Re: clarifying clarifying ontologies (Eduard Hovy)
Date: Mon, 7 Aug 1995 19:33:50 -0700
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To: "Kenneth D. Forbus" <>
From: (Eduard Hovy)
Subject: Re: clarifying clarifying ontologies
Cc: (Pat Hayes), (Eduard Hovy), (Fritz Lehmann),,,
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At 7:51 PM 8/7/95, Kenneth D. Forbus wrote:
>With some trepidation, here's my $0.02.  As far as I'm concerned, Pat and
>Doug are right.  Taxonomies of "concepts" (or even "predicates") without
>axioms (or their moral equivalent) that pin down their intended meaning are
>not at all useful.  

This very strong statement might be true for qualitative physics, but it 
certainly isn't for NLP.  Most large NLP systems, parsers and generators, 
find it convenient to use taxonomies of high-level generalizations under 
which their KR symbols are organized.  The most elaborate taxonomizations 
are usually used for Objects, and the least elaborate for Qualities, with 
Processes/Events somewhere in between.  

No doubt if NLP systems performed detailed semantic inference as part of 
their job they'd need the kinds of detailed axioms Ken and Pat are talking 
about, but in practise, for many applications, NLP systems seldom need to 
(instead being asked to operate over so wide a range that constructing 
axioms to support such reasoning is impractical).  Mainly the systems 
tend to need to know what general class of thing (syntactic or semantic, 
depending on the system) a symbol belongs to, in order that it may be 
properly handled.  That's what a taxonomy provides.  

>I don't want to be too negative.  I think the growth of a community that
>takes knowledge representation seriously, that is, is actually committed to
>REPRESENTING KNOWLEDGE in ways that can be combined usefully to ultimately
>create the kind of understanding of intelligence and very smart software
>that we all ultimately want, is a wonderful thing.  But I ask that you
>please don't postpone diving into the deep waters of actually fleshing out
>the knowledge in some particular area(s) in favor of spending all your time
>splashing around in the shallows of taxonomy creation.  

It's not so easy to create useful taxonomies, actually.  Especially when 
you have to worry about 50,000+ symbols.  


Eduard Hovy
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