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Re: Denotation of URIs

From: Bill de hÓra <dehora@eircom.net>
Date: Fri, 11 Apr 2003 10:21:10 +0100
Message-ID: <3E968906.5030100@eircom.net>
To: Patrick.Stickler@nokia.com
CC: pfps@research.bell-labs.com, www-rdf-interest@w3.org

Patrick.Stickler@nokia.com wrote:

> If researchers want to grapple with the problem of ambiguity of
> denotation in knowledge bases, fine, but ambiguity should not be
> considered an acceptable characteristic of the SW architecture and
> should be guarded against, flagged, and fixed always.

Certainly, but it is unwise to expect it can be eradicated.


> Ambiguity of denotation on the SW will *always* be detrimental.

But to think it won't be there or can simply be architected out of 
existence is simpleminded positivism.


> Ambiguity of URI denotation on the SW will happen, but will always be bad.

My objection to your opinion is this: a semantic web system that 
can't or won't deal with ambiguity and prefers a perscriptive rather 
than descriptive approach is consigned to being a toy system. IMO, 
history bears this objection out. Insisting that the entire domain 
of the semantic web be a toy isn't going to have a happy ending. I 
hope at least we can learn *something* from 50 years of AI research.

I feel an 'eight fallacies of the semantic web' is needed.


> But there are different ways of dealing with it. One can presume
> unambiguous denotation and when one gets undesirable/unreliable
> results from a SW reasoner, one can identify the source of the
> the problem and either correct it or exclude that source from 
> ones reasoning due to being unreliable/untrusted.

It's good that we're recognizing the need to keep people in the 
reasoning loop, to deal with the ambiguity. So, I wonder whether we 
have any idea if housekeeping these knowledge bases is a viable 
task. Should we expect a rehash of the expert systems debacle? Or 
perhaps Forbus and De Kleer will become a deserved best seller if 
they port their code to Perl ;)


> The SW agent itself need not have any other presumption but that
> URIs have unambigous denotation.

That makes total sense. The problem with the current architecture is 
that it has no layer in its cake for distribution of denotations. 
There's RDF on the web, magic happens, and out comes a graph. This 
unfortunately involves URIQA, which without architectural guidance 
is a patch. I think that speaks quite badly of the architecture, 
rather than your program, which I'm really looking forward to.


> I guess time will tell which position is correct.

We don't need to wait to find that out - being correct is 
irrelevant. Utility is king in a complex system. It's evident that 
inference engines are inadequate for complex environments - they 
require filters to makes sense of the world. Layered architectures 
derived from robotics, insects and search engines are much more 
useful than inference engines and theorem provers or handwaving 
about architecture. As a matter of fact, the scruffy approach is 
already winning the argument, without resorting to five year plans - 
any ability to do logical inference with symbols is simply a useful 
optimization to a system predicated on statistical processing. And 
the chances are most of things people will want to do with the 
semancic web will tolerate a level of ambiguity that makes building 
the damn thing cost-effective. Anyone who needs more precision will 
have to pay for it, that's how engineering works.


> Then I think that you and I will not be using the same semantic web.

Yes, you'll be using a subset.

Bill de hÓra
-- 
Sorry, I don't know the word "sorry".- SHRDLU
Received on Friday, 11 April 2003 05:22:38 GMT

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