1. JACKSON What Mary Didn’t Know Or PHYSICAL SCIENCE OMITS THE MIND: QUALIA

2. Frank Jackson (born 1943) Qualia Freak

3. QUALIA Qualia = DEF properties of conscious (particularly sensory) states Background thought: the colors, odors, flavors, etc., that we experience do not exist in the external world, so must be properties of our own conscious sensory states.

4. PHYSICALISM Physicalism = DEF physical stuff is the only substance (metaphysics). SO: knowing all physics  knowing all (epistemology, Jackson)

5. THESIS 1 Physicalism is false because knowing all of physics does not entail knowing about qualia.

6. ARGUMENT 1 The Fred thought experiment. ASSUME: i) Fred can see two different sorts of red: red1 and red2. ii) We know everything about Fred’s nervous system. iii) BUT, we do not know what red1 or red2 look like (qualia). SO: physicalism is false, because its epistemic consequence is false. [1. If K & ~Q, then ~(K  Q); 2. If P  E, and ~E, then ~P]

7. ARGUMENT 2 Mary thought experiment ASSUME: i) Mary has never seen colors (other than black, white, and gray). ii) Mary knows everything there is to know about color perception. iii) BUT, Mary can learn what colors look like only by seeing them.

8. THESIS 2 Epiphenomenalism is acceptable. Epiphenomenalism = DEF physical states cause conscious states, but conscious states have no causal powers at all. [First formulated by T. H. Huxley in 1874]

9. 2 Arguments for Epiphenomenalism Argument 1: Hume has shown causal impotence is possible. - All we ever see is constant conjunction, so things do not have their effects necessarily. Argument 2: Evolution does not prohibit useless traits - Evolution requires only that traits do not lead to extinction.