[...] Interest, in the restricted sense it is given in economic theory, cannot be produced without producing its negative counterpart, disinterestedness. The class of practices whose explicit purpose is to maximize monetary profit cannot be defined as such without producing the purposeless finality of cultural or artistic practices and their products; the world of bourgeois man, with his double-entry accounting, cannot be invented without producing the pure, perfect universe of the artist and the intellectual and the gratuitous activities of art-for-art's sake and pure theory. In other words, the constitution of a science of mercantile relationships which, inasmuch as it takes for granted the very foundations of the order it claims to analyze---private property, profit, wage labor, etc.---is not even a science of the field of economic production, has prevented the constitution of a general science of the economy of practices, which would treat mercantile exchange as a particular case of exchange in all its forms.