That's a very good point. The AI theorist presumably knows more about avenues that have not done very well (neural nets, other forms of machine learning, expert systems) but isn't likely to have much general knowledge. However, that does mean the AI individual has a better understanding of how many different approaches to AI have failed miserably. But that's just a comparison to your example of the physics grad student who can code. Most of the people you mentioned in your reply to Yoreth are clearly people who have knowledge bases closer to that of the AI prof than to the physics grad student. Hanson certainly has looked a lot at various failed attempts at AI. I think I'll withdraw this argument. You are correct that these individuals on the whole are likely to have about as much relevant expertise as the AI professor.