Discussion of Frank Jackson’s a priori entailment thesis – which he employs to connect metaphysics and conceptual analysis. In From Metaphysics to Ethics. (2001) he develops this thesis within the two-dimensional framework and also proposes a formal argument for the existence of a priori truths. I argue that the two-dimensional framework doesn’t provide independent support for the a priori entailment thesis since one has to build into the framework assumptions as strong as the thesis itself.

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)

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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Can phenomenal consciousness be given a reductive natural explanation? Exponents of an.

Is conceptual analysis required for reductive explanation? If there is no a priori entailment from microphysical truths to phenomenal truths, does reductive explanation of the phenomenal fail? We say yes (Chalmers 1996; Jackson 1994, 1998). Ned Block and Robert Stalnaker say no (Block and Stalnaker 1999).

This paper is a defence of Terence Horgan’s claim that any genuinely physicalist position must distinguish itself from (what has been traditionally known as) emergentism. I argue that physicalism is necessarily reductive in character -- it must either give a reductive account of apparently non-physical entities, or a reductive explanation of why there are non-physical entities. I argue that many recent ‘nonreductive’ physicalists do not do this, and that because of this they cannot adequately distinguish their view from emergentism. The (...) conclusion is that this is the real challenge posed by Joseph Levine’s ‘explanatory gap’ argument: if physicalists cannot close the explanatory gap in Levine’s preferred way, they must find some other way to do it. Otherwise their view is indistinguishable from emergentism. (shrink)

One strategy for blocking Chalmers's overall case against physicalism has been to deny his claim that showing that phenomenal properties are in some sense physical requires an a priori entailment of the phenomenal truths from the physical ones. Here I avoid this well-trodden ground and argue instead that an a priori entailment of the phenomenal truths from the physical ones does not require an analysis in the Jackson/Chalmers sense. This is to sever the dualist's link between conceptual analysis and a (...) priori entailment by showing that the lack of the former does not imply the absence of the latter. Moreover, given the role of the argument from conceptual analysis in Chalmers's overall case for dualism, undermining that argument effectively undermines that case as a whole in a way that, I'll argue, undermining the conceivability arguments as stand-alone arguments does not. (shrink)

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.

Physicalists are committed to the determination without remainder of the psychological by the physical, but are they committed to this determination being a priori? This paper distinguishes this question understood de dicto from this question understood de re, argues that understood de re the answer is yes in a way that leaves open the answer to the question understood de dicto.

Frank Jackson champions the cause of conceptual analysis as central to philosophical inquiry. In recent years conceptual analysis has been undervalued and widely misunderstood, suggests Jackson. He argues that such analysis is mistakenly clouded in mystery, preventing a whole range of important questions from being productively addressed. He anchors his argument in discussions of specific philosophical issues, starting with the metaphysical doctrine of physicalism and moving on, via free will, meaning, personal identity, motion, and change, to ethics and the philosophy (...) of color. In this way the book not only offers a methodological program for philosophy, but also casts new light on some much-debated problems and their interrelations. (shrink)

Suppose P is the conjunction of all truths statable in the austere vocabulary of an ideal physics. Then phsicalists are likely to accept that any truths not included in P are different ways of talking about the reality specified by P. This ‘redescription thesis’ can be made clearer by means of the ‘strict implication thesis’, according to which inconsistency or incoherence are involved in denying the implication from P to interesting truths not included in it, such as truths about phenomenal (...) consciousness. Commitment to the strict implication thesis cannot be escaped by appeal to a posteriori necessary identities or entailments. A minimal physicalism formulated in terms of strict implication is preferable to one based on a priori entailment. (shrink)

According to the self-representational theory of consciousness – self- representationalism for short – a mental state is phenomenally conscious when, and only when, it represents itself in the right way. In this paper, I consider how self- representationalism might address the alleged explanatory gap between phenomenal consciousness and physical properties. I open with a presentation of self- representationalism and the case for it (§1). I then present what I take to be the most promising self-representational approach to the explanatory gap (...) (§2). That approach is threatened, however, by an objection to self-representationalism, due to Levine, which I call the just more representation objection (§3). I close with a discussion of how the self-representationalist might approach the objection (§4). (shrink)

among them Joseph Levine, David Chalmers, Frank Jackson and Jaegwon Kim?have claimed that there are conceptual grounds sufficient for ruling out the possibility of a reductive explanation of phenomenal consciousness. Their claim assumes a functional model of reduction (regarded by Kim as an alternative to the traditional Nagelian model) which requires an a priori entailment from the facts in the reduction base to the phenomena to be explained. The aim of this paper is to show that this is an unreasonable (...) requirement?a requirement that no reductive explanation in science should be expected to satisfy. I argue that the functional model is not substantively different from the Nagelian model properly understood, and that the question whether consciousness is reductively explainable?in a sense involving property identifications or in some weaker sense compatible with Nagelian reduction?is a fundamentally empirical question, not one that can be settled on conceptual grounds alone. Introduction Kim's critique of the Nagelian model of reduction The functional model of reduction Is consciousness reducible? Psychophysical reduction: concluding remarks. (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.

From Plato down to the logical empiricists, philosophers assumed that all empirical knowledge must rest on apriori semantic foundations. According to this philosophical tradition, empirical knowledge is possible only if the subject has an implicit apriori understanding of what it is her words and concepts refer to. You can.

What has come to be known as “a priori physicalism” is the thesis, roughly, that the non-physical truths in the actual world can be deduced a priori from a complete physical description of the actual world. To many contemporary philosophers, a priori physicalism seems extremely implausible. In this paper I distinguish two kinds of a priori physicalism. One sort – strict a priori physicalism – I reject as both unmotivated and implausible. The other sort – liberal a priori physicalism – (...) I argue is both motivated and plausible. This variety of a priori physicalism insists that the necessitation of non-physical truths by the physical facts must be underwritten in a certain fashion by a priori knowledge, but the a priori knowledge need not amount to a simple deduction of the non-physical truths from a complete physical description of the world. Further, this sort of liberal a priori physicalism has the advantage that it offers hope for a genuinely satisfying account of how the physical facts manage to necessitate the facts about phenomenal consciousness – thereby in effect solving the “hard problem” of consciousness. The first half of the paper sets out the motivation for liberal a priori physicalism and its superiority to the strict version; the second half presents one strategy available to the liberal a priori physicalist for showing how consciousness can be accommodated in a purely physical world. (shrink)