Comments on a post by Doug Foxvog: (01)
> > JFS>> There is no [stage in the development of an ontology] that is
> > >> "just enough" for *all* applications. Cyc, for example, found
> > >> that no matter how much knowledge they have formalized over the
> > >> past 26 years, they can't get up to a level that is "enough".
> > >> Every new application requires more.
>
> > MW> What this does is change the problem slightly from actually
> having an ontology that does capture everything, to having an ontology
> that is easily extensible when things are found that are beyond its
> current scope.
>
> JFS> I agree. But if you think of a ontology as a single, unified
> theory, then you have many thorny issues about what it means to be
extensible.
> (02)
[DF] > An ontology with a single theory would complicate the idea of a
> foundational ontology as an interlingua to which all external
> ontologies can be mapped. Competing external theories could be
incorporated by
> defining new concepts/relations for the relata of the competing
> theories (which map directly to the terms of the source ontology) and then
> adding rules relating them with the ostensible "sameAs" terms already in
the
> foundational ontology.
>
Yes, but I would express the process as "logically specifying the terms of
each extension ontology using only the terms in the FO" rather than "map
directly" since that suggests that the entities in the extension ontology
are already on the FO, which in general they will not be. (03)
> >
> JFS> But if you think of an ontology as a collection of theories
> organized in a hierarchy, no single theory ever changes. Instead, each
> innovation adds another theory to the hierarchy, which may be a
generalization,
> > a specialization, a sibling, or a cousin of some other theory. You
> > can also compare and combine theories.
>
[DF] > Agreed. This is part of the reasoning behind Cyc method of
> "microtheories" or contexts.
> (04)
[PC] And that would be true for the FO and its extensions also. But there is
an additional aspect to the FO as I have proposed it. The CYC BaseKB is
part of every other more specialized microtheory, but it was not designed
as, nor used as, an inventory of basic elements that is sufficient to
specify (as combinations) the intended meanings of the symbols that are in
all of the other linked microtheories. CYC didn't try that tactic, which
could have been very informative. But a proper test would in any case
require that a good number of separate groups with different applications
and viewpoints try to use the same FO to describe their different domain
ontologies. (05)
> > JFS>> But for any given set of applications, it is not too difficult
> > >> to formalize just enough for those applications.
> >
> > MW> Doing this for a known set of applications is relatively easy.
> > > The challenge is to enable arbitrary addition of applications.
>
> > I agree. And my suggestion for supporting an open-ended number of
> > applications of any kind is to organize the collection of theories
> > in a hierarchy. Any change of any kind can be accommodated by
> > inserting a generalization, specialization, sibling, or cousin.
>
[DF] > I agree. An FO would need to have a reasonably restrictive
> generalization of classes included in any microtheory that is to be mapped
to it.
> Defining "reasonably restrictive" could be hard, but it seems to me that
SUMO
> (with extensions) and Cyc both would currently meet this requirement.
> Including concepts from UMLS and GoodRelations would lower the rough lower
edge
> of the directed acyclic graph of classes in several key areas.
>
[PC] Those would be valuable resources for finding the proper set of
elements for an FO. I can think of a number of others as well, and I would
want to search for a representative set of basic knowledge models that might
benefit from semantic interoperability with each other. (06)
[DF] > One question is on what basis should individuals should be included
in
> an FO. Certainly units of measure should be. Currencies & countries
> surely. Cities and every instance in the GeoNames base? How should the
> selection of people to add be made? Organizations? Conceptual works
(books,
> movies, songs, albums, paintings, constitutions, poems, ...)? Sports and
games?
> Events (disasters, wars, elections, mergers, ...)? Etc.
>
[PC] Units of measure for sure; likewise countries and currencies. Beyond
that, I think it would be useful to include a few well-known instances of
each distinct category, so as to have *examples* that are the topic of
multiple web pages, that can provide useful tests for the ability of an NL
interpreter to relate the external world to the entities of the FO. Other
lists of instances can be in mid-level or domain extensions. (07)
[DF] > > The breadth of coverage of the proposed FO needs to clarified. Is
it
> to be an ever-expanding set of all terms defined in any ontology? Should
it
> include all individuals ever defined on the Semantic Web?
>
> Or could there be a basic, relatively fixed, FO to which an expanding
> number of contextually restricted, but still centralized, ontologies
> are related? I could see such for brand-name products, GeoNames, UMLS,
> IMDB, GeneBase, etc.
> (08)
[PC] The FO itself should try to include all primitives that are used by
more than a small set of specific domain ontologies, and only those
non-primitive elements that are needed for ease of use and are
non-controversial. Primitives required by domain ontologies should also be
maintained, but as part of a domain extension. Not part of the FO itself,
but maintained by the same organization maintaining the FO should be one or
more mid-level ontologies, and all domain ontologies that have been
specified using the FO and are open-source. Maintaining public domain
ontologies will make it easier to avoid reinventing ontology elements, and
reduce the risk of having differently structured elements that supposedly
represent the same intended meaning. (09)
It is unclear at this point how one would handle large lists of individuals
- either as maintained in some FO extension, or just pointed to elsewhere on
the net. Except for some common things like units of measure, they would
not be needed in the FO itself. Local or remote lists would both probably
work, though I tend to prefer to maintain a local copy for things that are
not frequently changed, just for convenience and efficiency. (010)
Pat (011)
Patrick Cassidy
MICRA, Inc.
908-561-3416
cell: 908-565-4053
cassidy@xxxxxxxxx (012)
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