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Re: rdfs:class and rdfs:resource

From: Richard H. McCullough <rhm@cdepot.net>
Date: Thu, 8 May 2003 04:02:02 -0700
Message-ID: <003a01c31551$6adb0a20$bd7ba8c0@rhm8200>
To: <www-rdf-interest@w3.org>, Dieter Köhler <dieter.koehler@philo.de>

Dieter
I agree with you.
The way I see it, every resource is EITHER an individual OR a class.

However, OWL FULL says that a class can be an individual.
The way I see it, that can only be true in another context.
But OWL and RDF don't know what a context is.
============
Dick McCullough
knowledge := man do identify od existent done;
knowledge haspart proposition list;
----- Original Message ----- 
From: "Dieter Köhler" <dieter.koehler@philo.de>
To: <www-rdf-interest@w3.org>
Sent: Thursday, May 08, 2003 3:07 AM
Subject: RE: rdfs:class and rdfs:resource
>
> >Thanks to everyone on attempting to clarify this rdfs:class and
> >rdfs:resource issue. But, either I'm missing something, or these
> >explanations are. Specifically, I need to see a careful description of
the
> >classes and *instances* involved.
>
> Perhaps things get clearer by concentrating on the essential statements
> about rdfs:Resource and rdfs:Class in the [RDF Schema] specification. In
> terms of the calculus specified in [RDF Schema] the following RDF
> statements are true (the numbers in brackets refer to the paragraph in the
> specification):
>
> <rdfs:Resource> <rdf:type> <rdfs:Class> . (2.1)
> <rdfs:Class> <rdf:type> <rdfs:Class> . (2.2)
> <rdfs:Class> <rdfs:subClassOf> <rdfs:Resource> . (2.1)
> <rdfs:Resource> <rdf:type> <rdfs:Resource> . (Because all instances of
> rdfs:Class are instances of rdfs:Resource, and rdfs:Resource is an
instance
> of rdfs:Class (2.1 and 3.4).)
>
> But the following is, as far as I can see, *not* true:
> <rdfs:Resource> <rdfs:subClassOf> <rdfs:Class> .
>
> In other words: There may exist instances of rdfs:Resources which are not
> instances of rdfs:Class.  Or again in other words: Not everything must be
a
> class.
>
> Footnote: I think it is unnecessary to talk *here* about
> meta-languages:  One may or may not on a meta-level require that all
> resources are classes (or in terms of scholastic philosophy: that all
> individuals are concepts).  And the question what comes first, resources
or
> classes, might be interesting if we try to form a hierarchy of different
> calculuses based on each other, but the simple answer for [RDF Schema] is
> that it has no hierarchical structure and should be considered as a
> whole.  Of course one could try to reduce the number of its axioms while
> the possible conclusions remain the same, but because of the
> dissimilarities of rdfs:Resource and rdfs:Class neither can simply be
> reduced to the other.
>
> Dieter Köhler
>
> Institute of Philosophy
> University of Karlsruhe
> Germany
Received on Thursday, 8 May 2003 07:03:13 GMT

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