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

RE: Denotation of URIs

From: <Patrick.Stickler@nokia.com>
Date: Fri, 4 Apr 2003 15:29:36 +0300
Message-ID: <A03E60B17132A84F9B4BB5EEDE57957B5FBB6D@trebe006.europe.nokia.com>
To: <pfps@research.bell-labs.com>, <zednenem@psualum.com>
Cc: <www-rdf-interest@w3.org>



> -----Original Message-----
> From: ext Peter F. Patel-Schneider 
> [mailto:pfps@research.bell-labs.com]
> Sent: 04 April, 2003 15:00
> To: zednenem@psualum.com
> Cc: www-rdf-interest@w3.org
> Subject: Re: Denotation of URIs
> 
> 
> 
> From: David Menendez <zednenem@psualum.com>
> Subject: Denotation of URIs (was: URI for language identifiers)
> Date: Fri, 4 Apr 2003 02:13:02 -0500
> 
> > 
> > At 7:49 PM -0500 2003-04-02, Peter F. Patel-Schneider wrote:
> > >However, even
> > >in this very expansive notion of property there are 
> (still) considerable
> > >``fair use'' provisions.  Hopefully these provisions will not be so
> > >weakened that I will be prohibited from making the claim that the
> > >denotation of http://www.whitehouse.gov/#43 is Tipper 
> Gore's husband.
> > 
> > The only reason anyone might object to that would be if there was 
> > already a widespread understanding that 
> > <http://www.whitehouse.gov/#43> denotes "The 43rd President of the 
> > U.S."
> 
> But even so, one might want to argue that "The 43rd President 
> of the U.S."
> is not George W. Bush.  Requiring a common, fixed denotation 
> for all URI
> references would eliminate this possibility.  (Unless, of 
> course, you meant
> that there was some sort of intensional denotation here.)

Not at all. As I've given examples before, if you want to talk
about the denotation of a URI, you have to reify that URI and
make statements about the URI, not the resource denoted by that
URI.

You can't say 

<http://www.whitehouse.gov/#43> denotes "The 43rd President of the U.S."

to mean that the URI http://www.whitehouse.gov/#43 denotes the 43rd
president of the US. What you've said above is that the resource
denoted by the URI http://www.whitehouse.gov/#43 denotes the 43rd
president of the US, or in other words, the 43rd president of the US
denotes the 43 president of the US.

Rather, you have to reify the URI, e.g.

<uri:http://www.whitehouse.gov/#43> denotes "The 43rd President of the US" .

Now you made a statement about the denotation of the URI. Before, you
just made a statement about the resource denoted by the URI.

And if you wish to disagree with the above, and express that it denotes
something else, you could say e.g.

<uri:http://www.whitehouse.gov/#43> denotes "The Planet Neptune" .

Of course, that doesn't actually *make* the URI denote the Planet Neptune,
but you can still say it does or should.

> > Since the whole point of the SW, at some level, is to 
> communicate, it 
> > seems reasonable to go with the flow. If there is 
> disagreement about 
> > what a particular URI denotes, then it's probably a good 
> idea not to 
> > use it.
> 
> I completely disagree with this.  If you nail down the denotations of
> everything, then why bother with the Semantic Web?  

Eh? Huh? URIs are atomic primitives of the semantic web which allow
us to describe the *things* denoted by those URIs. The point of nailing
down consistent unambiguous denotations is so that we can all talk 
about the same *things* with consistency and clarity (or at least more
consistency and clarity than natural language).

I really wonder what kind of semantic web you are envisioning...

You seem rather to be wanting a semantic web to define the semantic web.
You appear to want a framework below the semantic web for defining the atomic
primitives used by the semantic web. Well, fine and good. Go for it.
But until you provide it, the semantic web will have to operate on
the presumption that URIs are fully opaque, globally unambiguous
names for things and that a given URI always is *supposed* to mean
the same thing (not that there is any guaruntee is actually will).

> It 
> appears to me that
> the benefits of the Semantic Web (over XML, for example) are 
> intimately
> involved with partial and conflicting information.

Sorry, but I will have to see a clear and motivating example of
such a benefit. What you are suggesting sounds irrational to me.
 
Show me the code... Show me a use case... Show me...

And note specifically (and I've tried to stress this before) that
I differentiate between the denotation of a URI and knowledge
expressed about the denoted resource using that URI.

I agree that there can and will be disagreement between statements
about resources denoted by URIs, but there should not be disagreement
about the denotation of the URIs themselves. If there is, then 
how do you even know that you are disagreeing about statements
about a resource, if in fact, you are simply talking about
different resources?

Ambiguity in the SW is anathema, and will always be detrimental.

Yes, SW agents will have to deal with it more or less, but the
less the better.

It is *never* going to be beneficial.

Though feel free to prove me wrong.

> > My friends and I could use a private interpretation where 
> > <http://www.apple.com/> denotes Microsoft, but any data 
> created under 
> > that interpretation would have limited usefulness because 
> we couldn't 
> > share it with the outside world. Particularly since the 
> another point 
> > of the SW is to be less ambiguous than natural language.
> 
> Why could you not share this with the outside world?  Perhaps 
> your view is
> correct.  Perhaps Apple and Microsoft are in reality the same 
> corporation.

I don't think that's what he was suggesting. Rather, that even
though it is known that Apple and Microsoft are different, and
that others use http://www.apple.com to denote Apple, they are
going to use it to denote Microsoft. That's a different case.

Patrick
Received on Friday, 4 April 2003 07:29:40 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Monday, 7 December 2009 10:51:58 GMT