Pat and Doug, (01)
The point I've emphasized about the lattice of theories (of which
the hierarchy would be a subset) is that it is infinite and can
accommodate *all possible* theories expressed within a given logic. (02)
The logic I would consider for the hierarchy would be Common Logic
or any subset of it. That would include RDF(S) and OWL as proper
subsets. But we could also consider the next step beyond CL, which
is IKL. Doug Lenat said that they would require the IKL extensions
to Common Logic in order to support full CycL. (03)
PC> Do you envision this particular version of an oor as one in
> which all of the ontologies are related to each other by subsumption
> from some "BaseKB" as in CYC? Or would you include ontologies that
> do not have their relations to the base starting ontology fully
> specified? (04)
DF> With all the acronyms floating around, it would be nice to
> define this one at this point in the thread. (05)
OOR = Ontology Registry / Repository. See the thread by Peter Yim
with that subject line. (06)
Since we want to accommodate all reasonable upper levels (such
as SUMO, DOLCE, BFO, etc) in addition to OpenCyc, there wouldn't
be a single upper level to start with. And since it seems unlikely
that the 4D and 3D partisans are unlikely to merge into a single
consistent theory, there will probably be a need to support more
than one upper level indefinitely. (07)
PC> Did you have any particular version of OpenCyc in mind? (08)
DF> We could certainly talk to Cycorp to request that they release
> axioms from Research Cyc into the public domain for use in an FO.
> As they wish to promulgate Cyc, they might be willing to release
> a significant subset of generic rules that they have in non-project
> specific microtheories. (09)
Yes. Many details have to be discussed, analyzed, and agreed. Before
we go much further, we have to discuss many issues with subscribers
to ontolog forum, with Lenat & Co., and with other groups that have
important ontologies that should be included. (010)
PC> (The Umbel files are in N3 format - anyone know of a converter
> to OWL?). (011)
N3 is useful for those subsets that can abide by its limitations,
but full FOL is necessary to support the SQL WHERE clause, SUMO
requires Common Logic, Cyc requires the IKL extensions to CL,
and SBVR (Semantics of Business Vocabulary and Business Rules)
also requires the IKL extensions. (012)
Therefore, the lingua franca for translations among all the logics
would require at least the expressive power of Common Logic and
preferably IKL. (013)
PC> Cyc used to have attributes separate, and they formed a hierarchy
> (they also form a hierarchy in SUMO), but Cyc changed (a major change)
> to the current view. I was told that this was done because it led
> to fewer errors in representation. It may also be more computationally
> efficient. But since I am quite concerned about the ontology being
> as close as possible to language (English, specifically) to make
> development of an NL interface easier, I would prefer to have
> attributes represented as such, rather than as objects with that
> attribute. (014)
Those issues are important for human factors and design methodologies,
but a general logic such as CL or IKL can accommodate any of them.
I discuss some of the issues in my tutorial on controlled NLs: (015)
http://www.jfsowa.com/talks/cnl4ss.pdf
Controlled Natural Languages for Semantic Systems (016)
But those are more topics to be put on the list for further discussion. (017)
PC> I feel that this is very important because my appreciation of the
> biggest problem with the IEEE-SUO project was that alternative views
> were *excluded*... But the result was that too many potential users
> did not find their preferred representations, and stayed with their
> own ontologies. (018)
I believe that we should support all views and methodologies that have
proved to be widely used. In particular, we should accommodate and
integrate the technologies of *both* the W3C and the OMG as well as
the various research developments that extend them in various ways. (019)
PC> Cyc is a bit bizarre in some respects, so this could be a critical
> principle that makes the project feasible. (020)
I agree. In fact, that is one reason why I believe that this project
should be hosted on neutral grounds, rather than an organization that
is dedicated to one specific technology or family of technologies. (021)
PC> For me it would also be important that the intended meanings of
> the base terms (primitive or otherwise) be described with sufficient
> detail -logical or linguistic - so that they are used consistently
> by all *human* users, whether they are very vague ("object") or
> very specific. (022)
As I say in the cnl4ss.pdf slides, I recommend controlled NLs as an
auxiliary notation that can be translated to whatever logic is used.
But CNLs are still a formal notation. I also believe that we should
have *informal* commentary and metadata that explains the intended
purpose and modes of use for an ontology (or even any specific
statement in an ontology). (023)
PC> That is one reason why I continue to emphasize the need for clear
> and (if necessary) comprehensive documentation of each element. (024)
Absolutely. And the metadata should also include (or at least point to)
reviews, evaluations, and case studies of applications of each ontology
by people other than the developers. (025)
PC> The biggest problem I anticipate is simply that [the project] is
> very complex and time-consuming, and in the absence of funding will
> move very slowly. (026)
Actually, it is extremely modular, and each step along the way is
useful by itself. For example, step #1 could consist of a one-level
hierarchy that contains several different ontologies hanging off the
top node: OpenCyc, SUMO, DOLCE, BFO, etc. (027)
Most of the work would consist of developing guidelines that specify
formats, the kind of information that should be included, and the
various topics we have been discussing in this and other notes.
The actual work of massaging the ontologies and gathering whatever
information should be included would be done by the people who
develop each ontology (or some user group associated with it). (028)
SourceForge is an example of an organization that maintains an
open-ended number of contributions with a minimal amount of funding.
But we should go several steps beyond SourceForge in vetting the
contributions and ensuring that they meet the guidelines. (029)
The number of steps beyond SourceForge depends on two things:
money and/or volunteers. With enough volunteers, you don't
need much money. With enough money, you can buy volunteers.
And with some promising initial steps, I would hope we could
attract some of both. (030)
John (031)
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