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. -/- .

Chalmers and Jackson (2001) offer an epistemic interpretation of the two-dimensional semantic framework advanced by Kaplan (1979, 1989), Stalnaker (1978), and others. Epistemic two-dimensional semantics (E2D) aims to re-forge the link between necessity and a priority seemingly broken by Kripke (1972/1980). On the E2D strategy, a priori knowledge of certain semantic intensions provides a route to a priori knowledge of a wide range of modal truths---nice outcome, if we can get it. E2D faces the serious challenge, however, that we typically (...) don't have even in-principle a priori access to the intensions at issue (Byrne and Pryor 2006, Melnyk 2001; see also Wilson 1982). As we substantiate, the "access-based challenge" to Chalmers and Jackson's version of E2D is successful; but the problem here isn't for E2D per se, but rather to E2D interpreted as appealing to a conceiving-based epistemology of intensions. Here we develop a version of E2D appealing to abduction rather than conceivability. We argue that abduction gives rise to beliefs that are reasonably taken to be a priori; and we show that E2D when combined with an abductive epistemology of intensions---that is, abductive two-dimensionalism---can successfully respond to the access-based challenge. We finish up with a case study, involving zombies and the mind-body problem, illustrating how the two versions of E2D may differ in application. (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)

The papers in this special issue are all descended from papers presented at the second Online Consciousness Conference. I founded the Online Consciousness Conference at Consciousness Online (http://consciousnessonline.wordpress.com) in 2008 mostly because no one else would. Being inspired by the Online Philosophy Conference, I mentioned to several people that it would be great if we had something like that in Consciousness Studies. People I talked to were very enthusiastic but no one seemed like they wanted to initiate the process. I (...) figured I would give it a shot and have been pleasantly surprised by the results. Papers from the first conference were published in a special issue of the Journal of Consciousness Studies, papers from the second are in this special issue, and papers from the third conference (2011) are due to come out as a book in Springer’s series Studies in Brain and Mind. As I write this I am planning the fourth conference for February 2012. There is no way I could have known back in 2008 how well the conference would be received but I am grateful for that reception. (shrink)

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

Uncorrected proofs for Constructing the World (contents, introduction, chapter 1, and first excursus).

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)

In this paper I examine Chalmers and Jackson’s defence of the a <span class='Hi'>priori</span> entailment thesis, that is, the claim that microphysical truths a <span class='Hi'>priori</span> entail ordinary non-phenomenal truths such as ‘water covers 60% of the Earth surface’, which they use as a premise for an argument against the possibility of a reductive explanation of consciousness. Their argument relies on a certain view about the possession conditions of macroscopic concepts such as WATER, known as ascriptivism. In the paper I (...) distinguish two versions of ascriptivism: reductive versus non-reductive ascriptivism. According to reductive ascriptivism, competent users of a concept have the ability to infer truths involving such concept from lower-level truths, whereas according to non-reductive ascriptivism, all that is required in order to be a competent user of a concept is to be able to infer truths involving that concept from other truths, which need not be lower-level truths. I argue, first, that the a <span class='Hi'>priori</span> entailment thesis is committed to reductive ascriptivism, and secondly, that reductive ascriptivism is problematic because it trivializes the notion of a <span class='Hi'>priori</span> knowledge. Therefore, I conclude that Chalmers and Jackson have not presented a convincing case for the claim that microphysical truths entail ordinary non-phenomenal truths a <span class='Hi'>priori</span>, especially when we understand this claim in the sense that is relevant for their argument against the possibility of a reductive explanation of consciousness. (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)

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.

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)

In this paper I discuss the claim (advanced in various ways by Joseph Levine, Frank Jackson and David Chalmers) that the successful reduction of qualitative to physical states requires some sort of intelligible connection between our qualitative and physical concepts, which in turn requires a conceptual analysis of our qualitative concepts in causal-functional terms. While I defend this claim against some of its recent critics, I ultimately dispute it, and propose a different way to get the requisite intelligible connection between (...) qualitative and physical concepts. (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)