Quine: Normativity and logic

Starting in two weeks, Arché's two Professorial Fellows, Graham Priest and Stewart Shapiro, will be giving a research seminar on Quine, relating different aspects of his philosophy to the Arché projects: logic and normativity, philosophy of mathematics, vagueness, and modality. There will be two sessions a week, all going through key texts from Quine's bibliography plus important responses to Quine's work.

Must say that I particularly look forward to the logic and normativity part, since this was one of the topics I wrote on during my M.Litt. Famously, Quine argued in his Philosophy of Logic that the classicist and the deviant logician talked past eachother when arguing over the meaning of connectives. On Quine's account, there is no real disagreement, only talk of different logical constants. Incidentally, Stephen Read just stressed earlier today that accepting such an argument has an important impact on the monism/pluralism debate in the philosophy of logic. The question "which logic is the right logic?" (adopted from Tharp's classical 1975 paper, arguing against Quine), is left hanging if the classicist and the deviant talk past eachother when trying to establish the superiority of their logic.

One paper which applies this Quinean insight is McGee and McLaughlin's 'Distinctions Without a Difference' (1994):

An observation of Quine is worth repeating: we cannot hope to determine the correct rules of inference by a semantic investigation, trying to determine which rules are truth-preserving, because the same question 'What are the legitimate rules of inference?' is going to recur as we try to develop the metatheory. The meaning of the logical connectives cannot be given by the metatheory, because the very same connectives are employed in the metalanguage. Instead, what determines what the connectives mean are the inferences in which we employ them; the rules of inference implicitly define the connectives. People who employ different rules of inference mean different things by connectives; so they are inevitably talking at cross purpose. (p. 206)

McGee and McLaughlin conjures this argument up from the hat in the context of vagueness, but I will not go into details about that now (in a word, McGee and McLaughlin wants to justify keeping CL for the sorites argument, and instead denying the sorites premise). Rather, I want to briefly consider the argument in its own right. Because, although McGee and McLaughlin calls it an observations, it certainly looks more like an argument to me. Actually, the manner in which the "observation" is presented by the authors belies the fact that not all of this is entirely uncontroversial. I agree with the inferentialist position, but it does not follow from inferentialism for logical constants that there can be no question of which rules are appropriate (in a given discourse), or which rules are "right" in some normative sense. In fact, Dummett holds precisely this position: inferentialism in conjunction with revisability of use, i.e., revisability of logical laws (see for instance Dummett 1991, ch. 8-9, in particular pp. 209-215).

There will be more on these issues later. For now, read an interesting post by Colin Caret.