Re: ER schemas and ontologies
phayes@cs.uiuc.edu (Pat Hayes)
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Date: Mon, 26 Sep 1994 15:10:10 +0000
To: szabo@netcom.com
From: phayes@cs.uiuc.edu (Pat Hayes)
Subject: Re: ER schemas and ontologies
Cc: srkb@cs.umbc.edu, edi-new@tegsun.harvard.edu
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At 9:04 PM 9/24/94 -0500, Fritz Lehmann wrote:
> Nick Szabo wrote on the edi-new@tegsun.harvard.edu list:
>---begin quote---
>>From an information theoretic point of view, it often
>makes much more sense for businesses to specify and evolve
>their own semantics, rather than using semantics imposed from above.
>That's why, for example, industry specific jargon develops.
>That's why, for example, free-form microcomputer software
>such as spreadsheets and word processors are so popular -- they
>allow expression in a near infinity of ways completely unimagined
>by their creators, and thus _unconstrained by_ their creators.
>The people creating "semantic standards" necessarily lack most of
>both the intuitive knowledge and the formal knowledge (laws, contractual
>clauses, managerial procedures, technological details, etc., etc.,
>etc.) of of how business relationships are conducted in the wide
>variety industries that are intended to actually use these semantic
>structures. These "semantic standards" promise to confuse and
>constrain their customers in a multitude of ridiculous ways.
>---end quote----
>
> I think this is an important and valid warning to those
>of us who aspire to ontology-based business systems. The
>cost, howvever, of a lack of ontological foundation is near-
>complete lack of interoperability. .....
Let me agree with Fritz and add a note. Of course it would be ridiculous
for a group of academcs to try to axiomatise the entire commercial world in
some kind of Principia Commercalia, and still more ridiculous, and even
insulting, to call the result a "standard". The idea behind the ontologies
is, as Fritz emphasises, to look at much 'lower' levels; to try to make
precise the meanings of concepts that the folk in the wide world usually
take for granted and do not bother to even discuss. This is also the aim of
the celebrated CYC project, which began with the goal of formalising an
encyclopedia but rapidly discovered itself to be involved with all the
knowledge that was NOT in the encyclopedia, knowledge that the writers had
assumed that their readers already possessed; "common-sense" knowledge, as
it is often called.
And for myself, the aim is not to create a standard in the sense of
deciding on a particular best way of doing anything, but rather to uncover
as exactly as possible the various meanings that these low-level concepts
can be taken to have. At the risk of boring people, let me again use time
as an example. There are at least three distinct, incompatible, ways to
think of the fine structure of the timeline. The differences don't matter a
damn in ordinary conversation, but they are of critical importance if one
is trying to make a coherent, consistent, body of formal knowledge. Getting
them confused them can lead - and indeed has led - to enormous waste of
resources. The point of getting the ontologies "right" is not to choose
betwen any one of these three and insist on it being the 'standard', but to
insist that a formaliser become aware of the distinctions and pay them
attention; and maybe to provide some ready-made formal tools which they can
use for whichever view of time they might find comfortable, and to allow
one system to be able to tell another simply "I use the point-interval
temporal model" and be understood.
Pat Hayes
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