Ok, so Dennett is being eloquent and both participants are very intelligent, but "explain the joke" is probably a good test. The point is to get the AI to do so

Ok, so Dennett is being eloquent and both participants are very intelligent, but "explain the joke" is probably a good test. The point is to get the AI to do something that requires meta-knowledge. That isn't to say all humans have to have meta-knowledge, but the test passing would be more convincing if the AI could do something most everyone can do, like explain a joke.