Re: SUO: Re: REQUEST: survey of available ontologies, taxonomies, thesauri, lexicons?

Bill and Charles,

The preface of the best available book on knowledge representation
discusses the following 3-way subdivision:

    Knowledge representation is a multidisciplinary subject that applies
    theories and techniques from three other fields:

    1. Logic provides the formal structure and rules of inference.

    2. Ontology defines the kinds of things that exist in the application
       domain.

    3. Computation supports the applications that distinguish knowledge
       representation from pure philosophy.

    Without logic, a knowledge representation is vague, with no criteria
    for determining whether statements are redundant or contradictory.
    Without ontology, the terms and symbols are ill-defined, confused,
    and confusing. And without computable models, the logic and ontology
    cannot be implemented in computer programs. Knowledge representation
    is the application of logic and ontology to the task of constructing
    computable models for some domain.

Source:  http://www.jfsowa.com/krbook/krpref.htm

I would apply this distinction to the following question.

"Charles McCathieNevile" <charles@w3.org> wrote:

CM> To What extent would you consider an XML schema as an ontology?
 > Some of them are fairly vague - XHTML, or SVG, are representing fairly
 > broad areas of information without a lot of detail, but MathML and
 > ChemML (and many other examples) are fairly detailed ontologies, as
 > I understand it.

I would agree that an XML schema could be used as a knowledge
representation.  It has computational presuppositions that depend
on the constraints of the XML notation and the available tools for
processing it.

Various XML schemata incorporate ontological assumptions about the
kinds of entities that are being represented, but since they do not
use a clearly defined version of logic, the definitions tend to be
rather vague.  The reason why MathML and ChemML are more precise is
not because the terms are adequately defined in the XML schemata,
but because the many centuries of research and development in math
and chemistry have provided the definitions.

I agree with the following comments by Bill Andersen:

BA> So, how well has the schema done for us?  Not well.  And it CAN'T do
 > better -- its syntax and semantics don't have enough power.   Of
 > course one could try to encode all of this somehow in some arcane
 > syntax that someone is going to have to interpret as doing what logics
 > already do.  The RDF and RDF-Schema efforts are just such encodings.

I also agree with the following:

BA> That said, WE SHOULD NOT fool ourselves that any of these quick fix
 > tools (RDF(/S), XML(/S), DAML) are going to solve the real problems
 > of (applied) ontology, let alone the two relatively easy ones I
 > mentioned above.  The long range solution to problems of data and
 > information system integration depend on their solution.

I would add that such XML-based tools can be used to encode a suitable
ontology, but only *after* some suitable logic-based tools are used to
define it.  My major complaint about much of the work on the semantic
web is that people have drawn their diagrams to show that logic is built
on top of XML and RDF.  I would turn those diagrams upside-down to show
that a suitable logic-based methodology is necessary *before* you can
begin to use RDF effectively.

John Sowa

Received on Monday, 1 April 2002 13:24:10 UTC