Chapter 67: PHYSICS

INTRODUCTION

For the subject matter of physics, one thing seems to be traditionally taken for granted. The object of its study is the sensible world of changing things or matter in motion. When Plato, for example, conceives astronomy as dealing not with the actual and observable motions of the heavenly bodies, but with the possible forms of the motions of solids, he gives it the character of a mathematical rather than a physical science. He associates it with geometry, as for a similar reason he associates music—divorced from concern with audible harmonies—with arithmetic. In anyone’s view, if a science does not investigate sensible realities, if it does not undertake to account for the motions of actual bodies, or, stated most generally, if it has no concern with the phenomena of change, then it does not have the character of physical or natural science.

The early Greek physicists, the pre-Socratics, to whom Plato and Aristotle refer, inaugurate the study of change with speculations about ultimate origins, the underlying principles or causes of natural phenomena. Sometimes they are called philosophers and sometimes scientists—or, at least, precursors of empirical science. But there seems to be no difference of opinion about their title as physicists. Their undisputed claim to this title derives, not from the method they employ, but from the object they study—change. In that primary meaning of the word “nature” which comes from the Latin natura—the equivalent of physis in Greek—they can be called “naturalists” or “physicists” indifferently. The realm of nature is the realm of change.

It is for this reason that Aristotle, considering the theories of his predecessors in the opening chapters of his Physics, sets Parmenides apart from all the rest. Parmenides’ affirmation of the unity of being, which leads to his denial of the reality of change or motion, cannot be treated as a physical theory. On the contrary, it is, according to Aristotle, a complete negation of the subject matter of physics. No matter what other points physicists may dispute among themselves, they must all at least agree in taking a stand against Parmenides. Aristotle does not even seem to think that a book on physics is the proper place to argue against Parmenides. That argument belongs to another part of philosophy. The reality of change seems to him sufficiently evident to assure the physicist that he has a subject matter to investigate.

The question whether the early physicists were scientists or philosophers calls attention to different methods of investigating natural phenomena. Agreement on the subject matter of physics may prevail, therefore, only in very general terms. When, in a manner to accord with the method employed, the object of physical inquiry is more specifically defined, there seem to be two physics, not one—a philosophical and a scientific physics, a philosophy of nature and a natural science, or, to use Kant’s phrasing, a rational or pure physics and an empirical or experimental physics.

Though Newton may call his work a philosophy of nature, he also refers to it as an experimental philosophy, in order to distinguish it from the work of earlier natural philosophers who did not perform experiments. The difference between the physics of Newton and that of Aristotle seems, however, to involve more than a divergence in method. The problems which Newton and Aristotle try to solve indicate a difference in subject matter as well. Nevertheless, this difference falls within what, in the most general terms, must be conceived as the domain of physics. For all their differences, both are physicists, though both are not philosophers or scientists in the same sense.

There are other sources of variation in the definition of physics. The problem of the relation of physics to other disciplines—whether these are other branches of philosophy or other fields of empirical research—raises issues about the object and scope of physics. Aristotle, Bacon, Descartes, and Kant, for example, do not seem to have a common understanding of the relation of physics to mathematics and metaphysics. In consequence they conceive physics itself differently.

On the level of empirical research, physics is sometimes regarded as just one of the natural sciences and sometimes as the whole group of natural sciences. In the latter case it includes such fields as astronomy, mechanics, optics, acoustics, thermodynamics, magnetism, and electricity; and sometimes chemistry, biology, and even psychology are included under the head of physical or natural sciences, contrasted in the broadest terms to the social sciences. The conception of physics obviously changes when its scope is determined by a boundary line which separates it from chemistry, or from biology and psychology, or from the study of society.

The separation of these other sciences from physics does not necessarily imply a discontinuity in nature or the natural sciences. The biologist and the psychologist, for example, consider the physical bases of life and the physical conditions or correlates of mental phenomena. Hybrid sciences like biophysics and psychophysics have developed. Even the study of society draws upon physics to the extent that the laws of matter in motion and considerations of space and time must be appealed to for an understanding of the physical foundations of economic and political life.

Other chapters deal with specific physical sciences, e.g., ASTRONOMY and MECHANICS. The latter tries to cover the various branches of mechanics and related fields of study, such as dynamics, optics, the theory of heat, magnetism, and electricity; particularly so far as these are represented in the work of Galileo, Newton, Huygens, Gilbert, Fourier, and Faraday. The basic concepts of mechanics and its branches or affiliates are also treated in that chapter. Still other chapters deal with fundamental terms representing concepts or problems in the larger domain of physics, philosophical or scientific, e.g. CAUSE, CHANGE, ELEMENT, INFINITY, MATTER, PRINCIPLE, QUANTITY, SPACE, and TIME—not to mention NATURE and WORLD, terms which represent in the most comprehensive way the reality studied by the physicist.

Our discussion here can therefore be restricted to the problems raised in the great books concerning the conception of physics, its subject matter and method, its relation to other sciences or other parts of philosophy. It will lead to such questions as whether physics is supreme among the sciences studying reality or the nature of things and, at the other extreme, whether physics is at all possible as a science, whether there can be scientific knowledge of bodies in motion or of the whole realm of change and becoming.

The problem of the distinction between philosophical and scientific physics would appear to be only a special case of the distinction between philosophy and science in general. But it is more than that. It is the case which tests the main distinction itself, since here both philosopher and scientist claim to be expounding the same subject matter or at least to be dealing with the same general field of phenomena.

Mathematics and metaphysics bear on the distinction between philosophy and science in a different way. If, for example, we take experimentation or empirical research to be characteristic of science in distinction from philosophy, then mathematics would seem to resemble philosophy rather than science. On no understanding of the nature of mathematical knowledge is mathematics ever divided into two kinds which are capable of being described as empirical and rational. The possibility of metaphysical knowledge may be challenged, but no one has ever proposed an experimental metaphysics to challenge the metaphysics of the philosophers.

But physics seems to permit both an experimental and a philosophical treatment. Whether they are to be regarded as in conflict with one another depends on whether they are attacking the same problems by different methods or whether they represent something like a division of labor. In the latter view, each would deal, according to its method, with different problems and tend to supplement rather than to exclude the other. Psychology is another subject matter which seems to receive a dual treatment—philosophical and experimental—in the tradition of the great books. It raises issues similar to those just mentioned. They are considered in the chapter on MAN.

As the chapters on PHILOSOPHY and on SCIENCE indicate, the discussion of their difference from and relation to one another is complicated by the double use of both terms. The word “science,” for example, is used for both the philosophical and the experimental sciences throughout the greater part of the tradition. Similarly, until quite recently, the name of philosopher is taken by those who experiment as well as by those who do not.

It is impossible, therefore, to speak without confusion of a scientific and a philosophical physics unless the verbal ambiguities are resolved by some convention, such as the understanding that when the context indicates that the words “science” and “philosophy” are being used as opposites rather than as synonyms, then “science” shall signify the experimental and “philosophy” the non-experimental mode of treatment. Beyond this, it is necessary to proceed as if the chapters on PHILOSOPHY and SCIENCE formed a background for some of the matters to be discussed here. Otherwise the consideration of natural philosophy and natural science would tend to become a general discussion of philosophy and science.

