[hist-analytic] L-truth, A-truth: Carnap and Grice
Roger Bishop Jones
rbj at rbjones.com
Mon Mar 8 12:52:36 EST 2010
On Monday 08 Mar 2010 14:33, Bruce Aune wrote:
> 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."
Yes, I was on my way to confessing my error, when I found
Its true (as I had said) that Carnap does use only L-
concepts in "Meaning Postulates", but he has already fallen
into line, at least for the purposes of this exposition.
with Quine, and is now using L- concepts for the narrow
notion of logical truth.
Carnap talks here, JL, of logical "particles".
> 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.
Yes, I agree. Though it would have been under the previous
meaning for L-true (had he not made an error in this respect
which this paper is correcting). The correction of the
error in his definition of analyticity (which mirrors one in
the Tractatus) does not depend on the shift in terminology
with which here here concedes on terminology to Quine.
(i.e. the use of L-true for "the narrower conception" of
> 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.
Yes, this he gives as the explicandum of "L-true with
respect to P".
> 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.
This is an odd little alternative, he would have been better
not to mention it.
> 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
That's an interesting explanation of the introduction of the
term. But I don't see how it helps to reduce the confusion
arising from that manner of defining analyticity, which can
only be fixed by dropping the alternative definition.
> 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.
So which earlier terminology is it that you consider
My understanding is that the primary purpose of the "Meaning
Postulates" is to correct an error in "Meaning and
Necessity" which Carnap had inherited by following the
Tractatus too closely in its definition of logical truth.
(this is definition 2-2). For this purpose a change in
terminology is unnecessary, and does not help, though in the
circumstances it was an understandable concession.
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