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what is the meaning of the RDF model theory?

From: Seth Russell <seth@robustai.net>
Date: Thu, 4 Oct 2001 08:19:55 -0700
Message-ID: <006d01c14ce8$07c8ac40$657ba8c0@c1457248a.sttls1.wa.home.com>
To: "Pat Hayes" <phayes@ai.uwf.edu>
Cc: "RDFIG" <www-rdf-interest@w3.org>, <www-rdf-logic@w3.org>, "Peter Suber" <peters@earlham.edu>
From: "Pat Hayes" <phayes@ai.uwf.edu>


> You are living in a paranoid fantasy world. There are no Priests of
> logic. There is however a working group charged with defining a
> formal language called RDF, and the model theory (soon to be
> improved, BTW) is what that body says RDF means. Of course you are
> free to treat RDF files in any way you like; but just as a practical
> matter, if you plan to use RDF to communicate with others, it might
> be wise to adopt the same conventions that everyone else is adopting,
> if you intend to be understood by them. Or, you can use some other
> language; nobody is calling you to prayer here. The MT just sets the
> RDF standards into public view to help people avoid mutual confusion.


Yeah sure ... I'm well aware of the nature of standards and the consequences
of deviating from them.    Sorry if my questions have been asked with such
bumbling confusion.   I'm just trying to understand, not only the technical
issues of the RDF Model Theory [1], but also how it will be used, what it
means to me as a developer, and how that  meaning will flow to users
cruising the Semantic Web [7].     So let me go out and come in again ....

It seems to me, and you seem to have confirmed this, that this document will
tell us, in no uncertain terms,  what circumstances must obtain for a RDF
graph to be true or false.  Is that a fair summary ?    ... and may I
proceed as if it were ...

But it seems to me that whether a RDF graph is true or false may not have
much bearing on how a well formed graph affects its author or its audience.
As you well know, there are some of us who seek to adopted radically
different epistemologies.  In my own words let me briefly attempt to sketch
mine:  which, as far as I can see, holds the truth of a RDF graph to be
somewhat irrelevant .. or if not irrelevant, at least relegated to the
status of a propositional attitude.  Suppose that each agent (human or
cybernetic) carries around a grab bag of tools ... and that these tools in
these bags create an intricate network of possible interactions.  Agents
transmitting messages from bag to bag cause changes that ripple around the
global network .. and in this environment:  which tools work, will survive
in the bags.  Analyzing what works in terms of two values, {true or false},
becomes too complex, too inexact,  and ends up being unnecessary.

I don't expect you or the W3C to adopt that philosophy ... but by the same
token I don't expect you to rule it out by what you write in our
specifications.

Now let me ask a more practical question which, hopefully, will help me
focus my understanding of your document.   Before the Model Theory [1], we
had RDF graphs and detailed specifications of how to form and communicate
them [2 - 6].  Can you provide an actual example of a RDF graph that adheres
to those specifications, yet is invalid according to the Model Theory ?

[1 RDF Model Theory] http://www.w3.org/TR/2001/WD-rdf-mt-20010925/
[2 RDF M&S] http://www.w3.org/TR/REC-rdf-syntax/
[3 RDF Schema Specification ]
http://www.w3.org/TR/2000/CR-rdf-schema-20000327/
[4 RDF revisions draft] http://www.w3.org/TR/rdf-syntax-grammar/
[5 RDF W3C homepage ]http://www.w3.org/RDF/
[6 DAML ] http://www.daml.org/2001/03/daml+oil-index.html
[7 Semantic Web] http://semanticweb.org/

cc: news:comp.ai.philosophy

Seth Russell
Logic is great!  Survival is better :)
Received on Thursday, 4 October 2001 11:21:24 GMT

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