The task of a critical theory of society is to make visible the colonization and fragmentation processes which lead to distorted communication and to barriers to effective (political) action. Such a theory is however not very illuminating about the practical dimensions of how to go about — in concrete political contexts — organizing the processes of enlightenment, the selection of appropriate strategies, the solution of tactical questions, and the conduct of social and political struggle. Science therefore has to be very modest and careful in making recommendations. Theory can support counsellors with critical analysis of the contexts and conditions of the lives and problems of their clients, as well as of their own professional situation. It can for instance clarify the conditions for communication and intersubjectivity and describe and explain the structural and material conditions which prevent free symbolic interaction or unconstrained communication from taking place. But this assessment of the relation between theory and practice jeopardizes all those who believe in the rather unproblematic nature of applied sciences. We make no attempt to survey the various contributions to this debate, but restrict ourselves to presenting important aspects of the work of one of the most active actual adherers of critical theory: Jürgen Habermas.