The great books of experimental physics seem to have three characteristics in common. First, and most naturally, they insist upon experimentation as either the indispensable source or the ultimate test of scientific formulations. Second, they tend to rely upon mathematics as much as upon experiment, both for the formulation of nature’s laws and for the demonstration of the consequences or corollaries of the primary laws. Third, though experiments and observations multiply as science develops, they seek to bring all the phenomena of nature under the smallest number of generalizations, which have the utmost simplicity in mathematical statement.

On the second and third points, Newton’s declarations seem to be most explicit. “Nature,” he says, “is pleased with simplicity and affects not the pomp of superfluous causes.” Accordingly, Newton directs his efforts toward the simplest statement of the laws of motion, and these he seeks to give the universality requisite for covering every type of natural phenomenon. At the opening of the third book of the Mathematical Principles of Natural Philosophy, he explains that in the preceding books, he has:

laid down the principles of philosophy, principles not philosophical but mathematical; such, namely, as we may build our reasonings upon in philosophical inquiries. These principles are the laws and conditions of certain motions, and powers or forces.

From these same principles, he will now undertake to “demonstrate the frame of the System of the World.”

In the Preface to the first edition of this work, Newton describes the third book as one in which he derives “from the celestial phenomena the forces of gravity with which bodies tend to the sun and the several planets. Then from these forces, by other propositions which are also mathematical,” he goes on, “I deduce the motions of the planets, the comets, the moon, and the sea.” But he does not consider his work to have attained the goal of physics—the comprehension of all natural phenomena by a few simple mathematical formulae.

His confession of failure may also be read as a prognostication of what an experimental physics based on mathematical principles might some day be able to achieve. “I wish we could derive the rest of the phenomena of nature by the same kind of reasoning,” he writes, “for I am induced by many reasons to suspect that they may all depend upon certain forces by which the particles of bodies, by some causes hitherto unknown, are either mutually impelled towards one another, and cohere in regular figures, or are repelled and recede from one another.” Einstein’s unified field equations, covering both gravitational phenomena on the astronomical scale and the electrical attractions and repulsions of sub-atomic particles, seem to realize, or at least closely to approximate, the ideal Newton has in mind.

Midway between Newton and Einstein, Fourier also bears testimony to the ideal of physics as a science at once simple in its principles and universal in the scope of their application. The successors of Newton and Galileo, he writes, “have extended their theories and given them an admirable perfection; they have taught us that the most diverse phenomena are subject to a small number of universal laws which are reproduced in all the acts of nature. It is recognized that the same principles regulate all the movements of the stars, their form, the inequalities of their courses, the equilibrium and the oscillations of the seas, the harmonic vibrations of air and sonorous bodies, the transmission of light, capillary actions, the undulations of fluids, in fine the most complex effects of all natural forces. Thus has the thought of Newton been confirmed,” he concludes, referring to Newton’s praise of geometry, whose glory it is that the few mathematical principles it provided for use in physics should have been “able to produce so many things.”

On the experimental side, the great works of physical science seem to contain diverse notions of the purposes served by experimentation, accompanied by a fairly uniform recognition of the dependence of natural science upon experiment. In the field of magnetism, for example, Gilbert sets aside as unscientific all those authors who “have written about amber and jet as attracting chaff… but with never a proof from experiments…. These writers deal only in words,… Such philosophy bears no fruit.” The fruitfulness of experiments on the vacuum, the equilibrium of fluids, and the weight of air leads Pascal to conclude that the secrets of nature remain hidden until “the experiments which supply us with knowledge about it” can be performed and multiplied. “We ought never to search for truth but by the natural road of experiment and observation,” writes Lavoisier; and Faraday describes himself as “an experimentalist” who feels “bound to let experiment guide me into any train of thought which it may justify.” The science of electricity, he finds, “is in that state in which every part of it requires experimental investigation, not merely for the discovery of new effects,” but ultimately for “the more accurate determination of the first principles of action of the most extraordinary and universal power in nature.”

Methods of experimentation necessarily differ in different fields of physical research. Newton’s optical experiments with mirrors and prisms were adapted to the phenomena of light, as Galileo’s experiment with the inclined plane, Pascal’s experiment on the equilibrium of fluids, or Faraday’s experiments with induction coils were adapted to the phenomena of dynamics, hydrostatics, and electricity. The materials employed, the apparatus or instruments devised, the factors controlled or isolated from irrelevant circumstances, and the units of measurement in which the results are recorded, naturally vary with the phenomena under observation. Yet one thing is common to the variety of experiments described in the great books of physical science. They all involve the construction of an artificial physical system which permits more accurate and refined observation than does nature uncontrolled or untampered with.

The student of nature must observe in any case, no matter whether he is a philosopher or a scientist. To say that philosophical physics is non-experimental does not mean for Aristotle that knowledge of nature is possible without observation or induction from experience. But the experimentalists insist upon the distinction between the kind of observations which men normally make in the course of everyday experience and the kind which involve the special experience enjoyed only by those who observe and, in addition, measure the results of specially contrived experiments.

This point of distinction seems to be strikingly illustrated by a passage in Galileo’s Two New Sciences. One of the persons in the dialogue, Simplicio, declares “everyday experience to show the propagation of light to be instantaneous.” He explains that “when we see a piece of artillery fired at a great distance, the flash reaches our eyes without lapse of time; but the sound reaches the ear only after a noticeable interval.” Sagredo replies that this familiar bit of experience permits him to infer only that “sound, in reaching our ear, travels more slowly than light.” It does not inform us, he says, “whether the coming of light is instantaneous or whether, although extremely rapid, it still occupies time.” The choice between these alternatives could not be determined by ordinary experience. An experiment had to be constructed in order to measure the velocity of light.

Recourse to experimentation to find by observation and measurement the answers which ordinary experience fails to yield does not exhaust the uses of experiment. The great experimental physicists indicate at least three distinct uses to which experiments can be put in addition to a merely exploratory use for “the discovery of new effects.”

In natural philosophy as in mathematics, writes Newton, “the method of analysis ought ever to precede the method of composition” or synthesis. In physics, the method of analysis “consists in making experiments and observations, and in drawing conclusions from them by induction.” In contrast, the synthetic method begins with the principles assumed, therefrom “explaining the phenomena… and proving the explanations.”

Here experiments perform a probative rather than an inductive function. As Huygens observes, proof in physics does not have the certitude of mathematical demonstration, but it can have an extremely high degree of probability—“very often scarcely less than complete proof”—as a result of the experimental confirmation of a conclusion deduced from the assumed principles. This occurs “when things which have been demonstrated by the principles that have been assumed, correspond perfectly to the phenomena which experiment has brought under observation, especially when there are a great number of them.” A single crucial experiment, so perfect in construction that all relevant factors have been controlled, makes unnecessary the multiplication of experiments to establish the conclusion.

A third use of experiment is illustrated by Galileo when he measures the velocity of a ball rolling down an inclined plane, in order to decide whether a certain mathematical definition of uniformly accelerated motion describes the acceleration “which one meets in nature in the case of falling bodies.” The persons in the dialogue seem to be satisfied with some mathematical reasoning which shows that the velocity increases with the units of time elapsed rather than with the intervals of space traversed. But when Simplicio asks for an experiment to show that the mathematical conclusion has physical reality, in the sense of describing observable phenomena, Salviati replies that this request “is a very reasonable one, for this is the custom—and properly so—in those sciences where mathematical demonstrations are applied to natural phenomena” and “where the principles once established by well-chosen experiments become the foundations of the entire superstructure.” Here experiment does not confirm conclusions. It establishes principles, not by inductive generalization but by comparing actual measurements with mathematical expectations.

