Online research in philosophy

A philosophical zombie is a being physically indistinguishable from an actual or possible human being, inhabiting a possible world where the physical laws are identical to the laws of the actual world, but which completely lacks consciousness. For zombies, all is dark within, and hence they are, at the most fundamental level, utterly different from us. But, given their definition, this singular fact has no direct implications about the kind of motion, or other physical processes, the zombie will undergo within its own world. Under quite standard physicalist assumptions, such as certain assumptions about the 'initial conditions' of the zombie's world and that of the causal closure of the physical1, a zombie's behaviour, as well as its underlying physical state, should be indistinguishable from the behaviour and physical state of a genuine human being.

Representational theorists identify experiences’ phenomenal properties with their representational properties. Qualia theorists reject this identity, insisting that experiences’ phenomenal properties can come apart from and completely outrun their representational properties. Qualia theorists account for phenomenal properties in terms of “qualia,” intrinsic mental properties they allege experiences to instantiate. The debate between representational theorists and qualia theorists has focused on whether phenomenal properties really can come apart from and completely outrun representational properties. As a result, qualia theorists have failed (1) to explain how experiences owe their phenomenal properties to their instantiation of qualia and (2) to clarify the nature of subjects’ epistemic access to qualia. I survey qualia theorists’ options for dealing with each issue and find them all wanting.

Most materialist responses to the zombie argument against materialism take either a ?type-A? or ?type-B? approach: they either deny the conceivability of zombies or accept their conceivability while denying their possibility. However, a ?type-Q? materialist approach, inspired by Quinean suspicions about a priority and modal entailment, rejects the sharp line between empirical and conceptual truths needed for the traditional responses. In this paper, I develop a type-Q response to the zombie argument, one stressing the theory-laden nature of our conceivability and possibility intuitions. I argue that our first-person access to the conscious mind systematically misleads us into thinking that the distinctive qualities of conscious experience?qualia?are nonfunctional. Qualia, I contend, are functional, even though they do not seem to be. To support my claim, I introduce the ?meditations? of Rene Descartes? zombie twin. This establishes the plausibility of an appearance/reality distinction for consciousness and it undermines various anti-materialist objections based on privileged first-person access. I conclude that the best overall theory posits an appearance/reality distinction for qualia, and this, for the type-Q materialist, is decisive.

According to the zombie conceivability argument, phenomenal zombies are conceivable, and hence possible, and hence physicalism is false. Critics of the conceivability argument have responded by denying either that zombies are conceivable or that they are possible. Much of the controversy hinges on how to establish and understand what is conceivable, what is possible, and the link between the two—matters that are at least as obscure and controversial as whether consciousness is physical. Because of this, the debate over physicalism is unlikely to be resolved by thinking about zombies—or at least, zombies as discussed by philosophers to date.



In this paper, I explore an alternative strategy against the zombie conceivability argument. I accept the possibility of zombies and ask whether that possibility is accessible (in the sense of ‘accessible’ used in possible world semantics) to our world. It turns out that the question of whether zombie worlds are accessible to our world is equivalent to the question of whether physicalism is true. By assuming that zombie worlds are accessible to our world, supporters of the zombie conceivability argument beg the question against physicalists. I will then consider what happens if a supporter of the zombie conceivability argument should insist that zombie worlds are accessible to our world. I will argue that the same ingredients used in the zombie conceivability argument—whatever they might be—can be used to construct an argument to the opposite conclusion. If that is correct, we reach a stalemate between physicalism and property dualism: while the possibility of some zombies entails property dualism, the possibility of other creatures entails physicalism. Since these two possibilities are inconsistent, one of them is not genuine. To resolve this stalemate, we need more than thought experiments.

If zombies were conceivable in the sense relevant to the ‘conceivability argument’ against physicalism, a certain epiphenomenalistic conception of consciousness—the ‘e-qualia story’—would also be conceivable. But (it is argued) the e-qualia story is not conceivable because it involves a contradiction. The non-physical ‘e-qualia’ supposedly involved could not perform cognitive processing, which would therefore have to be performed by physical processes; and these could not put anyone into ‘epistemic contact’ with e-qualia, contrary to the e-qualia story. Interactionism does not enable zombists to escape these conclusions.

ABSTRACT. In this paper I propose a defense of a posteriori materialism. Prob- lems with a posteriori identity materialism are identi?ed, and a materialism based on composition, not identity, is proposed. The main task for such a proposal is to account for the relation between physical and phenomenal properties. Compos- ition does not seem to be ?t as a relation between properties, but I offer a peculiar way to understand property-composition, based on some recent ideas in the literature on ontology. Finally, I propose a materialist model for the mind-body relation that is able to resist the attack from conceivability arguments.

It is widely accepted that conscious experience has a physical basis. That is, the properties of experience (phenomenal properties, or qualia) systematically depend on physical properties according to some lawful relation. There are two key questions about this relation. The first concerns the strength of the laws: are they logically or metaphysically necessary, so that consciousness is nothing "over and above" the underlying physical process, or are they merely contingent laws like the law of gravity? This question about the strength of the psychophysical link is the basis for debates over physicalism and property dualism. The second question concerns the shape of the laws: precisely how do phenomenal properties depend on physical properties? What sort of physical properties enter into the laws' antecedents, for instance; consequently, what sort of physical systems can give rise to conscious experience? It is this second question that I address in this paper.

Case 1: Perhaps the phenomenal facts—facts about what it’s like to see red, or to taste freshly made pesto—do not supervene with metaphysical necessity on the physical facts and physical laws. This might be because the connections between the physical and the phenomenal are entirely unprincipled. Alternatively, it might be because whatever psychophysical laws do govern those connections are contingent. Either way, the claim is that there are metaphysically possible worlds that are just like the actual world in terms of what physical laws hold, and in terms of the distribution of physical properties, but which are phenomenally different from the actual world. In some such worlds, different phenomenal facts obtain. In other such worlds, no phenomenal properties are instantiated at all. Call the latter sort of world a ‘phenomenal zombie world’, or, for short, just a ‘zombie world’.

In this paper I begin by explaining the concept of supervenience. I then describe the problem of qualia and explain why qualia are a problem for physicalist theories of the mind. Next, I outline the zombie argument and explain Chalmers' attempt to use it as an argument for the conclusion that qualia do not logically supervene on the physical. My goal is to show that the supposed conceivability of zombies does not offer any serious refutation of physicalist theories of the mind.