[hist-analytic] Carnap and Grice on "logical"
Roger Bishop Jones
rbj at rbjones.com
Thu Mar 4 07:08:47 EST 2010
On Thursday 04 Mar 2010 06:25, Jlsperanza at aol.com wrote:
> I see, in a way, I was going to say it relates to Grice
> (That's what I _always_ say, right?). But on second
> thoughts, I realise Grice speaks, somewhat irritatingly,
> but I love him, of
> -, &, v, ->, (x), (Ex), ix
> as "formal devices" -- not "logical devices".
> I always thought the correct is "constant", but you may
> teach me out of that!
No, not at all. It was Witters who was adamant that the
logical constants aren't constants.
Actually whether the terminology is appropriate depends on
the particular formal language you are talking about, since
most of them make use of the concept "constant" but they
differ in what things are constants.
So in HOL all the usual suspects really are logical
constants (names which denote entities),
So you can say things like:
(Ex)(x = $/\)
Where the "$" is use to suspend the usual lexical status of
conjunction and allow you to use it (not mention it) without
supplying two things to conjoin.
However, in first order logic, none of the logical operators
In natural languages, who knows?
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