Awareness of the inconsistency, incompleteness, and one-sidedness of the old materialism led Marx to the conviction of the necessity "to harmonize the science of society with the materialist foundation and to reconstruct it accordingly"{61}. If materialism generally explains consciousness from being, and not the reverse, then when applied to the social life of mankind, materialism demanded an explanation of social consciousness from social being. "Technology," says Marx (Capital, Vol. I), "reveals man's active relation to nature, the direct process of his life production, and with it also his social life and the spiritual ideas flowing from it"{62}. Marx gave a complete formulation of the fundamental propositions of materialism, extended to human society and its history, in the preface to his work Critique of Political Economy in the following words:

"In the social production of their existence, men enter into definite, necessary relations that are independent of their will – production relations that correspond to a definite stage of development of their material productive forces.

The sum total of these production relations constitutes the economic structure of society, the real base, on which rises a legal and political superstructure and to which correspond definite forms of social consciousness. The mode of production of material life conditions the social, political and intellectual life process in general. It is not the consciousness of men that determines their existence, but, on the contrary, their social existence that determines their consciousness. At a certain stage of development, the material productive forces of society come into conflict with the existing relations of production, or – what is only a legal expression for the same thing – with the property relations within which they have been at work hitherto. From forms of development of the productive forces these relations turn into their fetters. Then begins an era of social revolution. With the change of the economic foundation the entire immense superstructure is more or less rapidly transformed. In considering such transformations a distinction should always be made between the material, economically defined transformation of the conditions of production, and the legal, political, religious, artistic or philosophic – in short, ideological forms in which men become conscious of this conflict and fight it out.

Just as one cannot judge an individual on the basis of what he thinks of himself, just so one cannot judge such a period of transformation by its consciousness; on the contrary, this consciousness must be explained from the contradictions of material life, from the conflict between the social productive forces and the relations of production... As to the various forms of property, the progression has been: Asiatic, ancient, feudal, and modern bourgeois, which can be designated as progressive epochs in the economic formation of society"{63}. (Compare Marx's brief formulation in his letter to Engels of July 7, 1866: "Our theory that organization of labor by means of productive capital"{64}.)

The discovery of the materialist conception of history, or more precisely, the consistent development and extension of materialism to the domain of social phenomena, removed two fundamental defects of the earlier historical theories. First, those theories at best examined only the ideological motives of the historical activity of men, without investigating what gave rise to those motives, without grasping the objective regularity in the development of the system of social relations, without discovering the roots of these relations in the degree of development of material production; second, the earlier theories did not embrace the actions of the masses of the population, whereas historical materialism for the first time made it possible, with natural-historical accuracy, to investigate the social conditions of the life of the masses and the changes in those conditions. Pre-Marxist "sociology" and historiography at best gave an accumulation of raw facts haphazardly collected and descriptions of separate aspects of the historical process. Marxism pointed out the way to a comprehensive, many-sided investigation of the process of the origin, development, and decline of socio-economic formations, by studying the totality of all contradictory tendencies, reducing them to precisely determinable conditions of life and production of various classes of society, eliminating subjectivism and arbitrariness in the selection of individual "dominant" ideas or in their interpretation, revealing the roots of all ideas and all varied tendencies without exception in the condition of the material productive forces. Men make their own history, but what determines the motives of men and precisely of the masses of men, what gives rise to the clash of contradictory ideas and strivings, what is the aggregate of all such clashes of all masses of human societies, what are the objective conditions of production of material life creating the base of all historical activity of men, what is the law of development of these conditions – to all this Marx directed attention and pointed out the way to scientific investigation of history as a unified, law-governed process in all its tremendous multiformity and contradictoriness.