Even though it has little to do with his thesis, I found his assumptions regarding how we'd view the stabby guy at trial and the bear in the zoo differently. That is based on our expectations of animal behavior. We expect humans to act differently than bears. And for that matter, I might hate the fucking bear anyway. If I am not a threat or food, the fuck him.
As I said, though, that's not really his thesis. That is more along the lines of demonstrating how silly we are for believing in free will (stabby guy has it, bear doesn't, in our weak superstitious minds). What examples he does give, that of becoming a surgeon, is wanting.