Kripke says that physicalists like me can't explain the 'apparent contingency' of mind-brain identities. He maintains that, if I really believed that pains are C-fibres, then I ought no longer to have any room for the thought that 'they' might come apart. His argument is that, since pains aren't identified via some contingent description, but in terms of how they feel, I have no good way of constructing a possible world, so to speak, where C-fibres are present yet pains absent.
David PapineauIf neuroscientific research shows that those mechanisms only contain comparative information about colour differences, and have 'thrown away' more fine-grained information about the absolute colours of single surfaces, then that would support my position, in a way that just introspecting our colour experiences can't.
David PapineauIn truth a clear-headed physicalist shouldn't be thinking any of these dualist thoughts. If pains are one and the same as C-fibres firing, then there really isn't any possibility of having 'one' without the 'other'. Once you properly appreciates physicalism, this dissociation should cease to appear possible - C-fibres with pains should strike you as no more possible than squares without rectangles.
David PapineauEverybody agrees that a future in which you are dead is a very bad thing, and that it isn't made any better by your not being around to notice how bad it is.
David PapineauI favour an interpretation of quantum mechanics (the 'Everett interpretation') according to which reality branches in any chancy quantum situation. On this view, Schrรถdinger's set-up will give rise to in two future branches of reality, one with a live cat, and one with a dead cat - and the talk of '50% chances' just indicates that the two branches are both equally real futures of the cat that originally entered the box.
David Papineau