Recognising the existence of objective reality, i.e.., matter in motion, independently of our mind, materialism must also inevitably recognise the objective reality of time and space, in contrast above all to Kantianism, which in this question sides with idealism and regards time and space not as objective realities but as forms of human understanding. The basic difference between the two fundamental philosophical lines on this question is also quite clearly recognised by writers of the most diverse trends who are in any way consistent thinkers. Let us begin with the materialists.
“Space and time,” says Feuerbach, “are not mere forms of phenomena but essential conditions (Wesensbedingungen) . . . of being” (Werke, II, S. 332). Regarding the sensible world we know through sensations as objective reality, Feuerbach naturally also rejects the phenomenalist (as Mach would call his own conception) or the agnostic (as Engels calls it) conception of space and time. Just as things or bodies are not mere phenomena, not complexes of sensations, but objective realities acting on our senses, so space and time are not mere forms of phenomena, but objectively real forms of being. There is nothing in the world but matter in motion, and matter in motion cannot move otherwise than in space and time. Human conceptions of space and time are relative, but these relative conceptions go to compound absolute truth. These relative conceptions, in their development, move towards absolute truth and approach nearer and nearer to it. The mutability of human conceptions of space and time no more refutes the objective reality of space and time than the mutability of scientific knowledge of the structure and forms of matter in motion refutes the objective reality of the external world.
Engels, exposing the inconsistent and muddled materialist Dühring, catches him on the very point where he speaks of the change in the idea of time (a question beyond controversy for contemporary philosophers of any importance even of the most diverse philosophical trends) but evades a direct answer to the question: are space and time real or ideal, and are our relative conceptions of space and time approximations to objectively real forms of being, or are they only products of the developing, organising, harmonising, etc., human mind? This and this alone is the basic epistemological problem on which the truly fundamental philosophical trends are divided. Engels, in Anti-Dühring, says: “We are here not in the least concerned with what ideas change in Herr Dühring’s head. The subject at issue is not the idea of time, but real time, which Herr Dühring cannot rid him self of so cheaply [i.e.., by the use of such phrases as the mutability of our conceptions]” (Anti-Dühring, 5th Germ. ed., S. 41).
This would seem so clear that even the Yushkeviches should be able to grasp the essence of the matter! Engels sets up against Dühring the proposition of the reality, i.e.., objective reality, of time which is generally accepted by and obvious to every materialist, and says that one cannot escape a direct affirmation or denial of this proposition merely by talking of the change in the ideas of time and space. The point is not that Engels denies the necessity and scientific value of investigations into the change and development of our ideas of time and space, but that we should give a consistent answer to the epistemological question, viz., the question of the source and significance of human knowledge in general. Any moderately intelligent philosophical idealist—and Engels when he speaks of idealists has in mind the great consistent idealists of classical philosophy—will readily admit the development of our ideas of time and space; he would not cease to be an idealist for thinking, for example, that our developing ideas of time and space are approaching towards the absolute idea of time and space, and so forth. It is impossible to hold consistently to a standpoint in philosophy which is inimical to all forms of fideism and idealism if we do not definitely and resolutely recognise that our developing notions of time and space reflect an objectively real time and space; that here, too, as in general, they are approaching objective truth.
“The basic forms of all being,” Engels admonishes Dühring, “are space and time, and existence out of time is just as gross an absurdity as existence out of space” (op. cit.).
Why was it necessary for Engels, in the first half of the quotation, to repeat Feuerbach almost literally and, in the second, to recall the struggle which Feuerbach fought so successfully against the gross absurdities of theism? Because Dühring, as one sees from this same chapter of Engels’, could not get the ends of his philosophy to meet without resorting now to the “final cause” of the world, now to the “initial impulse” (which is another expression for the concept “God,” Engels says). Dühring no doubt wanted to be a materialist and atheist no less sincerely than our Machians want to be Marxists, but he was unable consistently to develop the philosophical point of view that would really cut the ground from under the idealist and theist absurdity. Since he did not recognise, or, at least, did not recognise clearly and distinctly (for he wavered and was muddled on this question), the objective reality of time and space, it was not accidental but inevitable that Dühring should slide down an inclined plane to “final causes” and “initial impulses"; for he had deprived himself of the objective criterion which prevents one going beyond the bounds of time and space. If time and space are only concepts, man, who created them is justified in going beyond their bounds, and bourgeois professors are justified in receiving salaries from reactionary governments for defending the right to go beyond these bounds, for directly or indirectly defending medieal “absurdity.”
