Postmodernism is a political ideology that developed in the late 20th century. It is characterized by subjectivism and relativism—a deconstruction of the Age of Enlightenment ideas of reason and objectivity—with the root idea being "everything is a social construct". It can be thought of more as a strategy for asserting political and economic power.

 Jacques Derrida, French postmodernist philosopher

Jacques Derrida, French postmodernist philosopher

Jordan Peterson discusses this post-logic and post-discussion political cult of postmoderism, which is spreading across the United States, Canada, and Europe...

I'd also recommend this detailed history and analysis of postmodernism by Stephen Hicks...



Postmodernism. Encyclopedia Britannica (summary). 

Hicks, S. (2004). Explaining Postmodernism: Skepticism and Socialism from Rousseau to Foucault. Ockham's Razor.

For the writings of the individual philosophers see Jacques DerridaMichel FoucaultJean Baudrillard and Jean-François Lyotard.