Robin Hanson: I don't think that's what he's getting at. Yes, surface similarities are correlated with structural similarities, or mathematical similarities (I know of a guy who found a couple big research papers towards his astrophysics PhD via a colleage's analogy between gravitational and electromagnetic waves), but they show up so often under other circumstances that it is meet to be suspicious of them. The outside view works really well for Christmas shopping, essay writing, program development, and the like because it is obvious that the structural similarities are present.