H Habermas, Jiirgen (b. 1929) German philosopher devoted to the development of a critical theory of society grounded in language and interaction. Associated early in his career with the Frankfurt School of critical theory, Habermas is an eclectic thinker who draws on Marxism, hermeneutics, Freudian psychoanalysis, speech-act theory, and critical theory to suggest a theory of emancipation from domination. His theory has evolved in the course of his writings, which include, among others, Knowledge and Human Interests, Theory and Practice, Communication and the Evolution of Society, The Theory of Communicative Action (two volumes), and On the Logic of the Social Sciences. His theory can be conceptualized as a four-tiered model that encompasses epistemology, individual language use, communicative action, and critical theory.