Jean-François Lyotard (1924–1998) was born at Versailles, wrote political essays with Cornelius Castoriadis in the Marxist group Socialisme ou Barbarie in the early 1950s, and moved away from Marxist analysis after May 1968. In the early 1970s his attention turned to aesthetics and theories of language; in 1979, asked by the Conseil des universités du Québec for 'a report on the condition of knowledge in advanced societies', he wrote La condition postmoderne. More a compact diagnosis than an academic essay, the book became, after its English translation, the recognised source of the term 'postmodern'.

Lyotard's central thesis can be put in one sentence: 'I define postmodern as incredulity toward metanarratives.' Modernity, on his account, legitimated itself by leaning on two great stories: the progressive emancipation of reason and freedom (the Enlightenment narrative), and the speculative unity of total knowledge (the German Idealist narrative). At the end of the twentieth century — after Auschwitz, the Stalinist camps, and technoscience — these grand narratives can no longer be believed. In their place come 'little narratives', local legitimations, parallel language games; Wittgenstein's plural language games are the philosophical vehicle.

Lyotard does not say 'everything is relative'; he says the legitimation of knowledge has shifted, and that science itself is now judged within techno-capital flows by a criterion of 'performative efficiency'. The book became a shared reference for architecture (Charles Jencks), literary criticism, law, and political theory. Habermas' counter-thesis that 'modernity is an unfinished project', delivered in the 1980 Adorno lecture, is aimed directly at Lyotard; the shape of the postmodernity debate over two generations was set by this confrontation.