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Re: [ontac-forum] Semantic Interoperability: Sowa's Collection of Module

To: ONTAC-WG General Discussion <ontac-forum@xxxxxxxxxxxxxx>
From: "Smith, Barry" <phismith@xxxxxxxxxxx>
Date: Fri, 25 Nov 2005 10:04:44 +0100
Message-id: <>

Responding to John    (01)

>The major question is what strategies for designing and deploying 
>ontologies might be more successful.
>Following are some points to consider:
>  1. Standardized vocabularies, terminologies, and nomenclatures
>     were developed long before computers became available, and
>     their value has been abundantly demonstrated, even without
>     formal axioms associated with any of the terms.
>  2. Many such terminologies have logical errors that must be
>     corrected.  For example, three major links between terms
>     must be clearly distinguished:  type-subtype, type-instance,
>     and whole-part.  Some classifications lump all three under
>     the heading broader-narrower, but that leads to serious
>     confusion.    (02)

BFO puts these precise distinctions at the heart of its organization. 
It is being used currently to correct logical errors in various large 
biomedical ontologies. It has been used successfully by a medical 
terminology company to improve the reliability of its coding.    (03)

>  3. Other relationships should also be represented, such
>     as locationOf, containerOf, attributeOf, and various
>     relations of geography, kinship, and politics.    (04)

BFO includes the first three of these; the remainder belong in 
compliant domain ontologies, some of which are being developed.    (05)

>  4. When two or more terms in the vocabulary have the same
>     supertype, the differentiae that distinguish them should
>     be explicitly stated, but very detailed axioms can often
>     be more of a hindrance than a help.    (06)

I agree. For very high-level types (aka categories) we need a small 
number of simple axioms (the low hanging fruit), rather than precise 
statements of necessary and sufficient conditions for their 
instantiation. Moreover, some categories must be left primitive (we 
could not define everything, even if we wanted to).    (07)

>  5. More detailed axioms from science, engineering, law,
>     philosophy, sociology, etc., are likely to be far too
>     specialized, theory dependent, and not only unnecessary,
>     but highly undesirable in a general-purpose ontology.    (08)

Absolutely.    (09)

>     For example, a general ontology should be neutral with
>     respect to 3-D or 4-D models of space-time, situation
>     calculus vs. pi calculus, or continuant-based vs.
>     process-oriented ontologies.    (010)

I agree. BFO has two modules, one 3-D (defined for representing 
continuants), one 4-D (designed for representing processes), together 
with relations between them. Users are welcome to use either both 
modules together, or just one of them, according to preference.    (011)

>  6. The logic required for the general ontology should be
>     very simple.  Aristotle's syllogisms, which are a subset
>     of description logics, are sufficient for the definitions
>     discussed in points #2, #3, and #4 above.  More complex
>     logics should be limited to more specialized microtheories
>     for particular applications, not for the general ontology.    (012)

I agree with this too, though we will need a bit more than the 
syllogism if we are to deal adequately with the distinction between 
instances (Toronto) and types (city). The fact that this distinction 
has not been dealt with adequately flows in part from the fact that 
people were assuming that something like syllogistic would be 
adequate for their needs.    (013)

>This outline suggests a major reduction in the complexity of
>the logic and highly controversial issues about the nature
>of space-time, processes, objects, etc.  Those issues may
>be extremely important for many purposes, but the fact that
>they are controversial means that they should be relegated
>to specialized microtheories, not the fundamental framework.    (014)

Absolutely.    (015)

>What I do recommend is that the general ontology contain only
>a precise definition of the minimal assumptions that are
>commonly accepted for the various categories.  That policy
>permits anyone to add as much detail as they like.  But
>it would also allow anyone with any specialized need to
>add idiosyncratic axioms that nobody else would agree to.
>All of the perspectives would agree on the minimal common
>content, but they could diverge on the details.    (016)

NCOR is attempting to create mechanisms for ontology evaluation. (See 
now the wiki at http://ontologist.org .) These should not only help 
us to decide what is the best upper ontology, but also allow us to 
differentiate between different proposals for domain ontologies and 
sort them according to quality. Already more than a dozen ontologies 
of 'agent' have been created in the OWL world. The fact that these 
also have a variety of different names (ontologies of Action, 
actions, agency, Act, act, ...) tells us that quite trivial syntactic 
constraints will be needed, too, if ontologies are to work together.    (017)

>Instead of saying it is vague or imprecise, it would be more
>accurate to say that I am recommending an *underspecified*
>general ontology, which could be specialized in different
>ways for different purposes.    (018)

This is precisely the BFO (and the DOLCE) line.    (019)

> > For example, if a set of interfaces were mapped to something
> > like wordnet, it is easy to see how tools would help the
> > human make connections between interfaces by matching
> > the concepts.  If it were correct 75% of the time - that
> > would be a big win!
>What I am suggesting is something like a corrected WordNet --
>i.e., with a more accurate and consistent treatment of the
>type-subtype, type-instance, and whole-part relations.
>It would be 100% correct *all the time* for what it says,
>but it would not make any commitment on any controversial
>issue.    (020)

This describes exactly the methodology of BFO, as described here for 
the biomedical case (but the ideas there proposed are easily generalizable):
I would be very interested to hear of other ontological frameworks 
which support reasoning with part-whole and similar relations in the 
way that is outlined here (thus for example which allow you to infer from    (021)

Ottawa instance_of capital city
capital city part_of country    (022)

Ottawa part_of country    (023)

(I still, in spite of Michael's claims, cannot see how his oil 
ontology [ISO 15926] can support such inferences.)    (024)

> > ...  as well as the capability to "ground" domain concepts
> > in ONE OR MORE "hubs", like wordnet or even Cyc.
>Instead of calling it a "hub", I would call it a framework.
>It would provide a placeholder for all the terminology or
>vocabulary that anyone might want to add to it.  It could
>in fact become as big (in terms of number of entries) as
>the OED together with the union of all the specialized
>vocabularies anyone would like to add.
>But I want to emphasize that this framework would be much
>less detailed in its axiomatization than Cyc.  It would
>be more like a precisely defined and corrected WordNet
>extended with many additional vocabularies.    (025)

WordNet has some 117,000 synsets. This would take us all day.    (026)

>Many of us had been participating in the SUO (Standard Upper
>Ontology) project for over five years, and we never made any
>progress in resolving these controversies.  If we insist on
>producing a hub, or an upper level, or whatever you want to
>call it, that takes one position or the other on any of these
>controversies, we'll go on for another five years without
>reaching a consensus.
>Therefore, I recommend that we exclude from the framework any
>axiom or assumption that is in any way controversial.  It would
>be very precise for what it says -- much more so than WordNet --
>but underspecified.  As a framework, it would provide placeholders
>for adding whatever specialized microtheories anyone would care
>to add.  Those microtheories could be added at any level from
>top to bottom or in the middle.
>With such a framework, we could make progress.  Without it, we
>could end up with another five years of wrangling over subtle
>principles, theories, and distinctions of physics, philosophy,
>linguistics, and semiotics -- as we have seen with the SUO project.
I agree exactly with John here (and I should note that he and I have 
very different views on many things ).
BS     (027)

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