The major divide in contemporary epistemology is between those who embrace and those who reject a priori knowledge. Albert Casullo provides a systematic treatment of the primary epistemological issues associated with the controversy. By freeing the a priori from traditional assumptions about the nature of knowledge and justification, he offers a novel approach to resolving these issues which assigns a prominent role to empirical evidence. He concludes by arguing that traditional approaches to the a priori, which focus primarily on the (...) concepts of necessity and analyticity, are misguided. (shrink)

Many important metaphysical arguments validly deduce an actuality from a possibility. For example: Because it is possible for me to exist in the absence of anything material, I am not my body. I argue that there is no reason to suppose that our capacity for modal judgment is equal to the task of determining whether the "possibility" premise of any of these arguments is true. I connect this thesis with Stephen Yablo's recent work on the epistemology of modal statements.

Confronted with the apparent explanatory gap between physical processes and consciousness, there are many possible reactions. Some deny that any explanatory gap exists at all. Some hold that there is an explanatory gap for now, but that it will eventually be closed. Some hold that the explanatory gap corresponds to an ontological gap in nature.

are synthetic a priori judgements possible?" In both cases, i~thas usually been t'aken for granted in fife one case by Kant that synthetic a priori judgements were possible, and in the other case in contemporary,'d-". philosophical literature that contingent statements of identity are ppss. ible. I do not intend to deal with the Kantian question except to mention:ssj~".

A transcript of three lectures, given at Princeton University in 1970, which deals with (inter alia) debates concerning proper names in the philosophy of language.

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)

I argue that zombies are inconceivable. More precisely, I argue that the conceivability-intuition that is used to demonstrate their possibility has been misconstrued. Thought experiments alleged to feature zombies founder on the fact that, on the one hand, they _must_ involve first-person imagining, and yet, on the other hand, _cannot_. Philosophers who take themselves to have imagined zombies have unwittingly conflated imagining a creature who lacks consciousness with imagining a creature without also imagining the consciousness it may or may not (...) possess. (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 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)

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’s impact on modal arguments in the philosophy of mind -- for example, Yablo’s disembodiment argument and Chalmers’s zombie argument. A less (...) vulnerable style of modal argument is defended, which nevertheless wins the same anti-materialist conclusions sought by these other arguments. (shrink)

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 , from there to a modal claim , and from there to a metaphysical claim.

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 explanatory gap . Consciousness is a mystery. No one has ever given an account, even a highly speculative, hypothetical, and incomplete account of how a physical thing could have phenomenal states. Suppose that consciousness is identical to a property of the brain, say activity in the pyramidal cells of layer 5 of the cortex involving reverberatory circuits from cortical layer 6 to the thalamus and back to layers 4 and 6,as Crick and Koch have suggested for visual consciousness. .) (...) Still, that identity itself calls out for explanation! Proponents of an explanatory gap disagree about whether the gap is permanent. Some say that we are like the scientifically naive person who is told that matter = energy, but does not have the concepts required to make sense of the idea. If we can acquire these concepts, the gap is closable. Others say the gap is uncloseable because of our cognitive limitations. Still others say that the gap is a consequence of the fundamental nature of consciousness. (shrink)

The book is an extended study of the problem of consciousness. After setting up the problem, I argue that reductive explanation of consciousness is impossible , and that if one takes consciousness seriously, one has to go beyond a strict materialist framework. In the second half of the book, I move toward a positive theory of consciousness with fundamental laws linking the physical and the experiential in a systematic way. Finally, I use the ideas and arguments developed earlier to defend (...) a form of strong artificial intelligence and to analyze some problems in the foundations of quantum mechanics. (shrink)

The explanatory gap. Consciousness is a mystery. No one has ever given an account, even a highly speculative, hypothetical, and incomplete account of how a physical thing could have phenomenal states. (Nagel, 1974, Levine, 1983) Suppose that consciousness is identical to a property of the brain, say activity in the pyramidal cells of layer 5 of the cortex involving reverberatory circuits from cortical layer 6 to the thalamus and back to layers 4 and 6,as Crick and Koch have suggested for (...) visual consciousness. (See Crick (1994).) Still, that identity itself calls out for explanation! Proponents of an explanatory gap disagree about whether the gap is permanent. Some (e.g. Nagel, 1974) say that we are like the scientifically naive person who is told that matter = energy, but does not have the concepts required to make sense of the idea. If we can acquire these concepts, the gap is closable. Others say the gap is uncloseable because of our cognitive limitations. (McGinn, 1991) Still others say that the gap is a consequence of the fundamental nature of consciousness. (shrink)

