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RE: Re[1] DAML-ONT: the case for closedness

From: Je'ro^me Euzenat <Jerome.Euzenat@inrialpes.fr>
Date: Mon, 23 Oct 2000 09:02:25 +0200
Message-Id: <p04310101b61917f3d8b9@[194.199.17.135]>
To: "Hart, Lewis" <lhart@grci.com>, Pierre-Antoine CHAMPIN <pachampi@caramail.com>, Jeff Heflin <heflin@cs.umd.edu>
Cc: www-rdf-logic@w3.org, "Emery, Pat" <pemery@grci.com>
Hello,

	I must first say that I subscribe to Deborah L. McGuinness 
tentative ontology of closing issues. Moreover, my initial though 
when initiating the threads were not about belief and trust, but more 
oriented toward software (ontology) engineering. I.e. how can I be 
sure that the weakest part of the
reused classes will not damage the strongest.

In his message (RE: Re[1] DAML-ONT: the case for closedness) of 20/10/00,
Hart, Lewis wrote:
>and also..
>Jeff Heflin said:
>
>   >Here's what it looks like in RDF (assuming http:/www.daml.org/damlont
>   >and http:/www.commerce.org/econt are the daml and ec namespaces from
>   >above):
>   >
>   >  <rdf:Description about="http://www.daml.org/damlont#Thing">
>   >     <rdfs:subClassOf resource="http://www.commerce.org/econt#Computer"
>/>
>   >  </rdf:Description>
>   >
>   >This is an unfortunate consequence of RDF's "anyone can say anything
>   >about anything" property." Thus, trust becomes 100 times more important
>   >for ontologies than it does for ordinary RDF documents. If you
>   >mistakenly trust a plain RDF document, at worst you may believe a
>   >hundred false assertions. If you mistakenly trust an ontology, all of
>   >your subsequent beliefs could turn out to be wrong!
>The "bad:" ontology can state whatever it likes. The question is
>do you believe it.

The situation I had in mind at the beginning is not that simple. The point is
in having three Ontologies:
- myO, your ontology for whatever that you will build,
- bigO, the well-known ontology that anybody uses in your field and 
that you know you can trust very much.
- theotherO, the ontology that is provided by the little startup you 
don't know if you must trust but that provides you with the lastthing 
widgets in ebusiness and that claim to be bigO compliant.
	Well, you would like to be able to use these in such a way 
that even if theotherO is flawed in some parts (that maybe you do not 
use), this cannot affect the well-established concepts that you know 
from bigO.
	Unfortunately, due to the open character of the definitions, 
someone can come and restrict a definition of a concept in bigO (and 
this can be silent because it does not raise incoherence, just 
restrict one or two extensions).

	So the point is: I trust bigO for sure. I am not really 
confident about theotherO, but their new concepts are interesting and 
they are bigO compliant (let say that I can still use the concepts I 
know very well from bigO with their stuff).
	Now, DAML does not provide any way for the bigO makers to 
force some compliance. The guys from theotherO.com are not BAD guys 
as have been said: they just believe that Thing=Nothing and thus 
everything is a computer. And, after all, this is a model of the bigO 
ontology!
	This can be less dramatic and less obvious (as soon as you 
begin to consider an object, you will realize that Thing=Nothing) but 
more insidious. So I really would like to see a way to have some 
restrictions of that kind in some DAML definition.

>The good things about this are:
>
>1) Anybody can still say anything.
>2) There is no central authority.
>   2a) Authorities will arise out of usage.
>3) The scope of bad a ontology is limited.
>   3a) Search engines can cut them off at the root if desired.
>4) Information can still be found.

The last point can be debated, since a bad ontology can describe very 
relevant information (but maybe you mean that the sites will be 
annotated with several differing ontologies?).

>The Bad things are:
>
>1) Systems will have to delineate between what it knows about
>    and what it believes.
>2) Keeping track of this could be resource intense.
>3) Some sites will think everything is a computer.

And? Isn't it correct? ;-)

-- 
  Jérôme Euzenat                  __
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Received on Monday, 23 October 2000 03:03:29 GMT

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