W3C home > Mailing lists > Public > www-rdf-logic@w3.org > April 2002

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

From: Bill Andersen <andersen@ontologyworks.com>
Date: Mon, 01 Apr 2002 15:36:34 -0600
To: Jim Hendler <hendler@cs.umd.edu>, RDF Logic <www-rdf-logic@w3.org>
CC: "John F. Sowa" <sowa@bestweb.net>, SUO <standard-upper-ontology@ieee.org>
Message-ID: <B8CE2F02.361E%andersen@ontologyworks.com>
On 4/1/02 15:09, "Jim Hendler" <hendler@cs.umd.edu> wrote:

>> 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.
> Nonsense (who taught this guy Andersen's AI classes??? :->)!

Aww... I didn't think you remembered! :-D

> When 
> you write classical logic with all the usual symbols it is
> meaningless scrawling on a piece of paper until we have the social
> agreement about how the symbols map to mathematical concepts.
> Similarly
>  <ImplicationRule>
>    <Antecedent> x </Antecedent>
>    <Consequent> y </consequent>
>  </ImplicationRule>
> is not something to "interpret what logics already do" but a means of
> encoding a particular bit of logic, assuming a social agreement as to
> what the meaning of this RDF is with respect to some mathematical
> model of entailment.

But, Jim, I was talking in particular about RDF-schema and XML-schema, which
include weak constraint languages in them.  One can treat them as logics and
give them a model-theoretic semantics, as Pat has done.

In addition, if the above serves to "encode some particular bit of logic" it
seems reasonable to interpret it *as* an alternate syntax for some logic,
either some standard logic like FOL, or some new logic being proposed by the
proposer of such structures.

> The confusion is that the term "logic" on the layercake diagram
> doesn't mean "there exists a logic" it means "there is a formal
> logic, expressible on the web, embedded properly in web architecture
> (i.e. URIs and the like), and able to passed between web entities via
> proper protocols.  These things are different than the need for a
> logic per se -- those are a dime a dozen and easily found in about
> 2000 years of literature -- heck your own books describe numerous of
> them -- just none that could be called a "web logic" at this point.

I don't know about John's point of view, but whenever you propose a language
like RDF-schema or XML-schema that includes non-logical symbols as those
languages do, those symbols ought to be *interpreted*.  If the
interpretation is supposed to come later in terms of mapping the defining
axioms for these symbols to some web-expressible logic, then that seems to
be putting the cart before the horse.

Why not say up front exactly what these languages are supposed to do, either
by defining a new logic (nothing wrong with that) or by mapping it to a
well-understood existing logic like FOL?

Anyway, all of this discussion is good and healthy.  One of the things I've
wanted to see for a long time is for the SUO and philosophical ontology
folks who care about such things, to start paying attention and get involved
with the Web-ontology crowd.  This seems like a good start.

Received on Monday, 1 April 2002 16:36:48 UTC

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