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Re: [ontac-forum] Neutrality Principle

To: ONTAC-WG General Discussion <ontac-forum@xxxxxxxxxxxxxx>
From: "John F. Sowa" <sowa@xxxxxxxxxxx>
Date: Sun, 27 Nov 2005 11:21:42 -0500
Message-id: <4389DD16.5080709@xxxxxxxxxxx>
Barry,    (01)

That's an excellent question, and controversial
as well:    (02)

 > Building Rome one brick at a time:
 > Will John accept for UF the following definition of
 > part_of between types A and B:
 > A part_of B =def every instance of A is PART of some
 > instance of B
 > where PART is the usual, mereological, instance-level
 > relation of [proper or improper] parthood, as for
 > instance between John's heart and John's body?    (03)

This leads us to the old question:  Is a keyhole a
part of a house?  Most people (and ontologies) would
agree that a door is part of a house, that a lock is
part of a door, and that a keyhole is part of a lock.    (04)

But they might hesitate at keyhole for more than one
reason:  unlimited transitivity of the informal English
"part of" is not universally accepted, and holes raise
ontological issues that are peculiar to "things" that
"consist of" of an absence of stuff.    (05)

Neutrality would imply that if any "major" system,
however we define "major", does not accept transitivity
of partOf, then that axiom should be omitted from UF.    (06)

There are other possible solutions:  introduce a very
general, nontransitive partOf and define the transitive
version as a special case.    (07)

Since the neutrality principle does allow the names of
types and relations to be modified at import and export
time, it would be possible for System X to import
a UF version of partOf by prefixing it as UF_partOf
on import and removing the prefix on export.  Then
System X could add axioms to relate UF_partOf to its
native version of partOf as an identity, a specialization,
or a generalization.    (08)

John Sowa    (09)

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