In the interest of providing some sense of the range of the debate surrounding postmodernism, a debate which is central to much current thinking on hypertext, here is a definition provided by James Morley. It appears here as it was posted on the Postmodern Culture electronic conference list.
What is postmodernism?
Firstly, postmodernism was a movement in architecture that rejected the modernist, avant garde, passion for the new. Modernism is here understood in art and architecture as the project of rejecting tradition in favour of going "where no man has gone before" or better: to create forms for no other purpose than novelty. Modernism was an exploration of possibilities and a perpetual search for uniqueness and its cognate--individuality. Modernism's valorization of the new was rejected by architectural postmodernism in the 50's and 60's for conservative reasons. They wanted to maintain elements of modern utility while returning to the reassuring classical forms of the past. The result of this was an ironic brick-a-brack or collage approach to construction that combines several traditional styles into one structure. As collage, meaning is found in combinations of already created patterns.
Following this, the modern romantic image of the lone creative artist was abandoned for the playful technician (perhaps computer hacker) who could retrieve and recombine creations from the past--data alone becomes necessary. This synthetic approach has been taken up, in a politically radical way, by the visual, musical,and literary arts where collage is used to startle viewers into reflection upon the meaning of reproduction. Here, pop-art reflects culture (American). Let me give you the example of Californian culture where the person--though ethnically European, African, Asian, or Hispanic--searches for authentic or "rooted" religious experience by dabbling in a variety of religious traditions. The foundation of authenticity has been overturned as the relativism of collage has set in. We see a pattern in the arts and everyday spiritual life away from universal standards into an atmosphere of multidimentionality and complexity, and most importantly--the dissolving of distinctions. In sum, we could simplistically outline this movement in historical terms:
1. premodernism: Original meaning is possessed by authority (for example, the Catholic Church). The individual is dominated by tradition.
2. modernism: The enlightenment-humanist rejection of tradition and authority in favour of reason and natural science. This is founded upon the assumption of the autonomous individual as the sole source of meaning and truth--the Cartesian cogito. Progress and novelty are valorized within a linear conception of history--a history of a "real" world that becomes increasingly real or objectified. One could view this as a Protestant mode of consciousness.
3. postmodernism: A rejection of the sovereign autonomous individual with an emphasis upon anarchic collective, anonymous experience. Collage, diversity, the mystically unrepresentable, Dionysian passion are the foci of attention. Most importantly we see the dissolution of distinctions, the merging of subject and object, self and other. This is a sarcastic playful parody of western modernity and the "John Wayne" individual and a radical, anarchist rejection of all attempts to define, reify or re-present the human subject.