seen from our examination of the "experiences" of the exchange relation that there is some residuum of usefulness, general usefulness to society, which plays some role in it. We have seen both as a matter of logic and of experience that it is not, nor could it be, either the cause or the measure of value. What, then, is its role? True to himself, Marx would not leave any actual fact unaccounted for. It is absolutely untrue that Marx disregards usefulness as a factor of value. Notwithstanding the fact that this is assumed by every critic of the Marxian theory of value, it is absolutely and unqualifiedly untrue, and is only one additional link in the long chain of proof that an absolute lack of understanding of the Marxian doctrine seems to be the first qualification of a modern Marx-critic.
General, social usefulness has some influence on exchange-value. It is not its cause nor its measure. What is it? It is its limitation. The facts of exchange, the "experiences" of the "exchange-relation," prove that general, social usefulness, the only usefulness which plays any part in the exchange of commodities under our capitalistic system, is neither the cause nor the measure of exchange-value, but its limitation. And this is borne out by Marx's very "logical" analysis, which so much aroused the ire and indignation of Böhm-Bawerk that he almost forgot the respectful attitude which he usually assumes towards Marx. This result of experience and analysis is one of the main features of Marx's theory of value, that feature which more than any other, stamps it as peculiarly his own. We have already seen that, according to Marx, it is not every labor that creates value, but socially necessary labor. We have also seen already that Marx's conception of "socially necessary" includes the general as well as the relative usefulness of the commodity to society. That is why, according to the Marxian theory, the value of a commodity is not measured by the labor actually contained in a commodity, but the labor socially necessary to reproduce it. In the last chapter we have seen the historical basis of Marx's theoretical conclu-
