blows, but they do not fight on scientific principles, and so these thinkers do not seem to know what they say; for it is evident that, as a rule, they make no use of their causes except to a small extent. – Metaphysics, I.4, 985a10–17 (Barnes ed. translation)
For we should not do physics by following groundless postulates and stipulations, but in the manner called for by the phenomena; for our life does not now need irrationality and groundless opinion, but rather for us to live without tumult. And everything happens smoothly and (providing everything is clarified by the method of several different explanations) consistently with the phenomena, when one accepts appropriately what is plausibly said about them. But when one accepts one theory and rejects another which is equally consistent with the phenomenon in question, it is clear that one has thereby blundered out of any sort of proper physics and fallen into mythology. – Letter to Pythocles, nn. 86–87 (Inwood & Gerson ed.)
St. Thomas Aquinas
The ancient philosophers [a.k.a. the materialists] gradually, and as it were step by step, advanced to the knowledge of truth. At first being of grosser mind, they failed to realize that any beings existed except sensible bodies. – Summa Theologiae, Ia, q. 44, a. 1, c.
Aristotle affords the most eminent instance of the first [a.k.a. false philosophy]; for he corrupted natural philosophy by logic—thus he formed the world of categories, assigned to the human soul, the noblest of substances, a genus determined by words of secondary operation, treated of density and rarity (by which bodies occupy a greater or lesser space), by the frigid distinctions of action and power, asserted that there was a peculiar and proper motion in all bodies, and that if they shared in any other motion, it was owing to an external moving cause, and imposed innumerable arbitrary distinctions upon the nature of things; being everywhere more anxious as to definitions in teaching and the accuracy of the wording of his propositions, than the internal truth of things. And this is best shown by a comparison of his philosophy with the others of greatest repute among the Greeks. For the similar parts of Anaxagoras, the atoms of Leucippus and Democritus, the heaven and earth of Parmenides, the discord and concord of Empedocles, the resolution of bodies into the common nature of fire, and their condensation according to Heraclitus, exhibit some sprinkling of natural philosophy, the nature of things, and experiment; while Aristotle’s physics are mere logical terms, and he remodelled the same subject in his metaphysics under a more imposing title, and more as a realist than a nominalist. Nor is much stress to be laid on his frequent recourse to experiment in his books on animals, his problems, and other treatises; for he had already decided, without having properly consulted experience as the basis of his decisions and axioms, and after having so decided, he drags experiment along as a captive constrained to accommodate herself to his decisions: so that he is even more to be blamed than his modern followers (of the scholastic school) who have deserted her altogether. – The New Organon, Book I, Aphorism LXIII
It is observable, accordingly, that scarcely in a single instance has any one of their disciples surpassed them; and I am quite sure that the most devoted of the present followers of Aristotle would think themselves happy if they had as much knowledge of nature as he possessed, were it even under the condition that they should never afterwards attain to higher. In this respect they are like the ivy which never strives to rise above the tree that sustains it, and which frequently even returns downwards when it has reached the top; for it seems to me that they also sink, in other words, render themselves less wise than they would be if they gave up study, who, not contented with knowing all that is intelligibly explained in their author, desire in addition to find in him the solution of many difficulties of which he says not a word, and never perhaps so much as thought. Their fashion of philosophizing, however, is well suited to persons whose abilities fall below mediocrity; for the obscurity of the distinctions and principles of which they make use enables them to speak of all things with as much confidence as if they really knew them, and to defend all that they say on any subject against the most subtle and skillful, without its being possible for any one to convict them of error. In this they seem to me to be like a blind man, who, in order to fight on equal terms with a person that sees, should have made him descend to the bottom of an intensely dark cave: and I may say that such persons have an interest in my refraining from publishing the principles of the philosophy of which I make use; for, since these are of a kind the simplest and most evident, I should, by publishing them, do much the same as if I were to throw open the windows, and allow the light of day to enter the cave into which the combatants had descended. – Discourse on Method, Part VI
[The philosophers] themselves avow that the nature of their motion is very little known. To render it in some way intelligible, they have still not been able to explain it more clearly than in these terms: motus est actus entis in potentia, prout in potentia est, which terms are for me so obscure that I am constrained to leave them here in their language, because I cannot interpret them. (And, in fact, the words, “motion is the act of a being in potency, insofar as it is in potency,” are no clearer for being in [English].) On the contrary, the nature of the motion of which I mean to speak here is so easy to know that mathematicians themselves, who among all men studied most to conceive very distinctly the things they were considering, judged it simpler and more intelligible than their surfaces and their lines. So it appears from the fact that they explained the line by the motion of a point, and the surface by that of a line. – The World, ch. 7, “On the Laws of Nature of this New World”
Those who have treated of natural philosophy, may be nearly reduced to three classes. Of these some have been attributed to the several species of things, specific and occult qualities; on which, in a manner unknown, they make the operations of the several bodies to depend. The sum of the doctrine of the Schools derived from Aristotle and the Peripatetics is herein contained. They affirm that the several effects of the bodies arise from the particular natures of those bodies arise from the particular natures of those bodies. But whence it is that bodies derive those natures they don’t tell us; and therefore they tell us nothing. And being entirely employed in giving names to things, and not in searching into things themselves, we may say that they have invented a philosophical way of speaking, but not that they have made known to us true philosophy.
