Steve Sailer has in interesting comment on a question I’ve thought about from time to time, why multicultural societies are less creative. Basically, he says that necessity is the mother of invention: if there had been a lot of black musicians in early-60s Liverpool, the Beatles wouldn’t have had to come up with their own rock ‘n roll. If you can go out and get multiethnic cuisine, you don’t bother developing your own cooking.

Here are some other reasons that have occurred to me:

High-level creativity needs a coherent setting and tradition to give it materials and possibilities. That’s why there is no Shakespeare of pidgin. As Sailer points out, ethnic cuisines developed in monocultural settings.
In multicultural society the only principles of order are arm’s length contract and top-down management. There’s not enough of a network of ties and common understandings for anything else to work. Neither allows for much creativity, because they’re too simple and single-minded.

Then there’s the obvious point, that if you have a multicultural society that has to pretend to be free, equal and democratic you have to control thought and expression in boring ways to keep the whole house of cards from collapsing. “Celebrating diversity” means refusal to deal with any important issue in an interesting way, because you might end up saying that something is better than something else.

Don’t evolutionary biologists talk about the importance of isolated niche situations for speciation? Whatever its status in biology, the reasoning suggests that cosmopolitan societies would be uncreative.