Engels pointed out to Dühring that denial of the objective reality of time-and space is theoretically philosophical confusion, while practically it is capitulation to, or impotence in face of, fideism.
Behold now the “teachings” of “recent positivism” on this subject. We read in Mach: “Space and time are well ordered (wohlgeordnete) systems of series of sensations” (Mechanik, 3. Auflage, S. 498). This is palpable idealist nonsense, such as inevitably follows from the doctrine that bodies are complexes of sensations. According to Mach, it is not man with his sensations that exists in space and time, but space and time that exist in man, that depend upon man and are generated by man. He feels that he is falling into idealism, and “resists” by making a host of reservations and, like Dühring, burying the question under lengthy disquisitions (see especially Knowledge and Error) on the mutability of our conceptions of space and time, their relativity, and so forth. But this does not save him, and cannot save him, for one can really overcome the idealist position on this question only by recognising the objective reality of space and time. And this Mach will not do at any price. He constructs his epistemological theory of time and space on the principle of relativism, and that is all. In the very nature of things such a construction can lead to nothing but subjective idealism, as we have already made clear when speaking of absolute and relative truth.
Resisting the idealist conclusions which inevitably follow from his premises, Mach argues against Kant and insists that our notion of space is derived from experience (Knowledge and Error, 2nd Germ. ed., pp. 350, 385). But if objective reality is not given us in experience (as Mach teaches), such an objection to Kant does not in the least destroy the general position of agnosticism in the case either of Kant or of Mach. If our notion of space is taken from experience without being a reflection of objective reality outside us, Mach’s theory remains idealistic. The existence of nature in time, measured in millions of years, prior to the appearance of man and human experience, shows how absurd this idealist theory is.
“In the physiological respect,” writes Mach, “time and space are systems of sensations of orientation which together with sense-perceptions determine the discharge (Auslösung) of biologically purposive reactions of adaptation. In the physical respect, time and space are interdependencies of physical elements” (ibid., p. 434).
The relativist Mach confines himself to an examination of the concept of time in its various aspects! And like Dühring he gets nowhere. If “elements” are sensations, then the dependence of physical elements upon each other cannot exist outside of man, and could not have existed prior to man and prior to organic matter. If the sensations of time and space can give man a biologically purposive orientation, this can only be so on the condition that these sensations reflect an objective reality outside man: man could never have adapted himself biologically to the environment if his sensations had not given him an objectively correct presentation of that environment. The theory of space and time is inseparably connected with the answer to the fundamental question of epistemology: are our sensations images of bodies and things, or are bodies complexes of our sensations? Mach merely blunders about beiween t’ne two answers.
In modern physics, he says, Newton’s idea of absolute time and space prevails (pp. 442-44), of time and space as such. This idea seems “to us” senseless, Mach continues—apparently not suspecting the existence of materialists and of a materialist theory of knowledge. But in practice, he claims, this view was harmless (unschädlich, p. 442) and therefore for a long time escaped criticism.
This naïve remark regarding the harmlessness of the materialist view betrays Mach completely. Firstly, it is not true that for a “long time” the idealists did not criticise this view. Mach simply ignores the struggle between the idealist and materialist theories of knowledge on this question; he evades giving a plain and direct statement of these two views. Secondly, by recognising “the harmlessness” of the materialist views he contests, Mach thereby in fact admits their correctness. For if they were incorrect, how could they have remained harmless throughout the course of centuries? What has become of the criterion of practice with which Mach attempted to flirt? The materialist view of the objective reality of time and space can be “harmless” only because natural science does not transcend the bounds of time and space, the bounds of the material world, leaving this occupation to the professors of reactionary philosophy. Such “harmlessness” is equivalent to correctness.
It is Mach’s idealist view of space and time that is “harmful,” for, in the first place, it opens the door wide for fideism and, in the second place, seduces Mach himself into drawing reactionary conclusions. For instance, in 1872 Mach wrote that “one does not have to conceive of the chemical elements in a space of three dimensions” (Erhaltung der Arbeit, S. 29, repeated on S. 55). To do so would be “to impose an unnecessary restriction upon ourselves. There is no more necessity to think of what is mere thought (das bloss Gedachte) spatially, that is to say, in relation to the visible and tangible, than there is to think of it in a definite pitch” (p. 27). “The reason why a satisfactory theory of electricity has not yet been established is perhaps because we have insisted on explaining electrical phenomena in terms of molecular processes in a three-dimensional space” (p. 30).
