Frank Jackson’s famous Knowledge Argument moves from the premise
that complete physical knowledge about experiences is not complete
knowledge about experiences to the falsity of physicalism. Some physicalists (e.g., John Perry) have countered by arguing that what Jackson’s Mary, the perfect scientist who acquires all physical knowledge about experiencing red while being locked in a monochromatic room, lacks before experiencing red is merely a piece of recognitional knowledge of an identity, and that since lacking a piece of recognitional knowledge of an identity does not entail lacking any pieces of knowledge of worldly facts, physicalism is safe. I will argue that what Mary lacks in her room is not merely a piece of recognitional knowledge of an identity and that some physicalists have failed to see this because of a failure to appreciate that Mary’s epistemic progress when she first experiences red has two different stages. While the second epistemic stage can perhaps be plausibly considered as acquiring merely a piece of recognitional knowledge of an identity, there is good reason to think that the first epistemic stage cannot be thus considered.