Many philosophers accept the conceivability of zombies: creatures that lack consciousness but are physically and functionally identical to conscious human beings. Many also believe that the conceivability of zombies supports their metaphysical possibility. And most agree that if zombies are metaphysically possible, then physicalism is false. So, the claim that zombies are conceivable may have considerable significance.¹.

The most discussed arguments for mental-physical property dualism in recent years have been the so-called conceivability arguments. Recently, the most sophisticated champion of such arguments has been David Chalmers. His recipe for such an argument goes like this.¹ Take two actual truths, P and Q, such that most of us have the intuition that.

b>. This essay is a sustained attempt to bring new light to some of the perennial prob- lems in philosophy of mind surrounding phenomenal consciousness and introspection through developing an account of sensory and phenomenal concepts. Building on the information- theoretic framework of Dretske (1981), we present an informational psychosemantics as it applies to what we call _sensory concepts_, concepts that apply, roughly, to so-called secondary qualities of objects. We show that these concepts have a special informational character and semantic (...) struc- ture that closely tie them to the brain states realizing conscious qualitative experiences. We then develop an account of introspection which exploits this special nature of sensory concepts. The result is a new class of concepts, which, following recent terminology, we call _phenomenal con-_ _cepts_: these concepts refer to phenomenal experience itself and are the vehicles used in introspec- tion. On our account, the connection between sensory and phenomenal concepts is very tight: it consists in different semantic uses of the same cognitive structures underlying the sensory con- cepts, such as the concept of red. Contrary to widespread opinion, we show that information the- ory contains all the resources to satisfy internalist intuitions about phenomenal consciousness, while not offending externalist ones. A consequence of this account is that it explains and pre- dicts the so-called conceivability arguments against physicalism on the basis of the special nature of sensory and phenomenal concepts. Thus we not only show why physicalism is not threatened by such arguments, but also demonstrate its strength in virtue of its ability to predict and explain away such arguments in a principled way. However, we take the main contribution of this work to be what it provides in addition to a response to those conceivability arguments, namely, a sub- stantive account of the interface between sensory and conceptual systems and the mechanisms of introspection as based on the special nature of the information flow between them.. (shrink)

It is widely suspected that arguments from conceivability, at least in some of their more notorious instances, are unsound. However, the reasons for the failure of conceivability arguments are less well agreed upon, and it remains unclear how to distinguish between sound and unsound instances of the form. In this paper I provide an analysis of the form of arguments from conceivability, and use this analysis to diagnose a systematic weakness in the argument form which reveals all its instances to (...) be, roughly, either uninformative or unsound. I illustrate this conclusion through a consideration of David Chalmers. (shrink)

RÉSUMÉ: Cette étude examine la relation entre la demande que les zombies sont logiquement/métaphysiquement possible et de la position que la conscience phénoménal est epiphenomenal. Il est souvent présumé que la première entraîne ce dernier, et que, par conséquent, toute implausibility dans la notion de conscience epiphenomenalism remet en question la possibilité réelle de zombies. Quatre façons dont les zombist pourrait répondre sont examinées, et je soutiens que les deux les plus fréquemment rencontrés sont insuffisantes, mais les autres—dont l’un est (...) rarement formulés et l’autre nouveaux—sont plus persuasif. Le résultat, cependant, est que le zombist pourraient en effet être confronté à un engagement indésirables à l’epiphenomenalism de conscience. (shrink)

During the last two decades, several different anti-physicalist arguments based on an epistemic or conceptual gap between the phenomenal and the physical have been proposed. The most promising physicalist line of defense in the face of these arguments – the Phenomenal Concept Strategy – is based on the idea that these epistemic and conceptual gaps can be explained by appeal to the nature of phenomenal concepts rather than the nature of non-physical phenomenal properties. Phenomenal concepts, on this proposal, involve unique (...) cognitive mechanisms, but none that could not be fully physically implemented. David Chalmers has recently presented a Master Argument to show that the Phenomenal Concept Strategy – not just this or that version of it, but any version of it – fails. Chalmers argues that the phenomenal concepts posited by such theories are either not physicalistically explicable, or they cannot explain our epistemic situation with regard to qualia. I argue that it is his Master Argument that fails. My claim is his argument does not provide any new reasons to reject the Phenomenal Concept Strategy. I also argue that, although the Phenomenal Concept Strategy is successful in showing that the physicalist is not rationally compelled to give up physicalism in the light of the anti-physicalist arguments, the anti-physicalist is not rationally compelled to give up the anti-physicalist argument in the light of the Phenomenal Concept Strategy either. (shrink)