Others therefore by laying aside that useless heap of words, thought to employ their pains to better purpose. These supposed all matter homogeneous, and that the variety of forms which is seen in bodies arises from some very plain and simple affections of the component particles. And by going on from simple things to those which are more compounded they certainly proceed right; if they attribute no other properties to those primary affections of the particles than Nature has done. But when they take a liberty of imagining at pleasure unknown figures and magnitudes, and uncertain situations and motion of the parts; and moreover of supposing occult fluids, freely pervading the pores of bodies, endued with an all-performing subtilty, and agitated, with occult motions; they now run out into dreams and chimera’s, and neglect the true constitution of things; which certainly is not to be expected from fallacious conjectures, when we can scarce reach it by the most certain observations. Those who fetch from by hypotheses the foundation on which they build their speculations, may form indeed an ingenious romance, but a romance it will still be.
There is left then the third class, which prosess experimental philosophy. These indeed derive the causes of all things from the most simple principles possible; but then they assume nothing as a principle, that is not proved by phænomena. They frame no hypotheses, nor receive them into philosophy otherwise than as questions whose truth may be disputed. They proceed therefore in a two-fold method, synthetical and analytical. From some select phænomena they deduce by analysis the forces of nature, and the more simple laws of forces; and from thence by synthesis shew the constitution of the rest. This is that incomparably best way of philosophizing, which our renowned author most justly embraced before the rest; and thought alone worthy to be cultivated and adorned by his excellent labours. Of this he has given us a most illustrious example by the explication of the System of the World, most happily deduced from the Theory of Gravity. That the virtue of gravity was found in all bodies, others suspected, or imagined before him; but he was the only and the first philosopher that could demonstrate it from appearances, and make it a solid foundation to the most noble speculations. – “Preface” to the 2nd ed. of Newton’s Principia
- Hermann von Helmholtz
Accordingly, Hegel himself, convinced of the importance of winning for his philosophy in the field of physical science that recognition which had been so freely accorded to it elsewhere, launched out, with unusual vehemence and acrimony, against the natural philosophers, and especially against Sir Isaac Newton, as the first and greatest representative of physical investigation. The philosophers accused the scientific men of narrowness; the scientific men retorted that the philosophers were crazy. And so it came about that men of science began to lay some stress on the banishment of all philosophic influences from their work; while some of them, including men of the greatest acuteness, went so far as to condemn philosophy altogether, not merely as useless, but as mischievous dreaming. Thus, it must be confessed, not only were the illegitimate pretensions of the Hegelian system to subordinate to itself all other studies rejected, but no regard was paid to the rightful claims of philosophy, that is, the criticism of the sources of cognition, and the definition of the functions of the intellect. – Popular Lectures on Scientific Subjects, “On the Relation of Natural Science to General Science,” p. 7
- Edmund Husserl
Wenn wirklich die Naturwissenschaft spricht, hören wir gerne und als Jünger. Aber nicht immer spricht die Naturwissenschaft, wenn die Naturforscher sprechen; und sicherlich nicht, wenn sie über “Naturphilosophie” und “naturwissenschaftliche Erkenntnistheorie” sprechen.
