"Now the leap by which this reasoning lands us in labour as the sole constituent element of value appears to me so surprising that I am prepared to learn that the yet unpublished portions of Das Kapital contain supplementary or elucidatory matter which may set it in a new light. Meanwhile the analysis appears to be given as complete and adequate, so far as it goes, and I can, therefore, only take it as I find it and try to test its validity. But instead of directly confronting it with what seems to be the true analysis of the phenomenon of exchange, I will follow it out a little further, and we shall see that Marx himself introduces a modification into his result (or develops a half-latent implication in it), in such a way as to vitiate the very analysis on which that result is founded, and to lead us, if we work it out, to what I regard as the true solution of the problem."