Carnap and Grice on Deviant Logics

--- by J. L. S.
------ for the Carnap Corner

G. RESTALL HAS provided an instantiation of the 'disyunctive syllogism', and R. B. Jones was then rightly moved to reminisce about that encounter with Restall at the Cambridge Centre of Mathematics.

It has to do with 'or'

The dog went to the right or to the left.
The dog didn't go to the right.
----
Ergo, the dog went to the left.


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It was Quine, I would think, who all started it (sic). "Deviant" logics -- later taken up by Susan Haack in her manual. It had, I think, in Quine, to do with 'changing the subject'.

Quine noted that the way to compare the 'classical' logic framework with alternative ones was not an easy one: there were some incompatibilities or incommensurabilities of paradigms (or 'language frameworks', as Carnap would call them in "LSO").

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The point may be Lockean:

"the meaning is what you keep in your head". So, two parrots (to use his example) may be talking 'or', and yet for one parrot it means 'v' and for another it means 'w'. While 'w' can be defined in terms of 'v' (vel), the parrot may not! (do it).

How Grice would react:

I think he would abide by 'language frameworks' alla Carnap, only perhaps would call them 'idiosyncratic' procedures. The word, 'idio-', Grice uses specifically in WoW:
124:

This is Grice's nominalist strategy, as misunderstood by Bennett ("Foundations of Language" -- "The Meaning-nominalist Strategy"):

Grice:

it will be convenient first to
consider the idea of [a gesture, signal]
timeless meaning for an individual
(within a signalling IDIOLECT so to speak)

I prefer idiosyncratic since the signal should not be vocalised (as 'lect-' suggests).

So, when he goes to define his System Q (in honour of Quine) for the Quine festschrift -- and later turned onto System G by Myro -- it's best to regard the introduction of 'or' (and its elimination) as idiolectal, or idiosyncratic. Philosophical problems, for Grice (vide his "Wellesey" lecture in WoW:Part II on 'conceptual analysis') arise from individual problems for a philosopher -- not to respond to a 'social' or 'collective' one:

my philosophical puzzles
have arisen in connection with my
use of [an expression or concept], and my
conceptual analysis will be of value to
me

-- and it is in this context where he does mention 'idiosynrasies', including linguistic, and I'd say, logical ones.

I would asume that "nobody as pluralistic as Carnap" would yield that the System C will have quite a few subdivisions: C', C", C"', etc.