When science really speaks, we listen gladly and like disciples. But science does not always speak when the natural scientists speak; and certainly not when they talk about “natural philosophy” and “scientific epistemology”. – Ideen zu einer reinen Phaenomenologie un phaenomenologischen Philosophie (1922)
To sum up, physics tries to discover the pattern of events which controls the phenomena we observe. But we can never know what this pattern means or how it originates ; and even if some superior intelligence were to tell us, we should find the explanation unintelligible. Our studies can never put us into contact with reality, and its true meaning and nature must be for ever hidden from us.
Such is physics, but it is less easy to say what philosophy is. While most philosophers seem to have had their private and differing views on the question, few have been willing to venture on a definition. . . . While the workshop of the scientist is his laboratory, or perhaps the open field or the star-lit sky, that of the philosopher is his own brain.
In whatever ways we define science and philosophy, their territories are contiguous; wherever science leaves off and in many places its boundary is ill-defined—there philosophy begins. Just as there are many departments of science, so there are many departments of philosophy. Contiguous to the department of physics on the scientific side of the boundary lies the department of metaphysics on the philosophical side. The boundary here is clearly defined, at least if we accept the positivist view of physics explained above. For then we must agree with Comte that the task of physics is to discover and formulate laws, while that of philosophy is to interpret and discuss. But the physicist can warn the philosopher in advance that no intelligible interpretation of the workings of nature is to be expected. – Physics And Philosophy, pp. 16–17
Our discussion seems to bring us back to the age-old conclusion that if we wish to discover the truth about nature the pattern of events in the universe we inhabit the only sound method is to go out into the world and question nature directly, and this is the long-established and well-tried method of science. Questioning our own minds is of no use ; just as questioning nature can tell us truths only about nature, so questioning our own minds will tell us only truths about our own minds.
The general recognition of this has brought philosophy into closer relations with science, and this approach has coincided with a change of view as to the proper aims of philosophy. – Physics And Philosophy, p. 80
In addition to such crude and rudimentary difficulties of pure language, further difficulties originate in the different idioms employed by the philosopher and the scientist. Not only do they express their thoughts in different languages, but the thoughts themselves tend to run on different lines of rails. This seems to result, at least in part, from the third and last of our suggested causes. The philosophers still think in a way which dates back to the earliest days of their subject, to times when no instruments of measurement were available of greater precision than the five human senses; they still describe things in terms of the effects they produce on these senses, while the scientist describes them in terms of the effects they produce on his sensitive instruments of measurement. The philosopher not only speaks but thinks in subjective, and the scientist in objective, terms. – Physics And Philosophy, p. 89
- Bertrand Russel
Philosophy, like all other studies, aims primarily at knowledge. The knowledge it aims at is the kind of knowledge which gives unity and system to the body of the sciences, and the kind which results from a critical examination of the grounds of our convictions, prejudices, and beliefs. But it cannot be maintained that philosophy has had any very great measure of success in its attempts to provide definite answers to its questions. If you ask a mathematician, a mineralogist, a historian, or any other man of learning, what definite body of truths has been ascertained by his science, his answer will last as long as you are willing to listen. But if you put the same question to a philosopher, he will, if he is candid, have to confess that his study has not achieved positive results such as have been achieved by other sciences. It is true that this is partly accounted for by the fact that, as soon as definite knowledge concerning any subject becomes possible, this subject ceases to be called philosophy, and becomes a separate science. The whole study of the heavens, which now belongs to astronomy, was once included in philosophy; Newton’s great work was called ‘the mathematical principles of natural philosophy’. Similarly, the study of the human mind, which was a part of philosophy, has now been separated from philosophy and has become the science of psychology. Thus, to a great extent, the uncertainty of philosophy is more apparent than real: those questions which are already capable of definite answers are placed in the sciences, while those only to which, at present, no definite answer can be given, remain to form the residue which is called philosophy.
