Consciousness, Conceivability, and Intrinsic Reduction

Abstract

Conceivability arguments (Descartes in Discourse on method; and, meditations on first philosophy, Hackett Pub. Co, Indianapolis, 1993; Kripke in: Munitz (ed) Identity and Individuation, New York University Press, New York, pp 135–164, 1971; Kripke in Naming and necessity, Harvard University Press, Cambridge 1980; Jackson in Philos Stud 42(2):209–225, 1982; Chalmers in The conscious mind: in search of a fundamental theory, Oxford University Press, Oxford, 1996; Chalmers in: Chalmers (ed), The character of consciousness, Oxford University Press, Oxford, 2010) constitute a serious threat against reductive physicalism. Recently, a number of authors (Bayne in Philosophia 18:265–270, 1988; Marton in Southwest Philos Rev 14(1):131–138, 1998; Sturgeon in Matters of mind: consciousness, reason, and nature, Routledge, Abingdon, 2000; Frankish in Philos Q 57(229):650–666, 2007; Brown in J Conscious Stud 17(3–4):47–69, 2010; Campbell et al. in Philos Q 67(267):223–240, 2017; VandenHombergh in Analysis 77(1):116–125, 2017) have proven and characterized a devastating logical truth, (IN), centered on these arguments: namely, that their soundness entails the inconceivability of reductive physicalism. In this paper, I demonstrate that (IN) is only a logical truth when reductive physicalism is interpreted in its stronger, intrinsic sense (e.g., as an identity theory), as opposed to its weaker—yet considerably more popular—extrinsic sense (e.g., as a supervenience theory). The basic idea generalizes: perhaps surprisingly, stronger (intrinsic) forms of reduction are uniquely resistant to the conceivability arguments opposing them. So far as the modal epistemology of reduction is concerned, therefore, it pays to go intrinsic.