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Social Meaning and RDF

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Wed, 05 Feb 2003 11:12:20 -0500 (EST)
Message-Id: <20030205.111220.94023208.pfps@research.bell-labs.com>
To: www-rdf-comments@w3.org


This is a continuation of my comments on what I consider to be a fatal flaw
in the RDF specification.  I had submitted my views on this flaw to the W3C
RDF Core Working Group before the beginning of the Last Call period in the
message archived at
	http://lists.w3.org/Archives/Public/www-rdf-comments/2002OctDec/0297.html
but the working group chose to go into last call without addressing my
comments on this issue.


What is the ``social meaning'' (Section 4.2 of RDF Concepts) of RDF?  Does
it have any relationship to how an RDF application should act?  If so, what
is this relationship and how can it be conveyed to an application?  If not,
what business does this have in a document about RDF?

How does an RDF expression get to be asserted?  What syntax can I use to
assert RDF expressions, or to prevent their assertion?  Can I use this
notion in OWL?  If not, then what good is it?  Without any method given for
asserting an RDF expression or graph, what good is a paragraph that starts
``When an RDF graph is asserted in the Web''?  

How is social meaning determined?  Does it have to be part of the RDF model
theory?  Does it have to be part of an RDF graph?  Does it have to be
accessible on the Web?  Must it be common knowledge, and for what
community?  Must it be written down somewhere?  Can it exist only in
someone's mind?


The idea that RDF graphs contain ``defining information'' that is opaque to
logical reasoners is ludicrous.  An RDF graph is simply a set of RDF
triples.   It is certainly possible that there can be communities that have
intended meanings for these RDF graphs, but these intended meanings are
external to the RDF graph, and, indeed, external to RDF as a whole, and
thus have no place in a normative part of a document about RDF. 

What social conventions surround the use of RDF?  Even if there were some,
why should they make their way into a normative section of an RDF document?
The idea that some owner of a URI reference can control the use of that URI
reference goes counter to the bedrock goal that RDF allows one to say
anything about anything.   The RDF model theory contains no hint that any
of these sorts of restrictions are possible. 


The example in Section 4.5 of RDF Concepts brings forward these problems.
The document at http://skunk.example.org/ does not entail anything
derogatory about C:JohnSmith, which is reinforced in the section just
above.  This being the case, there is no reason for any notion related to
RDF to bring this forward.

If, however, the opposite was the case then there would be no way for any
organization to deploy any RDF-based application.   Such applications would
not be able to understand the social meaning of the RDF they created or
manipulated, and thus could easily create documents holding the
organization liable for just about any imaginable consequence.  In this
case I would have no choice but to tell Lucent Technologies not to deploy
any RDF applications.   


Peter F. Patel-Schneider
Bell Labs Research
Lucent Technologies
Received on Wednesday, 5 February 2003 11:12:33 GMT

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