That is what Marx tells us. And there is no apparent reason why we should not take him at his word. In fact, while reading Capital we can prove that his economic analyses do depend on these basic concepts in the last instance. We can, so long as our reading is a careful one. But this proof is not self-evident. It presupposes a great struggle for rigour – and above all it necessarily implies from the beginning something which is present in Marx’s declared discoveries – but present in a strange absence – if we are to complete this proof and see clearly in the very clarity it produces.
As an index which gives a negative foretaste of this absence, one comment will do: the concepts to which Marx expressly relates his discovery and which underlie all his economic analysis, the concepts of value and surplus-value, are precisely the concepts on which all the criticism addressed to Marx by modern economists has focused. It is not immaterial to know in what terms these concepts have been attacked by non-Marxist economists. Marx has been criticized on the grounds that they are concepts which, although they make allusion to economic reality, remain at heart non-economic, ‘philosophical’ and ‘metaphysical’ concepts. Even as enlightened an economist as Conrad Schmidt – who was intelligent enough to deduce the law of the tendency of the rate of profit to fall from Volume Two of Capital soon after its publication, even though that law was first expounded in Volume Three – even Conrad Schmidt attacked Marx’s law of value as a ‘theoretical fiction’, a necessary one no doubt, but a fiction all the same. I do not quote these criticisms for fun, but because they are directed at the very foundation of Marx’s economic analyses, the concepts of value and surplus-value, which are rejected as ‘non-operational’ concepts designating realities which are non-economic because they are non-measurable, non-quantifiable. Obviously, this reproach in its own way betrays the conception the economists in question have of their own object, and of the concepts it authorizes: but if this reproach does show us the point in which their opposition to Marx is at its most palpable, these economists do not give us Marx’s object in their reproach, precisely because they treat that object as ‘metaphysical’. However, I indicate this point as the point of misunderstanding, the point where the Economists misconstrue Marx’s analyses. But this misunderstanding in their reading was only possible because of a misunderstanding of Marx’s object itself: a misunderstanding that made the Economists read their own object into Marx, instead of reading another object in Marx which is not their own object but a quite different one. This point of misunderstanding which the Economists declare the point of Marx’s theoretical weakness and error is, on the contrary, the point at which he is strongest! the point which marks him off radically from his critics, and also, on occasion, from some of his closest followers.