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SEM: "natural" entailments

From: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Date: Tue, 27 Aug 2002 05:24:29 +0100
Message-ID: <3D6AFEFD.10803@hpl.hp.com>
To: www-webont-wg@w3.org


Thread: Re: revised version of semantics document
deep in this thread, Peter wrote:
 > Why should anyone care at all about the entailment rules?


This seems a crucial question.

If, we insist that the entailments we have are the "natural" entailments 
then I think we end up with a lot of work. Not least, arguing about what is 
natural - (we could easily wonder whether God is a web ontologist!).

My view is that the key role of the entailments is clarification.

Yes, of course, we all know that if John is a student and John is an 
employee then John is both a student and an employee. How does this piece 
of our knowledge get expressed in our language.

So far we have two candidates.

Peter's entailment, in which this "natural" fact appears; and Jeremy/Jos's 
solipsistic version, in which you have to posit the existence of "both a 
student and an employee".

The point about these two candidates is that they are different, and we 
understand the difference. By the time we are finished we will have chosen 
one or the other as the entailment supported by Owl. The Owl documents will 
then line up to show how the entailment or non-entailment holds (or does not).

After this we will have been clear.

That's it. That's why this is important.

Nothing we will say will stop the "natural" entailment from being the one 
that actually matters in practice to an application, but we can decide how 
much of that entailment to give to the application on a plate, and how much 
is outside the scope of what we are doing. The entailments will help us 
communicate to ourselves and our users the choices that we make.

I don't see any a priori reason why set theoretic truths have any greater 
need to be included in Owl than arithmetic truths.
  Both set thery and arithmetic are really somebody else's concern.


Jeremy
Received on Tuesday, 27 August 2002 01:03:07 GMT

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