Re: The case against URNs

Paul Prescod wrote:

>
> A name becomes precise through assertions. What if we required EVERY URI
> in the world to assert its class through rdf:type. Then the white house
> site either declares "rdf:type='politicalDocument'" or
> "rdf:type='politicalOrganization". It can also assert something like:
> rdf:describingDocument="./index.html".
>
> I'm not suggesting that we really require the whole Web to do this...but
> people who want their URIs to be used unambiguously could.

Exactly. This really works.

>
> A program either knows what the URI means (perhaps by its surrounding
> context) and thus is not tempted to dereference it, even if it is
> "http://" or it does not know, in which case dereferencing it is the
> right thing to do.
>
> >...
> > For that matter, I don't think I would care if some small set of methods
> > *did* apply to now:// URIs, so long as those were appropriately specific
to
> > the abstractess of the URI, i.e. GETing now://www.whitehouse.gov was
defined
> > as retrieving the owner of the namespace's assertions about itself or
> > something like that.
>
> If you follow some links from that page you will find some asertions
> about the type and state of that resource! "Three branches of
> government" etc.
>
> It isn't machine readable but that's what "Accept: xml/rdf" is for.
>
> > ... But since the results of a GET on
> > http://www.whitehouse.gov are already understood by hundreds of millions
of
> > pieces of software and millions of web developers, it seems too late to
say
> > that it SHOULD be a way of describing the type, state, etc. of that
abstract
> > resource.
>
> Third parties ALREADY use it that way. "The <a
> href="http://www.whitehouse.gov">DAMN FOOLS in WASHINGTON</a> need a
> kick in the ass".
>

Exactly.


>
> So I see Roy's view as being consistent and complete. I don't see any
> harm with Tim B-L's view that the type of all resources addressed with
> URIs without "#" are implicitly "document" (where document is defined to
> include "service") but I'm not convinced it solves anything. URIs are
> likely to be used ambiguously unless they are defined unambiguously by
> their creators in the first place. (so "http://www.whitehouse.gov/" is
> probably way too ambiguous to be used for machine reasoning).
>

TimBL is trying to convince us that HTTP URIs without a '#' are implicitly
"document" but I have yet to see a convincing argument. In terms of
reasoning RDF/OWL treats URIs as logical constants, i.e. could care less
what characters go in the string, so http://www.whitehouse.gov/ is no better
or worse than any other URI as far as machine reasoning goes. It seems to
provide fodder for these sorts of arguments that occupy frequent abstract
discussions about what URIs necessarily identify, but for actual software I
see no inherent problem ... and would certainly change my mind if such an
actual practical problem were demonstrated to exist.

I think the reason that the TAG had decided to [try to] suspend the
discussion, is that the result has no _practical_ consequence for actual
software practice as specified by e.g. RDF, OWL, etc. and hence in the
absense of consensus there is no benefit to forcing the issue.

Jonathan
Jonathan

Received on Sunday, 6 October 2002 21:07:32 UTC