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RE: philosophy of SWBPD (was Re: [OPEN] and/or [PORT] : a practical question)

From: Jim Hendler <hendler@cs.umd.edu>
Date: Wed, 31 Mar 2004 15:03:25 -0500
Message-Id: <p06020403bc90d12fe49d@[]>
To: "Uschold, Michael F" <michael.f.uschold@boeing.com>, "Bernard Vatant" <bernard.vatant@mondeca.com>, "SWBPD" <public-swbp-wg@w3.org>


>MFU> Fine, so if you argue that in come cases you want or need 
>inconsistency and it is backed up with practical examples, then by 
>all means let users know that. If users can live with the 
>consequences of being able to prove anything at all, in return for 
>being able to do what they need, then they should be so informed. If 
>users requirements are such than they can get the job done and also 
>have a logically consistent representation, then there is a good 
>chance that it is  going to better serve them than an inconsistent 
>one, all other things being equal.

Ahhh - the root of a lot of our disagreements becomes clear -- in my 
world view, reasoners are not likley to be a major force on the Sem 
Web, and those that are are not likely to last very long if they 
cannot handle inconsistency -- I won't make the argument here, I've 
done it lots of times in many other forums and in print (see my talk 
at ISWC last year [1] for one example) -- thus, I think that the 
claim "being able to prove anything at all" is clearly just plain 
ridiculous for any tool that has any chance of working on the Web. 
So in that light, I have no objection to consistent stuff, I just 
don't see it as the single most important thing to always worry 
about...   but notice Mike, we' ve just turned this into a trade-off 
discussion - so where you said we sometimes have to take sides, I 
just basically think this is harder than you think....


>>4. similar things should be modeled similarly, this also helps perspecuity.
>I think similar things should be modeled differently when used for
>different purposes -
>MFU: no disagreement there, I failed to state an implicit 
>asusmption: all other things being equal. Perhaps we can agree that 
>in general, it is confusing to represent similar things differently 
>if there is no good reason to do so?

I doubt I could agree to this - I have no idea what "all other things 
being equal" means in a dynamic changing system like the Web.

>Look - my goal here isn't to be difficult -- it's to remind everyone
>that we are not writing up "AI Ontology" Best Practices.  We're
>writing up SEMANTIC WEB best practices, and we're still very early in
>that game, largely making it up as we go along.
>MFU: you have a point. The discussion has mostly been about Ontology 
>Engineering (not too surprising given the title of the working 
>group) and not specific to the Semantic Web. The implicit assumption 
>is that ontologies are a foundation for the Semantic Web, so it 
>makes sense to build them to that they best serve their intended 
>purpose.   If you can think of things that should be out of scope 
>for this TF because they do not explicitly address the Semantic Web, 
>ithen say so.

In case anyone hasn't figured it out by now - I THINK IT SHOULD BE 
Working Group.  If you'd like me to state it clearer, let me know 
what to addd

>Let's focus on sharing the things we're learning from applying RDF
>and OWL, not from the previous years of other languages -- they are
>simply not the same
>MFU: this is a suprising claim, given that the core of OWL is 
>basically no more different than any other knowledge/ontology 
>language than any of them are different from each other.  There are 
>some key things that make OWL appropriate for the Web (e.g. URIs), 
>but these are not central to the language in the sense that you can 
>easly remove them and be left with a fully functioning KR/ONTOLOGY 

Yes, but it wouldn't be a SEMANTIC WEB langauge, and thus I would 
argue (see above) this WG should not spend time discussing it

They ARE central to the design of OWL, in the sense that OWL is 
specifically FOR the Web, and thus had to have a few things that 
typical KR/O languages lack.

Yes, and strangely, this makes them SIGNIFICANTLY new and different, 
and this WG, being part of the W3C SEMANTIC WEB activity should 
primarily be concerned with the new aspects.  For all the other 
stuff, we can point them at entire books full of decriptions of best 
practices, and I don't see why we would waste our time as a Working 
Group replicating 50 years of AI work

Professor James Hendler			  http://www.cs.umd.edu/users/hendler
Director, Semantic Web and Agent Technologies	  301-405-2696
Maryland Information and Network Dynamics Lab.	  301-405-6707 (Fax)
Univ of Maryland, College Park, MD 20742	  240-277-3388 (Cell)
Received on Wednesday, 31 March 2004 15:15:53 EST

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