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RE: What the meanging of "is" is

From: Larry Masinter <masinter@adobe.com>
Date: Sat, 14 Mar 2009 09:14:16 -0700
To: Jonathan Rees <jar@creativecommons.org>
CC: "www-archive@w3.org" <www-archive@w3.org>
Message-ID: <8B62A039C620904E92F1233570534C9B0118CD2A0E10@nambx04.corp.adobe.com>
> The httpRange-14 rule can be reinterpreted: If you make an RDF theory
> of HTTP or of  some 200-yielding HTTP resource,

I don't understand the category of "200-yielding HTTP resource"
in terms of the temporal behavior. There are resources which are
identified by URIs, and there are HTTP servers that respond to 
requests. Some requests will get a 200 response and some requests 
will get some other response, or no response at all, or will fail 
to open a TCP connection or other behavior will be evidenced, and
the behavior varies over time.  I don't understand how
"200-yielding" is used as a category distinction. Some URIs
have never produced a 200 in the past but might in the future.
Others have consistently produced 200 responses in the past,
but might stop any minute now.

("duri" provides a way of at least fixing the temporal behavior
if you want to talk about the 'expected operational behavior'
at a point in time. My view is that all web servers had a 
time of initial operation, and have (or will have) a time when
they cease to function, and so temporal variance of operational
behavior is a serious problem for assertions made about 
time-independent concepts.)

>  please try to put
> the RDF referent of the URI in classes that are fairly closely tied to the way
> HTTP is used - e.g. documents, web pages, REST resources, web services,
> and so on.

What does it mean to "put the RDF reference of the URI in classes"?
If you have an assertion expressed in RDF using a URI, how do you
"put the RDF reference" in a class? There's a model in which an
assertion written in terms of RDF and URIs is mapped to an assertion
about the real world. Is your request ("please try") in the context
of "when constructing the model"?

I think I understand what you're asking if it's in terms
of constructing a model, but I’m less sure what's involved
in constructing a model. I like the idea that a "model" is
(abstractly) the way in which you map the identifiers in a
language to concepts or entities in the real world, but I
can't imagine how one would "write down" a model, since the
only languages we have for writing anything down require
a model themselves to understand them.

>  Make "identification" under HTTP as close as you can to
> "identification" in a model of your RDF theory.  

HTTP doesn't have a theory of "identification" -- at least
"identification" was not a topic of the HTTP working group. 
httpRange might be proposing a model of "identification", and
then proposing that RDF model makers use it? Which I suppose
is useful to those thinking about using RDF and making RDF
models?

> If we could relate HTTP to RDF, this could set an example for relating
> other protocol pairs, and if the approach became methodical, we might
> be able to make suggestions about some general theory of the
> (recommended) meanings of URIs - identifying equivalences, types, and
> relations in one domain and showing how they correspond to
> equivalences, types, and relations in another.

> Personally I think HTTP/RDF is the only case worth pursuing, and
> it should be useful to limit the hunt to this one quarry.

I don't understand your optimism that any possible relationship 
between the HTTP protocol and the RDF representation system
would be useful enough in general to be worth pursuing.

I don't think there's any generic model of http URIs that
can serve to give RDF the representational power it needs to
make assertions about anything other than web servers and
how they behavior.

("tdb" and HTTP URIs might be used with such a model to
allow assertions about other things, of course, at the cost
of the extra syntax necessary.)

> Whether anyone else will like this, I'm not sure - certainly the semantic web
> view is different from the above, since it thinks the world is just
> one big happy
> ontology. I don't buy that. (RDF != semantic web)

I don't think the world is "just one big happy ontology", but
I'm not sure I've seen anyone stand up directly for that point
of view -- when pushed on it, most seem to think that someone
else made that assumption when RDF was designed, and they're
happy that someone else has figured this out. So I think it's
a disconnect, not a difference of opinion.

Larry

Received on Saturday, 14 March 2009 16:15:11 UTC

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