Chalmers in point 2 is not saying to imagine such a world, but that such a world is logically possible. Chalmers gives as an example of a logical impossibility a male vixen since it is contradictory. He states "... a flying telephone is conceptually coherent, if a little out of the ordinary, so a flying telephone is logically possible. Nevertheless, that zombies are logically possible, may be begging the question, that consciousness is non physical.