Without experiment but not without inductions from experience, without measurements but not without recourse to observation, Aristotle’s Physics—and with it such physical treatises as his works On the Heavens and On Generation and Corruption—represents a philosophy of nature. In Aristotle’s meaning of the term ‘science,’ these treatises expound sciences, but they also constitute one part of philosophy, to be distinguished from mathematics and from what Aristotle regards as the first or highest part of philosophy, i.e., the science of metaphysics.

Aristotle’s tripartite division of the theoretic sciences or speculative philosophy into physics, mathematics, and metaphysics raises a question concerning his numerous biological works, and perhaps also his treatise On the Soul. Are these to be classified as physical sciences or parts of natural philosophy? The fact that Aristotle distinguishes between the forms and properties of living and non-living matter does not seem to affect the answer. By his criteria of physical inquiry—namely, that it investigates what neither exists nor can be conceived apart from matter and motion, and that it is concerned with every type of change—all these works belong to the domain of physics. Accordingly even such apparently psychological studies as those dealing with sensation, memory, dreams, justify the title under which they have been traditionally grouped—Parva Naturalia, i.e., short physical treatises.

For all these more specialized considerations of natural phenomena the Physics seems to serve as a general introduction, as well as being in its own right an exposition of the most fundamental science in the sphere of natural philosophy. It tries to define change and to state the principles underlying every type of change. It tries to classify the types of change, separating coming to be and passing away simply (or generation and corruption), from coming to be in a special respect (or change in quality, quantity, and place) which Aristotle usually calls “motion” in distinction from “becoming” or “generation.” It undertakes to analyze the conditions or causes of change or motion, to distinguish what happens by chance from what happens of necessity, to discriminate between natural and unnatural or violent motions, to treat the relation of mover and moved, to deal with the continuity and divisibility of motions, to consider place and time as conditions or aspects of motion, and to ask about the infinity of body and of change, and about the eternity of motion or the whole order of becoming, the natural world of things in motion.

Aristotle’s physics thus seems to stand in sharp contrast to the physics of the experimentalists, not merely in method, but in the questions it tries to answer and in the principles to which it appeals. The effort to define change in general and to state the principles and causes operative in every type of change might appear to correspond to the search for formulae of maximum generality to cover all natural phenomena. But where Newton and Fourier hope thereby to reduce nature’s variety to the simplest terms—a few laws of motion comprehending the whole framework of nature—Aristotle tends on the contrary to insist upon an irreducible variety of types of motion, kinds of matter, and causes of change.

Furthermore, the principles to which Aristotle appeals are not mathematical. He criticizes the discussion of becoming which takes place in Plato’s Timaeus, on the ground that it tries to substitute mathematical for physical terms in the analysis of change. “Physical bodies contain surfaces and volumes, lines and points,” he writes, “and these are the subject matter of mathematics”; but the mathematician is not concerned with these things as the attributes of physical bodies, but only as separated, in thought at least, from matter and motion. There are sciences which represent mixtures of mathematics and physics, such as optics and harmonics, but the existence of these mixed sciences—the equivalent of what is later called ‘mathematical physics’—seems to Aristotle to imply rather than deny the separation of purely physical science from pure mathematics.

Where Newton (who can be taken as the exemplary author of a physics which is at once mathematical and experimental) goes to mathematics for the principles of natural philosophy, Aristotle seems to think that physics has its own proper principles. If any deeper understanding of these principles is sought, it is not to be found in mathematics, but in metaphysics, or what Aristotle calls “the first philosophy.”

For example, matter, form and privation, are proposed by Aristotle as the basic physical principles. In such terms he is able to state his insight that all change involves a substratum (or that which changes) and contraries (or that from which and that to which the change occurs). But the analysis of matter and form in terms of potentiality and actuality as modes of being, and the consideration of form and privation in terms of being and non-being, belong to metaphysics rather than physics.

Furthermore, Aristotle as a physicist deals with bodies in motion and with the difference between the generation of bodies and their alteration, increase and decrease, or change of place. But he leaves to metaphysics—to the books which come after the books on physics—the discussion of physical bodies as substances composite of matter and form, and the distinction of substance and accident which bears on the difference between substantial and accidental change (i.e., generation and corruption as opposed to the change in quality, quantity, or place).

Though for Aristotle physics is as separate from metaphysics as it is from mathematics in subject matter, physics depends upon metaphysics, as it does not upon mathematics, for the establishment as well as the elucidation of its principles. It is in this sense that metaphysics is logically prior to physics. But there may also be a sense in which philosophical physics is logically prior to experimental natural science. To the extent that the experimentalist employs physical as opposed to mathematical principles, he may have to derive these from a philosophy of nature. Galileo, for example, investigates the properties of natural and violent motions in the Third and Fourth Day of his Two New Sciences (i.e., the motions of freely falling bodies and of projectiles). The problem of establishing the reality of this distinction and of defining the natural and the non-natural types of motion seems to be a matter of philosophical analysis rather than of experimental investigation.

Bacon and Kant appear to agree with Aristotle about the separation of physics from mathematics. Rational (or pure, as opposed to empirical) physics is, according to Kant, “entirely separate from mathematics.” It is not to be confused with “what is commonly called physica generalis, which is mathematics rather than a philosophy of nature.” Criticizing the natural philosophy of the ancients because it is corrupted by logic in the school of Aristotle and by mathematics in the school of Plato, Bacon says that mathematics should “terminate natural philosophy rather than generate or create it. We may hope for better results,” he adds, “from pure and unmixed natural philosophy.”

Bacon elsewhere observes that “the investigation of nature is best conducted when mathematics are applied to physics.” He does not deny “the great use of mathematics in physics,” but rather insists that mathematics be regarded as “an appendage or auxiliary” of natural philosophy, not its master. He is writing against the mathematicians “who would have their science preside over physics.”

But to whatever extent Aristotle, Bacon, and Kant are in agreement concerning the relation of physics and mathematics, their theories of the scope and subject matter of physics seem to be at variance. For Bacon, physics is only one of the theoretic parts of natural philosophy; the other is metaphysics. Both are sciences of nature or the physical world, though one investigates material and efficient, the other formal and final causes. Both studies, moreover, can be conducted experimentally and can yield practical fruits (in mechanics and what Bacon calls “magic”) through the production of effects by the application of a knowledge of causes.

For Kant, the whole body of theoretical knowledge which is rational and a priori, not empirical and a posteriori, is the metaphysic of nature, of which one part is rational physics, and the other rational psychology. “The metaphysic of corporeal nature,” he writes, “is called physics, or, because it must contain the principles of an a priori knowledge of nature only, rational physics.” Here physics and metaphysics do not have distinct objects as they do for Aristotle; nor does Kant’s conception of physics as purely a priori knowledge of nature seem to agree with Aristotle’s conception of physics as inductive and empirical, if not experimental.

These issues concerning the relation of physics to mathematics and metaphysics have significance for the experimental as well as the philosophical study of nature. If, for example, following the position taken by Hume, metaphysical inquiry is dismissed as incapable of yielding knowledge, and mathematical knowledge is restricted to the realm of ideal entities, then natural science, which for Hume consists in experimental reasoning about matters of fact, becomes the only knowledge of reality. Even though Hume looks upon the conclusions of experimental reasoning as at best probable, it remains the case that questions about nature which cannot be answered by physics cannot be answered scientifically.

