Roughly, Hegelian materialism differs from Hegelian orthodoxy by inverting the main logical sequence, not by discarding the logic or resorting to new tests of truth or finality. One might say, though perhaps with excessive crudity, that, where Hegel pronounces his dictum, Das Denken ist das Sein, the materialists, particularly Marx and Engels, would say Das Sein macht das Denken. But in both cases some sort of a creative primacy is assigned to one or the other member of the complex, and in neither case is the relation between the two members a causal relation. In the materialistic conception man's spiritual life—what man thinks—is a reflex of what he is in the material respect, very much in the same fashion as the orthodox Hegelian would make the material world a reflex of the spirit. In both, the dominant norm of speculation and formulation of theory is the conception of movement, development, evolution, progress; and in both the movement is conceived necessarily to take place by the method of conflict or struggle. The movement is of the nature of progress,—gradual advance toward a goal, toward the realisation in explicit form of all that is implicit in the substantial activity involved in the movement. The movement is, further, self-conditioned and self-acting: it is an unfolding by inner necessity. The struggle which constitutes the method of movement or evolution is, in the Hegelian system proper, the struggle of the spirit for self-realisation by the process of the well-known three-phase dialectic. In the materialistic conception of history this dialectical movement becomes the class struggle of the Marxian system.

The class struggle is conceived to be "material," but the term "material" is in this connection used in a metaphorical sense. It does not mean mechanical or physical, or even physiological, but economic. It is material in the sense that it is a struggle between classes for the material means of life. "The materialistic conception of history proceeds on the principle that production and, next to production, the exchange of its products is the groundwork of every social order."[8] The social order takes its form through the class struggle, and the character of the class struggle at any given phase of the unfolding development of society is determined by "the prevailing mode of economic production and exchange." The dialectic of the movement of social progress, therefore, moves on the spiritual plane of human desire and passion, not on the (literally) material plane of mechanical and physiological stress, on which the developmental process of brute creation unfolds itself. It is a sublimated materialism, sublimated by the dominating presence of the conscious human spirit; but it is conditioned by the material facts of the production of the means of life.[9] The ultimately active forces involved in the process of unfolding social life are (apparently) the material agencies engaged in the mechanics of production; but the dialectic of the process—the class struggle—runs its course only among and in terms of the secondary (epigenetic) forces of human consciousness engaged in the valuation of the material products of industry. A consistently materialistic conception, consistently adhering to a materialistic interpretation of the process of development as well as of the facts involved in the process, could scarcely avoid making its putative dialectic struggle a mere unconscious and irrelevant conflict of the brute material forces. This would have amounted to an interpretation in terms of opaque cause and effect, without recourse to the concept of a conscious class struggle, and it might have led to a concept of evolution similar to the unteleological Darwinian concept of natural selection. It could scarcely have led to the Marxian notion of a conscious class struggle as the one necessary method of social progress, though it might conceivably, by the aid of empirical generalisation, have led to a scheme of social process in which a class struggle would be included as an incidental though perhaps highly efficient factor.[10] It would have led, as Darwinism has, to a concept of a process of cumulative change in social structure and function; but this process, being essentially a cumulative sequence of causation, opaque and unteleological, could not, without an infusion of pious fancy by the speculator, be asserted to involve progress as distinct from retrogression or to tend to a "realisation" or "self-realisation" of the human spirit or of anything else. Neither could it conceivably be asserted to lead up to a final term, a goal to which all lines of the process should converge and beyond which the process would not go, such as the assumed goal of the Marxian process of class struggle, which is conceived to cease in the classless economic structure of the socialistic final term. In Darwinism there is no such final or perfect term, and no definitive equilibrium.

The disparity between Marxism and Darwinism, as well as the disparity within the Marxian system between the range of material facts that are conceived to be the fundamental forces of the process, on the one hand, and the range of spiritual facts within which the dialectic movement proceeds,—this disparity is shown in the character assigned the class struggle by Marx and Engels. The struggle is asserted to be a conscious one, and proceeds on a recognition by the competing classes of their mutually incompatible interests with regard to the material means of life. The class struggle proceeds on motives of interest, and a recognition of class interest can, of course, be reached only by reflection on the facts of the case. There is, therefore, not even a direct causal connection between the material forces in the case and the choice of a given interested line of conduct. The attitude of the interested party does not result from the material forces so immediately as to place it within the relation of direct cause and effect, nor even with such a degree of intimacy as to admit of its being classed as a tropismatic, or even instinctive, response to the impact of the material force in question. The sequence of reflection, and the consequent choice of sides to a quarrel, run entirely alongside of a range of material facts concerned.

