UNDIFFERENTIATION BY IDENTITY: FROM HISTORY AND CLASS CONSCIOUS-NESS TO DIALECTIC OF ENLIGHTENMENTA central statement in classical and contemporary sociological theory is one that conceives the modernization of societies as a rupture in relation to a pre-modernity totalized by myth and religion and, as a consequence, the growing closure of the orders, spheres or subsystems of society in their inherent legalities or intrinsic and intransitive codes. This article intends to make a reading of the tradition that goes from the reification (Lukács) to the identity promoted by the instrumental rationality (Adorno and Horkheimer) as a radical critique to that imaginary in the measure in which it conceives the constitution of a new form of undifferentiation in the way of capitalist modernity.