The effect is the same as that achieved by Hobbes, who makes physics the primary science of reality on the ground that nothing exists except bodies in motion. The assertion of the primacy of physics, in short, may be due either to the denial that immaterial objects can be known by us, or to the denial that such objects have any real existence. Of quite opposite tenor is the view that only immaterial and eternal things can be scientifically known, and that the sensible world of things which come to be, pass away, and are forever undergoing change, belongs to the realm of probability and opinion, not knowledge.

For Plato, mathematics and dialectic can be, respectively, science and wisdom because they study the intelligible reality of being in its immutable forms. But the physicists who try to give an account of becoming in all its changing sensible appearances can do no better than “adduce probabilities as likely as any others.” On such matters, Timaeus says, “we ought to accept a tale which is probable and inquire no further.” After discoursing at length of physical matters, Timaeus apologizes for the merely conjectural character of his account of natural phenomena, saying that “a man may sometimes set aside meditations about eternal things, and for recreation turn to consider the truths of becoming which are probable only; he will thus gain a pleasure not to be repented of, and secure for himself wise and moderate pastime.”

This view goes further than Hume’s in depreciating physics by contrasting its probability with the certitude of mathematics. It praises mathematics and dialectic, as Hume’s theory does not, for something more than their certitude—for their being knowledge of reality rather than of appearances.

Furthermore, Hume, unlike Plato, does not think the probability of physics detracts from its utility, the sort of utility which Bacon magnifies more eloquently than Hume—the invention of machines and the technical applications of physics whereby man extends his dominion over nature. In the traditional discussion of the dignity and value of physics, Plato and Bacon seem to represent attitudes as far apart as are the theories of Aristotle and Newton in the discussion of the subject matter and method of physics.

OUTLINE OF TOPICS

1. Physics as the general theory of becoming and the order of nature or change: philosophical physics, the philosophy of nature, pure or rational physics
   • 1a. The relation of the philosophy of nature to metaphysics and dialectic
   • 1b. The relation of the philosophy of nature to mathematics: mathematical method and mathematical principles in natural philosophy
2. Experimental physics and the empirical natural sciences: the relation of experimental and philosophical physics
   • 2a. The derivation of definitions, distinctions, and principles from the philosophy of nature: the metaphysics of the scientist
   • 2b. The treatment of causes in philosophical and empirical physics: description and explanation, theory and prediction
3. The role of mathematics in the natural sciences: observation and measurement in relation to mathematical formulations
4. The experimental method in the study of nature
   • 4a. The distinction between simple observation and experimentation: the art of creating ideal or isolated physical systems
   • 4b. Experimental discovery: inductive generalization from experiment; the role of theory or hypothesis in experimentation
   • 4c. Experimental testing and verification: the crucial experiment
   • 4d. Experimental measurement: the application of mathematical formulae
5. The utility of physics: the invention of machines; the techniques of engineering; the mastery of nature

REFERENCES

To find the passages cited, use the numbers in heavy type, which are the volume and page numbers of the passages referred to. For example, in 4 Homer: Iliad, BK II [265-283] 12d, the number 4 is the number of the volume in the set; the number 12d indicates that the passage is in section d of page 12.

Page Sections: When the text is printed in one column, the letters a and b refer to the upper and lower halves of the page. For example, in 53 James: Psychology, 116a-119b, the passage begins in the upper half of page 116 and ends in the lower half of page 119. When the text is printed in two columns, the letters a and b refer to the upper and lower halves of the left-hand side of the page, the letters c and d to the upper and lower halves of the right-hand side of the page. For example, in 7 Plato: Symposium, 163b-164c, the passage begins in the lower half of the left-hand side of page 163 and ends in the upper half of the right-hand side of page 164.

Author’s Divisions: One or more of the main divisions of a work (such as PART, BK, CH, SECT) are sometimes included in the reference; line numbers, in brackets, are given in certain cases; e.g., Iliad, BK II [265-283] 12d.

Bible References: The references are to book, chapter, and verse. When the King James and Douay versions differ in title of books or in the numbering of chapters or verses, the King James version is cited first and the Douay, indicated by a (D), follows; e.g., OLD TESTAMENT: Nehemiah, 7:45—(D) II Esdras, 7:46.

Symbols: The abbreviation “esp” calls the reader’s attention to one or more especially relevant parts of a whole reference; “passim” signifies that the topic is discussed intermittently rather than continuously in the works or passage cited.

For additional information concerning the style of the references, see the Explanation of Reference Style; for general guidance in the use of The Great Ideas, consult the Preface.

1. Physics as the general theory of becoming and the order of nature or change: philosophical physics, the philosophy of nature, pure or rational physics

7 Plato: Republic, BK VI, 391b-398c / Timaeus, 447a-477a,c

8 Aristotle: Physics, BK I, CH 1 259a-b; CH 2 [184b25-185a19] 259c-260a; CH 9 [192b33-193a2] 268c-d; BK II, CH 2 270a-271a; CH 7-9 275b-278a,c; BK III, CH 1 [200b12-24] 278a; CH 5 [204b34-205a3] 282b-c; BK IV, CH 1 [208a27-33] 287a; BK VIII, CH 3 [253b32-254a6] 337c / Heavens, BK I, CH 1 [268a1-7] 359a; CH 5 [271b1-18] 362c-d; BK III, CH 1 [298b13-30] 390a-b; CH 7 [306a1-18] 397b-c / Metaphysics, BK I, CH 9 [992a29-b9] 510c-d; BK III, CH 3 [995b15-20] 513d; BK VI, CH 1 547b,d-548c; BK VII, CH 11 [1037a10-18] 560d; BK XI, CH 3 [1061a29-b12] 589c-d; CH 4 589d-590a; CH 7 592b-593a / Soul, BK I, CH 1 [403a25-b19] 632b-d / Sense and the Sensible, CH 1 [436a16-b2] 673b / Youth, Life, and Breathing, CH 27 [480b21-31] 726d

9 Aristotle: Parts of Animals, BK I, CH 1 161a-165d esp [639b32-640a10] 162a-b

16 Ptolemy: Almagest, BK I, 5a-6a

18 Augustine: City of God, BK VIII, CH 2 265b-266a; CH 4 266d-267c; CH 5-6, 268b-269c; BK XI, CH 25 336b-d

19 Aquinas: Summa Theologica, PART I, Q 1, A 1, REP 2 3b-4a

23 Hobbes: Leviathan, PART I, 71c-d; 72a-d; PART IV, 271d

30 Bacon: Advancement of Learning, 33b-34b; 40a-c; 42c-43d

31 Descartes: Rules, XIV, 31c-d / Discourse, PART VI, 61b-62c / Meditations, I, 76c / Objections and Replies, 215a-b; 285b-d

