I once read about a cannibal tribe in which nobody could become a chieftain without disposing of one of the earlier ones and eating him. It seems to me sometimes that philosophers must be descendants of that tribe. When a philosopher develops a new theory, it almost invariably seems more important to him to use it to try to clobber an earlier one rather than to try to see if the two are perhaps complementary — and to see what there is, perhaps, to be learned from the earlier theory.