Postmodernism is a late-20th-century movement in the arts, architecture, and criticism that was a departure from modernism.Postmodernism includes skeptical interpretations of culture, literature, art, philosophy, history, economics, architecture, fiction, and literary criticism.ostmodern music is either music of the postmodern era, or music that follows aesthetic and philosophical trends of postmodernism. As the name suggests, the postmodernist movement formed partly in reaction to the ideals of the modernist.