A defence of Papineau and mental causes

Abstract

1. In Philosophical Naturalism, David Papineau proposes a nonreductive physicalism consisting of the conjunction of two metaphysical theses. The first thesis concerns supervenience, and asserts that two organisms cannot differ with regard to their intrinsic, nonrelational mental properties without differing with regard to their physical properties. The second is a 'token congruence' thesis, whose purpose is to ward off epiphenomenalism. Epiphenomenalism holds that mental events never cause any physical events; yet according to Papineau's token congruence thesis, 'each dated mental occurrence is the same as some dated physical occurrence, even if we cannot identify the mental type in question with any one physical type' (1993: 12). In Papineau's view, such token congruence is enough to insure a measure of causal efficacy for mental events, and presumably for mental properties as well. Papineau's supervenience thesis is straightforward, and can accommodate relational, as well as nonrelational, mental properties if we allow that they 'supervene, not on the internal physical characteristics of the system at issue, but rather on those plus the physical characteristics of the relevant related system' (1993: 10). As for Papineau's token congruence thesis, note that just as we cannot identify mental types with physical types, in his view, so too we cannot identify mental tokens with physical ones. Papineau rejects token identities because he views causal relata as facts rather than bare particulars (a la Davidson). Since mental causes and physical causes, construed as facts, involve different properties, they cannot be identical. At the same time, Papineau maintains that mental causes are the 'same' as physical causes in the sense that the former are realized by the latter. Such realization is what explains the token congruence of mental and physical tokens, and is to be understood thus: