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[issue needed] Re: RDFCore last call WD's: Two comments on the RDF documents

From: Frank Manola <fmanola@mitre.org>
Date: Wed, 26 Feb 2003 16:10:56 -0500
Message-ID: <3E5D2D60.42F7971@mitre.org>
To: Bob MacGregor <macgregor@isi.edu>
CC: www-rdf-comments@w3.org, macgreg@isi.edu

Brian--

Can I have an issue for this please?  Basically I'm raising this (or at
least the part about the Primer;  the message also has a comment about
Concepts) to the WG level because I need input from the WG (especially
Pat, but others may have opinions as well) on how we should handle these
comments about reification.  Pat and I need to be in synch on this in
order to also deal with Bob's comments on the Semantics document in
http://lists.w3.org/Archives/Public/www-rdf-comments/2003JanMar/0211.html,
and we also have issue danc-03 raised in
http://lists.w3.org/Archives/Public/www-rdf-comments/2003JanMar/0218.html
that suggests deleting the Primer reification section entirely.  And I
recall some messages from Pat about "propositional attitudes" (I can't
recall the thread right now) that are pertinent to Bob's comments.  

--Frank

Bob MacGregor wrote:
> 
> Frank,
> 
> At 03:04 PM 2/13/2003 -0500, Frank Manola wrote:
> > >
> >snip
> > >
> > > So, how am I recommending that you fix things?  Unfortunately, I'm mostly
> > > stating what you should NOT do.  I'm claiming that
> > > using nested syntax will convey the wrong impression to many readers (e.g.,
> > > those that model belief they way I did above), so something like an
> > > EXPLICIT quotation needs to be included.  To me, the use of double brackets
> > > didn't adequately convey the notion of quotation.
> > >
> >snip
> >
> >I will try using a diagram, rather than what appears to be nested
> >syntax, since we don't support nested syntax (and I didn't intend for
> >what the Primer uses to be interpreted as nested syntax). However, we
> >don't really support explicit quotation either, so we can't really
> >substitute that.  Whatever is said in the Primer on reification will
> >have to be consistent with what is said in the Semantics document, which
> >means this is related to your message
> >http://lists.w3.org/Archives/Public/www-rdf-comments/2003JanMar/0211.html
> >"Statings -- Much ado about nothing".
> 
> I agree that figuring out a representation is tough.  I'm used to KIF, where
> I can say pretty much anything that I want to.  Its hard even to have an
> e-mail conversation about certain aspects of RDF, since the vocabulary just
> isn't available.
> 
> > > I consider introducing "what we would *like* to be able to do" very
> > > dangerous.  It
> > > gives the impression that RDF might be used to represent propositional
> > > attitudes,
> > > when in fact it can't.  I would prefer that the WG be as up front as
> > > possible about
> > > stating the limitations it has placed on RDF.
> >
> >I don't think the Primer actually conveys this impression, and I think
> >it tries to be up front about the limitations of RDF reification (it
> >certainly spends a lot of space talking about them at any rate).
> >However, I could see adding a caveat at the beginning along the lines of
> >"you might think you're going to be able to do foo, but watch carefully,
> >because you can't".  Does this make sense?
> 
> Yes.  Again, we have a vocabulary problem.  I've seen the phrase "propositional
> attitude" pop up now and again, but the notion of "proposition" is quite
> difficult
> to pin down, so that makes it hard to discuss.  But, I will try.
> 
> I think of propositions as being the proper objects of belief.  So, one doesn't
> believe in a *sentence* "George is a clown".  Rather, one believes in the
> proposition
> that that sentence is true.  In KIF, I'm used to seeing nested syntax
> employed when
> representing statements about belief.  Thus, if RDF allowed nested
> statements, then
> I would use them to represent belief.  But it doesn't, and hence I'm thinking
> that an example that *does* employ nesting gives the wrong impression.
> 
> However, the following text appears in the Concepts and
> Abstract Syntax document:
> 
>     > Not every RDF/XML expression is asserted. Some may convey meaning
> that is partly
>     > determined by the circumstances in which they are used. For example,
> in English, a
>     > statement "I don't believe that George is a clown" contains the words
> "George is a clown",
>     > which, considered in isolation, has the form of an assertion that
> George exhibits certain
>     > comic qualities. However, considering the whole sentence, no such
> assertion is considered
>     >to be made.
> 
> I'm still waiting to see an example of an RDF statement that is not
> asserted.  If someone
> could illustrate one, that would be a big help.  If, in fact this passage
> is meant to
> refer to reified statements, then please write down how this would look in
> RDF using reified
> statements.
> 
> Note: The text above actually uses term "expression" rather than
> "statement" when it
> talks about things being asserted.  RDF terms are expressions, and terms cannot
> be asserted, so that makes the
> first sentence trivially true.  But I assume that that was not the authors'
> intent.
> Suggestion: Replace "expression" by "statement" in the first sentence, if
> that's what's
> meant.
> 
> My impression is that its impossible to express the sentence
>       "I don't believe that George is a clown"
> in RDF.  In the OLD RDF, I would have said yes, but not now that we have
> switched
> to "statings".  If it is acceptable for a stating to serve as the object of
> a statement
> about belief, then I would have to withdraw my objection.  So, can we represent
> beliefs in RDF?
> 
> Cheers, Bob

-- 
Frank Manola                   The MITRE Corporation
202 Burlington Road, MS A345   Bedford, MA 01730-1420
mailto:fmanola@mitre.org       voice: 781-271-8147   FAX: 781-271-8752
Received on Wednesday, 26 February 2003 16:11:09 GMT

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