One does not have to agree with the main conclusions of David Chalmers’s book in order to find it stimulating, instructive, and frequently brilliant. If Chalmers’s arguments succeed, his achievement will of course be enormous; he will have overthrown the materialist orthodoxy that has reigned in philosophy of mind and cognitive science for the last half century. If, as I think, they fail, his achievement is nevertheless considerable. For his arguments draw on, and give forceful and eloquent expression to, widely (...) held intuitions; seeing how they go astray, if they do, cannot help but deepen our understanding of the issues he is addressing. (shrink)

One does not have to agree with the main conclusions of David Chalmers’s book in order to find it stimulating, instructive, and frequently brilliant. If Chalmers’s arguments succeed, his achievement will of course be enormous; he will have overthrown the materialist orthodoxy that has reigned in philosophy of mind and cognitive science for the last half century. If, as I think, they fail, his achievement is nevertheless considerable. For his arguments draw on, and give forceful and eloquent expression to, widely (...) held intuitions; seeing how they go astray, if they do, cannot help but deepen our understanding of the issues he is addressing. (shrink)

_Naming and Necessity_ has had a great and increasing influence. It redirected philosophical attention to neglected questions of natural and metaphysical necessity and to the connections between these and theories of naming, and of identity. This seminal work, to which today's thriving essentialist metaphysics largely owes its impetus, is here reissued in a newly corrected form with a new preface by the author. If there is such a thing as essential reading in metaphysics, or in philosophy of language, this is (...) it. (shrink)

Philosophical zombies are exactly as physicalists suppose we are, right down to the tiniest details, but they have no conscious experiences. Are such things even logically possible? My aim is to contribute to showing not only that the answer is 'No', but why. My strategy has two prongs: a fairly brisk argument which demolishes the zombie idea; followed by an attempt to throw light on how something can qualify as a conscious perceiver. The argument to show that zombies are impossible (...) exploits the point that in order to be able to detect our own 'qualia' we should have to be somehow sensitive to them; which the zombie idea rules out. The attempt to make clear why my zombie twin must be conscious exploits the idea that we have a reasonably clear grasp of a 'Basic Package' of psychological concepts. (shrink)

Philosophical zombies are exactly as physicalists suppose we are, right down to the tiniest details, but they have no conscious experiences. Are such things even logically possible? My aim is to contribute to showing not only that the answer is 'No', but why. My strategy has two prongs: a fairly brisk argument which demolishes the zombie idea; followed by an attempt to throw light on how something can qualify as a conscious perceiver. The argument to show that zombies are impossible (...) exploits the point that in order to be able to detect our own 'qualia' we should have to be somehow sensitive to them; which the zombie idea rules out. The attempt to make clear why my zombie twin must be conscious exploits the idea that we have a reasonably clear grasp of a 'Basic Package' of psychological concepts. (shrink)

In this paper I argue that certain so-called conceivability arguments fail to show that a currently popular version of physicalism in the philosophy of mind is false. Concentrating on an argument due to David Chalmers, I first argue that Chalmers misrepresents the relation between conceivability and possibility. I then argue that the intuition behind the conceivability of so-called zombie worlds can be accounted for without having to suppose that such worlds are genuinely conceivable. I conclude with some general remarks about (...) the nature of conceivability. (shrink)

Do facts about water have a priori, transparent, reductive explanations in terms of microphysics? Ned Block and Robert Stalnaker hold that they do not. David Chalmers and Frank Jackson hold that they do. In this paper I argue that Chalmers.

One does not have to agree with the main conclusions of David Chalmers’s book in order to find it stimulating, instructive, and frequently brilliant. If Chalmers’s arguments succeed, his achievement will of course be enormous; he will have overthrown the materialist orthodoxy that has reigned in philosophy of mind and cognitive science for the last half century. If, as I think, they fail, his achievement is nevertheless considerable. For his arguments draw on, and give forceful and eloquent expression to, widely (...) held intuitions; seeing how they go astray, if they do, cannot help but deepen our understanding of the issues he is addressing. (shrink)

The leading arguments supporting the existence of a priori knowledge fall into three broad categories: conceptual arguments, which offer an analysis of the concept of a priori knowledge and maintain that some knowledge satisfies the conditions in the analysis; criterial arguments, which identify criteria of the a priori, such as necessity, certainty, and irrefutability, and maintain that some knowledge satisfies the criteria; and deficiency arguments, which allege that radical empiricist theories of knowledge are deficient in some respect, and that the (...) only remedy for the deficiency is to embrace the a priori. This chapter contends that these arguments fail: the conceptual arguments involve implausible conceptions of a priori knowledge; the criterial arguments involve false epistemic premises; and the deficiency arguments fail because theories endorsing the a priori suffer from the same deficiencies alleged to plague radical empiricism. (shrink)