"Once these ‘relations of production’ are taken for granted, there is of course no reason why one may not theorize effectively on the economic level or elucidate the ‘economic history’ of the lands and epochs where such relations have prevailed. But this is just why the historian who wants to be a Marxist will refuse to confine himself within ‘economic history’ (except to study this or that case empirically). I have said onother occasions and I will maintain that so-called ‘quantitative histories’ are nothing but retrospective econometrics, and that the ‘New Economic History’ cannot measure the realm of Clio. As Colin Clark has stated, history stands ‘higher up’ in the hierarchy of the sciences than economics, because it contains the latter. Fidelity to Marx demands that one add: and because it cannot be divided."
— Pierre Vilar - Marxist History, a History in the Making: Towards a Dialogue with Althusser.