Noa Latham Davidson and Kim on Psychophysical Laws

Nearly 30 years have passed since Donald Davidson first presented his argument against the possibility of psychophysical laws in “Mental Events”. The argument applies to intentional rather than phenomenal properties, so whenever I refer to mental properties and to psychophysical laws it should be understood that I mean intentional properties and laws relating them to physical properties. No consensus has emerged over what the argument actually is, and the subsequent versions of it presented by Davidson show significant differences. But many have been inclined to agree with the spirit of the argument and with its conclusion. Yet it is now commonly held that mental properties strongly supervene on physical properties and that this guarantees that for every mental property M there is a physical property P and supervenience conditional P → M saying that necessarily if something is P then it is M. Such supervenience conditionals would certainly appear to be laws and thus to contradict the conclusion of Davidson’s argument. Jaegwon Kim, one of the pioneers of the work on supervenience, has recently confessed that he firmly believes in psychophysical supervenience laws, yet cannot see what is wrong with the Davidsonian argument as he reconstructs it (Kim 1993, xiii). Davidson’s response to this apparent inconsistency has been to deny the strong psychophysical supervenience that apparently entails supervenience laws, in favour of a weak supervenience that attaches no necessity to the supervenience conditionals (see Davidson 1991). But few follow him in this view. I shall not undertake to examine here the arguments for strong supervenience and against weak supervenience,1 although I shall argue in Section 5 that, given some plausible assumptions, a Davidsonian view of mental states actually entails that there are psychophysical supervenience laws. Others swayed by the argument have preferred reconciliation by accepting strong psychophysical supervenience, but denying that supervenience conditionals or principles count as laws in the sense of ‘law’ used in the Davidsonian argument (or that they are the kind of law that the Davidsonian argument rules out). In Section 1 of this paper I provide some introductory remarks about laws and supervenience. Then in Section 2, I examine the avenues of