Re: What do the ontologists want

I agree with you here, Miles. Pat is correct, however, in that the
quoted material is really in a different language and as such is
syntactically only a string, without known semantics (or only string
semantics).

Apparently, what the RDF-ers term "reification" is meant to be the
ability not to quote per se but to semantically interpret the material
between the quotes as if it were comparable semantically to the material
outside the quotes, i.e., to "reify" the object language statement in
these kinds of examples into the meta-language (don't mean to confuse
people more by this object/meta usage). 

So that the statement

John said "Snow is white" 

is to be interpreted as:

P: John said [Q: snow is white].
P: John said that Q.

More like a propositional attitude construct.

P labels a statement in the meta-language, whereas, without the 'that',
Q labels a statement in the object language. 

Is this what people mean by reification in RDF?

Leo



Miles Sabin wrote:
> 
> pat hayes wrote,
> > As far as I understand what is meant by 'reification' in this
> > context, I see only a very limited utility, basically things like
> > tagging a string/expression with information about its source,
> > time-stamping and so on.
> 
> I think this is a little hasty. Quotation and 'reification', in your
> scare quote sense of abstract syntax rather than propositional
> content, have some very important roles to play. To borrow some
> examples from Tarski and Davidson,
> 
>   "Snow is white" is-true-in-english iff snow is white
>   "Schnee ist weiss" is-true-in-german iff snow is white
> 
> or better,
> 
>   "Snow is white" means-in-english that snow is white
>   "Schnee ist weiss" means-in-german that snow is white
> 
> The first example in each of these pairs baffles first year philosophy
> undergraduates, but the second makes things somewhat clearer: where
> the quoted expressions are drawn from an given object language the
> respective truth and meaning predicates can be used to set up
> correspondances target (I won't say meta- here) language. Fill this
> out sufficiently and toss in some syntactic structure on the quoted
> side and you have a translation scheme for the object language to the
> target language.
> 
> Bearing in mind that a lot of the stuff that people will be wanting
> to do with RDF is set up mappings between local and non-local
> vocabularies this strikes me as being of more that 'very limited
> utility'.
> 
> But don't take my word for it: cp. Tarski, "The concept of truth in
> formal languages".
> 
> > Most of the proposed uses of reification in the RDF literature seem
> > to me to be based on confusion, and many of them - most notably, the
> > idea that propositional structure and quantification can be provided
> > by reification - are just nonsense.
> 
> This I agree with wholeheartedly.
> 
> Cheers,
> 
> Miles
> 
> --
> Miles Sabin                                     InterX
> Internet Systems Architect                      27 Great West Road
> +44 (0)20 8817 4030                             Middx, TW8 9AS, UK
> msabin@interx.com                               http://www.interx.com/

-- 
_____________________________________________
Dr. Leo Obrst           The MITRE Corporation
mailto:lobrst@mitre.org Intelligent Information Management/Exploitation
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Received on Tuesday, 15 May 2001 17:06:26 UTC