W3C home > Mailing lists > Public > www-rdf-interest@w3.org > April 2003

Re: URI for language identifiers

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Tue, 01 Apr 2003 09:19:34 -0500 (EST)
Message-Id: <20030401.091934.68551093.pfps@research.bell-labs.com>
To: Patrick.Stickler@nokia.com
Cc: miles@milessabin.com, www-rdf-interest@w3.org

From: <Patrick.Stickler@nokia.com>
Subject: RE: URI for language identifiers
Date: Tue, 1 Apr 2003 16:32:09 +0300

> > -----Original Message-----
> > From: ext Miles Sabin [mailto:miles@milessabin.com]
> > Sent: 01 April, 2003 16:10
> > To: www-rdf-interest@w3.org
> > Subject: Re: URI for language identifiers
> > 
> > 
> > 
> > Patrick Stickler wrote,
> > > *How* or *where* a given URI is used does not affect its
> > > authoritative meaning. Usage can only reflect the presumptions
> > > of the user, but that does not usurp the authority fo the owner,
> > > and may very well result in disagreement or ambiguity.
> > 
> > I'm sorry, but this is just wrong.
> > 
> > Other than intrinsic network and DNS semantics, there isn't currently 
> > any notion of an authority for a URI which has semantic relevance to 
> > RDF.
> 
> Either you have not understood what I was saying, or you are simply wrong
> (or both ;-)
> 
> The denotation of a given URI is that which the owner of that URI
> specifies. Period.

Hmm.  Where does this come from?  Can you provide anything besides your own
gut feeling for this?

> And any disagreement about the denotation of a given URI utimately
> must be resolved by the owner of that URI.

Hmm.  Where does the notion of the (unique) owner for (every) URI come
from?   For example, who is the owner of
	http://www.bellllabs.com/user/pfps/#me
Even if there is an owner of a URI, how does that owner determine what a
URI means?  Even if there is some platonic notion of the ultimate meaning
of a URI, how is that meaning conveyed to RDF (or DAML+OIL, or OWL, or
LBase, or any other formal system in the Web)?

> If I mint a URI and say it denotes the city of Paris, France. And
> you come along and use it to denote the city of Paris, Mississippi,
> then you are wrong and I am right, because it's *my* URI. 

How is it your URI?

> It's as
> simple as that. 

This is not simple, it is, instead, extraordinarily complex.  
For example, suppose DC Comics mints a URI reference, 
	http://www.dccomics.com/#clarkkent
what exactly does this denote?  Can I use this as a synonym for
	http://www.dccomics.com/#superman

> The owner of a URI gets to say what it denotes and
> if you don't agree, then don't use that URI. Use of someone elses
> URI is an implicit agreement about what the owner says it denotes
> (leaving aside cases of misunderstanding, etc.)

So how then can I utilize URI references such as 
	http://www.whitehouse.gov/#43
I may want to use this well-known URI as a common source of URI references
for the U. S. presidents, so that I can communicate with other people.
However, I, like Michael Moore, may disagree with the denotation that
www.whitehouse.gov gives to this particular URI reference.  If I have to
use the denotation given by www.whitehouse.gov, then I have no way of even
expressing disagreement with that denotation.

> Likewise, if I have a URI that denotes a document that I wrote and
> of which I am the owner, and I make a statement that e.g. it has
> 4293 characters of textual content in it and you say it has only
> 1882 characters of textual content in it, then my assertion bears
> an authority that yours does not. True, it may very well be that you
> are correct and I might be incorrect, but that doesn't in any way
> change the fact that assertions about a resource made by the 
> owner of the resource bear special authority over assertions made
> by third parties.

Huh?  How?  Why?  What good does this do?

> > Ironically, your claiming that there is such an authority is 
> > an example 
> > of a local ascription of meaning based on idiosyncratic use ;-)
> 
> I don't see that. I think you should re-read my post. Perhaps you
> missed what I was saying...

I don't think so.  I think that Mile's comments are exactly correct.  All
that there is in your post is one person's feelings as to how URI
references are to denote.  Any other person could have a different view of
how URI references are to denote, and that other view would have just as
much validity as your view.

For example, here is a view that I happen to subscribe to

	In any formal system, such as RDF, the denotation of a name
	(including URI references as a special case) is left unspecified.
	Statements in the formal system, including RDF statements, serve
	only as constraints on that denotation.  Any agent (including
	people) choose to believe certain statements, and thus every agent
	can potentially have a different view of the denotation of any
	particular name.

For contrast here is another view, that might be closer to your view

	There is some ultimate, timeless reality.  The denotation of every
	possible name is fixed and unchangeable in this reality.  

This second view appears to be very nice, but there are quite a number of
problems in it, including how to provide a denotation of
	http://www.whitehouse.gov/#46
and
	http://www.dccomics.com/#clarkkent
as well as how to deal with agents whose connection to this ultimate
reality is incomplete or incorrect.

> Patrick

Peter F. Patel-Schneider
Bell Labs Research
Lucent Technologies
Received on Tuesday, 1 April 2003 09:19:49 GMT

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