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Re: My action item on Moby Dec, issue 14, etc

From: Michael Mealling <michael@neonym.net>
Date: Thu, 19 Sep 2002 12:30:34 -0400
To: Tim Bray <tbray@textuality.com>
Cc: Norman Walsh <Norman.Walsh@Sun.COM>, www-tag@w3.org
Message-ID: <20020919123034.H640@bailey.dscga.com>

On Thu, Sep 19, 2002 at 09:15:28AM -0700, Tim Bray wrote:
> Norman Walsh wrote:
> >The error, I think, is that you've brought representations into the
> >picture. The important part about "Absolute URI references are
> >unambiguous: Each absolute URI reference unambiguously identifies one
> >resource." isn't the consistency of the representations you can
> >dereference, it's the fact that they're fully qualified and globally
> >unique. That's why we can paint them on billboards, write them on
> >busses, and flash them in commercials.
> 
> OK, I think that what you're saying is that a resource is simply that 
> which is identified by a URI.  I agree with this and think it's 
> consistent with the 2396 definition too.  Given this, our "principle" is 
> a tautology and not in the slightest worth saying.
> 
> Spin it another way: the URI, and the representations you can (maybe) 
> get with it, are all there is.  There is no point in arguing about the 
> fundamental nature of what the URI identifies and what the 
> representations represent, because (a) you can never know, and (b) it 
> doesn't matter.

I think there's one concept here that we have to keep in mind: URIs are
used in other places besides HTTP and web browsers. Many applications
are using them in places where concepts of 'representations' and 'content
negotiation' are not valid or are are least different from what the TAG
has been considering. I agree with 90% of what's being said in this thread
but I would like at least some verbage in there noting that the concept
of 'representations' is a web specific concept and may not be universal
to all systems that use URIs. 

> Furthermore, in the context of using URIs to build KR systems a la RDF, 
> the notion that you can banish ambiguity by architectural fiat is simply 
> wrong and dangerous to the future of the semantic web. -Tim

I wouldn't say its wrong or dangerous to do so, ever. Its just that its
wrong and dangerous to attempt to do so at a universal architectural level.
RDF (or any other KR system) may create additional constraints on the
types and usage of URIs within the system and IMHO, that's perfectly valid.

I would state your second paragraph slightly differently:

The URI, and the conceptual resource it identifies, are all there is 
universally.  There is no point in arguing about the fundamental nature 
of what the URI identifies and what the representations represent, 
because (a) you can never know universally, and (b) it doesn't matter. 
Systems that make use of URIs can and do specify concepts such as 
representations, content negotiation, resource equivalence, etc but 
these concepts are internal to those application, not universal to
all URIs or to all systems that use them.

-MM

-- 
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Michael Mealling	|      Vote Libertarian!       | urn:pin:1
michael@neonym.net      |                              | http://www.neonym.net
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Received on Thursday, 19 September 2002 12:32:29 GMT

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