This is an excellent question, and it is a shame (perhaps slightly damning) that no-one has answered it. On the other hand, much of this chapter will have been old material for many LW members. I am ashamed that I couldn't think of anything either, so I went back again looking for things I had actually changed my opinion about, even a little, and not merely because I hadn't previously thought about it.

• p6 I hadn't realised how important combinatorial explosion was for early AI approaches.
• p8 I hadn't realised, though I should have been able to work it out, that the difficulties in coming up with a language which matched the structure of the domain was a large part of the problem with evolutionary algorithms. Once you have done that you're halfway to solving it by conventional means.
• p17 I hadn't realised about how high volume could have this sort of reflexive effect.