 More on zombies’ utterances. Consider a zombie world that is an exact physical duplicate of our world and contains zombie twins of all philosophers, including some who appeal to the conceivability argument. Katalin Balog (1999) argues that while their utterances would be meaningful, their sentences would not always mean what they do in our mouths. She further argues — to oversimplify — that if the conceivability argument were sound in actual philosophers’ mouths, then it would be sound in the mouths of zombie philosophers too. But since by hypothesis physicalism is true in their world, their argument is not sound. Therefore the conceivability argument used by actual philosophers is not sound either. If this argument works, it has the piquant feature that ‘the zombies that antiphysicalists think possible in the end undermine the arguments that allege to establish their possibility’ (502. Chalmers offers brief replies in his 2003; 2010, pp. 159–60).