state that he intends in a later work to put before the public some matters which will, in his opinion, put the whole subject in a new light. Those matters are, however, not specifically treated by Marx, and as the present work is merely intended to present the Marxian theory as stated by Marx, and the criticism of the theory as so stated, no reference will be made to them here, except to say that their net result does not in any way change the Marxian theory as here outlined, but amplifies it.
The Contradiction was first formulated and placed before the public in a somewhat sensational manner by Frederick Engels himself. In his preface to the second volume of Capital, published in 1884, after the death of Karl Marx, Engels challenged those Marxian critics of that day who had declared that Marx said nothing that was new, and that all the wisdom contained in Capital had already been promulgated before by Rodbertus (from whom Marx was supposed by them to have borrowed his theory of value), to explain "how an equal average rate of profit can and must be formed, not only without injury to the law of value, but really by reason thereof." He argued that if Marx said nothing new and his theory of value is no different than that of Rodbertus, these critics ought to be able to do that by the aid of Robertus' writings as supplemented by Marx's. This had the effect of setting a host of men to solving the problem. Most of those who attempted to accomplish the task were, however, not the Marx-critics to whom the challenge was directed, but disciples of Marx who went about the business not on the basis of Rodbertus' writings, which had very little to offer towards the solution of the problem, but on the basis of the laws of value as laid down by Marx in the first volume of Capital. It was the ambition of these writers to forestall the solution which Engels promised would be given by Marx himself in the third volume. In his preface to the third volume, published by him in 1894, Engels reviews the various efforts at solving this problem, and comes to the conclusion that
