Re: [ontolog-forum] Truth

[Chris Menzel <chris.menzel@xxxxxxxxx>]

On Wed, Jul 11, 2012 at 3:16 PM, John F Sowa <sowa@xxxxxxxxxxx> wrote:

On 7/11/2012 3:13 PM, Pat Hayes wrote:
> They are not context *logics*. There is no provision in CL
> for the referent of any name to vary with contexts.

What?!?!?!?

Where did you get requirement?

From the semantics of CL.

 

For example, many logicians recommend that proper names in
natural languages be mapped to monadic relations in logic
rather than individual constants.

The name Aristotle, for example, would be true of the ancient
philosopher, and it would also be true of the second husband
of Jackie Bouvier.

But that is not how names work in the semantics of Common Logic. Names simply have a denotation. If you introduce objectified contexts into CL (via IKL extensions, say), it doesn't alter how names work. Every name will have exactly the same denotation in every context.

 

If you want a theory in which names can vary with contexts,
then you can map each name in any NL to a dyadic relation
instead of a monadic relation.  The relation Aristotle(X,c),
for example, would be true iff the individual X had the
word 'Aristotle' as name in context c.

But that's not how the semantics of names works in CL. And, anyway, I'm not sure I get it. Is the idea that "Aristotle(Aristotle,c)" be true? Presumably so, because you want Aristotle to be named by 'Aristotle'. But how is that shown by the above, since it doesn't actually involve the name 'Aristotle' as an entity? You can't just say that it is so; it needs to be made so by the axioms and the semantics.

So it seems to me that if the idea in question is to have any purchase, then what you need is a predicate like "NameOf" in the language that holds between persons, names, and (perhaps) contexts. Then you could say things like "NameOf(X,'Aristotle',c). But now you've got names in the language as well as a semantic relation NameOf, and such relations are notoriously prone to paradox and notoriously difficult to axiomatize consistently. Your suggestion is not nearly as simple as you seem to think.

-chris

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