From the standpoint of the straightforward and unmuddled Machism which Mach openly advocated in 1872, it is indisputable that if molecules, atoms, in a word, chemical elements, cannot be perceived, they are “mere thought” (das bloss Gedachte). If so, and if space and time have no objective reality, it is obvious that it is not essential to think of atoms spatially! Let physics and chemistry “restrict themselves” to a three-dimensional space in which matter moves; for the explanation of electricity, however, we may seck its elements in a space which is not three-dimensional!
That our Machians should circumspectly avoid all reference to this absurdity of Mach’s, although he repeats it in 1906 (Knowledge and Error, 2. Auflage, S. 418), is understandable, for otherwise they would have to raise the question of the idealist and materialist views of space point-blank, without evasions and without attempting to “reconcile” these antagonistic positions. It is likewise understandable that in the ‘seventies, when Mach was still entirely unknown and when “orthodox physicists” even refused to publish his articles, one of the chiefs of the immanentist school, Anton von Leclair, should eagerly have seized upon precisely this argument of Mach’s as a noteworthy renunciation of materialism and recognition of idealism! For at that time Leclair had not yet invented, or had not yet borrowed from Schuppe and Schubert-Soldern, or J. Rehmke, the “new” sobriquet, “immanentist school,” but plainly called himself a critical idealist. This unequivocal advocate of fideism, who openly preached it in his philosophical works, immediately proclaimed Mach a great philosopher because of these statements, a “revolutionary in the best sense of the word” (p. 252); and he was absolutely right. Mach’s argument amounts to deserting science for fideism. Science was seeking, both in 1872 and in 1906, is now seeking, and is discovering—at least it is groping its way towards—the atom of electricity, the electron, in three-dimensional space. Science does not doubt that the substance it is investigating exists in three-dimensional space and, hence, that the particles of that substance, although they be so small that we cannot see them, must also “necessarily” exist in this three-dimensional space. Since 1872, during the course of three decades of stupendous and dazzling scientific successes in the problem of the structure of matter, the materialist view of space and time has remained “harmless,” i.e.., compatible, as heretofore, with science, while the contrary view of Mach and Co. was a “harmful” capitulation to the position of fideism.
In his Mechanik, Mach defends the mathematicians who are investigating the problem of conceivable spaces with n dimensions; he defends them against the charge of drawing “preposterous” conclusions from their investigations. The defence is absolutely and undoubtedly just, but see the epistemological position Mach takes up in this defence. Recent mathematics, Mach says, has raised the very important and useful question of a space of n dimensions as a conceivable space; nevertheless, three-dimensional space remains the only “real case” (ein wirklicher Fall) (3rd German ed., pp. 483-85). In vain, therefore, “have many theologians, who experience difficulty in deciding where to place hell,” as well as the spiritualists, sought to derive advantage from the fourth dimension (ibid.).
Very good! Mach refuses to join company with the theologians and the spiritualists. But how does he dissociate himself from them in his theory of knowledge? By stating that three-dimensional space alone is real! But what sort of defence is it against the theologians and their like when you deny objective reality to space and time? Why, it comes to this, that when you have to dissociate yourself from the spiritualists you resort to tacit borrowings from the materialists. For the materialists, by recognising the real world, the matter we perceive, as an objective reality, have the right to conclude therefrom that no human concept, whatever its purpose, is valid if it goes beyond the bounds of time and space. But you Machian gentlemen deny the objective validity of “reality” when you combat materialism, yet secretly introduce it again when you have to combat an idealism that is consistent, fearless and frank throughout! If in the relative conception of time and space there is nothing but relativity, if there is no objective reality (i.e.., reality independent of man and mankind) reflected by these relative concepts, why should mankind, why should the majority of mankind, not be entitled to conceive of beings outside time and space? If Mach is entitled to seek atoms of electricity, or atoms in general, outside three-dimensional space, why should the majority of mankind not be entitled to seek the atoms, or the foundations of morals, outside three-dimensional space?
“There has never been an accoucheur who has helped a delivery by means of the fourth dimension,” Mach goes on to say.
An excellent argument—but only for those who regard the criterion of practice as a confirmation of the objective truth and objective reality of our perceptual world. If our sensations give us an objectively true image of the external world, existing independently of us, the argument based on the accoucheur, on human practice generally, is valid. But if so, Machism as a philosophical trend is not valid.
“I hope, however,” Mach continues, referring to his work of 1872, “that nobody will defend ghost-stories (die Kosten einer Spukgeschichte bestreiten) with the help of what I have said and written on this subject.” One cannot hope that Napoleon did not die on May 5, 1821.
