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 . Ned Block and Robert Stalnaker say no.

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)

In Epistemic Two-Dimensional Semantics, David Chalmers seeks to develop a version of 2-D semantics which can vindicate the rationalist claim that there are constitutive connections between meaning, possibility and a priority. Chalmers lays out different ways of filling in his preferred epistemic approach to 2-D semantics so as to avoid controversial philosophical assumptions. In these comments, however, I argue that there are some distinctively rationalist commitments in Chalmers's epistemic approach to 2-D semantics. I start by explaining why Chalmers's approach requires (...) a canonical language that affords subjects accurate a priori access to the space of possibility. I then argue that traditional worries about rationalism will simply re-emerge as worries about whether there can be a canonical vocabulary and how we could come to recognize one if there were. The moral is that Chalmers's 2-D semantic framework builds in substantive metaphysical and epistemological commitments which stand in need of further defense. (shrink)

It would be nice if good old a priori conceptual analysis were possible. For many years conceptual analysis was out of fashion, in large part because of the excessive ambitions of verificationist theories of meaning._ _However, those days are over._ _A priori conceptual analysis is once again part of the philosophical mainstream._ _This renewed popularity, moreover, is well-founded. Modern philosophical analysts have exploited developments in philosophical semantics to formulate analyses which avoid the counterintuitive consequences of verificationism, while vindicating our ability (...) to know a priori precisely what it is our words and thoughts represent._ _Despite its apparent promise, however, I. (shrink)

Frank Jackson and David Chalmers have suggested that the diagonal intensions defined by their two-dimensional framework can play the two key roles of Fregean senses: they provide a priori accessible extension conditions for a representation and they provide the identity conditions for meanings and thought contents. In this paper, I clarify the nature of the psychological abilities that are needed to underwrite the first role. I then argue that these psychological abilities are not sufficiently stable or cognitively salient to individuate (...) meanings or thought contents. (shrink)