Postmodernism can be described as anything which reminds the viewer that they are watching a performance, that a thing has been constructed by human agency.
Larry Wall argues that postmodernism is more about not seeing any given thing in absolute all-or-nothing terms but rather being able to take it apart (deconstructionism) and re-use just the good bits. This aspect of it shows postmodernism's roots in modernism, which (among other things) embraces the Enlightenment notion of rejecting the need for a feudal lord, rejecting the need for blind fealty to any particular person. Postmodernism takes this a step further by applying this idea to ideas (art, etc.), i.e. we don't have to simplistically evaluate any particular thing as all-good, all-bad, or all-something-in-between; we can take it apart, see what makes it tick, and keep the best parts. In this particular regard, postmodernism is actually rather scientific.
It is often presented by the Right as being synonymous with (or based on) moral relativism, but this is inaccurate. It seems likely that right-wing interests feel a need to attack postmodernism because of the threat it poses to authoritarianism in its deconstruction of items which authority would rather present as inevitable, eternal, and invariant. The idea of noting that something is a performance, a human creation – e.g. a person wrote a piece of scripture, no matter how divinely inspired; people declared its divinity – is fundamentally anti-authoritarian.
- Conservapedia "Postmodernism is an antichristian, far-left, 20th century worldview and academic movement characterized by denial of objective truth, and which asserts that assertions of objective knowledge are essentially impossible." Wow, there's a lot to unpack there...
- 1993-06 How To Deconstruct Almost Anything: "My Postmodern Adventure" by Chip Morningstar