- From: pat hayes <phayes@ai.uwf.edu>
- Date: Thu, 7 Nov 2002 13:42:36 -0600
- To: Jeff Heflin <heflin@cse.lehigh.edu>
- Cc: www-webont-wg@w3.org
>Pat, there is a terminology problem here. What you and Peter call >ontologies are different from what I call ontologies. Yeh, I had that impression. My problem is that I don't really know what you are talking about. I have never come across any useful definition of "ontology" in our non-philosophical sense other than something like "set of sentences" or maybe a document containing a a set of sentences, etc.. If there is a real difference in your mind between ontologies and other OWL thingies, then we ought to get this clear and incorporate it into the language in some way. >My practical >definition is that OWL ontologies are only those OWL documents that >include the <owl:Ontology> tag. Hmm, I have to confess that I wasn't aware that 'owl:Ontology' was in the OWL namespace. What is it supposed to mean?? Does it appear in the RDF graph anywhere? But OK, an ontology is a *document*. In what language? I'm guessing it has to be in OWL/RDF/XML, right? So an OWL/RDF graph is not an ontology(?) >All other OWL documents are not OWL >ontologies. Now, you are correct that a document with <owl:Ontology> >could consist of nothing but ground facts, and as such you don't >technically need to have a separate class of document for data. However, >the fact is, people only use the <Ontology> tag when they are defining >vocabularies (this statement is based on common usage in DAML). Are you >suggesting that these people should include <Ontology> tags is all of >their documents (see daml.org's list of data sets for a number of >examples of DAML documents without these tags)? I really don't give a rats about this tag, to tell you the truth, but certainly people should somehow mark their OWL as being OWL; if they don't, then they can't complain if an OWL engine misses it entirely. We might want to follow RDF's lead and register an OWL media type, though I think that idea is wrong-headed, myself. All I care about is that we have some way to detect well-formed OWL which is being asserted. Well-formed OWL means what it means as defined by the OWL specs. The distinction between ground and non-ground OWL is unimportant, seems to me, and there is no need to even refer to it. If some piece of OWL has 10|6 ground facts and one non-ground fact, I'm cool with that. What would you call it? Data with a dash of ontology? >Or are you suggesting >that we should call these ontologies too? If we use the term at all, then yes, they are ontologies, in much the same sense that a gazetteer is a book. > I think the later would really >confuse users to call every document an ontology, but only some >ontologies are <Ontology> ontologies. In any case, all of our documents >need to be a lot more clear about terminology (e.g., which definition of >ontology does our WG use) and about how people should use ontologies to >describe real content. As to the last point, the distinction between ontology and data just seems to make things more confusing, suggesting a distinction in meaning that isn't there. Pat > >Jeff > >pat hayes wrote: >> >> >pat hayes wrote: >> >> >> >> >Here's some initial comments on the Semantics document dated Nov. 3: >> >> > >> >> >1) Sect. 2.2. The syntax needs the ability to represent documents that >> >> >consist soley of facts (that is, something other than ontologies). >> >> >> >> ? Can you explain what you mean by "other than ontologies" ?Do you >> >> mean, not in OWL? >> >> >> > >> >Part of this depends on what you consider OWL. From your response, I >> >assume that you think of OWL as just a language for defining ontologies, >> >and that you must use it with RDF in order to describe data >> >> No. I fail to see the distinction you are drawing between 'ontology' >> and 'data'. I don't know what you mean by this, or what importance it >> has. One can have valid OWL documents which consist of nothing but >> ground RDF facts. So? >> >> >(e.g., a >> >product catalog, a univeristy's course offerings, etc.). I tend to think > > >of OWL as an extension to RDF, so this data is still part of OWL, it >> >just has the standard RDF syntax. >> > >> >In any case, our model theory must talk about data to the same extent >> >that it talks about ontologies. >> >> It does. It always has done. What is the problem? >> >> Pat >> >> -- >> --------------------------------------------------------------------- >> IHMC (850)434 8903 home >> 40 South Alcaniz St. (850)202 4416 office >> Pensacola (850)202 4440 fax >> FL 32501 (850)291 0667 cell >> phayes@ai.uwf.edu http://www.coginst.uwf.edu/~phayes >> s.pam@ai.uwf.edu for spam -- --------------------------------------------------------------------- IHMC (850)434 8903 home 40 South Alcaniz St. (850)202 4416 office Pensacola (850)202 4440 fax FL 32501 (850)291 0667 cell phayes@ai.uwf.edu http://www.coginst.uwf.edu/~phayes s.pam@ai.uwf.edu for spam
Received on Thursday, 7 November 2002 14:42:26 UTC