35 Locke: Human Understanding, BK IV, CH XXI, SECT 1-2 394d; SECT 5 395c

35 Berkeley: Human Knowledge, SECT 101-117 432c-436b

42 Kant: Pure Reason, 5a-13d esp 5d-6c; 18d-19a / Fund. Prin. Metaphysic of Morals, 253a-d; 271a-c / Judgement, 578a-b

53 James: Psychology, 882a-886a; 889a-890a

1a. The relation of the philosophy of nature to metaphysics and dialectic

7 Plato: Phaedo, 240d-242b / Republic, BK VI, 385c-388a; BK VII, 391b-398c

8 Aristotle: Physics, BK I, CH 2 [184b25-185a19] 259c-260a; CH 9 [192b33-193a2] 268c-d; BK II, CH 2 [194a8-15] 271a; CH 7 [198a22-31] 275b-c; BK III, CH 5 [204b34-205a3] 282b-c; BK VIII, CH 1 [250b11-251a8] 334a-c / Heavens, BK III, CH 1 [298b13-30] 390a-b / Metaphysics, BK I, CH 8 [989b21-990a8] 507d-508a; BK III, CH 3 [995b15-20] 513d; BK VI, CH 1 547b,d-548c; BK VII, CH 11 [1037a10-18] 560d; BK XI, CH 3 [1061a29-b12] 589c-d; CH 4 589d-590a; CH 7 592b-593a; BK XII, CH 1 [1069a30-b2] 598b-c / Soul, BK I, CH 1 [403a25-b19] 632b-d

16 Ptolemy: Almagest, BK I, 5a-6a

19 Aquinas: Summa Theologica, PART I, Q 85, A 1, REP 2 451c-453c

23 Hobbes: Leviathan, PART I, 72a-d

30 Bacon: Advancement of Learning, 33b-34b; 42c-43d / Novum Organum, BK II, APH 1 137a; APH 9 140b-c

42 Kant: Pure Reason, 17d-19a / Fund. Prin. Metaphysic of Morals, 253a-d / Practical Reason, 351b-352c / Judgement, 561c-562a,c; 578a-b

51 Tolstoy: War and Peace, EPILOGUE II, 693d-694d

53 James: Psychology, 862a-866a; 884b-886a esp 886a

1b. The relation of the philosophy of nature to mathematics: mathematical method and mathematical principles in natural philosophy

7 Plato: Republic, BK VII, 391b-398c / Timaeus, 449b-450b; 453b-454a; 458a-460b

8 Aristotle: Physics, BK II, CH 2 270a-271a; CH 9 [200a15-29] 277c-d / Heavens, BK III, CH 1 [299a1-300a19] 390b-391c / Metaphysics, BK I, CH 9 [992a29-b9] 510c-d; BK III, CH 3 513c-d; BK VI, CH 1 547b,d-548c; BK XI, CH 3 [1061a29]-CH 4 [1061b33] 589c-590a; CH 7 592b-593a; BK XII, CH 8 [1073b1-17] 603d-604a; BK XIII, CH 3 609a-610a / Soul, BK I, CH 1 [403b10-19] 632d

9 Aristotle: Parts of Animals, BK I, CH 1 [639b6-12] 161c-d

11 Nicomachus: Arithmetic, BK I, 812b-d; 813d-814a

19 Aquinas: Summa Theologica, PART I, Q 1, A 1, REP 2 3b-4a; Q 7, A 3, ANS 32c-33c

23 Hobbes: Leviathan, PART I, 72a-d; PART IV, 268c-d

28 Galileo: Two New Sciences, FIRST DAY, 133b; THIRD DAY, 236d-237a; FOURTH DAY, 252a-b

31 Descartes: Rules, IV, 7a-c; XIV, 31c-d / Objections and Replies, 169c-170a

34 Newton: Principles, 1a-2a; BK III, 269a

42 Kant: Pure Reason, 5a-13d; 17d-19a; 211c-218d

51 Tolstoy: War and Peace, EPILOGUE II, 695b-c

53 James: Psychology, 882a-883a

2. Experimental physics and the empirical natural sciences: the relation of experimental and philosophical physics

7 Plato: Republic, BK VII, 391b-398c

8 Aristotle: Heavens, BK II, CH 13 [293a15-31] 384d; BK III, CH 7 [306a3-18] 397b-c / Generation and Corruption, BK I, CH 2 [316a5-14] 411c-d

9 Aristotle: Parts of Animals, BK I, CH 1 161a-165d esp [639b32-640a10] 162a-b

28 Gilbert: Loadstone, PREF, 1a-b; BK II, 27b-c

28 Galileo: Two New Sciences, THIRD DAY, 202d-203a; 214d

30 Bacon: Advancement of Learning, 16a-b; 30d-31a; 33b-34b; 42a-43d; 46c-47c / Novum Organum, PREF 105a-106d; BK I, APH 15 108a; APH 51 111c; APH 54 111c-d; APH 63-64 113d-114b; APH 66 114d-115c; APH 80 120a-b; APH 95 126b-c; APH 107 128c; APH 109 128d-129c; BK II, APH 1-10 137a-140d esp APH 1 137a, APH 9 140b-c

31 Descartes: Discourse, PART VI, 61d-62c

34 Newton: Principles, 1a-2a; BK III, 269a; RULE I-IV 270b-271b; GENERAL SCHOLIUM, 371b-372a / Optics, BK III, 542a-543b

35 Locke: Human Understanding, BK IV, CH II, SECT 24-29 320c-323a esp SECT 26 321b-c; CH VI, SECT 13 335c-d; CH XII, SECT 9-13 360d-362d passim, esp SECT 10 361b-c

35 Berkeley: Human Knowledge, SECT 59 424b

35 Hume: Human Understanding, SECT IV, DIV 23-27 459a-460d esp DIV 26 460b-c; SECT XII, DIV 131-132 508d-509d

39 Smith: Wealth of Nations, BK V, 336b-c

41 Gibbon: Decline and Fall, 299a

42 Kant: Pure Reason, 5a-13d esp 5c-6c; 17d-19a / Fund. Prin. Metaphysic of Morals, 253a-d / Intro. Metaphysic of Morals, 387a-b / Judgement, 561c-562a,c; 578a-b

45 Lavoisier: Elements of Chemistry, PREF, 1c-2d

49 Darwin: Origin of Species, 239c

50 Marx: Capital, 6c

53 James: Psychology, xiiib-xiva; 883b

54 Freud: Narcissism, 400d-401a / General Introduction, 545c-d / Inhibitions, Symptoms, and Anxiety, 722a-b / New Introductory Lectures, 873d-875a esp 874d-875a

2a. The derivation of definitions, distinctions, and principles from the philosophy of nature: the metaphysics of the scientist

8 Aristotle: Heavens, BK III, CH 7 [306a3-18] 397b-c / Sense and the Sensible, CH 1 [436a16-b17] 673b-c / Youth, Life, and Breathing, CH 27 [480b21-30] 726d

10 Hippocrates: Ancient Medicine, PAR 1-2 1a-d

28 Gilbert: Loadstone, BK V, 104b-105d; BK VI, 109a-b

28 Galileo: Two New Sciences, FIRST DAY, 135b-136b; THIRD DAY, 197a-b; 200a-c

33 Pascal: Vacuum, 366a-368b

34 Newton: Principles, BK III, RULE I-II 270a-271a; GENERAL SCHOLIUM, 369b-372a / Optics, BK I, 409b; BK III, 540a; 541b-542a

