Carnap and Cooley on "postulate"

By J. L. Speranza


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The idea of a meaning-postulate, especially in the Johnson/Lakoff variant, is one which is familiar with Griceans.

Carnap introduces it in his "Necessity" book with a nod to Cooley. Carnap allows that perhaps the term, 'postulate', _is_ controversial, but then Cooley (1942) had used it in "a similar sense".

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The two he works with in his appendix are

(x) Bx --> - Mx

(with "B" and "M" for bachelor and married, respectively)

and a similar one, minus the "-", of course, with "R" and "Bl" for 'raven' and 'black', for which he proposes a counterexample in terms of state-descriptions challenging its status as such (alleged meaning postulate).

While Johnson/Lakoff play with Gricean ideas in terms of these postulates ("Conversational postulates" in Cole/Morgan) it is to Grice/Strawon, Defense of a dogma (repr. WoW) that we must go for a better elaboration of the Carnap concept.

The term or predicate Grice/Strawson consider in that essay is

adult
3-year old

-- My neighbour's three year old is an adult.

This they deem, intuitively enough (and of course against Quine's 'dogma of empiricism' as he saw it), analytic. It will provoke the counterreply: "That cannot be!"

Grice/Strawson contrast, then

(x)((3YO)x --> - Ax)

with things like

My neighbour's three-year old son understands Russell's theory of types.

This will rather provoke, "I can't _believe_ that!" (rather that, "I fail to understand what you mean") and is thus better NOT seen as a meaning-postulate (Carnap's "All ravens are black" scenario).

Of course with the 'raven-black' the scenario is subtler. My mentor on this has been Thomas Simpson, in a rather obscure book. He goes on to fantasy about the white-raven. Surely an albino raven won't do. We want a genotype of the right phenotype. And the corvus corvus does require 'black' as phenotype, making the thing "almost" "like" a meaning postulate. I know ALL my birder friends will agree!