On the Methodological Shortcomings of My Textbook Mechanics

Letter to the Editor

The methodological premises of my textbook Mechanics have repeatedly been subjected to sharp criticism both by individual comrades and by entire collectives of physicists. In particular, the second edition of the textbook was criticized at the Department of General Physics of the Physics Faculty of Moscow State University and in the Party organization of the P. N. Lebedev Physical Institute of the Academy of Sciences of the USSR. I must acknowledge that, in general, this criticism—and above all the criticism to which my textbook was subjected in the collective of the Physical Institute of the Academy of Sciences of the USSR—was justified.

It was precisely this businesslike, principled criticism that helped me clearly see the methodological shortcomings of my textbook. After the shortcomings of my textbook became clear to me, I consider myself

obliged to point them out and, at least in part (insofar as this is possible in a journal article), to correct them. I hope that this article will help the student who uses my book to avoid those mistakes into which he may be led by the incomplete, imprecise, and therefore incorrect exposition of a number of basic methodological questions in my textbook. Such is the main purpose of the present article. At the same time, since a critical article by F. A. Korolev about my book has appeared in Uspekhi fizicheskikh nauk (vol. XXXVII, no. 3), I consider it necessary briefly to state my attitude toward F. A. Korolev’s criticism.

Before proceeding to consider the individual methodological shortcomings of my textbook, I consider it necessary once again to formulate the task that confronts every author of a Soviet textbook of physics. Physics is not only the scientific foundation of all modern technology, but also plays an important role in the development of the correct scientific worldview of the philosophy of dialectical materialism. On the one hand, this correct scientific worldview develops and is deepened on the factual material of the natural sciences, in particular physics. On the other hand, dialectical materialism is the only philosophy that makes it possible correctly to comprehend and illuminate all the vast factual material of modern physics. It is precisely for this reason that V. I. Lenin, in his classic work Materialism and Empirio-Criticism, devotes such attention to questions of physics. From what has been said it is clear that the task of a Soviet textbook of physics consists not only in conveying to the student a certain sum of knowledge, but also in strengthening in the student, on the one hand, the correct scientific worldview—the philosophy of dialectical materialism—and, on the other, in illuminating all the factual material represented by modern physics from the standpoint of this philosophy. My textbook does not fulfill these important methodological tasks, and in this lies its principal defect.

A number of important methodological questions in my textbook not only did not receive full and correct illumination from the standpoint of dialectical materialism, but, on the contrary, are presented in such a way that this presentation hinders a correct materialist understanding and, in some cases, may lead to errors of an idealistic character. It is needless to say that such an exposition of methodological questions, which leads to idealistic errors, or at least leaves open the possibility of such errors, is inadmissible in a Soviet textbook and considerably lowers its value, even if the factual material is presented satisfactorily in the textbook.

The necessity of a clear and correct illumination of methodological questions in the spirit of dialectical materialism has always been

was one of the most important requirements made of every Soviet textbook. In our time the significance of this requirement is especially great. The ideological aggression which is a component part of the general aggressive policy of the capitalist countries toward the country of socialism can be successfully repelled only on the condition that we are all well armed with the most powerful weapon of ideological struggle—the philosophy of Marx—Engels—Lenin—Stalin.

I now turn to individual shortcomings of my book. Of course, within the limits of a journal article I shall not be able, in exchange for the incomplete or incorrect treatment of a number of methodological questions in my book, to give an exhaustive and correct treatment of them. Therefore I shall be forced to confine myself only to the most important questions and only in general outline to indicate the correct treatment of these questions.

First of all, in speaking of the necessity of abstractions (“idealized schemes”) in the theoretical analysis of phenomena and of the approximate character of our theories conditioned by this (Introduction, § 1), it should have been emphasized that our theories, despite their approximate character, reflect objective reality more and more accurately, and that the development of science is not a closed movement within a circle of approximate theories, but is a progressive movement along the path toward absolute truth. In speaking (in connection with the same question of the necessity of abstractions) about the relation between theory and experience, it was necessary to give a materialist definition of the concept of “experience,” so that it would be clear that experience, practice, is an objective category. If such a correct materialist treatment of the question had been given in § 1, it could have served as a concrete illustration of Lenin’s doctrine of relative and absolute truth. The exposition of this whole question in my textbook not only does not serve this purpose, but creates the ground for errors of a Machist character.

In speaking of physical laws (pp. 22–23), it is completely incorrect, as is done in my book, to confine oneself only to the question of the formal content of these laws. It was necessary first of all to emphasize that physical laws reflect objective regularities existing in nature; to illuminate correctly the question of the origin of physical laws; to indicate that physical laws are a generalization of experimental facts. Without these necessary explanations, the exposition of the entire question in my book appears as though physical laws are “constructed” in our consciousness and only then verified by experience. And since, moreover, there is no materialist definition of the concept of “experience” in the book, the whole important question of the origin of physical laws did not receive in my book a correct materialist interpretation. True, in other places in the book (pp. 265, 274, 509)

frankly stated that physical laws are a generalization of experimental facts, but this, of course, is not enough. Precisely in the introduction, where the question of physical laws is touched upon for the first time, it was necessary at once to give a correct and exhaustive materialist illumination of this question. The exposition at this point in my book may lead to idealist errors.