One cannot hope that Machism will not be used in the service of “ghost-stories” when it has already served and continues to serve the immanentists!
And not only the immanentists, as we shall see later. Philosophical idealism is nothing but a disguised and embellished ghost-story. Look at the French and English representatives of empirio-criticism, who are less flowery than the German representatives of this philosophical trend. Poincaré says that the concepts space and time are relative and that it follows (for non-materialists “it follows” indeed) that “nature does not impose them upon us, but we impose them upon nature, for we find them convenient” (op. cit., p. 6). Does this not justify the exultation of the German Kantians? Does this not confirm Engels’ statement that consistent philosophical doctrines must take either nature or human thought as primary?
The views of the English Machist Karl Pearson are quite definite. He says: “Of time as of space we cannot assert a real existence: it is not in things but in our mode of perceiving them” (op. cit., p. 184). This is idealism, pure and simple. “Like space, it [time] appears to us as one of the plans on which that great sorting-machine, the human perceptive faculty, arranges its material” (ibid.). Pearson’s final conclusion, expounded as usual in clear and precise theses, is as follows: “Space and time are not realities of the phenomenal world, but the modes under which we perceive things apart. They are not infinitely large nor infinitely divisible, but are essentially limited by the contents of our perception” (p. 191, summary of Chapter V on Space and Time).
This conscientious and scrupulous foe of materialism, with whom, we repeat, Mach frequently expresses his complete agreement and who in his turn explicitly expresses his agreement with Mach, invents no special signboard for his philosophy, and without the least ambiguity names Hume and Kant as the classics from whom he derives his philosophical trend! (p. 192).
And while in Russia there are naïve people who believe that Machism has provided a “new” solution of the problem of space and time, in English writings we find that scientists, on the one hand, and idealist philosophers, on the other, at once took up a definite position in regard to Karl Pearson the Machian. Here, for example, is the opinion of Lloyd Morgan, the biologist: “Physics as such accepts the phenomenal world as external to, and for its purposes independent of, the mind of the investigator. . . . He [Professor Pearson] is forced to a position which is largely idealistic. . . ." “Physics, as a science, is wise, I take it, in dealing with space and time in frankly objective terms, and I think the biologist may still discuss the distribution of organisms in space and the geologist their distribution in time, without pausing to remind their readers that after all they are only dealing with sense-impressions and stored sense-impressions and certain forms of perception. . . . All this may be true enough, but it is out of place either in physics or biology” (p. 304). Lloyd Morgan is a representative of the kind of agnosticism that Engels calls “shamefaced materialism,” and however “conciliatory” the tendencies of such a philosophy are, nevertheless it proved impossible to reconcile Pearson’s views with science. With Pearson “the mind is first in space, and then space in it,” says another critic. “There can be no doubt,” remarked a defender of Pearson, R. J. Ryle, “that the doctrine as to the nature of space and time which is associated with the name of Kant is the most important positive addition which has been made to the idealistic theory of human knowledge since the days of Bishop Berkeley; and it is one of the noteworthy features of the Grammar of Science that here, perhaps for the first time in the writings of English men of science, we find at once a full recognition of the general truth of Kant’s doctrine, a short but clear exposition of it...."
Thus we find that in England the Machians themselves, their adversaries among the scientists, and their adherents among the professional philsophers have not even a shadow of doubt as to the idealistic character of Mach’s doctrine of time and space. Only some Russian writers, would-be Marxists, "failed to notice" it.
“Many of Engels’ particular views,” V. Bazarov, for instance, writes, in the Studies (p. 67), “as for example, his conception of ‘pure’ time and space, are now obsolete.”
Indeed! The views of the materialist Engels are now obsolete, but the views of the idealist Pearson and the muddled idealist Mach are very modern! The most curious thing of all is that Bazarov does not even doubt that the views of space and time, viz., the recognition or denial of their objective reality, can be classed among “particular views,” in contradistinction to the “starting point of the world outlook” spoken of by this author in his next sentence. Here you have a glaring example of that “eclectic pauper’s broth” of which Engels was wont to speak in reference to German philosophy of the ‘eighties. For to contrast the “starting point” of Marx’s and Engels’ materialist world outlook with their “particular view” of the objective reality of time and space is as utterly nonsensical as though you were to contrast the “starting point” of Marx’s economic theory with his “particular view” of surplus value. To sever Engels’ doctrine of the objective reality of time and space from his doctrine of the transformation of “things-in-themselves” into “things-for-us,” from his recognition of objective and absolute truth, viz., the objective reality given us in our sensations, and from his recognition of objective law, causality and necessity in nature—is to reduce an integral philosophy to an utter jumble. Like all the Machians, Bazarov erred in confounding the mutability of human conceptions of time and space, their exclusively relative character, with the immutabil-ity of the fact that man and nature exist only in time and space, and that beings outside time and space, as invented by the priests and maintained by the imagination of the ignorant and downtrodden mass of humanity, are disordered fantasies, the artifices of philosophical idealism—rotten products of a rotten social system. The teachings of science on the structure of matter, on the chemical composition of food, on the atom and the electron, may and constantly do become obsolete, but the truth that man is unable to subsist on ideas and to beget children by platonic love alone never becomes obsolete. And a philosophy that denies the objective reality of time and space is as absurd, as intrinsically rotten and false as is the denial of these latter truths. The artifices of the idealists and the agnostics are on the whole as hypocritical as the sermons on platonic love of the pharisees!
