Online research in philosophy

Conceivability is an important source of our beliefs about what is possible; inconceivability is an important source of our beliefs about what is impossible. What are the connections between the reliability of these sources? If one is reliable, does it follow that the other is also reliable? The central contention of this paper is that suitably qualified the reliability of inconceivability implies the reliability of conceivability, but the reliability of conceivability fails to imply the reliability of inconceivability.

This paper examines the ramifications of Hume's view of the relation of conceivability to metaphysical possibility. It argues that the limitations Hume places of the representations involved in moves to conceivability to metaphysical possibility preclude any straightforward argument against full-blooded causal realism in Hume from conceivability. Furthermore, our finding certain states of affairs conceivable when they are not metaphysically possible is perfectly compatible with the thrust of the causal realist position.

In the history of modern philosophy systematic connections were assumed to hold between the modal concepts of logical possibility and necessity and the concept of conceivability. However, in the eyes of many contemporary philosophers, insuperable objections face any attempt to analyze the modal concepts in terms of conceivability. It is important to keep in mind that a philosophical explanation of modality does not have to take the form of a reductive analysis. In this paper I attempt to provide a response-dependent account of the modal concepts in terms of conceivability along the lines of a nonreductive model of explanation.

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.

To what extent and how is conceivability a guide to possibility? This essay explores general philosophical issues raised by this question, and critically surveys responses to it by Descartes, Hume, Kripke and "two-dimensionalists.".

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.

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.

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.