A further characteristic of the doctrine of class struggle requires mention. While the concept is not Darwinian, it is also not legitimately Hegelian, whether of the Right or the Left. It is of a utilitarian origin and of English pedigree, and it belongs to Marx by virtue of his having borrowed its elements from the system of self-interest. It is in fact a piece of hedonism, and is related to Bentham rather than to Hegel. It proceeds on the grounds of the hedonistic calculus, which is equally foreign to the Hegelian notion of an unfolding process and to the post-Darwinian notions of cumulative causation. As regards the tenability of the doctrine, apart from the question of its derivation and its compatibility with the neo-Hegelian postulates, it is to be added that it is quite out of harmony with the later results of psychological inquiry,—just as is true of the use made of the hedonistic calculus by the classical (Austrian) economics.

Within the domain covered by the materialistic conception, that is to say within the domain of unfolding human culture, which is the field of Marxian speculation at large, Marx has more particularly devoted his efforts to an analysis and theoretical formulation of the present situation,—the current phase of the process, the capitalistic system. And, since the prevailing mode of the production of goods determines the institutional, intellectual, and spiritual life of the epoch, by determining the form and method of the current class struggle, the discussion necessarily begins with the theory of "capitalistic production," or production as carried on under the capitalistic system.[11]

Under the capitalistic system, that is to say under the system of modern business traffic, production is a production of commodities, merchantable goods, with a view to the price to be obtained for them in the market. The great fact on which all industry under this system hinges is the price of marketable goods. Therefore it is at this point that Marx strikes into the system of capitalistic production, and therefore the theory of value becomes the dominant feature of his economics and the point of departure for the whole analysis, in all its voluminous ramifications.[12]

It is scarcely worth while to question what serves as the beginning of wisdom in the current criticisms of Marx; namely, that he offers no adequate proof of his labor-value theory.[13] It is even safe to go farther, and say that he offers no proof of it. The feint which occupies the opening paragraphs of the Kapital and the corresponding passages of Zur Kritik, etc., is not to be taken seriously as an attempt to prove his position on this head by the ordinary recourse to argument. It is rather a self-satisfied superior's playful mystification of those readers (critics) whose limited powers do not enable them to see that his proposition is self-evident. Taken on the Hegelian (neo-Hegelian) ground, and seen in the light of the general materialistic conception, the proposition that value = labor-cost is self-evident, not to say tautological. Seen in any other light, it has no particular force.

In the Hegelian scheme of things the only substantial reality is the unfolding life of the spirit. In the neo-Hegelian scheme, as embodied in the materialistic conception, this reality is translated into terms of the unfolding (material) life of man in society.[14] In so far as the goods are products of industry, they are the output of this unfolding life of man, a material residue embodying a given fraction of this forceful life-process. In this life-process lies all substantial reality, and all finally valid relations of quantivalence between the products of this life-process must run in its terms. The life-process, which, when it takes the specific form of an expenditure of labor power, goes to produce goods, is a process of material forces, the spiritual or mental features of the life-process and of labor being only its insubstantial reflex. It is consequently only in the material changes wrought by this expenditure of labor power that the metaphysical substance of life—labor power—can be embodied; but in these changes of material fact it cannot but be embodied, since these are the end to which it is directed.

This balance between goods in respect of their magnitude as output of human labor holds good indefeasibly, in point of the metaphysical reality of the life-process, whatever superficial (phenomenal) variations from this norm may occur in men's dealings with the goods under the stress of the strategy of self-interest. Such is the value of the goods in reality; they are equivalents of one another in the proportion in which they partake of this substantial quality, although their true ratio of equivalence may never come to an adequate expression in the transactions involved in the distribution of the goods. This real or true value of the goods is a fact of production, and holds true under all systems and methods of production, whereas the exchange value (the "phenomenal form" of the real value) is a fact of distribution, and expresses the real value more or less adequately according as the scheme of distribution in force at the given time conforms more or less closely to the equities given by production. If the output of industry were distributed to the productive agents strictly in proportion to their shares in production, the exchange value of the goods would be presumed to conform to their real value. But, under the current, capitalistic system, distribution is not in any sensible degree based on the equities of production, and the exchange value of goods under this system can therefore express their real value only with a very rough, and in the main fortuitous, approximation. Under a socialistic régime, where the laborer would get the full product of his labor, or where the whole system of ownership, and consequently the system of distribution, would lapse, values would reach a true expression, if any.

Under the capitalistic system the determination of exchange value is a matter of competitive profit-making, and exchange values therefore depart erratically and incontinently from the proportions that would legitimately be given them by the real values whose only expression they are. Marx's critics commonly identify the concept of "value" with that of "exchange value,"[15] and show that the theory of "value" does not square with the run of the facts of price under the existing system of distribution, piously hoping thereby to have refuted the Marxian doctrine; whereas, of course, they have for the most part not touched it. The misapprehension of the critics may be due to a (possibly intentional) oracular obscurity on the part of Marx. Whether by his fault or their own, their refutations have hitherto been quite inconclusive. Marx's severest stricture on the iniquities of the capitalistic system is that contained by implication in his development of the manner in which actual exchange value of goods systematically diverges from their real (labor-cost) value. Herein, indeed, lies not only the inherent iniquity of the existing system, but also its fateful infirmity, according to Marx.