You said it. Funny, its been awhile since I've heard the term post-modern. I don't know if you have read any of CS Lewis's works. But he warns about post-modernism. I don't think that's the name he gives to it, but he saw its birth in his day. Perhaps it was starting out in England (and Europe) before it reached America.
CS Lewis? Oh yessss! I'm a big fan of his. Have you read J. Budziszewski's "What We Can't Not Know"? In Budziszewski's words, it's a "book about the lost world of the common truths........what we all really know about right and wrong." In a way, it's Budziszewski's version of CS Lewis's "Mere Christianity."