Postmodernism is one of those things, like pornography, that’s difficult to define, but you know it when you see it.
Today’s example: The Real Gilligan’s Island, a “reality” show based on a sitcom. And then, on network TV news, an interview with an original cast member from the “real” Gilligan’s Island.
Disentangling the strands of reality is left as an exercise for the reader.