I'm watching Nova Science Now on living forever, and there's a section on artificial intelligence. In one scene, a researcher talks about how the avatar isn't gesticulating, and they need to start thinking about making the avatar communicate with its hands.
To me, this illustrates the reason why the traditional approach to artificial intelligence will never work. We cannot build an intelligence from the top down. We can't copy the gross aspects of life, i.e. behaviors, we need to figure out the basic building blocks that generate that behavior.
This comes back to the computational theory of mind. We do have to program certain basic assumptions about the world, but the fewer, the better.
I think that the basic programming is going to be based on a binary-like yes/no language. Light is good, darkness is bad. Warmth good, cold bad, etc.