This is, however, only a part of the truth concerning the uncertainty of philosophy. There are many questions—and among them those that are of the profoundest interest to our spiritual life—which, so far as we can see, must remain insoluble to the human intellect unless its powers become of quite a different order from what they are now. Has the universe any unity of plan or purpose, or is it a fortuitous concourse of atoms? Is consciousness a permanent part of the universe, giving hope of indefinite growth in wisdom, or is it a transitory accident on a small planet on which life must ultimately become impossible? Are good and evil of importance to the universe or only to man? Such questions are asked by philosophy, and variously answered by various philosophers. But it would seem that, whether answers be otherwise discoverable or not, the answers suggested by philosophy are none of them demonstrably true. Yet, however slight may be the hope of discovering an answer, it is part of the business of philosophy to continue the consideration of such questions, to make us aware of their importance, to examine all the approaches to them, and to keep alive that speculative interest in the universe which is apt to be killed by confining ourselves to definitely ascertainable knowledge. – Problems of Philosophy, Ch. 15, “The Value of Philosophy”
- Albert Einstein
The only justification for our concepts and system of concepts is that they serve to represent the complex of our experiences; beyond this they have no legitimacy. I am convinced that the philosophers have had a harmful effect upon the progress of scientific thinking in removing certain fundamental concepts from the domain of empiricism, where they are under our control, to the intangible heights of the a priori. For even if it should appear that the universe of ideas cannot be deduced from experience by logical means, but is, in a sense, a creation of the human mind, without which no science is possible, nevertheless this universe of ideas is just as little independent of the nature of our experiences as clothes are of the form of the human body. This is particularly true of our concepts of time and space, which physicists have been obliged by the facts to bring down from the Olympus of the a priori in order to adjust them and put them in a serviceable condition. – The Meaning of Relativity (1923), p. 2
There is a remarkable difference between physics and philosophy. On the one hand, physicists agree with one another in general at any one time, yet the physical theories of any one decade will differ profoundly from those of each succeeding decade—at any rate in the twentieth century. On the other hand, philosophers disagree with one another at any one time, yet the grand problems of philosophy remain the same from age to age. – Modern Cosmology and the Christian Idea of God (1952); quoted in Edward Harrison, Cosmology, 2nd ed. (2000), p. 23
- C. P. Snow
A good many times I have been present at gatherings of people who, by the standards of the traditional culture, are thought highly educated and who have with considerable gusto been expressing their incredulity at the illiteracy of scientists. Once or twice I have been provoked and have asked the company how many of them could describe the Second Law of Thermodynamics. The response was cold: it was also negative. Yet I was asking something which is the scientific equivalent of: Have you read a work of Shakespeare’s?
I now believe that if I had asked an even simpler question—such as, What do you mean by mass, or acceleration, which is the scientific equivalent of saying, Can you read?—not more than one in ten of the highly educated would have felt that I was speaking the same language. So the great edifice of modern physics goes up, and the majority of the cleverest people in the western world have about as much insight into it as their neolithic ancestors would have had. – The Two Cultures
- Richard Feynman
Poincaré made the following statement of the principle of relativity: “According to the principle of relativity, the laws of physical phenomena must be the same for a fixed observer as for an observer who has a uniform motion of translation relative to him, so that we have not, nor can we possibly have, any means of discerning whether or not we are carried along in such a motion.”
When this idea descended upon the world, it caused a great stir among philosophers, particularly the “cocktail-party philosophers,” who say, “Oh, it is very simple: Einstein’s theory says all is relative!” In fact, a surprisingly large number of philosophers, not only those found at cocktail parties (but rather than embarrass them, we shall just call them “cocktail-party philosophers”), will say, “That all is relative is a consequence of Einstein, and it has profound influences on our ideas.” In addition, they say “It has been demonstrated in physics that phenomena depend upon your frame of reference.” We hear that a great deal, but it is difficult to find out what it means. Probably the frames of reference that were originally referred to were the coordinate systems which we use in the analysis of the theory of relativity. So the fact that “things depend upon your frame of reference” is supposed to have had a profound effect on modern thought. One might well wonder why, because, after all, that things depend upon one’s point of view is so simple an idea that it certainly cannot have been necessary to go to all the trouble of the physical relativity theory in order to discover it. That what one sees depends upon his frame of reference is certainly known to anybody who walks around, because he sees an approaching pedestrian first from the front and then from the back; there is nothing deeper in most of the philosophy which is said to have come from the theory of relativity than the remark that “A person looks different from the front than from the back.” The old story about the elephant that several blind men describe in different ways is another example, perhaps, of the theory of relativity from the philosopher’s point of view.
But certainly there must be deeper things in the theory of relativity than just this simple remark that “A person looks different from the front than from the back.” Of course relativity is deeper than this, because we can make definite predictions with it. It certainly would be rather remarkable if we could predict the behavior of nature from such a simple observation alone.