34 Huygens: Light, CH 1, 553b-554a

35 Berkeley: Human Knowledge, SECT 102 432d-433a

42 Kant: Intro. Metaphysic of Morals, 387a-b

45 Lavoisier: Elements of Chemistry, PART I, 36b; 41b-c

45 Fourier: Theory of Heat, 172a

45 Faraday: Researches in Electricity, 582b-584a; 595a; 670a; 673d; 824a-b; 837b-c; 839b-c

53 James: Psychology, viib-viiia; 69b-70a; 84a-119b esp 89b-90a, 95a; 882a-886a; 889a-890a

54 Freud: Narcissism, 400c-401d / Instincts, 412a-b

2b. The treatment of causes in philosophical and empirical physics: description and explanation, theory and prediction

7 Plato: Phaedo, 240d-246c / Republic, BK VI-VII, 383d-398c / Timaeus, 455a-b

8 Aristotle: Posterior Analytics 97a-137a,c passim, esp BK I, CH 13 107c-108c, BK II, CH 1-2 122b,d-123c, CH 9 128a-b, CH 11 128d-129d, CH 16-18 134b-136a / Physics, BK II, CH 3 [194b16-23] 271a-b; CH 7-9 275b-278a,c; BK IV, CH 4 [211a6-11] 290a / Metaphysics, BK I, CH 1 [981a24-982a1] 499c-500b; CH 2 [982a28-30] 500c; BK III, CH 2 [996a18-26] 514d-515b; BK VI, CH 1 [1025b1-18] 547b,d; BK VII, CH 17 [1041a10-b11] 565b-d; BK VIII, CH 4 [1044a33-b20] 569a-b; BK XI, CH 7 [1063b36-1064a9] 592b

9 Aristotle: Parts of Animals, BK I, CH 1 [639b10-642b4] 161d-165d esp [642a1-30] 165a-c / Gait of Animals, CH 1 243a-b / Generation of Animals, BK I, CH 1 [715a1-18] 255a-b; BK IV, CH 1 [765b35-766a5] 306c; BK V, CH 1 [778b7-10] 320d

10 Galen: Natural Faculties, BK I, CH 4 169a

12 Lucretius: Nature of Things, BK V [509-533] 67d-68a; BK VI [703-711] 89c-d

16 Copernicus: Revolutions of the Heavenly Spheres, 505a-506a

16 Kepler: Epitome, BK IV, 959a-960a

19 Aquinas: Summa Theologica, PART I, Q 32, A 1, REP 2 175d-178a; Q 57, A 3, ANS 297b-298a; Q 86, A 4, ANS 463d-464d

23 Hobbes: Leviathan, PART I, 60a-b; PART IV, 267a-b

28 Gilbert: Loadstone, BK I, 6a-7a; BK II, 27b-c

28 Galileo: Two New Sciences, THIRD DAY, 202d-203a; FOURTH DAY, 252a-b

28 Harvey: Circulation of the Blood, 319c / On Animal Generation, 335c-336c; 393b-c; 425a

30 Bacon: Advancement of Learning, 42a-c; 43a-d; 45a-46a; 46c-47c / Novum Organum, BK I, APH 48 110d-111a; APH 99 127b-c; BK II, APH 2 137b-c / New Atlantis, 210d

31 Descartes: Rules, IX, 15b-d / Discourse, PART VI, 61b-62c; 66a-b / Meditations, IV, 90a-b / Objections and Replies, AXIOM I 131d; 215a-b

31 Spinoza: Ethics, PART I, APPENDIX 369b-372d

34 Newton: Principles, 1a-2a; DEF VII 7b-8a; BK III, RULE I-II 270a; GENERAL SCHOLIUM, 371b-372a / Optics, BK III, 542a; 543a-b

34 Huygens: Light, CH 1, 553b-554a

35 Locke: Human Understanding, BK IV, CH III, SECT 28-29 322a-323a

35 Berkeley: Human Knowledge, SECT 32 418d-419a; SECT 50-53 422c-423a passim; SECT 60-66 424b-426a passim; SECT 101-109 432c-434b passim

35 Hume: Human Understanding, SECT I, DIV 9 454c-455a; SECT IV, DIV 26 460b-c; SECT VII, DIV 57, 475d-476b [fn 2]; DIV 60, 477a; SECT VIII, DIV 67 480c-481a

42 Kant: Pure Reason, 46d-47c / Practical Reason, 311d-314d / Judgement, 557c-558b; 564a-c; 581a-582c

45 Lavoisier: Elements of Chemistry, PART I, 9d-10b

45 Fourier: Theory of Heat, 169a; 183a-b

49 Darwin: Origin of Species, 239c-240d

51 Tolstoy: War and Peace, BK IX, 344a-b; BK XI, 470a-c; BK XIII, 563a-b; EPILOGUE I, 650b-c; EPILOGUE II, 694d-696d

53 James: Psychology, 69b-70a; 89b-90a; 742a-b; 745b; 882a-884b passim, esp 882b-883a, 884b; 885a-886a

54 Freud: General Introduction, 454b-c; 484a

3. The role of mathematics in the natural sciences: observation and measurement in relation to mathematical formulations

8 Aristotle: Posterior Analytics, BK I, CH 9 [76a3-25] 104b-d; CH 13 [78b31-79a16] 108b-c / Physics, BK II, CH 2 [194a7-11] 270b-c; BK VII, CH 5 333a-d / Metaphysics, BK XIII, CH 3 [1078a5-17] 609b-c

9 Aristotle: Gait of Animals, CH 9 247a-248a

11 Archimedes: Equilibrium of Planes 502a-519b / Floating Bodies 538a-560b / Method 569a-592a

14 Plutarch: Marcellus, 252a-255a

16 Kepler: Epitome, BK V, 964b-965a

18 Augustine: Confessions, BK V, PAR 3-6 27c-28c / Christian Doctrine, BK II, CH 29, 651b-c

19 Aquinas: Summa Theologica, PART I, Q 32, A 1, REP 2 175d-178a; PART I-II, Q 35, A 8, ANS 779c-780c

20 Aquinas: Summa Theologica, PART II-II, Q 9, A 2, REP 3 424b-425a

23 Hobbes: Leviathan, PART I, 72a-d; 73b; PART IV, 268c-d

28 Galileo: Two New Sciences, FIRST DAY, 131b-132a; 133b; FOURTH DAY, 245b-d; 252a-b

30 Bacon: Advancement of Learning, 46b-c / Novum Organum, BK I, APH 109, 129b; BK II, APH 8 140b; APH 39, 170b-c

31 Descartes: Rules, IV, 7a-c; XIV, 31c-d / Discourse, PART I, 43b-c; PART II, 50d / Objections and Replies, 169c-170a

34 Newton: Principles, 1a-2a; DEF VII 7b-8a; BK I, PROP 69, SCHOLIUM, 131a; BK III, 269a

34 Huygens: Light, PREF, 551b-552a

35 Hume: Human Understanding, SECT IV, DIV 27 460c-d

36 Swift: Gulliver’s Travels, PART III, 94b-103a

41 Gibbon: Decline and Fall, 299b-c

42 Kant: Judgement, 551a-552a

45 Lavoisier: Elements of Chemistry, PART I, 14a-c; 33b-36a; 41a-44d; PART III, 96b-103b

45 Fourier: Theory of Heat, 169a-b; 172a-173b; 175b; 177a; 182b-184a; 249a-b

45 Faraday: Researches in Electricity, 831b-c

50 Marx: Capital, 170a-c

51 Tolstoy: War and Peace, BK XI, 469a-d

53 James: Psychology, 126a-b; 348a-359a esp 351a-354a; 675b; 876a-b; 882a-884b

4. The experimental method in the study of nature

4a. The distinction between simple observation and experimentation: the art of creating ideal or isolated physical systems

