W3C home > Mailing lists > Public > www-rdf-interest@w3.org > May 2003

Re: rdfs:class and rdfs:resource

From: Francesco CannistrÓ <fracan@inwind.it>
Date: Fri, 9 May 2003 11:07:52 +0200
Message-ID: <01df01c3160a$79b190f0$8d951d97@Matrix>
To: "Richard H. McCullough" <rhm@cdepot.net>, <www-rdf-interest@w3.org>, Dieter K÷hler <dieter.koehler@philo.de>, "David Menendez" <zednenem@psualum.com>

> One can draw a parallel to Java here. Java has an Object class, which
> all objects are instances of, and a Class class, which all classes
> are instances of. Class is a subclass of Object, Object is an
> instance of Class, and Class is an instance of Object. However:
> Object is NOT a subclass of Class.

I was sure that someone would have cited Java :-)

I agree with everything you say, but I don't think that these are the terms
of the question.
What you say is either correct and precise, but it is only descriptive.

When you say:

> rdfs:Class rdfs:subClassOf rdfs:Resource .
> rdfs:Resource rdf:type rdfs:Class .
> rdfs:Class rdf:type rdf:Resource .
> rdfs:Resource rdfs:subClassOf rdfs:Class .

you do not do anything more than reading the schema.

The question is: is this a paradox? if yes or if not, why?
I think that the answer to these questions cannot be direct, but that it
depends on the meaning that we give to what we read in RDF Schema.
I think that the real questions that solve the problem are:
what is rdfs:Resouce?
is it "defined" by RDF Schema through the schema it proposes?
I do not consider the former question (whose answer, however, is not
"Resource is a Class"), but about the latter I say: if the answer to this
question is "no", then there is not any paradox, but if the answer is
"yes", then we are in presence of a paradox: within a deterministic world an
axiom is an axiom and cannot be demonstrated!

Therefore, I think that there is not any paradox because I do not think that
the schema of RDFS defines rdfs:Resource, it just gives a name to this

Maybe I'm wrong ... I'm concerned that these sound like metaphysical or
ontological problems which nobody is interested to and/or takes care of;
what is sure is that they do not affect anyway RDF's working fine. But ...

... does anybody know something about the Godel's theorem?
Received on Friday, 9 May 2003 05:08:07 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 22:44:42 UTC