ABSTRACT

One of the important criticisms that Marx made of Ricardo, and which applies equally to Sraffa and Postkeynesians, is to suppose the working day has a fixed size. We have already seen that Ricardo explains the origin of profit only as a physical surplus produced by the labourer during the working day thanks to labour productivity realised on the basis of capital. Ricardo actually starts from the value of the means of subsistence necessary to the labourer in order to postulate that a part of the working day is used for replacing the value of these means. But as Marx observes, he never ‘directly show[s] that one part of the labourer’s working day is assigned to the reproduction of the value of his own labour capacity’ (Marx, 1989b: 41). Although it is greatly to Ricardo’s credit to have considered wages in their antagonist relationship to profits, and thus as a social relationship (Marx, 1989b: 54), this does not mean that one fraction can increase only at the expense of the other. Insofar as the working day is a variable size,

both parts can grow, either to an equal or unequal extent. An increase in one is not brought about by a decrease in the other and vice versa. This is moreover the only case in which wages and surplus value, in terms of exchange value, can both increase and possibly even in equal proportions.

(Marx, 1989b: 43–4)