[hist-analytic] L-truth, A-truth: Carnap and Grice

[Bruce Aune]

As I see it, the following quotation from RBJ, though true, is misleading:

"at the last in the Schilpp volume he [Carnap] concedes defeat to the  Quine-Tarski 
conspiracy on use of the term "Logical Truth" and starts using  A-true  
instead of L-true. In "Meaning Postulates" he seems to use the "L-" concepts 
throughout."

In "Meaning Postulates" Carnap did use "L-true" in relation to meaning postulates, but he never considered a meaning postulate L-true or L-false simpliciter. His idea was that a sentence S is analytic in L just when P L-implies S, P being the conjunction of the meaning postulates for L. He extended this harmless way of talking by associating with L a language L' in which sentences of L can loosely be described as L-true: they are L-true in L' if they are L-implied by P.  The so-called L-truths of L' are thus the consequences of L's meaning postulates. Some of these consequences are L-truths in a narrow sense, since  L-truths, narrowly understood, are L-consequences of anything. But describing other P-consequences as L-true in L' is bound to produce confusion in careless readers. For this reason, Carnap began to speak of P-consequences as A-truths. Since L-truths (narrowly understood) are, trivially, consequences of P, they too can be described as A-true, but this is unlikely to cause the kind of confusion prompted by his earlier terminology.

Bruce Aune
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