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Re: [ontolog-forum] Role of definitions (Remember the poor human)

To: Pat Hayes <phayes@xxxxxxx>
Cc: "[ontolog-forum]" <ontolog-forum@xxxxxxxxxxxxxxxx>
From: "John F. Sowa" <sowa@xxxxxxxxxxx>
Date: Wed, 14 Feb 2007 18:28:39 -0500
Message-id: <45D39B27.9010007@xxxxxxxxxxx>
Pat,    (01)

There are multiple steps intermediate steps:    (02)

JFS>> We (and many others) have been debating various issues about
 >> ontology for multiple decades without reaching any kind of
 >> agreement.    (03)

PH> I think that is slightly unfair. We have managed to create RDF,
 > OWL, CL and more recently IKL and soon SPARQL. This represents
 > a considerable achievement, IMO.    (04)

Those are indeed important.  But the mere fact that there are so
many variations in the subsets and notations illustrates the number
of options even at the level of first-order logic.  When begin to
talk about things on top of that, the amount of variability increases
even more rapidly.    (05)

PH> If you mean agreement about actual ontological content, no of
 > course we have not reached agreement, and we never will. Neither
 > will any reasonably large group of people. People do all think
 > in the same way.    (06)

Trying to standardize content is equivalent to freezing an encyclopedia.
That is not possible or desirable.  But it is possible to recommend
formats for an organizing encyclopedia or similar resource to facilitate
access and interoperability.    (07)

PH> The best way for a standards-setting body or organization to
 > accommodate something is to ignore it.    (08)

To a certain extent, I agree.  Some of the best standards evolve from
cleaning up and harmonizing a de facto standard.  But first-order
logic was implemented in a large number of formats, none of which had
enough users to be considered a de facto standard.  That was why CL or
something like it was necessary.    (09)

JFS>> As Kathy has emphasized, probabilistic statements are extremely
 >> important for many domains, especially medicine.  They can be
 >> accommodated by one or more levels that are below the facts in
 >> entrenchment.    (010)

PH> Hmm, that is an extremely doubtful claim.    (011)

Which points are you doubting?  That probabilistic statements are
important for many domains?  That there is a similarity between
defaults and statements of probability?  That they can be considered
below factual statements in strength of entrenchment?  That they
should be accommodated by ontologies?    (012)

How would you suggest that probabilities be used in conjunction
with ontologies?    (013)

PH> If we say ANYTHING about this stuff, we are interfering with
 > someone's ability to experiment.  Unless we can say something that
 > (a) is widely agreed throughout a large community and (b) requires
 > uniformity of use in order to achieve interoperability of some kind,
 > then our only responsible action is to keep silent about it.    (014)

There is an enormous difference between expressing an opinion, making
a recommendation, and legislating an official standard.    (015)

PH> I strongly suggest that neither of these criteria are met by this
 > talk of entrenchment levels.    (016)

Entrenchment levels have been implemented in de facto standards
for the past 30 years.  The theoretical issues that underlie the
constraints and updates of a relational DB and the T-box and A-box
of KLONE and other DLs are very closely related.    (017)

The word "entrenchment" and its application to belief revision
systems and other approaches to nonmonotonic reasoning goes back
to R & D from the mid 1980s to the present.  There's a lot of good
work that has been done to explore the issues and test them in
practice.    (018)

Implementers have a right to ignore anybody's recommendations.
But often, they can benefit from helpful suggestions.    (019)

John    (020)

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