W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > January 2002

Re: use/mention and reification

From: Jan Grant <Jan.Grant@bristol.ac.uk>
Date: Tue, 22 Jan 2002 15:54:02 +0000 (GMT)
To: Dan Brickley <danbri@w3.org>
cc: Dan Connolly <connolly@w3.org>, RDFCore Working Group <w3c-rdfcore-wg@w3.org>
Message-ID: <Pine.GSO.4.44.0201221548220.4771-100000@mail.ilrt.bris.ac.uk>
[snipped for brevity to get to the crux of the issue]

On Tue, 22 Jan 2002, Dan Brickley wrote:

> Can we try a variation on this example instead, please? For those who get
> the cultural reference ('clark kent' and 'superman' being two names for
> the same thing, although Lois doesn't know this) it seems to draw out the
> issues nicely. Borrowing from
>  http://plato.stanford.edu/entries/prop-attitude-reports/index.html#amb :
>
> 	lois accepts "Superman is Strong"
> 	(lois does not accept "Clark Kent is Strong")
>
> > where "said" means, "emitted the following symbols"*, where I prefer
> (we could fuss over quite what 'emitted the following symbols' amounts to,
> but its good enough for me. i'm using 'accepts' instead of 'said' but the
> example still works, I think)
>
> > 	jan said that mary had a little lamb
>
> 	lois accepts Superman is Strong
> 	(lois does not accept Clark Kent is Strong)
>
> [substituting co-referring terms...]
>
> 	lois accepts Clark Kent is Strong
> 	(lois does not accept Superman is Strong)

You _do not_ need to quote URI labels on resources to make this
distinction. <foo:superman> and <foo:clarkKent> are labels on resources;
these labels are preserved using my version of reification; and the fact
that an interpretation means they denote "the same thing" isn't a
problem at all.

> So I'm claiming that more often the 'meaning not symbols' (de re) approach
> to rdf reification results in unacceptable information loss

I think it's clear now that it doesn't. Meaning comes from the
application of an interpretation function, which is where "clark kent"
and "superman" collide. Quoting URIs makes no difference here.

> Both forms have their uses. But we can go from a de dicto ascription to de
> re safely (I think...[1]), but not back the other way. Given that
> asymetry, chosing the preserve-the-symbols approach seems pretty
> attractive.

Preserve the resources, maybe, but turning URI labels on them into
strings isn't necessary here.


-- 
jan grant, ILRT, University of Bristol. http://www.ilrt.bris.ac.uk/
Tel +44(0)117 9287088 Fax +44 (0)117 9287112 RFC822 jan.grant@bris.ac.uk
"Roger Penrose can never be convinced that this sentence is true."
(If he doesn't get the joke, you can at least prove that he owes you money.)
Received on Tuesday, 22 January 2002 10:55:53 EST

This archive was generated by hypermail pre-2.1.9 : Wednesday, 3 September 2003 09:43:57 EDT