This is the title of my talk at the Eastern APA, in the session on Classical Computation and Hypercomputation (see previous post). The other presenter is Oron Shagrir and the commentator is Jack Copeland. Jack is probably the most distinguished philosopher of AI and computation, and Oron is one of the best philosophers in this area. Both are probably less well known in the US than they deserve. They are, respectively, from Israel and New Zealand. If you are based in the US, you may not have many other opportunities to see them in action. So if you are in NYC next week, you should consider coming to our session on Wednesday.