One of the perils of a mixed philosophy/politics blog is that if I write about one thing too long, I probably lose all my readers who do the other thing. But today we talked about Kripke's Wittgenstein on Rules and Private Language in the Gibbard "Normativity of Meaning" seminar and I want to talk about that with my ~3 remaining philosophical readers.
I don't think the skeptical problem of the first half of the book -- What makes it true that some agent's use of the '+' symbol represents addition rather than quaddition, where you add if the numbers are below 57 and otherwise the answer is 5? -- is a particularly big problem. My two points of contention with Kripke are these:
(1) He neglects the possibility of giving a synthetic reduction of the normativity of meaning.
(2) His objections to an idealized dispositional theory aren't good.
(1) is pretty simple. On page 37, he talks about how the dispositionalist will give a descriptive account of the addition relation. He says that "this is not the proper account of the relation, which is normative, not descriptive." But as naturalistic moral realists using Kripke and Putnam's own theory of reference are aware, normative and non-normative concepts can have the same reduction base. Just as water and H2O (assuming the Putnam intuition which I don't have, but whatever) are concepts that pick out the same property, normative and non-normative concepts can pick out the same property. If you see the dispositionalist as trying to run a synthetic reduction of this sort, the normative/descriptive contrast doesn't have any great significance.
If (2) is right, a dispositional theory can even work as a conceptual analysis, and not merely as a synthetic reduction. I think that one can solve the skeptical problem with an idealized dispositional theory -- you consider a counterfactual situation where people have perfect calculative power, flawless memory, and long enough lifespans to hear the longest numbers for sums. If they would say that 68+57=125 in this situation, they're doing addition, and if they say 5 it's quaddition. Kripke claims that an idealized version of the dispositional theory fails because any idealization sufficient to get addition as a result is so gerrymandered as to be question-begging. The account must have been constructed with the idea of getting addition and not quaddition to be the answer. I think this is far too quick. If we can isolate the set of psychological processes having to do with meaning, we can fix everything else so that those psychological processes will be the ones expressed in behavior. Whether one is an adder or a quadder will depend on what one would do in this counterfactual situation. The question hasn't been begged here -- if the psychological processes having to do with meaning are the right way, the subject will be quadding.