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[RDF-concepts:113-Various] Re: Social Meaning and RDF

From: Graham Klyne <GK@ninebynine.org>
Date: Wed, 19 Feb 2003 16:21:31 +0000
Message-Id: <5.1.0.14.2.20030218202239.03b9a5d0@127.0.0.1>
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Cc: www-rdf-comments@w3.org

Peter,

With reference to your previous message commenting on material in the RDF 
concepts document:
   http://lists.w3.org/Archives/Public/www-rdf-comments/2003JanMar/0192.html
I have recorded your message with the id 113-Various [**].

[**] for my own tracking purposes:  when the scope of the issue is 
established, I'll ask Brian to allocate WG tracking ID(s).


I need to better understand the basis of your concerns.  Reviewing your 
comments, I discern the following main issues:

1. Intended meanings are external to the RDF graph, not contained.  As 
such, why are they covered in the normative aspects of RDF specification?

2. Does the material on social meaning have any impact on the behaviour of 
an RDF application?  If not, why is the material here at all?

3. The idea that some party controls the meaning of a given URI is counter 
to the goal that "anyone can say things about anything".

4. What are the mechanisms by means of which an RDF expression is 
designated as being asserted, as opposed to an expression which is not 
regarded as asserting some truth?


These seem to cover four main areas:

(a) Can RDF be defined as having any social meaning?

This needs further exploration.  Is this simply a disagreement about what 
should and should not be considered normative, or is there a real scenario 
in which social meaning creates a serious problem?  To properly understand 
the issue raised, and taking  account of the answer below to (b), please 
provide an example of a situation where the problems described might 
materialize.


(b) If so, does any such meaning affect the behaviour of an RDF application?

My answer here is an emphatic "no".  RDF does not require or expect that 
RDF applications have awareness of any social meaning that may be conveyed 
by RDF content.  The formal aspects of RDF entailment are quite independent 
of any issues of social meaning.  This area of the document needs reworking 
so that this is clear.


(c) How is any such meaning related to the intended 
interpretation/denotation of URIs?  In particular, you seem to claim that 
there being an authority for any URI who defines its intended 
interpretation prevents the deployment of RDF applications.

I cannot understand how having a designated third party define the intended 
interpretation of some URI prevents the deployment of any RDF 
application.  I'll note that there are already a number of RDF applications 
in use in which parties depend on vocabulary meanings defined by third 
parties.  Please indicate a scenario in which this might be a real problem.


(d) What mechanisms are defined to distinguish asserted from non-asserted 
statements?

RDF does not define any such mechanisms, and simply notes (with examples) 
that not every occurrence of data that conforms to RDF syntax is 
interpreted as an RDF assertion.  Clearly, at some level, the distinction 
must be made.  An RDF reasoner will deal with whatever is presented to it, 
without concern for how that information is selected.  GIGO 
applies.  Definition of these mechanisms are not within scope of the 
current effort.

We do, however, aim to set the expectation that for social purposes, the 
same kinds of consideration apply to assertion of statements in RDF that 
may apply to assertion of statements in any other form, such as English 
text marked up with HTML.

#g
--


At 11:12 AM 2/5/03 -0500, Peter F. Patel-Schneider wrote:


>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

-------------------
Graham Klyne
<GK@NineByNine.org>
Received on Wednesday, 19 February 2003 11:28:31 GMT

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