Frank Jackson’s Knowledge Argument claims that Mary—a neuroscientist who knows all the physical facts about color perception but has never seen color—learns something new when she sees red, posing a challenge to physicalism. While physicalists deny that Mary acquires knowledge of new facts, they must still explain her apparent epistemic progress. I argue that the intuition that Mary gains new knowledge upon seeing red stems from the alleged opacity of propositional attitude ascriptions—the same phenomenon underlying Frege puzzles.
