- If it is conceivable that p, then it is possible that p.
- It is conceivable that p.
- (Therefore) It is possible that p.
- The possibility of zombies is taken as conclusive evidence against physicalism.
- The possibility of multiple realizability is taken as conclusive evidence against mind-body identity theories.
Descartes, of course, realized this, and so, in his conceivability argument, there is a step from mere possibility to actuality (even though it ultimately fails). This step is the following:
I know that everything which I clearly and distinctly understand is capable of being created by God so as to correspond exactly with my understanding of it.So, Descartes' conceivability argument looks something like this:
- I can conceive of the mind as separate from the body.
- If I can conceive of the mind as separate from the body, then God could have created the mind without the body.
- (Therefore) God could have created the mind without the body.
Nowadays, some dualists might be reluctant to appeal to God in support of their theories. So, can the gap in conceivability arguments be bridged?
Hi,
ReplyDeleteUnder reductive materialism the physical facts *entail* consciousness. So if p-zombies are metaphysically possible then this refutes reductive materialism. Hence it would be a misunderstanding to suppose that zombies have to exist in this world or any other. If reductive materialism is true then p-zombies must be conceptually incoherent.
Ian Wardell
Thanks for the comment, Ian. Although I’m not sure the issue is as simple as you make it to be.
DeleteYou write: “Under reductive materialism the physical facts *entail* consciousness. So if p-zombies are metaphysically possible then this refutes reductive materialism.”
Consider the theory of evolution, which, plus some physical facts, “entail” biological diversity. Does the metaphysical possibility of special creation, which also “entails” biological diversity, refutes evolution? Not at all, since evolution is not supposed to be a bunch of necessary truths.
You also write: “it would be a misunderstanding to suppose that zombies have to exist in this world or any other. If reductive materialism is true then p-zombies must be conceptually incoherent.”
From the SEP: “Φ is metaphysically possible if and only if Φ is true in some metaphysically possible world.” (http://plato.stanford.edu/entries/modality-epistemology/)
To say that p is metaphysically possible is to say that p is true in some metaphysically possible world. So, “it is metaphysically possible that there are zombies” is equivalent to “there is a metaphysically possible world in which there are zombies.” In that case, how do we know that the metaphysically possible world in which there are zombies is the actual world? After all, “Physicalism is the thesis [...] that the nature of the *actual world* (i.e. the universe and everything in it) conforms to a certain condition, the condition of being physical.” (http://plato.stanford.edu/entries/physicalism/) To argue that the metaphysical possibility of zombies "refutes" physicalism would be like arguing that the metaphysical possibility of special creation "refutes" evolution.