Online research in philosophy

A number of popular arguments for dualism start from a premise about an epistemic gap between physical truths about truths about consciousness, and infer an ontological gap between physical processes and consciousness. Arguments of this sort include the conceivability argument, the knowledge argument, the explanatory-gap argument, and the property dualism argument. Such arguments are often resisted on the grounds that epistemic premises do not entail ontological conclusion. My view is that one can legitimately infer ontological conclusions from epistemic premises, if one is very careful about how one reasons. To do so, the best way is to reason first from epistemic premises to modal conclusions (about necessity and possibility), and from there to ontological conclusions. Here, the crucial issue is the link between the epistemic and modal domains. How can one reason from theses about what is knowable or conceivable to theses about what is necessary or possible? To bridge the epistemic and modal domains, the framework of two-dimensional semantics can play a central role. I have used this framework in earlier work (Chalmers 1996) to mount an argument against materialism. Here, I want to revisit the argument, laying it out in a more explicit and careful form, and responding to a number of objections. In what follows I will concentrate mostly on the conceivability argument. I think that very similar considerations apply to the other arguments mentioned above, however. In the final section of the paper, I show how this analysis might yield a unified treatment of a number of anti-materialist arguments.

Hill and Levine offer alternative explanations of these conceivabilities, concluding that these conceivabilities are thereby defeated as evidence. However, this strategy fails because their explanations generalize to all conceivability judgments concerning phenomenal states. Consequently, one could defend absolutely any theory of phenomenal states against conceivability arguments in just this way. This result conflicts with too many of our common sense beliefs about the evidential value of conceivability with respect to phenomenal states. The general moral is that the application of such principles of explanatory defeat is neither simple nor straightforward.

There is a long tradition in philosophy of using a priori methods to draw conclusions about what is possible and what is necessary, and often in turn to draw conclusions about matters of substantive metaphysics. Arguments like this typically have three steps: first an epistemic claim (about what can be known or conceived), from there to a modal claim (about what is possible or necessary), and from there to a metaphysical claim (about the nature of things in the world).

Chalmers argues that zombies are possible and that therefore consciousness does not supervene on physical facts, which shows the falsity of materialism. The crucial step in this argument – that zombies are possible – follows from their conceivability and hence depends on assuming that conceivability implies possibility. But while Chalmers’s defense of this assumption – call it the conceivability principle – is the key part of his argument, it has not been well understood. As I see it, Chalmers’s defense of the conceivability principle comes in his response to the so-called objection from a posteriori necessity. The defense aims at showing that there is no gap between conceivability and possibility since no such gap can be generated by necessary a posteriori truths. I will argue that while Chalmers is right to the extent that there is no gap between conceivability and possibility within the standard Kripkean model of a posteriori necessity, his general conclusion is not justified. This is because the conceivability principle might be inconsistent with a posteriori necessity understood in some non-Kripkean way and Chalmers has not shown that no such alternative understanding of a posteriori necessity is available.

My aim here is threefold: (a) to show that conceptual facts play a more significant role in justifying explanatory reductions than most of the contributors to the current debate realize; (b) to furnish an account of that role, and (c) to trace the consequences of this account for conceivability arguments about the mind.

What can be inferred from the fact that something is, or is not, conceivable? In this paper I argue, contrary to some deflationary remarks in recent literature, that arguments which use such facts as their starting point may have significant philosophical import. I use Strawson's results from the first chapter of "Individuals" in order to show that Galileo's arguments in favor of the distinction between primary and secondary qualities, which are based on premises concerning conceivability, should not be dismissed: they are the first step towards recognizing an important conceptual truth.

Functionalism, the philosophical theory that defines mental states in terms of their causal relations to stimuli, overt behaviour, and other inner mental states, has often been accused of being unable to account for the qualitative character of our experimential states. Many times such objections to functionalism take the form of conceivability arguments. One is asked to imagine situations where organisms who are in a functional state that is claimed to be a particular experience either have the qualitative character of that experience altered or absent altogether. Many of these arguments are surprisingly advanced by materialist philosophers. I argue that if the conceivability arguments were successful against functionalism, then they would be successful against their alternative materialist views as well. So the conceivability arguments alone do not provide a good reason for materialists to abandon functionalism. I further argue that functionalism is best understood to be an empirical theory, and if it is so understood then the conceivability arguments have no force against it at all. A further consequence that emerges is that on an empirical functionalist view, qualia, if real, are properties in the domain of psychology.

Brian Loar believes he has refuted all those antiphysicalist arguments that take as their point of departure observations about what is or isn't conceivable. I argue that there remains an important, popular and plausible-looking form of conceivability argument that Loar has entirely overlooked. Though he may not have realized it, Saul Kripke presents, or comes close to presenting, two fundamentally different forms of conceivability argument. I distinguish the two arguments and point out that while Loar has succeeded in refuting one of Kripke's arguments he has not refuted the other. Loar is mistaken: physicalism still faces an apparently insurmountable conceptual obstacle.

The phenomenal concept strategy is one of the most attractive responses to the so-called conceivability arguments. A crucial step in these arguments is the inference from conceivability to possibility. The phenomenal concept strategy attacks this inference from conceivability to possibility: they argue that there is an alternative explanation of the conceivability of zombies, which does not involve the possibility of zombies. This alternative explanation appeals to special features of phenomenal concepts in order to explain the conceivability of zombies. Daniel Stoljar has recently argued that if the phenomenal concept strategy was a good strategy against the conceivability argument against physicalism, it would also be a good strategy against the conceivability argument against behaviourism. But he claims that the latter conceivability argument is sound, and therefore the phenomenal concept strategy cannot be correct. In this paper I show how the phenomenal concept strategy can respond to this objection.