Postmodernism is a movement which began in the social sciences, arts and humanities just after the second world war. Although various postmodernisms differ in intellectual heritage and theoretical perspective, they share in common a sceptical attitude towards the knowability or even existence of any uniform objective realities or criteria of truth, but instead insist on radical relativism. Another shared characteristic of various postmodernisms is that they respond to what Richard Rorty refers to as the "Linguistic Turn", in which language is seen not merely as a tool of an intellectual discipline but constituative of the modes of disciplinary knowledge.
In the arts, postmodernist works and criticism are characterized by self-referentiality. Rather than the artist being an invisible creator, often the artist intrudes into the work or the experience of the audience, and the work itslef, rather than attempting to seamlessly portray a subject, often contains jarring references to or commentaries on its own artificiality, in the form of visible structural elements in qrchitecture, intrusive narration in fiction, or the breaking of the illusion of the proscenium arch in Brecht.
The major philosophical systems of postmodernism divide into the "high theory" or metaphysics of Derrida, Lyotard, Heidegger and Baudrillard, the more historical work of Foucault and Jameson, and the Anglo-Saxon neo-pragmatism of Rorty and Fish.