There is another school of philosophers who feel very uncomfortable about the theory of relativity, which asserts that we cannot determine our absolute velocity without looking at something outside, and who would say, “It is obvious that one cannot measure his velocity without looking outside. It is self-evident that it is meaningless to talk about the velocity of a thing without looking outside; the physicists are rather stupid for having thought otherwise, but it has just dawned on them that this is the case. If only we philosophers had realized what the problems were that the physicists had, we could have decided immediately by brainwork that it is impossible to tell how fast one is moving without looking outside, and we could have made an enormous contribution to physics.” These philosophers are always with us, struggling in the periphery to try to tell us something, but they never really understand the subtleties and depths of the problem. – The Feynman Lectures on Physics, vol. I, 16–1
To summarize, I would use the words of Jeans, who said that “the Great Architect seems to be a mathematician.” To those who do not know mathematics it is difficult to get across a real feeling as to the beauty, the deepest beauty, of nature. C.P. Snow talked about two cultures. I really think that those two cultures separate people who have and people who have not had this experience of understanding mathematics well enough to appreciate nature once.
It is too bad that it has to be mathematics, and that mathematics is hard for some people. It is reputed—I do not know if it is true—that when one of the kings was trying to learn geometry from Euclid he complained that it was difficult. And Euclid said, “There is no royal road to geometry.” And there is no royal road. Physicists cannot make a conversion to any other language. If you want to learn about nature, to appreciate nature, it is necessary to understand the language that she speaks in. She offers her information only in one form; we are not so unhumble as to demand that she change before we pay any attention.
All the intellectual arguments that you can make will not communicate to deaf ears what the experience of music really is. In the same way all the intellectual arguments in the world will not convey and understanding of nature to those of “the other culture.” Philosophers may try to teach you by telling you qualitatively about nature. I am trying to describe her. But it is not getting across because it is impossible. Perhaps it is because their horizons are limited in the way that some people are able to imagine that the center of the universe is man. – The Character of Physical Law, p. 28
John Barrow and Frank Tipler
Whereas philosophers and theologians appear to possess an emotional attachment to their theories and ideas that requires them to believe in them, scientists tend to regard their ideas differently. They are interested in formulating many logically consistent possibilities, leaving any judgment regarding their truth to observation. Scientists feel no qualms about suggesting different but mutually exclusive explanations for the same phenomenon. – The Anthropic Cosmological Principle, p. 15
Compare Barrow and Tipler’s idea to Epicurus’s idea of “the method of several different explanations,” in the quote above.
We each exist for but a short time, and in that time explore but a small part of the whole universe. But humans are a curious species. We wonder, we seek answers. Living in this vast world that is by turns kind and cruel, and gazing at the immense heavens above, people have always asked a multitude of questions: How can we understand the world in which we find ourselves? How does the universe behave? What is the nature of reality? Where did all this come from? Did the universe need a creator? Most of us do not spend most of our time worrying about these questions, but almost all of us worry about them some of the time.
Traditionally these are questions for philosophy, but philosophy is dead. Philosophy has not kept up with modern developments in science, particularly physics. Scientists have become the bearers of the torch of discovery in our quest for knowledge. The purpose of this book is to give the answers that are suggested by recent discoveries and theoretical advances. They lead us to a new picture of the universe and our place in it that is very different from the traditional one, and different even from the picture we might have painted just a decade or two ago. – The Grand Design (with Leonard Mlodinow)
G. F. R. Ellis
Proclaiming that philosophy is useless or meaningless will not help: cosmologists necessarily indulge in it to some degree, whether they acknowledge this fact or not. Poorly thought out philosophy is still philosophy, but it is unsatisfactory. Rather than denying its significance, we should carefully consider the philosophy–cosmology relation and develop a philosophy of cosmology of adequate depth. – “On the Philosophy of Cosmology,” p. 7
But what actually is energy? Non-physicists may wonder why the enquiry isn’t broadened to cover questions such as ‘What does “energy” mean for humans and for society?’, ‘What is energy philosophically speaking?’, ‘How does “energy” occur in literature’, and so on. These questions have their own interest, but ‘What is energy?’ is a physics question, and needs a physics answer. Moreover, when the physics is right, then the philosophy is right, no matter how long it takes the philosophers to come around.*
*: I mean this most respectfully—in fact, I am especially interested in philosophical questions in physics. – Energy, the Subtle Concept, p. 355–56, and fn.