In this paper I begin to develop an account of the acquaintance that each of us has with our own conscious states and processes. The account is a speculative proposal about human mental architecture and specifically about the nature of the concepts via which we think in first personish ways about our qualia. In a certain sense my account is neutral between physicalist and dualist accounts of consciousness. As will be clear, a dualist could adopt the account I will offer (...) while maintaining that qualia themselves are non-physical properties. In this case the non-physical nature of qualia may play no role in accounting for the features of acquaintance. But although the account could be used by a dualist, its existence provides enormous support for physicalism. In particular it provides the makings of a positive refutation (i.e., a refutation by construction) of the conceivability arguments and the Mary argument for dualism. (shrink)

This paper was chosen by The Philosopher’s Annual as one of the ten best articles appearing in print in 2000. Reprinted in Volume XXIII of The Philosopher’s Annual. In his very influential book David Chalmers argues that if physicalism is true then every positive truth is a priori entailed by the full physical description – this is called “the a priori entailment thesis – but ascriptions of phenomenal consciousness are not so entailed and he concludes that Physicalism is false. As (...) he puts it, “zombies” are metaphysically possible. I attempt to show (I think successfully) that this argument is refuted by considering an analogous argument in the mouth of a zombie. The conclusion of this argument is false so one of the premises is false. I argue at length that this shows that the original conceivability argument also has a false premise and so is invalid. (shrink)

In this paper I survey the landscape of anti-physicalist arguments and physicalist responses to them. The anti-physicalist arguments I discuss start from a premise about a conceptual, epistemic, or explanatory gap between physical and phenomenal descriptions and conclude from this – on a priori grounds – that physicalism is false. My primary aim is to develop a master argument to counter these arguments. With this master argument in place, it is apparent that there is a puzzling symmetry between dualist attacks (...) on physicalism and physicalist replies. Each position can be developed in a way to defend itself from attacks from the other position. Therefore the debate comes down to which metaphysical framework provides the better overall explanatory/theoretical framework. (shrink)

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. (shrink)

The paper begins with a clarification of the notions of intuition (and, in particular, modal intuition), modal error, conceivability, metaphysical possibility, and epistemic possibility. It is argued that two-dimensionalism is the wrong framework for modal epistemology and that a certain nonreductionist approach to the theory of concepts and propositions is required instead. Finally, there is an examination of moderate rationalism.

Scientific essentialism is the view that some necessities (e.g., water = H2O) can be known only with the aid of empirical science. The thesis of the paper is that scientific essentialism does not extend to the central questions of philosophy and that these questions can be answered a priori. The argument is that the evidence required for the defense of scientific essentialism (e.g., twin earth intuitions) is reliable only if the intuitions required by philosophy to answer its central questions is (...) also reliable. Included is an outline of a modal reliabilist theory of basic evidence and a concept-possession account of the reliability of a priori intuition. (shrink)

I argue that property dualism is not supported by the purported logical possibility of qualitative zombies. Chalmers.

