 That response can be developed in different ways, such as rejecting epistemic premises on which the anti-materialist arguments rely (for other ways, see Chalmers 2010: 134–35; Pereboom 2011; Alter and Nagasawa 2012: 83–86). Regarding the conceivability argument, Russellian physicalists can argue as follows. On reflection, a zombie world is not ideally conceivable. If such a world initially appears conceivable, this is because we mistake a zombie world for a structural zombie world: a consciousness-free world that (minimally) duplicates all of the actual world’s structural features. If there is an ideally conceivable world in the vicinity, then that world is a structural zombie world. There is no good reason to accept the ideal conceivability of a full-fledged zombie world, which would lack consciousness despite duplicating not only the actual world’s structural features but its quiddistic features as well. Regarding the knowledge argument, Russellian physicalists can argue that because Mary’s black-and-white science lessons leave out quiddistic information, those lessons teach her only part of the physical truth. If so, then the truths she learns when she leaves might be physical. They would be non-structural quiddistic truths but physical truths nonetheless.