28 Galileo: Two New Sciences, FIRST DAY, 148d-149c; 166d-167b

28 Harvey: Circulation of the Blood, 320b

50 Marx: Capital, 6c

53 James: Psychology, 126a-127b

54 Freud: New Introductory Lectures, 815a-c

4b. Experimental discovery: inductive generalization from experiment; the role of theory or hypothesis in experimentation

10 Hippocrates: Ancient Medicine, PAR 1-8 1a-3b

28 Gilbert: Loadstone, PREF, 1a-b; BK I, 6a-7a; BK II, 27c-28a

28 Galileo: Two New Sciences, FIRST DAY, 131a-138b; 157b-171b passim; THIRD DAY, 203d-205b; 207d-208a

28 Harvey: Motion of the Heart, 273c-d; 280c-d; 285c-d / On Animal Generation, 331b-333d; 336b-d; 383d; 451b-c

30 Bacon: Advancement of Learning, 16a; 30d-31a; 34b; 42a-c; 56c-59c / Novum Organum, PREF-BK I 105a-136a,c esp BK I, APH 64 114b, APH 70 116b-117a, APH 82 120d-121b, APH 99-100 127b-c; BK II, APH 11-14 140d-148d; APH 36 164a-168d

31 Descartes: Discourse, PART VI, 61d-62c

33 Pascal: Vacuum, 359a-365b / Equilibrium of Liquids 390a-403a passim

34 Newton: Principles, BK III, RULE III-IV 270b-271b; GENERAL SCHOLIUM, 371b-372a / Optics, BK I, 379a; 386b-404b; 424a-440a; 450a-453a; BK II, 457a-478b; BK I-III, 496a-516a; BK III, 543a-b

34 Huygens: Light, PREF, 551b-552a

35 Locke: Human Understanding, BK III, CH VI, SECT 46-47 281d-282b; BK IV, CH XII, SECT 9-13 360d-362d passim

42 Kant: Intro. Metaphysic of Morals, 387a-b

45 Lavoisier: Elements of Chemistry, PREF, 2a-b; PART I, 10d-12d; 17a-20d esp 17a; 22d-24a; 29d-33b

45 Fourier: Theory of Heat, 172a; 175b; 184a

45 Faraday: Researches in Electricity, 265a-273a esp 272c-273a; 277a-300a; 319b,d-330d; 347a-351c; 362d-366c; 371d-377d; 440b,d; 607a,c; 659a; 774d-775a; 851a-c

49 Darwin: Origin of Species, 136b-139a passim

53 James: Psychology, 126a-127a; 265a-268a; 341a-344b; 348a-357b passim; 385a-b

4c. Experimental testing and verification: the crucial experiment

10 Galen: Natural Faculties, BK I, CH 13 173d-177a; BK II, CH 2 199d-200a; CH 4 201b-202c; CH 8 205a-207b

21 Dante: Divine Comedy, PARADISO, I [46-105] 108b-d

28 Galileo: Two New Sciences, FIRST DAY, 148c-149c; 166d-168a; THIRD DAY, 200a-b; 202d-203a; 203d-205b; 207d-208c

28 Harvey: Motion of the Heart, 268d-273c esp 268d, 273c; 286b-304a,c esp 286b-c, 295d-296a / Circulation of the Blood, 311c-312c; 324c-d

30 Bacon: Novum Organum, BK II, APH 36 164a-168d

31 Descartes: Discourse, PART VI, 61c-62c; 66a-b

33 Pascal: Vacuum, 368b-370a / Great Experiment 382a-389b / Weight of Air, 404a-405b; 425a-429a

34 Newton: Principles, LAWS OF MOTION, SCHOLIUM, 19b-22a; BK II, GENERAL SCHOLIUM 211b-219a; PROP 40, SCHOLIUM 239a-246b / Optics, BK I, 392a-396b; 408a-410b; 412a-416b; 453a-455a; BK III, 543a-b

34 Huygens: Light, PREF, 551b-552a

35 Locke: Human Understanding, BK IV, CH XII, SECT 13 362c-d

45 Lavoisier: Elements of Chemistry, PREF, 2a-b; PART I, 17a-b; 32a-33a

45 Fourier: Theory of Heat, 181b; 184a

45 Faraday: Researches in Electricity, 300b-316a; 334b-335c; 377d-383a; 385b-c; 388c-389d; 440b,d; 467a-b; 830b-832c

49 Darwin: Origin of Species, 12b-c; 149d-150a

53 James: Psychology, 865a; 882a-884b

54 Freud: Interpretation of Dreams, 291d-292a / Narcissism, 401a / New Introductory Lectures, 815a-b; 818c-819b

4d. Experimental measurement: the application of mathematical formulae

28 Gilbert: Loadstone, BK IV, 85c-89c; BK V, 92a-93b

28 Galileo: Two New Sciences, FIRST DAY, 136d-137c esp 137b-c; 148d-149c; 164a-166c esp 165c-166c; THIRD DAY, 207d-208c

28 Harvey: Motion of the Heart, 286c-288c

34 Newton: Principles, LAWS OF MOTION, SCHOLIUM, 20a-22a; BK II, GENERAL SCHOLIUM 211b-219a; PROP 40, SCHOLIUM 239a-246b

45 Lavoisier: Elements of Chemistry, PART I, 14a-c; 17a-20b; 22d-24a; 30a-32d; 33b-36a; PART III, 87d-90a; 91a-95a; 96b-103b

45 Fourier: Theory of Heat, 175b; 184b-185b

45 Faraday: Researches in Electricity, 277a-279a; 316b-318c; 366d-371d; 444a-451a; 465d-467a,c; 768d-773d; 778b,d-793c

53 James: Psychology, 56a-66a esp 61b-64a; 126a; 265a-268b; 341a-344b; 348a-359a

5. The utility of physics: the invention of machines; the techniques of engineering; the mastery of nature

14 Plutarch: Marcellus, 252a-255a

28 Gilbert: Loadstone, BK I, 75a-b; BK IV, 85c-89c; BK V, 100c-101d

28 Galileo: Two New Sciences, FIRST DAY, 160d-161a; SECOND DAY, 191b-193b

30 Bacon: Advancement of Learning, 34b / Novum Organum, BK I, APH 81 120b-c; APH 124 133c-d; APH 129 134d-135d; BK II, APH 39, 170b-c; APH 44-51 175d-194c / New Atlantis, 210d-214d

