Carnap and Quine on Truth by Convention

The Adoption Problem and Anti-Exceptionalism about Logic

“…As Hjortland notes, Quine is anti-exceptionalism's "most famous proponent". Hjortland(2017) p63110 Carnap (1937) endorses a sufficient amount of the tenants of exceptionalism to qualify as an exceptionalist, particularly with regard to the aspects thatQuine (1951) disagrees with.11Ebbs (2011) gives multiple examples of where this standard story has been assumed in the literature Yablo (1998). p232 also states "That Carnap is widely seen to have lost the ensuing debate is a fact from which the quizzical camp has never quite recovered".12 See Carnap (1937) p1 where he challenges the distinction between rules of logic and rules of syntax and says the logical characteristics of sentences are grounded in their syntactic character.Australasian Journal of Logic (16:7) 2019, Article no.…”

Quine against Lewis (and Carnap) on Truth by Convention

“…2 For examples of those who have denied that this is a debate in any ordinary sense, see Thomas Ricketts (1982) or Alexander George (2000). In a way, Ebbs (2011) is in this tradition. 3 Ebbs also shows that contrary to many interpreters, Quine himself is committed to a kind of truth-by-convention thesis, specifically with regard to set theory, and that this kind of truth by convention is entirely consistent with his own scientific naturalism.…”

“…But then logic is needed already in the metatheory to infer the individual logical truths from the general conventions. Hence, convention cannot provide an account of how the logical truths are true (Ebbs, , p. 195; Quine, , pp. 103–104, 1963, pp.…”

“…According to Ebbs, Quine directs his observation against himself: ‘Quine's criticisms of the thesis that logic is true by convention are not directed against a truth‐by‐convention thesis that Carnap actually held, but are part of Quine's own project of articulating the consequences of his scientific naturalism’ (Ebbs, , p. 193). According to Ebbs, the kind of truth by convention thesis that Quine's observation actually has force against is a view that Quine himself was tempted by at the time of writing ‘Truth by Convention’ (Ebbs, , p. 223).…”

“…According to Ebbs, Quine directs his observation against himself: ‘Quine's criticisms of the thesis that logic is true by convention are not directed against a truth‐by‐convention thesis that Carnap actually held, but are part of Quine's own project of articulating the consequences of his scientific naturalism’ (Ebbs, , p. 193). According to Ebbs, the kind of truth by convention thesis that Quine's observation actually has force against is a view that Quine himself was tempted by at the time of writing ‘Truth by Convention’ (Ebbs, , p. 223). As Ebbs explains this thesis,

The logical truths of a language system LS are all and only those sentences of LS that are true‐in‐ LS solely in virtue of the linguistic conventions for LS , where a sentence s of language system LS is true by convention if and only if the conventions laid down for LS and the inference rules and logical truths of the metalanguage in which those conventions are specified together imply that s is true and thereby explain why s is true, in some scientifically legitimate sense of ‘explain’ (2011, p. 219; Ebbs's italics).

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