Change of Logic, Change of Meaning

Abstract

There seems to be logical disagreement: philosophers and logicians apparently disagree about whether inference rules like modus ponens are valid and about whether contradictions are ever true. Against this, some philosophers have claimed that despite appearances, advocates of different logics aren't really disagreeing with each other. According to this way of thinking, the logical constants mean different things in the mouths of the warring parties-call this the Change of Logic, Change of Meaning (CLCM) thesis.The CLCM thesis has traditionally been popular amongst philosophers who think that logic is analytic or true in virtue of meaning, but even W.V. Quine, canonical critic of both analyticity and meaning, accepted a version of the thesis. In fact, in Quine's writings we find the most developed statement of an important argument for the CLCM thesis that I call the translation argument. 1 But despite a distinguished history, the CLCM thesis and the translation argument have recently fallen on hard times: when J.C. Beall and Greg Restall presented a novel form of logical pluralism, they took pains to distinguish their brand of pluralism from the CLCM-type, and even despite their efforts, influential commentators like Hartry Field and Graham Priest expressed concerns that the new brand of pluralism collapsed into the older, supposedly discredited CLCM-type. 2 The CLCM thesis is often treated as, if not dead, as being on life support. 3 Against this consensus, I will argue that, pace recent trends in the philosophy of logic, the CLCM thesis is true and a reformulation of Quine's translation argument is sound. Like Quine, I will proceed from a general metasemantic background, without assuming any particular metasemantics for the logical constants. My central concern is philosophical, but at 1

L'argument de Quine contre les logiques déviantes

“…Quine prétend que sa caractérisation des logiques déviantes comme ses arguments s'appliquent autant à la logique paraconsistante qu’à la logique intuitionniste. Or, dans le cas de la logique intuitionniste, rien n'est moins sûr (Morton, 1973, p. 503 ; Warren, 2018, p. 429). En effet, ce qui caractérise le logicien intuitionniste, ce n'est pas qu'il ratifie la négation de la loi du tiers exclu, c'est-à-dire la considère comme fausse, mais qu'il refuse de l'asserter.…”

Resolving Quine's Confict: A Neo-Quinean View of the Rational Revisability of Logic

“…13 I have treated the translation argument and the change of subject argument separately. Compare Warren (2016), who sees the translation argument as an argument for a 'change of logic, change of meaning' thesis, and defends the thesis. §3 Neo-Quinean Revisability So far I have argued that the apparent tension in Quine's work regarding the rational revisability of logic dissolves on analysis.…”

“…For my purposes here, I bracket cases where one neither accepts nor rejects the principle in question (seeWarren 2016) and where elements of the belief base are fuzzy (seeBooth and Richter 2005).3 See for exampleRipley (2013b),Roeper (2004), andBeall (2009).4 For examples of the sorts of reasons for which one might revise, seeBurgess (2012),Dummett (1978b),Field (2003),Haack (1974b) and(1996),Mares (2002),Priest (2006b) and(2008),Putnam (1957) and(1983),Salerno (2000), andWright (1992).5 For arguments that logic is not rationally revisable, seeBerger (2011),Katz (2000, §3.3), andShapiro (2000).6 See Chase (2012) for two formalizations of Quinean revisability.Australasian Journal of Logic (14:1) 2017, Article no. 2…”

Change of logic, without change of meaning

“…Here, evidently, is the deviant logician's predicament: when he tries to deny the doctrine he only changes the subject. (Quine, 1986, p. 81) Traditionally, the passage is considered as advancing the claim that when two parties connect different logical laws and/or inferences with a given connective, they are no longer attributing the same meaning to the connective, and, as a result, are no longer holding different views about the same thing (for a recent defense of this reading, see Warren, 2018). As Jared Warren (2018, p. 423).…”