In order to illustrate this distinction between the relativity of our concepts of time and space and the absolute opposition, within the bounds of epistemology, between the materialist and idealist lines on this question, I shall further quote a characteristic passage from a very old and very pure “empirio-criticist,” namely, the Humean Schulze-Aenesidemus who wrote in 1792:
“If we infer ‘things outside us’ from ideas and thoughts within us, [then] space and time are something real and actually existing outside us, for the existence of bodies can be conceived only in an existing (vorhandenen) space, and the existence of changes only in an existing time” (op. cit., p. 100).
Exactly! While firmly rejecting materialism, and even the slightest concession to materialism, Schulze, the follower of Hume, described in 1792 the relation between the question of space and time and the question of an objective reality out-side us just as the materialist Engels described it in 1894 (the last preface to Anti-Dühring is dated May 23,1894). This does not mean that during these hundred years our ideas of time and space have undergone no change, or that a vast amount of new material has not been gathered on the development of these ideas (material to which both Voroshilov-Chernov and Voroshilov-Valentinov refer as supposedly refuting Engels). This does mean that the relation between materialism and agnosticism, as the fundamental lines in philosophy, could not have changed, in spite of all the “new” names paraded by our Machians.
And Bogdanov too contributes absolutely nothing but “new” names to the old philosophy of idealism and agnosticism. When he repeats the arguments of Hering and Mach on the difference between physiological and geometrical space, or between perceptual and abstract space (Empirio-Monism, Bk. I, p. 26), he is fully repeating the mistake of Dühring. It is one thing, how, with the help of various sensc organs, man perceives space, and how, in the course of a long historical development, abstract ideas of space are derived from these perceptions; it is an entirely different thing whether there is an objective reality independent of mankind which corresponds to these perceptions and conceptions of mankind. This latter question, although it is the only philosophical question, Bogdanov “did not notice” beneath the mass of detailed investigations on the former question, and he was therefore unable clearly to distinguish between Engels’ materialism and Mach’s confusion.
Time, like space, is “a form of social co-ordination of the experiences of different people,” their “objectivity” lies in their “general significance” (ibid., p. 34).
This is absolutely false. Religion also has general significance as expressing the social co-ordination of the experience of the larger section of humanity. But there is no objective reality that corresponds to the teachings of religion, for example, on the past of the earth and the creation of the world. There is an objective reality that corresponds to the teaching of science (although it is as relative at every stage in the development of science as every stage in the development of religion is relative) that the earth existed prior to any society, prior to man, prior to organic matter, and that it bas existed for a definite time and in a definite space in relation to the other planets. According to Bogdanov, various forms of space and time adapt themselves to man’s experience and his perceptive faculty. As a matter of fact, just the reverse is true: our “experience” and our perception adapt themselves more and more to objective space and time, and reflect them ever more correctly and profoundly.
 Anton von Leclair, Der Realismus der modernen Naturwissenschaft im Lichte der von Berkeley und Kant angebahnten Erkenntniskritik [The Realism of Modern Science in the Light of Berkeley’s and Kant’s Critique of Knowledge], Prag, 1879. —Lenin
 Natural Science, Vol. I, 1892, p. 300. —Lenin
 J. M. Bentley, The Philosophical Review, Vol. VI, 5, Sept. 1897, p. 523. —Lenin
 R. J. Ryle, Natural Science, Aug. 1892, p. 454.] —Lenin
 See F. Engels, Anti-Duhring, Moscov.’, 1959, pp. 76.
 Natural Science—a monthly journal published in London from 1892 to 1899.
 The Philosophical Review—an American journal of an idealist tendency, founded by Jacob Gould Schurman. It began publication in 1892.