According to Lacan, it was none other than Karl Marx who invented the notion of symptom. Is this Lacanian thesis just a sally of wit, a vague analogy, or does it possess a pertinent theoretical foundation? If Marx really articulated the notion of the symptom as it is also at work in the Freudian field, then we must ask ourselves the Kantian question concerning the epistemological 'conditions of possibility' of such an encounter: how was it possible for Marx, in his analysis of the world of commodities, to produce a notion which applies also to the analysis of dreams, hysterical phenomena, and so on?
The answer is that there is a fundamental homology between the interpretative procedure of Marx and Freud -- more precisely, between their analysis of commodity and of dreams. In both cases the point is to avoid the properly fetishistic fascination of the 'content' supposedly hidden behind the form: the 'secret' to be unveiled through analysis is not the content hidden by the form (the form of commodities, the form of dreams) but, on the contrary, the 'secret' of this form itself. The theoretical intelligence of the form of dreams does not consist in penetrating from the manifest content to its 'hidden kernel', to the latent dream-thoughts; it consists in the answer to the question: why have the latent dream-thoughts assumed such a form, why were they transposed into the form of a dream? It is the same with commodities: the real problem is not to penetrate to the 'hidden kernel' of the commodity -- the determination of its value by the quantity of the work consumed in its production -- but to explain why work assumed the form of the value of a commodity, why it can affirm its social character only in the commodity-form of its product.