31 Descartes: Discourse, PART VI 60d-67a,c esp 61b-c

33 Pascal: Equilibrium of Liquids, 392b-393a

34 Newton: Optics, BK I, 412a-423b

35 Locke: Human Understanding, BK IV, CH XII, SECT 11-12 361c-362c

36 Swift: Gulliver’s Travels, PART III, 99b-112a

39 Smith: Wealth of Nations, BK I, 5d-6a

40 Gibbon: Decline and Fall, 661c-663c

41 Gibbon: Decline and Fall, 291d-292c; 509d-510a,c

45 Lavoisier: Elements of Chemistry, PART I, 26c-27a: 41a-44d; 45c-d

45 Fourier: Theory of Heat, 170a-172a; 184a; 213b

45 Faraday: Researches in Electricity, 390b; 433a-440a,c

50 Marx: Capital, 170a-c; 180d-188c; 239c-d

50 Marx-Engels: Communist Manifesto, 421d

54 Freud: Civilization and Its Discontents, 777a; 778b-779a

CROSS-REFERENCES

• For the general discussion of the distinction between philosophy and science, relevant to the difference between a philosophical and an experimental physics, see KNOWLEDGE 6c(4); PHILOSOPHY 1c; SCIENCE 1c.
• For the relation of physics as a philosophy of nature to mathematics and to metaphysics, see MATHEMATICS 1a; MATTER 8b; METAPHYSICS 3b; NATURE 4b; PHILOSOPHY 2b; SCIENCE 1a(2).
• For the relation of mathematics to experimental physics, and for the nature of mathematical physics, see ASTRONOMY 2c; MATHEMATICS 5b; MECHANICS 3; SCIENCE 5c.
• For other discussions relevant to the treatment of causes in philosophical and scientific physics, see ASTRONOMY 3a-3b; CAUSE 5b; SCIENCE 4c; and for other treatments of problems or concepts fundamental to physics, see CHANCE 1a-1b; CHANGE 2-2b, 5a-5b, 6a-6b, 7a-7d; ELEMENT 3-3d, 5; INFINITY 3d-3e, 4a-4b; MATTER 1-1b, 2a-2b; MECHANICS 1a-1c, 6a-6e; NATURE 3a-3c(3); QUANTITY 5a-5c; SPACE 1-2c, 3b; TIME 1.
• For the logic of the experimental method in the study of nature, see INDUCTION 5; LOGIC 4b; MECHANICS 2a; REASONING 6c; and for the theory of experimentation and the use of hypotheses and measurements, see ASTRONOMY 2a-2b; EXPERIENCE 5a-5c; HYPOTHESIS 4-4d; MATHEMATICS 5a; MECHANICS 2b, 3a; QUANTITY 6-6c; SCIENCE 5a-5b, 5d-5e.
• For other considerations of the utility of physics or natural science generally, see KNOWLEDGE 8a; SCIENCE 1b(1).
• For the various branches of physics, such as astronomy, statics, dynamics, optics, acoustics, hydrodynamics, magnetism, and electricity, see ASTRONOMY 8a-9f; MECHANICS 1b, 5a-5f(2), 6a-6e, 7a, 7b-7c, 7d, 7e.
• For discussions relevant to the distinction between physics and biology or psychology, see ANIMAL 4a; CHANGE 6c-6d, 8a-8b, 10a-10b; LIFE AND DEATH 2; MECHANICS 4b-4c; MIND 2e; and for the treatment of one aspect of psychophysics, see SENSE 3c(2).

ADDITIONAL READINGS

Listed below are works not included in Great Books of the Western World, but relevant to the idea and topics with which this chapter deals. These works are divided into two groups:

• I. Works by authors represented in this collection.
• II. Works by authors not represented in this collection.

For the date, place, and other facts concerning the publication of the works cited, consult the Bibliography of Additional Readings which follows the last chapter of The Great Ideas.

I.

• Aquinas. On the Trinity of Boethius, QQ 5-6
• Hobbes. Concerning Body, PART IV, CH 27
• Newton. Letters on Various Subjects in Natural Philosophy
• Kant. Prolegomena to Any Future Metaphysic, PAR 14-39
  • Metaphysical Foundations of Natural Science
• Hegel. Science of Logic, VOL II, SECT II, CH 2

II.

• Suarez. Disputationes Metaphysicae, I (4), XV (11)
• Boyle. New Experiments Physico-Mechanical
  • The Sceptical Chymist
  • The Origin of Forms and Qualities, According to the Corpuscular Philosophy
  • Experiments, Notes, etc. About the Mechanical Origin or Production of Diverse Particular Qualities
• Voltaire. Letters on the English, XIV-XVIII
• Black. Experiments upon Magnesia Alba, Quicklime, and Some Other Alcaline Substances
• J. Priestley. Experiments and Observations on Different Kinds of Air
• Cavendish. Experiments of Factitious Air
  • Electrical Researches
  • Experiments on Air
• Schelling. Ideen zu einer Philosophie der Natur
• T. Young. Lectures on Natural Philosophy and the Mechanical Arts
• Davy. Elements of Chemical Philosophy
• Dalton. A New System of Chemical Philosophy
• Comte. The Positive Philosophy, BK III-IV
• Whewell. The Philosophy of the Inductive Sciences, VOL I, BK V-VI
• Tyndall. On the Study of Physics
• Helmholtz. Popular Lectures on Scientific Subjects
• Herschel. A Preliminary Discourse on the Study of Natural Philosophy
  • Familiar Lectures on Scientific Subjects, VI-VIII, XII
• Mendeleev. The Principles of Chemistry
• W. Thomson and Tait. Treatise on Natural Philosophy and Elements of Natural Philosophy
• Lotze. Grundzüge der Naturphilosophie
• Maxwell. Matter and Motion
• Clifford. The Common Sense of the Exact Sciences, CH 2, 5
• Ostwald. Natural Philosophy
• Poincaré. The Value of Science, PART II
• Duhem. La théorie physique, son objet—sa structure
• Meyerson. Identity and Reality
• Cassirer. Substance and Function, PART I, CH 4; SUPP VII
• Broad. Perception, Physics, and Reality
• N. R. Campbell. Physics; the Elements
• Pauli. Relativitätstheorie
• Lorentz. Lectures on Theoretical Physics
  • Problems of Modern Physics
• Whitehead. The Concept of Nature, CH 9
  • The Principle of Relativity with Applications to Physical Science
  • Science and the Modern World, CH 7-8
• Bridgman. The Logic of Modern Physics
• Weyl. Space—Time—Matter
  • Philosophy of Mathematics and Natural Science
• Bohr. Atomic Theory and the Description of Nature
• Heisenberg. The Physical Principles of the Quantum Theory
• Santayana. The Realm of Matter, CH 1
• M. R. Cohen. Reason and Nature, BK II, CH 2
• Lenzen. The Nature of Physical Theory
• Einstein. Relativity: The Special and the General Theory
  • Sidelights on Relativity
  • The Meaning of Relativity
  • On the Method of Theoretical Physics
• Carnap. The Unity of Science
  • Philosophy and Logical Syntax, III (5-9)
• Maritain. An Introduction to Philosophy, PART II (3)
  • The Degrees of Knowledge, CH 3
  • Science and Wisdom, pp 34-69
• Gilson. The Unity of Philosophical Experience, CH 9
• Einstein and Infeld. The Evolution of Physics
• Watson. On Understanding Physics
• D’Abro. Decline of Mechanism in Modern Physics
• Eddington. The Mathematical Theory of Relativity
  • The Philosophy of Physical Science
• Riezler. Physics and Reality
• P. Frank. Between Physics and Philosophy
• B. Russell. Our Knowledge of the External World, III-IV
  • The Analysis of Matter, CH 1-26, 37
  • Human Knowledge, Its Scope and Limits, PART I, CH 3; PART II, CH 4
• Planck. A Survey of Physics
  • The Philosophy of Physics, CH 1
  • Scientific Autobiography
• Schlick. Philosophy of Nature