In this paper I argue that a priori arguments fail to present any real problem for physicalism. They beg the question against physicalism in the sense that the argument will only seem compelling if one is already assuming that qualitative properties are nonphysical. To show this I will present the reverse-zombie and reverse-knowledge arguments. The only evidence against physicalism is a priori arguments, but there are also a priori arguments against dualism of exactly the same variety. Each of these parity (...) arguments has premises that are just as intuitively plausible, and it cannot be the case that both the traditional scenarios and the reverse-scenarios are all ideally conceivable. Given this one set must be merely prima facie conceivable and only empirical methods will tell us which is which. So, by the time a priori methodology will be of any use it will be too late.
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This book covers a vast amount of material in the philosophy of mind, which makes it difficult to do justice to its tightly argued and nuanced details. It does, however, have two overarching goals that are visible, so to speak, from space. In the first half of the book Kirk aims to show that, contra his former self, philosophical zombies are not conceivable. By this he means that the zombie scenario as usually constructed contains an unnoticed contradiction, and explaining the (...) contradiction reveals a radical misconception about the nature of phenomenal consciousness. His second aim of the book is to construct a theory of perceptual-phenomenal consciousness that avoids this contradiction. The anti-zombie argument can be stated rather easily. According to the ‘zombist’ there can be a creature that is a molecule-for-molecule-duplicate of me and yet lacks phenomenal consciousness. At the same time they want to hold that we have ‘epistemic access’ to our phenomenal consciousness. These two claims are not consistent with each other. To see why, imagine a zombie world that is identical to ours except in respect of phenomenal consciousness. Since that world is just like ours we can assume that it is causally closed under the physical. Now, continues Kirk, it should be possible to add to that world whatever it is that the zombist thinks will transform it into a world that does have phenomenal consciousness. But since whatever we added would have to be nonphysical, since their world is identical to ours (excepting consciousness), and so could not interact causally with the physical world (which is closed under the physical), it follows that we could not know anything about these ‘e-qualia’. Therefore, we could not have ‘epistemic access’ to them. To make this vivid he offers what he calls the ‘sole-pictures’ argument. Again, consider our zombie world. Let’s add whatever it is that the zombist thinks will transform it into a world like ours. Now let’s imagine that by a “strange shift in the natural laws” of the zombie world the visual processes that in me cause e-qualia instead cause.... (shrink)

In The Conscious Mind, D. Chalmers appeals to his semantic framework in order to show that conceivability, as employed in his "zombie" argument for dualism, is sufficient for genuine possibility. I criticize this attempt.

Zombies are hypothetical creatures of the sort that philosophers have been known to cherish. A zombie is physically identical to a normal human being, but completely lacks conscious experience. Zombies look and behave like the conscious beings that we know and love, but "all is dark inside." There is nothing it is like to be a zombie.

What follows are compressed versions of three lectures on the subject of "Mind and Modality", given at Princeton University the week of October 12-16, 1998. The first two form a series; the third stands alone to some extent. All are philosophically technical, and probably of interest mainly to philosophers. I hope that they make sense, at least to those familiar with my book _The Conscious Mind_ . Lecture 1 recapitulates some of the material in the book in a somewhat different (...) form, and adds some further material on conditionals and on Kripke. Note that section has a more or less definitive formalization of the anti-materialist argument from the book (lots of people have asked for this). Lecture 2 pushes deeper into the heart of modality, further investigating the conceivability/possibility relationship and the epistemology of modality (with some material on the scrutability of truth in general), and arguing for a sort of modal rationalism. Lecture 3 gives an analysis of the content of beliefs about experiences, and applies this to a number of epistemological issues, including incorrigibility and the dialectic on "The Myth of the Given". (shrink)

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. (shrink)

John Perry's book Knowledge, Possibility, and Consciousness is a lucid and engaging defense of a physicalist view of consciousness against various anti-physicalist arguments. In what follows, I will address Perry's responses to the three main anti-physicalist arguments he discusses: the zombie argument (focusing on imagination), the knowledge argument (focusing on indexicals), and the modal argument (focusing on intensions).

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).

This appeared in Philosophy and Phenomenological Research 59:473-93, as a response to four papers in a symposium on my book The Conscious Mind . Most of it should be comprehensible without having read the papers in question. This paper is for an audience of philosophers and so is relatively technical. It will probably also help to have read some of the book. (There is a corresponding precis of the book, written for the symposium.) The papers I'm responding to are: Chris (...) Hill & Brian McLaughlin, There are fewer things in reality than are dreamt of in Chalmers' philosophy Brian Loar, David Chalmers' The Conscious Mind Sydney Shoemaker, On David Chalmers' The Conscious Mind Stephen Yablo, Concepts and consciousness Contents. (shrink)

In Section 5 of his interesting article, Goldman suggests that the consideration of imaginary cases can be valuable in the analysis of our psychological concepts. In particular, he argues that we can imagine a system that is isomorphic to us under any functional description, but which lacks qualitative mental states, such as pains and color sensations. Whether or not such a being is empirically possible, it certainly seems to be logically possible, or conceptually coherent. Goldman argues from this possibility to (...) the conclusion that our concepts of qualitative mental states cannot be analyzed entirely in functional terms. (shrink)