In beginning the exposition of questions concerning motion and space-time frames of reference (p. 29), it was necessary first of all to give a philosophical definition of matter and of motion as an inalienable attribute of matter, and of space and time as objective forms of the existence of matter. Without these necessary indications, the exposition of the whole question of motion and space-time relations given in my book may be understood in the spirit of philosophical relativism.

In analyzing the content of Newton’s laws (pp. 71–95), it was necessary first of all to dwell in detail on the origin of these laws, to show that the formation of laws reflecting the objective regularities of the external world includes the formation of physical concepts and definitions; moreover, these concepts and definitions, just like the laws themselves, reflect the objective properties of matter. In presenting various interpretations of the content of Newton’s laws, it was necessary to emphasize that all these interpretations reflect the same objective regularities, that under different interpretations Newton’s laws nevertheless have one and the same objective, i.e. independent of our consciousness, content.

In my book, various interpretations of the content of Newton’s laws are considered in detail, but the necessary general considerations indicated above are absent. Such a one-sided exposition of the whole question gives it an incorrect illumination. This exposition creates the impression that not only the interpretation but also the content of Newton’s laws depend on our choice.

The question of the equivalence of inertial forces and gravitational forces (Chap. XII, § 80) did not receive proper illumination in my textbook. It was necessary to explain the limitation in time and space of this equivalence and the absolute character of acceleration following from this limitation. Without these explanations, the exposition of the question of the equivalence of gravitational forces inevitably becomes a source of errors in the spirit of philosophical relativism. True, the reservation contained in my book (p. 212) about the fundamental difficulties that arise in carrying out the viewpoint of the equivalence of inertial forces and gravitational forces had in mind precisely this limited character of the equivalence. However, since this reservation does not explain exactly what the difficulties consist in, it is purely formal in character and therefore does not remove the danger of the errors indicated above.

In presenting the mechanics of the special theory of relativity (Chapter XXII), it was also necessary to give a correct methodological treatment of this important chapter of modern physics. In speaking of those new conceptions of space and time that were introduced by the theory of relativity, it was necessary to emphasize the objective character of space and time and to explain that the theory of relativity not only does not reconsider the question of the objective existence of time and space but, on the contrary, gives a fuller and more precise representation of this objective reality. With such a correct treatment, the entire exposition of the foundations of the theory of relativity could have served as an illustration of Lenin’s propositions on the relativity and mutability of our conceptions of time and space, on the one hand, and on the objective reality of time and space as forms of the existence of matter, on the other. Since such, the only correct, treatment of the foundations of the theory of relativity is absent from my textbook, the exposition of this theory may provide ground for those incorrect conclusions, in the spirit of philosophical relativism, which are sometimes drawn from the theory of relativity.

These are the principal methodological shortcomings of my textbook which I considered it necessary, first of all, to point out and at least partially correct in the present article. As has been said, I hope that in this way I shall succeed in at least to some extent paralyzing the harmful influence that the shortcomings of my textbook noted above might have had. I consider it necessary also to indicate where I see the cause of these shortcomings. This cause consists in the fact that, in compiling the textbook, I did not follow the Leninist principle of partisanship in science. Forgetting this principle led to the fact that my textbook not only does not strengthen a materialist world outlook in the student, but creates ground for idealist errors.

The same cause—the forgetting of the principle of partisanship in science—also accounts for another serious shortcoming of my textbook: the entirely unsatisfactory treatment of the works of Russian scholars and of the great role they played in the development of mechanics. The principle of partisanship in science requires of every Soviet scientist not only a correct methodological but also a correct historical treatment of the subject; it obliges us to strengthen in every way the authority of national science and to defend the rights of the Soviet people to those enormous cultural and, in particular, scientific values that the Russian people and the peoples of the Soviet Union have created. Meanwhile, my textbook does not give a correct treatment of the role of Russian and Soviet scholars in the development of mechanics. Quite apart from the fact that in my textbook the classical works on hydrodynamics and aerodynamics by N. E. Zhukovsky and S. A. Chaplygin are insufficiently treated, it makes absolutely no mention of

works of the pioneers in the field of reactive motion, Tsiolkovsky and Meshchersky; the pioneers in the field of ultrasonics, Lebedev and Neklep­aev; the profound ideas of M. V. Lomonosov on the question of the method of measuring the tide-producing force, etc., are not set forth. Unfortunately, within the framework of a journal article I have no opportunity even partially to correct this second serious shortcoming of my textbook—the insufficient elucidation of the role of Russian scientists.

