The owners of commodities entered the sphere of circulation simply as guardians of commodities. Within that sphere they confront each other in the opposite roles of buyer and seller, one as a personified sugar-loaf, the other as personified gold. As soon as the sugar-loaf is turned into gold, the seller becomes a buyer. These definite social functions are no outgrowths of human nature, but are the products of relations of exchange between men who produce their goods in the form of commodities. They are so far from being purely individual relations between buyer and seller that both enter this relation only to the extent that their individual labor is disregarded and is turned into money as labor of _no_ individual. Just as it is, therefore, childish to consider these economic bourgeois roles of buyer and seller as eternal social forms of human individuality, so it is on the other hand, preposterous to lament in them the extinction of individuality.[68] They are the necessary manifestations of individuality at a certain stage of the social system of production. Moreover, in the opposition of buyer and seller the antagonistic nature of capitalistic production is expressed as yet so superficially and as mere matter of form, that this opposition belongs also to precapitalistic forms of society, since it merely requires that the mutual relations of individuals should be those of owners of commodities. Now, if we consider the result of C―M―C, it comes down to mere interchange of matter, C―C. A commodity has been exchanged for a commodity, a use-value for a use-value, and the transformation of the commodity into money, or the commodity in its form of money, serves merely as a means of effecting this interchange of matter. Money thus appears merely as a _medium of exchange_ of commodities; not as a medium of exchange in general, but as a means of exchange in the sphere of circulation, i. e., a _medium of circulation_.[69]