Knock-down refutations are rare in philosophy, and unambiguous self-refutations are even rarer, for obvious reasons, but sometimes we get lucky. Sometimes philosophers clutch an insupportable hypothesis to their bosoms and run headlong over the cliff edge. Then, like cartoon characters, they hang there in mid-air, until they notice what they have done and gravity takes over. Just such a boon is the philosophers' concept of a zombie, a strangely attractive notion that sums up, in one leaden lump, almost everything that (...) I think is wrong with current thinking about consciousness. Philosophers ought to have dropped the zombie like a hot potato, but since they persist in their embrace, this gives me a golden opportunity to focus attention on the most seductive error in current thinking. (shrink)

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. (shrink)

One of the main strategies against conceivability arguments is the so-called phenomenal concept strategy, which aims to explain the epistemic gap between physical and phenomenal truths in terms of the special features of phenomenal concepts. Daniel Stoljar has recently argued that the phenomenal concept strategy has failed to provide a successful explanation of this epistemic gap. In this paper my aim is to defend the phenomenal concept strategy from his criticisms. I argue that Stoljar has misrepresented the resources of the (...) strategy, which can indeed accomplish the required explanatory task, once it is properly understood. (shrink)

The notion of conceivability has traditionally been regarded as crucial to an account of modal knowledge. Despite its importance to modal epistemology, there is no received explication of conceivability. In recent discussions, some have attempted to explicate the notion in terms of epistemic possibility. There are, however, two notions of epistemic possibility, a more familiar one and a novel one. I argue that these two notions are independent of one another. Both are irrelevant to an account of modal knowledge on (...) the predominant view of modal reality. Only the novel notion is relevant and apt on the competing view of modal reality; but this latter view is problematic in light of compelling counterexamples. Insufficient care regarding the independent notions of epistemic possibility can lead to two problems: a gross problem of conflation and a more subtle problem of obscuring a crucial fact of modal epistemology. Either problem needlessly hampers efforts to develop an adequate account of modal knowledge. I conclude that the familiar notion of epistemic possibility (and the very term ‘epistemic possibility’) should be eschewed in the context of modal epistemology. (shrink)

In recent years the 'zombie argument' has come to occupy a central role in the case against physicalist views of consciousness, in large part because of the powerful advocacy it has received from David Chalmers.1 In this paper I seek to neutralize it by showing that a parallel argument can be run for physicalism, an argument turning on the conceivability of what I shall call anti-zombies. I shall argue that the result is a stand-off, and that the zombie argument offers (...) no independent reason to reject physicalism. (shrink)

This paper advances the thesis that we can justifiably believe philosophically interesting possibility statements. The first part of the paper critically discusses van Inwagens skeptical arguments while at the same time laying some of the foundation for a positive view. The second part of the paper advances a view of conceivability in terms of imaginability, where imaginging can be propositional, pictorial, or a combination of the two, and argues that conceivability can, and often does, provide us with justified beliefs of (...) what is metaphysically possible. The notion of scenarios is developed, as is an account of how filling out scenarios can uncover a defeater or, in many cases, strengthen the justification for the relevant possibility statement. (shrink)

The capacity to represent things to ourselves as possible plays a crucial role both in everyday thinking and in philosophical reasoning; this volume offers much-needed philosophical illumination of conceivability, possibility, and the relations between them.

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.".

The current stand-off between reductionists and anti-reductionists about the mental has sparked a long-overdue reexamination of key issues in philosophi- cal methodology.1 The resulting debate promises to advance our understand- ing of how empirical discoveries bear on the numerous philosophical problems which involve the analysis or reduction of kinds. The parties to this debate disagree about how, and to what extent, conceptual facts contribute to justify- ing explanatory reductions.

Zombies are bodies without minds: creatures that are physically identical to actual human beings, but which have no conscious experience. Much of the consciousness literature focuses on considering how threatening philosophical reflection on such creatures is to physicalism. There is not much attention given to the converse possibility, the possibility of minds without bodies, that is, creatures who are conscious but whose nature is exhausted by their being conscious. We can call such a ‘purely conscious’ creature a ghost.