SUO: Re: SUO Comment #2
Mike Uschold wrote:
> * This standard will enable the development of a large (20,000+)
> > general-purpose standard ontology of common concepts to be
>> developed, which will provide the basis for [defining all of the
> > concepts in] middle-level domain ontologies and lower-level
> > application ontologies.
>
>'all' may be rather a tall order. It is certainly a worthy long term
>aim, but
>it may not be attainable in practice. There may always be interesting
>concepts that don't seem to fit anywhere. At best, we might
>asymptotically
>approach this goal.
I agree with Mike. I vote for deleting the words "defining all the
concept in" from the above statement.
Further comments:
1. Meaning of "defining".
The verb "define" occurs often in this discussion, but it would be
useful to make clear that, strictly speaking, most concepts just
CAN'T be defined, in the sense that there is no way to come up with
necessary and sufficient conditions for them. For sure, the majority
of concepts within a large standard ontology will be primitive, in
this sense. What we call "definitions" will be in practice
CHARACTERIZATIONS of a concept in terms of other concepts. This is
the case of many dictionary "definitions", for instance.
2. Meaning of "upper"
At 11:11 AM -0400 30/8/2000, Jon Awbrey wrote:
>Douglas McDavid/Boulder/IBM wrote:
> > At some point we need to understand whether
> > upper means generic, or whether upper means abstract, or whether upper
>> means ubiquitous, or whether upper means meta, or just exactly what
> > does "upper" mean?
>
>Seriously folks, let me try to formalize the alternative possibilities
>that Doug McDavid mentions. I will start out in the following way,
>just as an experiment with notation, nothing more:
>
>1. "upper" -<- "abstract"
>2. "upper" -<- "generic"
>3. "upper" -<- "meta"
>4. "upper" -<- "ubiquitous"
>5. "upper" -<- ???
In my opinion, the meaning of "upper" we need for the SUO is the
union of "meta" and "generic". That is, we need to include in the SUO
all the meta stuff Douglas McDavid mentioned, plus a reasonable
number of "generic" (or "general") concepts (a rough estimate of a
couple of thousand is OK with me, as we discussed in the previous
thread). With "generic" I mean here "common (and relevant) to
multiple domains/applications". Of course this is a very generic
definition of "generic"....
3. What kind of classes in the SUO?
At 6:21 AM -0600 30/8/2000, Douglas McDavid/Boulder/IBM wrote:
>Can we accept classes that would
>contain _identifiable_ things, or do we have a set of _properties_ that can
>be applied in a standardized manner to things that are only identifiable
>via more domain-specific ontological constructs?
>
>To me, the most useful piece of work we could provide would be a principled
>articulation of categories that are immediately applicable to identifiable
>things in the world. By principled, I mean that we would argue about
>whether each category in the SUO should be completely disjoint from all
>others, and whether the set of categories should be all-encompassing of all
>possible domains of concern to users of the SUO.
This observation seems to be very much related to the recent work
Chris Welty and I have done, presented at the AAAI tutorial on
conceptual modeling and ontological analysis. Among other things, we
present a formal way to distinguish between properties according to
whether or not their instances are "identifiable things" (using the
above expression). We further discuss the notion of a "backbone
taxonomy" that only contains properties of this kind, plus their
generalizations. This gives a criterion for deciding the properties
to be included in the SUO, which is pretty much in line with
McDavid's suggestion above. Disjointness constraints between these
properties are the result of ontological meta-properties that reflect
their formal behavior with respect to identity, unity, essence. See
http://www.cs.vassar.edu/faculty/welty/aaai-2000/ for further info.
4. Lattices and constraints
At 7:51 PM -0400 31/8/2000, Patrick Cassidy wrote:
>But the experiment that urgently needs trying is to create as best
>we can an inventory of basic concepts, and then work to define the
>more complex concepts in those terms, putting our definitions of
>complex concepts in a common repository for use by all. Only then
>will we be able to learn whether those hundred thousand-plus complex
>concepts will be definable as combinations of the basic concepts.
At 10:53 AM -0400 1/9/2000, John F. Sowa wrote:
>The long and honorable tradition for representing such
>combinations is called the theory of lattices. Leibniz used
>similar combinatorial methods for his "Universal Characteristic"
>which was a 17th century attempt to develop a "standard upper
>ontology."
>[...] The techniques apply to categories at every level of the
>ontology from top to bottom.
Just a word of caution: theory of lattices is of course very
powerful, but before exploring the combinatorial results of a set of
basic distinctions we must first check for possible mutual
dependencies. In many cases, basic primitives turn out to be NOT
mutually independent, so that some of their combinations are
naturally excluded. For instance, this is the case of the
distinctions appearing in Sowa's "crystal", discussed in the ontology
chapter of his book: according to my understanding, the distinction
"continuant/occurrent" is not independent from the distinction
"physical/abstract", since continuants and occurrents are both
physical (i.e., located in space/time). Therefore, there are no
entities that are both occurrents and abstract (scripts, for
instance, carry information about occurrents, but they are not
occurrents). [NOTE: this is just an example, whose detailed
discussion would require a different thread. The point is that
applying theory of lattices alone may lead to fascinating symmetric
structures that don't reflect actual ontological constraints].
-- Nicola
---------------------------------
Nicola Guarino
National Research Council phone: +39 O49 8295751
LADSEB-CNR fax: +39 O49 8295763
Corso Stati Uniti, 4 email: Nicola.Guarino@ladseb.pd.cnr.it
I-35127 Padova
Italy
http://www.ladseb.pd.cnr.it/infor/ontology/ontology.html
(***updated 28/8/2000***)