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

From: Jim Hendler <hendler@cs.umd.edu>
Date: Mon, 1 Apr 2002 16:09:15 -0500
Message-Id: <p05101506b8ce7979a0b1@[10.0.1.4]>
To: www-rdf-logic@w3.org
Cc: sowa@bestweb.net
Quotes from a message from John Sowa:
>
>    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.

while this is true, it doesn't mean the logic must be explicit in the 
language, just that their must be a formal model underlying the 
language -- thus, if I say X is in class Y and Y is in class Z. 
There could be an underlying model that entails the belief that X is 
in class Z, without my needing to be able to express the transitivity 
rule directly in the surface language.

>
>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??? :->)!  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.


>
>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.
>

But John, you yourself know that there is a clear difference between 
the encoding and the logic - so how can you make such a ridiculous 
claim.  Of course there must be an underlying logic -- but that logic 
doesn't need to be expressible on the web to be useful -- the 
underlying logic below DAML+OIL, for example, can be expressed in KIF 
(see the axiomatic semantics [1] ) or Model Theory (see the semantic 
model [2])

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.

  cheers
  Jim H.

[1] 
http://www.ksl.stanford.edu/people/dlm/daml-semantics/abstract-axiomatic-semantics.html
[2] http://www.daml.org/2001/03/model-theoretic-semantics.html

-- 
Professor James Hendler				  hendler@cs.umd.edu
Director, Semantic Web and Agent Technologies	  301-405-2696
Maryland Information and Network Dynamics Lab.	  301-405-6707 (Fax)
AV Williams Building, Univ of Maryland		  College Park, MD 20742
http://www.cs.umd.edu/users/hendler
Received on Monday, 1 April 2002 16:09:18 GMT

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