Re: URIs: resources and contradictions was: Re: httpRange proposed text

Miles Sabin wrote:
>
> If you want to say that URIs are logical constants in a uninterpreted
> formal system, then fine: that gets rid of ambiguity there. But to be
> relevant we need an interpretation (or a context if you'd prefer) which
> pins denotations of identifiers and extensions of predicates down to
> something tangible (cars or documents). And without a unique,
> cannonical, unequivocally intended interpretation, it's not possible to
> guarantee that interpreted uses of identifiers will be unambiguous,
> because the users might not share the same interpretation.

I don't claim that removing ambiguity about the mapping of URI to resource
somehow removes all ambiguity in the system ... that would be a miracle. I
think we need to move step by step and clarifying the relationship between
URI resource and representation would be a great first step.

>
> > We may choose to believe either one or the other context, that is we
> > may choose to believe either one or the other set of assertions about
> > a resource. That we might do this doesn't change the fact that the
> > resource is identified by a URI (under RDF and the RDF model theory
> > http://www.w3.org/TR/rdf-mt).
>
> Believing "one or the other context" is opting for one or other
> interpretation of an uninterpreted system. That affects the truth
> values of assertions by affecting the denotations of identifiers and
> the extensions of predicates. Given the way you've set this up, your
> resources look more like placeholders than actual referents, so I guess
> they're unaffected. But the "meanings" of those resources most
> certainly will be, and those are what's important (they're what
> determine, ultimately, whether we're talking about cars or documents).
> And without a unique, cannonical, unequivocally intended
> interpretation, that's enough to get us ambiguity.

This is largely correct. Perhaps ultimately the "meaning" of a URI/resource
will be determined by social mechanisms. Even then, if we didn't have
ambiguity, we wouldn't have civil courts.

>
> > "context" isn't a feature of RDF 1, but I think it's important.
>
> This I agree with, wholeheartedly. But I can't help wondering why _you_
> think it's necessary: context is important for disambiguation, but if
> there's no ambiguity ... ?
>

When did I say there was no ambiguity? All I am saying is that a URI
uniquely identifies a single resource, that is there is a 1:1 mapping
between URI and resource. Surely that alone doesn't solve the world's
problems :-)

Jonathan

Received on Saturday, 3 August 2002 23:25:57 UTC