Starting from the doctrine of ideology proposed by Destutt de Tracy in the late eighteenth century, the paper reconstructs its historical relationship with the social science, of which it was originally meant to be the ultimate expression. The historical necessity of ideology as a political science of the social is found in its ability to mediate and legitimize power relationships. It is not for chance that the Marxian critique of ideology is a radical critique of the constitution of power in a capitalist society. The attempt of the social science to neutralize the problem of power through the abandonment of the value judgments leads instead to the declaration of the end of ideologies. In the last part, the paper analyses the way in which i...