Labour is not a uniform and homogeneous quantity. Between various types of labour there is necessarily a qualitative difference, which leads to a different valuation according to the difference in the conditions of demand for and supply of their products. For instance, the supply of pictures cannot be increased, ceteris paribus, without damage to the quality of the product. Yet one cannot allow the labourer who had put in an hour of the most simple type of labour to be entitled to the product of an hour's higher type of labour. Hence, it becomes utterly impossible in any socialist community to posit a connection between the significance to the community of any type of labour and the apportionment of the yield of the communal process of production. The remuneration of labour cannot but proceed upon an arbitrary basis; it cannot be based upon the economic valuation of the yield as in a competitive state of society, where the means of production are in private hands, since—as we have seen—any such valuation is impossible in a socialist community. Economic realities impose clear limits to the community's power of fixing the remuneration of labour on an arbitrary basis: in no circumstances can the sum expended on wages exceed the income for any length of time.