us finally take labor carried on in common in its primitive natural form, as we find it at the dawn of history of all civilized races.4 It is clear that in this case labor does not acquire its social character from the fact that the labor of the individual takes on the abstract form of universal labor or that his product assumes the form of a universal equivalent. The very nature of production under a communal system makes it impossible for the labor of the individual to be private labor and his product to be a private product; on the contrary, it makes individual labor appear as the direct function of a member of a social organism. On the contrary, labor, which is expressed in exchange value, at once appears as the labor of a separate individual. It becomes social labor only by taking on the form of its direct opposite, the form of abstract universal labor.
Labor, which creates exchange value, is, finally, characterized by the fact that even the social relations of men appear in the reversed form of a social relation of things. Only in so far as two use-values are in a mutual relation of exchange values does the labor of different persons possess the common property of being identical universal labor. Hence, if it be correct to say that exchange value is a relation between persons,5 it must be added that it is a relation disguised under a material cover. Just as a pound of iron and a pound of gold represent the same weight in spite of their different physical and chemical properties, so do two use-values, as commodities containing the same quantity of labor-time, represent the same exchange value. Exchange value thus appears as the natural social destination of use-values, a property which they possess by virtue of being things and in consequence of which they are exchanged for one another in definite proportions, or form equivalents, just as chemical elements combine in certain proportions, forming chemical equivalents. It is only through the habit of everyday life that we come to think it perfectly plain and commonplace, that a social relation of production should take on the form of a thing, so that the relation of persons in their work appears in the form of a mutual relation between things, and between things and persons.