Jürgen Habermas

Habermas was born in Düsseldorf and grew up in Gummersbach, where his father directed the chamber of commerce and was a Nazi party member. Born with a cleft palate and operated on repeatedly, he spoke with difficulty, which he later said made him unusually alert to the fragility of, and dependence on, communication. At fifteen he was in the Hitler Youth; the Nuremberg trials and the films of the camps in 1945 made that year the lifelong starting point of his thought. He studied philosophy at Göttingen, Zurich and Bonn and took his doctorate in 1954 on Schelling.

In 1953 he drew notice by criticising in the press Heidegger's reprinting of his 1935 lectures without comment. In 1956 he became Adorno's assistant, and in 1961, Horkheimer judging him too far left, qualified to teach at Marburg with The Structural Transformation of the Public Sphere, which argued that the eighteenth-century coffee house, salon and press formed a sphere in which citizens reasoned about public affairs, later eroded by mass media and the welfare state. In 1964 he succeeded Horkheimer as professor of philosophy and sociology at Frankfurt; in 1968 he denounced the student movement's 'left fascism' and broke with it.

From 1971 to 1983 he directed a Max Planck institute near Munich and wrote the two volumes of The Theory of Communicative Action (1981). Drawing on Weber, Durkheim, Mead, Parsons and speech-act theory, it distinguished strategic action aimed at success from communicative action aimed at understanding, argued that language itself raises validity claims to truth, rightness and sincerity, and located reason not in the subject's consciousness but in communication between subjects. The pathology of modern society is the colonisation of the 'lifeworld' by 'system', that is by money and power. In 1983 he returned to Frankfurt and taught until retiring in 1994.

The Philosophical Discourse of Modernity (1985) struck back at Foucault, Derrida and Lyotard, defending modernity as an 'unfinished project'. In 1986 he launched the 'historians' dispute' against attempts to relativise the Nazi past. Between Facts and Norms (1992) built a discourse theory of law and democracy: legitimate law is law that citizens could agree to in public deliberation. He went on to write on dialogue between religion and secular reason, a European constitution, genetic technology and the post-national constellation, and after ninety published a two-volume history of philosophy. He has spoken in every major public controversy in Germany, the most enduring voice of critical theory in his generation.