Private Labour, the labour of isolated, outwardly independent commodity producers. Private ownership of the means of production is the foundation of private labour. It separates people, making the labour of an individual commodity producer his private affair. However, the social division of labour and the exchange of the products of labour between private producers reveal the inner links between outwardly independent private producers, exposing the social character of their private labour. The labour of every commodity producer is both private and social. So, in commodity production, labour is not directly socialised on the surface, but socialised in a concealed way. The social character of labour is revealed only in the process of the purchase and sale of commodities. In the process of exchange, the producer learns whether his commodity is in demand and what its value is. If the product created by private labour is not sold as a commodity because there is no demand for this use value or because it is overly expensive, it means that society does not recognise the private labour of the commodity producer. The contradiction between private and social labour is the principal contradiction of simple commodity production, and its moving force. Under capitalism, the contradiction between private and social labour deepens, and that between the social character of production and the private capitalist form of appropriating the results of labour becomes the main contradiction (see Basic Contradiction of Capitalism).