Thursday, September 22, 2016

An argument against pain being identical with c-fibre firing

Here's the slide I promised to make available from yesterday's talk. For X and Y substitute eg pain and c-fibre firing or red and reflects light of wavelength x. Note the argument does not work for heat and molecular motion, or water and H2O, because premise (iv) is then false. But is the argument cogent for pain and c-fibre firing?

Notice that, unusually, this conceivability argument turns not on what is conceivable (e.g. pain without c-fibre firing, zombies, etc.), but on what is inconceivable.

Why suppose (iv) is true for pain? Because it appears to be part of the concept of pain that one cannot be mistaken about whether one is experiencing it (at least in core cases). Hence there is a conceptual obstacle to imagining fool's pain (fool's pain = feels like pain but isn't really pain). But if pain were c-fibre firing, no such conceptual obstacle would exist (or indeed would exist if pain was potentially identifiable with any physical property at all; hence this conceptual truth about pain (that fool's pain is impossible) entails pain cannot be identified with any physical property at all).

This is the argument I attribute to Kripke in his Naming and Necessity. Notice it differs from that commonly attributed to Kripke by eg Brian Loar. As applied to colour, the above argument also seems to me to be presented by Colin McGinn in his The Subjective View as an argument against identifying red with a physical property such as reflecting a particular wavelength of light, and as part of his a priori, conceptual case for saying colour is a secondary quality.

For more see my paper Loar's Defence of Physicalism.

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