1. OBJECTIONS Identity Theory

2. The Identity Theory The Identity Theory: Mental states identical to physical states of the brain. To be in pain is to have C-fibers firing. The Token-Identity Theory: Every mental state token is identical to some token physical state of the brain. The Type-Identity Theory: Every mental state type is identical to some type of physical state of the brain.

3. The Modal Argument 1) If the Identity Theory is correct, then pain is identical to the firing of C-fibers. 2) If pain is identical to the firing of C-fibers, then pain is necessarily identical to the firing of C-fibers. 3) If pain is necessarily identical to firing of C-fibers, then pain could not have existed without the firing of C- fibers. 4) Pain could have existed without the firing of C-fibers. 5) [So] The Identity Theory is not correct.

4. Multiple Realization The Identity Theory: Mental states identical to physical states of the brain. To be in pain is to have C-fibers firing. The Relativized Identity Theory: Mental states are identical to physical states of the brain. To be in pain-for- humans is to have C-fibers firing, to be in pain-for-squids is to have D-fibers firing, to be in pain-for-Orkans is to have activity in silicon chip E, etc.

5. Multiple Realization The Identity Theory: Mental states identical to physical states of the brain. To be in pain is to have C-fibers firing. The Disjunctive Identity Theory*: Mental states are identical to physical states of the brain. To be in pain is to either have C-fibers firing or have D-fibers firing or to have activity in silicon chip E or…

6. Multiple Realization The Identity Theory: Mental states identical to physical states of the brain. To be in pain is to have C-fibers firing. The Disjunctive Identity Theory: Mental states are identical to physical states of the brain. To be in pain is to either be a human and to have C-fibers firing or to be a squid and to have D-fibers firing or to be an Orkan and to have activity in silicon chip E or…

7. Summary The Problem of Interspecies Multiple Realization  The Relativized Identity Theory  The Disjunctive Identity Theory The Problem of Intraspecies Multiple Realization

8. Preview In the previous chapter we noticed that mental states can be multiply realized. In humans the state which realizes pain is (say) c-fiber firing; in squid it’s (say) d-fiber firing. Multiple realization raises a puzzle: what do old Eight-legs and I have in common when we are both in pain? It can’t be c-fiber firing because Eight-legs has no c-fibers (or so I will assume). And it can’t be d-fiber firing because Eight-legs has no c-fibers (or so I will assume). And it can’t be d-fiber firing because I have no d-fibers (or so I will assume). In virtue of what, then, is it true that Eight-legs and I are both in pain? Functionalism provides an answer to this puzzle. Ravenscroft, p.50.