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Re: A use case for anon nodes - action from telecon

From: Dan Brickley <danbri@w3.org>
Date: Fri, 20 Jul 2001 09:40:33 -0400 (EDT)
To: Graham Klyne <Graham.Klyne@Baltimore.com>
cc: Brian McBride <bwm@hplb.hpl.hp.com>, rdf core <w3c-rdfcore-wg@w3.org>
Message-ID: <Pine.LNX.4.30.0107200934060.30552-100000@tux.w3.org>
On Fri, 20 Jul 2001, Graham Klyne wrote:
[...]
> I'm fine with asserting the existence of the buyer service.  The problem I
> have is that the *description* of the buyer service asserts the existence
> of something that may not actually exist.
>
[...]
> Yet we infer that in one case the goods offered for sale definitely exist,
> but in the other case no assertion is made about their existence.  There
> seems to be no *logical* basis for this difference in interpretation when
> the only difference is a naming difference.
>
> Currently, it seems to me that the Existential-Conjunctive (EC) subset of
> first order logic, hence RDF as I understand it, is incapable of expressing
> the buyer proposition without actually asserting the existence of that
> which is to be purchased.

I think part of the problem here is our natural tendency to take a
commonsense reading of what FOL "there exists" means, ie. reading
existential quantifier as taking about some form of "existence in the
world". If we try to take a strong reading of "there exists" we'll be
bouncing into a whole family of (what I understand to be) fairly well
known puzzles: how do we talk about pictures that depict Unicorns,
future events that may not come to pass etc.

Dan
Received on Friday, 20 July 2001 09:42:09 EDT

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