The main aim of my thesis is to defend the metaphysical doctrine of physicalism (which claims that everything is physical) from a very powerful class of anti-physicalist arguments, namely, the so-called conceivability arguments. These arguments are concerned with phenomenal consciousness, that is, the aspect of mentality having to do with what it is like to undergo mental states. Conceivability arguments purport to show that phenomenal consciousness is not physical, and therefore, physicalism fails since there is at least one phenomenon that is not physical.
Physicalism is usually characterised in terms of a supervenience thesis: physicalism is true if and only if all facts (including phenomenal facts) supervene on physical facts. Conceivability arguments try to show that the phenomenal does not supervene on the physical, that is, that there is at least one possible world that is physically identical to ours but where phenomenal facts differ.
Conceivability arguments start by stating that we can conceive of a possible world physically identical to the actual world, but where phenomenal facts are different (for instance, zombie-worlds). From this, they infer that such a world is possible. That is, they think that the conceivability of such a world entails its possibility. And as just noted, if such worlds are possible, physicalism fails.
In my thesis, I examine the use of conceptual methods in order to get metaphysical conclusions. In particular, I focus on the use of conceivability intuitions in order to falsify supervenience theses. Can we find out whether supervenience theses about the world are true or false, just by conceptual methods, such as examining what we are able to conceive?
My answer to this question is no. In particular, my goal is to argue that the conceivability-possibility link posited by advocates of conceivability arguments (such as Chalmers, Jackson, Kripke, White and others) is not correct. I examine two different strategies against such inference from conceivability to possibility, namely, the so-called exceptionalist and non-exceptionalist strategies, and I develop and defend both of them. One of my objectives is to show that the best over-all strategy is a combination of both exceptionalism and non-exceptionalism, which, I argue, is perfectly coherent.
The whole thing, as a pdf. document is HERE.