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Re: use/mention and reification

From: Dan Brickley <danbri@w3.org>
Date: Thu, 24 Jan 2002 22:46:00 -0500 (EST)
To: Pat Hayes <phayes@ai.uwf.edu>
cc: <w3c-rdfcore-wg@w3.org>
Message-ID: <Pine.LNX.4.30.0201242230140.27237-100000@tux.w3.org>

Pat,

On Thu, 24 Jan 2002, Pat Hayes wrote:

> First,  all the Superman discussion is very nice, but largely
> irrelevant to RDF. Most of this stuff about who knows which name
> means the same as which other name, de re versus de dicto, etc., only
> really has any content when the language contains some kind of
> equality, ie some way to *say* that two different names (of
> individuals) co-refer. RDF has no way to say this, and isn't likely
> to ever have it, so why are we even venturing into this philosophical
> minefield?

I agree, RDF 1.0 doesn't have a way to *say* that two different names (of
individuals) co-refer. But the Web in which we're deploying it (some say)
*does* allow multiple independently deployed names for the same
individual.  And specs that are built on top of RDF (eg. DAML+OIL,
WebOnt/OWL) do have mechanisms to say things about this feature of the
Web. Applications that use RDF will need to deal with this issue all the
time; it isn't an obscure corner of the technology, but slap in the middle
of what we're trying to do.

A minefield? quite probably. But it's the minefield that we're trying to
deploy RDF and WebOnt in...


		In fact, I'd suggest that any example that involves
> referring to anyone's state of belief, any assertion of co-identity
> (ie of the form this means the same as that, or this name refer to
> what that name refers to), or any assertions about what anyone says
> (when taken literally), should just be ruled out of our discussions
> as irrelevant and probably misleading.

I'd be happy to see belief states avoided in rdfcore discussions.

Co-identity is something I'm not so sure we can punt on, not least because
RDF makes such a fuss about resource identifiers. You've seen the threads
on www-rdf-interest and nearby. Enquiring minds are frequently asking us
questions on just this...

"if two rdf/xml resource descriptions are 'about' different URIs, can we
conclude that they are descriptions of different thingies?",
"can a resource have multiple URIs?" etc etc etc.

It may be that answers to some of the questions need to come from the TAG
rather than RDFCore. But we need to make sure RDF works on the Web, even
if the RDF core specs don't themselves explore every subtlety of Web
architecture.

It's precisely because this area (naming/reference) is such a minefield,
and some aspects of URIs so slippery, that I have a strong preference for
the 'show me the original URI strings' approach to RDF reification.
So what I saw as a minefield avoidance strategy, you saw as just the
opposite...

Dan


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Received on Thursday, 24 January 2002 22:46:01 EST

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