This intervention concerns the different statute of abstraction in Marx's work. By means of a critical confrontation with Chris Arthur's work, Finelli presents his thesis of the presence of a double theory and fuction of abstraction in Marx's work. In the early Marx, until the German Ideology, abstraction is, in accordance with the traditional meaning of this term, a product of the mind, an unreal spectre. More exactly, it consists in negating the common essence belonging to labouring humanity and projecting it, as alienated universal, into the idea of philosophy, into the state of politics and into the money of the market. In the later Marx, the nature of abstraction is, rather than mental, practical. It is directly related to the quantity without quality of capitalist labour, and it is the product of the systemic connection of machines to labour-power. In contrast to Arthur, Finelli maintains that practical abstraction in the Marx of Capital is not located in the zone of exchange and the market, where there is the mediation of money. On the contrary, it is located in the zone of production, which, for Marx, is a social ensemble not mediated by money but by relations of technological domination.