The expansion of value, which is the objective basis or main-spring of the circulation M-C-M, becomes his subjective aim, and it is only in so far as… - Paul Sweezy

Under simple commodity production, to which we have so far largely confined our attention, each producer owns and works with his own means of production; under capitalism ownership of the means of production is vested in one set of individuals while the work is performed by another. Both means of production and labor power, moreover, are commodities; that is to say, both are objects of exchange and hence bearers of exchange value. It follows that not only the relations among owners but also the relations between owners and non-owners have the character of exchange relations. The former is characteristic of commodity production in general, the latter of capitalism only.

In possessing use value a commodity is in no way peculiar. Objects of human consumption in every age and in every form of society likewise possess use value. Use value is an expression of a certain relation between the consumer and the object consumed. Political economy, on the other hand, is a social science of the relations between people.

Most people take capitalism for granted, just as they take the solar system for granted. The eventual passing of capitalism, which is often conceded nowadays, is thought of in much the same way as the eventual cooling of the sun, that is to say, its relevance to contemporary events is denied.