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RE: New issue - Meaning of URIs in RDF documents

From: pat hayes <phayes@ihmc.us>
Date: Sat, 19 Jul 2003 14:17:28 -0500
Message-Id: <p06001236bb3f475db6a3@[]>
To: "Bullard, Claude L (Len)" <clbullar@ingr.com>
Cc: www-tag@w3.org
>The parts of that which stand out IMO:
>1. The design has provable properties

In order for this to be true, we must understand the terminology 
reasonably precisely, so my responses are predicated on taking the 
claims given here as technical and precise.

>2. URIs denote one thing to all systems that use the URI

That statement does not make sense, taken literally. Denotations are 
not fixed by systems, they are relative to interpretations.

>3. Use of the term commits the user to the owner's definition
>    of the term by contract which all users share.

Again, that does not make strict sense either, since there are no 
definitions of the meanings of most of the URIs in use, and in some 
cases it is straightforward to show that there could not possibly be 
such definitions.

>4. The owner of the term defines it by publishing a document
>    containing its definition at a location named by the URI.

Since there are no definitions, this is likely to be difficult. What 
constitutes a definition of an HTML anchor in HTML?

>Most of the difficulties can be uncovered and clarified by
>ensuring all understand and commit to those four assertions
>about the system.

I refuse to commit to conditions that are either meaningless or 
provably false. I suggest that y'all either find a way to state these 
conditions precisely and meaningfully, or else say nothing about the 

>1a.  What properties are provable and what constitutes
>proof (logical?, analogical (case-based)?)
>2a.  What one "thing" is denoted?  Is this one system
>or a system of systems?  (provable properties?) (Most
>of the angst is in here.)
>3a.  Is the contract established by the act? (provable
>4a.  Does this document have a type or are there
>properties of any document that can prove it is
>eligible to be a defining document?
>I realize the peril of dropping back into the
>philosophical ratholes, but I think that you have
>in those four assertions covered the topics
>that are the essential glue of the system
>architecture with number two being the one
>that gets most of the arguments and for which
>one either accepts the resource/representation
>abstraction or it falls apart definitionally if
>not practically.

Not sure what you mean, but if you feel that the Web architecture 
requires that URIs have unique globally fixed denotations, then you 
are simply wrong. It does not, never has done, and never will do. 
Nothing "falls apart" except theories which are false in any case.

Pat Hayes

>  For example, IMO, "on the web"
>is a provable property and only in the context
>of such a proof is it meaningful which is why
>I suggested the proof of observable dereferenceability
>instead of URI assignment although proof of
>URI assignment may be sufficient.
>Hmmm... one doesn't have to dereference.  One
>has to prove assignment such that dereferencing
>is possible (see #4).
>-----Original Message-----
>From: Tim Berners-Lee [mailto:timbl@w3.org]
>Like with all technical specs, the fact of imperfect adherence in 
>some cases does not detract from the importance of having made the 
>perfect idealistic design which has provable properties
>  .
>Currently, different logical systems can deduce different things, 
>but the important point is that they are talking about the same 
>thing when they use the same URI.
>  .. using a term does (modulo social things such as fraud and 
>engineering things such as broken cables) commit you to the term 
>owner's definition of it, and the document they publish at its URI 
>is taken by design to be information deemed shared by those using 
>the term. That's the contract.

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Received on Saturday, 19 July 2003 15:17:31 UTC

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