Quora Answer : What makes postmodern music so difficult to define?
It's like asking why the fish has difficulty seeing the water.
Modernism, in terms of culture, was a belief that culture followed a particular set of rules.
Post-modernism was the belief that culture was free to do whatever people wanted from it and didn't follow rules.
One of the main inspirations for the post-modernist theorists was watching the enticing variety of products that the capitalist market was producing in the second half of the 20th century. And, of course, the varieties of popular music are a big part of that market.
So what is "post-modern" music?
It's ALL THE MUSIC we have today. It's big band jazz, and cool jazz, and cosmic jazz, and jazz funk, and rock'n'roll and rock, and soul and psychedelic, and metal, and lounge, and funk and disco and house and techno and hip-hop and punk and goth and gospel and worship and trap and country.
All of which genres see the world in different ways. All of which have different theories of what they should be like.
Reactionaries are frantic, declaring all these things as "NOT REALLY MUSIC" because they don't accept the rules of how music should be.
But that's the point. Post-modernism isn't a "movement". It's not "prescriptive". It's descriptive. Telling us nothing but "give up your aspirations for the one true theory of how art is".
And music has given up on the one true theory. And each genre and community go off and do their own thing, celebrating their own particular tropes and sounds and heroes.
So we can't say what "post-modern music" is. It's the kaleidoscope of all of them.