The theory of surplus value

Although much of Capital is concerned with economic analysis, Marx's overriding interest in the work is always in the dynamics of bourgeois society: the primary object of Capital is to disclose the ‘economic law of motion’ of this society, through an examination of the dynamics of the productive foundation upon which it rests.

Capitalism, as Marx emphasises on the first page of Capital, is a system of commodity production. In the capitalist system producers do not simply produce for their own needs, or for the needs of individuals with whom they are in personal contact; capitalism involves a nation-wide, and often an international, exchange-market. Every commodity, Marx states, has a ‘two-fold’ aspect: its ‘use-value’, on the one hand, and its ‘exchange-value’ on the other. Use-value, which ‘is realised only in the process of consumption’, has reference to the needs which the properties of a commodity as a physical artifact can be employed to cater to. An object can have use-value whether or not it is a commodity; while to be a commodity a product must have use-value, the reverse does not hold. ‘Exchange-value’ refers to the value a product has when offered in exchange for other products. In contrast to use-value, exchange-value presupposes ‘a definite economic relation’, and is inseparable from a market on which goods are exchanged; it only has meaning in reference to commodities.