Pat and Nicola, (01)
Before we can make a good case to present to the world,
we have to make a good case among ourselves. (02)
PC> I think that the comments of Mills Davis (below, sent to
> Brand Niemann) provide a good example of the work that the
> upper ontology community has to do in order to explain to
> the wider world – including most people in the IT field
> – why upper ontologies are important for achieving broad
> semantic interoperability among diverse applications. (03)
Right now, we have three major UO projects -- Cyc, SUMO, and
Dolce -- whose developers do not show any inclination to abandon
their own UOs in favor of a common UO acceptable to all of them. (04)
Nicola was assuming that axioms are the most important point: (05)
NG> 1. Reasons for having axiomatic ontologies
> 2. Reasons for having upper-level ontologies
> 3. Reasons for having (a small set of) common
> upper-level ontologies
>
> Note that points 1-3 above are ordered in terms of priority
> (or importance, if you prefer). (06)
But Adam noted that the axioms are the biggest stumbling blocks
to merging ontologies. Somehow, Cyc, SUMO, and Dolce have
been useful for many similar applications, *despite* the fact
that their axioms are incompatible. That suggests that axioms
may *create* more incompatibilities than they resolve. (07)
For example, a detailed axiomatization of what it means to
be human is irrelevant for 99% of all applications. If two
database designers tried to state such a definition, they
would be very unlikely to come up with identical statements.
For most applications, they can just accept on faith that
Adam, Pat, Nicola, and John are human beings. (08)
But there are some applications for which it is essential to
distinguish human blood from the blood of other animals. For
such applications, detailed axioms are needed that don't belong
in an upper ontology. (09)
This point is central to what it means to be an upper or general
purpose ontology as opposed to a low-level task-oriented ontology.
Axioms are essential for specific tasks, but detailed axioms at
the upper levels are counterproductive -- i.e., they may create
conflicts rather than resolve them. (010)
This fact, which might seem paradoxical, is actually familiar
to mathematicians, who always try to reduce the number of axioms
needed to prove any theorem. Axioms are necessary for proofs,
but whenever possible, the number of axioms should be reduced
to the barest minimum. (011)
That is the whole point of Ockham's razor: eliminate any axioms
that are not absolutely essential to the task at hand. (012)
John Sowa (013)
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