From a social point of view, the working-class is just as much an appendage of capital as the ordinary instruments of labour. The appearance of independence is kept up by means of a constant change of employers, and by the legal fiction of a contract. In former times capital legislatively enforced its proprietary rights over the free labourer. Capitalist production reproduces and perpetuates the condition for exploiting the labourer. The economical bondage of the labourer is both caused and hidden by the periodic sale of himself to changing masters. Capitalist production, under its aspect of a continuous connected process, produces not only commodities, not only surplus value, but it also produces and reproduces the capitalist relation; on the one side the capitalist, on the other the wage-labourer. Capital pre-supposes wage-labour, and wage-labour pre-supposes capital. One is a necessary condition to the existence of the other. The two mutually call each other into existence. Does an operative in a cotton-factory produce nothing but cotton goods? No, he produces capital. He produces values that give fresh command over his labour, and that, by means of such command, create fresh values. Every individual capital is a larger or smaller concentration of means of production, with a corresponding command over a larger or smaller labour-army. Every accumulation becomes the means of new accumulation. The growth of social capital is affected by the growth of many individual capitals. With the accumulation of capital, therefore, the number of capitalists grows to a greater or less extent. Two points characterise this kind of concentration which grows directly out of, or rather is identical with, accumulation. First, the increasing concentration of the social means of production in the hands of individual capitalists is, other things remaining equal, limited by the degree of increase of social wealth. Secondly, the part of social capital domiciled in each particular sphere of production is divided among many capitalists who face one another as independent commodity-producers competing with each other. Accumulation and the concentration accompanying it are, therefore, not only scattered, but the increase of each functioning capital is thwarted by the formation of new and the subdivision of old capitals. Accumulation, therefore, presents itself on the one hand as increasing concentration of the means of production and of the command over labour; on the other, as repulsion of many individual capitalists one from another. JOHN STUART MILL Principles of Political Economy