I now turn to the specific criticism contained in the article by F. A. Korolev, printed in Uspekhi fizicheskikh nauk (Vol. XXXVII, No. 3). As is evident from what I have said above, I agree with a whole series of F. A. Korolev’s statements. First of all, his reproach is entirely fair that the role of Russian scientists is quite inadequately illuminated in my textbook. Further, F. A. Korolev correctly points out a number of passages in my textbook which are presented unsatisfactorily from a methodological point of view. Which passages these are is clearly seen from a comparison of what I have said above with F. A. Korolev’s article, and therefore there is no need to list them again. However, even in those cases where F. A. Korolev correctly indicates the shortcomings of my textbook, the argumentation by which he supports his criticism often proves unconvincing, since it either contains fundamental errors or is based on an incorrect interpretation and inaccurate quotation of my book. Not at all in order to diminish the shortcomings of my textbook, but only in order to clarify correctly certain important methodological questions, I wish to dwell very briefly on some errors of a philosophical character which are contained in F. A. Korolev’s article.

In order to make clear the basic error in F. A. Korolev’s argumentation, I shall quote two statements by V. I. Lenin, in which the foundations of the theory of knowledge of dialectical materialism are set forth concisely but with the utmost clarity: “Before man there is a network of natural phenomena. Instinctive man, the savage, does not distinguish himself from nature. Conscious man does distinguish; categories are stages of distinguishing, i.e. of knowing the world, nodal points in the network, which help to know it and to master it” (V. I. Lenin, Philosophical Notebooks, Gospolitizdat, 1947, p. 67). “Logic is the doctrine of cognition. It is the theory of knowledge. Knowledge is the reflection of nature by man. But this is not a simple, not an immediate, not an integral reflection, but the process of a series of abstractions, the formation and development of concepts, laws, etc.; these concepts, laws (thought, science—the ‘logical idea’) conditionally, approximately embrace the universal law-governed character of eternally moving and developing nature. Here there are indeed, objectively, three members: 1) nature; 2) human cognition—the brain of man (as the highest product of that same nature), and 3) the form of the reflection of nature in human cognition; this form is precisely concepts, laws,”

categories, etc. Man cannot encompass—that is, reflect—depict nature in its entirety, in its “immediate wholeness”; he can only eternally approach this, creating abstractions, concepts, laws, a scientific picture of the world, and so on and so forth” (V. I. Lenin, Philosophical Notebooks, Gospolitizdat, 1947, pp. 156–157).

In the light of these statements by V. I. Lenin, the errors of F. A. Korolev stand out quite clearly, as does his failure to understand the very foundations of the materialist theory of knowledge. F. A. Korolev confuses the objective regularities of the external world, the “universal regularity of eternally moving and developing nature,” with physical laws, i.e., with the conditional, approximate reflection of this universal regularity in our knowledge. This error appears especially clearly in the very formulation of the question he poses: “If there were no one in the world who makes ‘assertions and definitions,’ would the laws of nature, including Newton’s laws, exist then or not?” But the laws of nature and Newton’s laws are not one and the same from the standpoint of the theory of knowledge. The laws of nature are the objective regularities of the external world, existing independently of our consciousness, whereas Newton’s laws are an approximate reflection of these regularities in our consciousness. And therefore the materialist theory of knowledge gives to the question posed by F. A. Korolev an answer quite different from the one F. A. Korolev expects: if there were no human being and his consciousness, then the laws of nature would exist, but those of our representations which approximately reflect objective regularities and which we call Newton’s laws would not exist. I shall note only one more statement by F. A. Korolev in which he reveals a misunderstanding of the very foundations of the philosophy of dialectical materialism. It concerns the exposition of the content of Newton’s laws in the case where frictional forces are absent. § 28 begins with the stipulation that we exclude frictional forces from consideration, and the entire subsequent exposition refers to the case in which frictional forces are absent. Why F. A. Korolev thinks that, by formulating for this particular case the fundamental proposition of mechanics, “Prof. Khaikin on this basis immediately commits a falsification,” is difficult to understand. True, the case in which frictional forces are absent is a particular case, but a very important one, since it encompasses, for example, almost all problems of celestial mechanics. (So long as we are not speaking of very long epochs, tidal friction may be completely neglected.) And the fact that, in the absence of frictional forces, concretely, for example, for the motion of celestial bodies, the accelerations of bodies depend only on coordinates and do not depend on velocities is an empirical fact,

to which it is wholly inappropriate to oppose philosophical considerations about motion as an inseparable attribute of matter. What is “expelled” from the discussion is by no means motion in the general philosophical sense (which, only when understood in this sense, is an inseparable attribute of matter), but velocity; moreover, velocity is “expelled” only in the sense that acceleration, as experience shows, does not depend on velocity. From the point of view of the philosophy of dialectical materialism, it is completely inadmissible, on the basis of certain supposedly philosophical considerations (which, of course, have been incorrectly understood), to object to objective facts.

Such an opposition distorts the very spirit of the philosophy of dialectical materialism, which, as a genuinely scientific philosophy, can never come into conflict with the objective data of science.

I repeat that, in objecting to certain statements by F. A. Korolev, I am by no means trying to minimize the shortcomings of my textbook. I see these shortcomings clearly; I feel the responsibility that rests on me for not having eliminated them in due time, and I consider it my duty to eliminate them at the first opportunity.

Prof. S. E. Khaikin