Abstract

Certain conceivable situations figure as premises in arguments for the conclusion that conscious experiences have nonphysical properties or qualia. Frank Jackson's knowledge argument considers the hypothetical scientist Mary, who despite having complete scientific knowledge of colour vision, supposedly lacks knowledge of qualia. Both Saul Kripke's and David Chalmers' modal arguments involve zombies, conceivable creatures physically identical to us who lack qualia. Several physicalists have replied to all these objections by endorsing the phenomenal concept reply. Without trying to undermine this reply in general, I argue that recent versions of it proposed by John Perry and David Papineau are unsatisfactory.