Postmodern and Postmodernism are difficult terms to grasp and having somewhat different significance in architecture, literary criticism and art than in the social sciences.
In social theory postmodern and postmodernism are best seen as a rejection of central assumptions of the modern world or of what has been described as the enlightenment project. This project has had at least two core beliefs.
First is the assumption that modern society will become more democratic and just because of our growing ability to rationally and objectively understand the community's best interests.
Second is the assumption that scientists and social theorists hold a privileged viewpoint since they are taken to operate outside of local interests or bias. Each of these assumptions suggests the possibility of disinterested knowledge, universal truths and social progress.
The late twentieth century writings of Michel Foucault (1929-1984) and Jean Francois Lyotard called these assumption into question. Foucault's work has argued that knowledge and power are always intertwined and that the social sciences, rather than empowering human actors, have made humans into objects of inquiry and have subjected them to knowledge legitimated by the claims of science.
Similarly Lyotard has argued that social theory has always imposed meaning on historical events rather than providing for the understanding of the empirical significance of events.
This rejection of the idea of social and intellectual progress implies that people must accept the possibility of history having no meaning or purpose, abandon the idea that we can know what is or is not true and accept that science can never create and test theories according to universal scientific principles because there is no unitary reality from which such principles can be established.
The clearest signs of a postmodern approach to sociology can be found in social constructionism, ethnomethodology and labeling theory.
The term postmodern can be described as meaning an era after a modern one or of, relating to, or being any of various movements in reaction to modernism that are typically characterized by a return to traditional materials and forms as one notices in architecture or by ironic self-reference and absurdity as one finds in literature. The term postmodern relates to, or involves a radical reappraisal of modern assumptions about culture, identity, history, or language.