What he does a lot of is looking at weird worldviews as if they were real. He asks a lot of "what if" questions. What if the world really worked like this? What if they really had built the Tower of Babylon? What would the engineering challenges have been? What would they have found? What would happen if someone found a simple and elegant proof that mathematics is inconsistent? What would happen to someone who didn't see time as linear?
The stories are fabulous. The ideas behind them were all interesting. I never had that horrible feeling that I had entirely missed the point of the story. The characters were engaging (I didn't really like the super-smart guy, but I think that was kind of the point) and the stories all made sense in a very satisfying way.
The one about the mathematician who discovered a basic inconsistency was awesome. It was as if she had woken up in the Matrix, except the Matrix wasn't being run by evil beings out to get us, it was just the way things are, always have been, and always will be. When she explains this to other people, the ones who understand it at the level she does get horribly upset and depressed, but only a very few are really capable of that. Everyone else mostly just ignores it. Either they have a theoretical understanding of the situation but can mostly just get on with their lives, or they simply cannot grasp that this in any way affects them. I found her reactions, her colleagues, and her husband to be fascinating.
This is exactly what a book of short stories should be. Totally engaging, satisfying the first time you read it, with enough depth to make you want to re-read.