The study focuses on the analysis of principle post-modern theories, on their major scholar, such as Walter Benjamin, Jürgen Habermas, Francois Lyotard- and their correlation with social theory. The work is twofold : traditional critic of ideology as sociology of lie on the one hand, sociology of knowledge as sociology of truth on the other. The first deals with constitutive assumptions of Marxism, the second takes a critic about relation between economic liberalism and post-modern thinking. Through Habermas and the idea of modernity as unfinished historical project I see in No-global social movements the claim of an active role of ideologies.