Brian, if this definition is more useful, then why isn't that license to take over the term?

Carey, I didn't say it was a more useful definition. I said that Eliezer may feel that the thing being referred to is more useful. I feel that money is more useful than mud, but I don't call my money "mud."

More specifically, how can there be any argument on the basis of some canonical definition, while the consensus seems that we really don't know the answer yet?

I'm not arguing based on a canonical definition. I agree that we don't have a precise definition of intelligence, but we do have a very rough consensus on particular examples. That consensus rejects rocks, trees, and apple pies as not intelligent. It also seems to be rejecting paperclip maximizers and happy-face tilers.

It seems akin to arguing that aerodynamics isn't an appropriate basis for the definition of 'flight', just because a preconceived notion of flight includes the motion of the planets as well as that of the birds, even though the mechanisms turn out to be very different.

I've never heard anyone say a planet was flying, except maybe poetically. Replace "planets" with "balloons" and it'll get much closer to what I'm thinking.