Re: Can there be a URI for the concepts "I", "you", "this", "it", "here", "there", "now", etc.?

I think the methodology of contexts (which could also be thought of as a
variation of named graphs, where the URI of the "name" names the
context) that Joshua Tauberer has suggested might be the best for the
time being.

In essence, part of the problem is that "I" and "you" and other
indexicals are actually "variables" that, as Joshua put it, then given
in a context, map to individuals. Since there is no notion of a variable
in RDF as it is (although there is in N3, and one would assume, whatever
RIF turns out to be), well, then this is going to be hard to model
coherently given current standards. It would, actually, be a good
use-case for including variables in the SW layer cake.

One aside - the treatment of deixis in formal semantics is hard (I'd
recommend looking at Barwise and Perry's work in situation theory for
one way to do it, and Guha's work on this is also excellent) and since
by its very nature, formal semantics is trying to achieve some degree of
context-independence, it's always going to be messy.

However, I'd like to make an aside - in the Semantic Web  community,
we're always striving for globally sharing information, and this means 
in practice elimating some of the context in order to share - and this
will always do some violence to the subject matter being modelled, so no
matter how hard we try to get context independence there's always going
to be some level of brushing context under the carpet :)

Furthermore, if we're going to use "context", we're going to need some
way of putting it up front, and my bet is variables, possibly with
"names" is the way to go.

Joshua Tauberer wrote:
> John Black wrote:
>> Are the following URI allowable according to web and semantic
>> web standards? Are they ambiguous? Are they useful? In each case,
>> the referent would depend on the context of the use[1] of the URI.
> I think one of the major benefits of RDF is that applications completely
> oblivious to any schemas can still at least make one conclusion about
> URIs, which is that if two documents use the same URI, they are
> referring to the same thing.  Context-dependent URIs break this.  It
> might be fine in some cases, but in general it would break the principle
> that <indexicals.owl#I> refers to the very same thing no matter where it
> appears.
>> Therefore they would only be of use if they could be embedded in a
>> structure that specified a context.
> That would be fine, except afaik the only way to publish a triple in an
> embedded context is with N3 formulas.  You can't, for instance, create
> an embedded context in RDF/XML.  (It wouldn't be sufficient to add a
> triple to an RDF/XML document to say "hey, this is one of those
> documents where you interpret <indexicals.owl#I> as ME" because it
> doesn't solve the problem that oblivious applications won't know to do
> that.)
> But, there is a way to get around these problems, which is to use some
> indirection.  Actually, that actually parallels the real-world side of
> things.  That is, we're not all named "I" (in the sense that a URI is a
> name for something).  "I" is really a function from a context to an
> individual.  The closest thing to a function in RDF is a predicate, so
> you could do this (in N3):
> <> indexicals:isBeingReadBy _:you .
> <> indexicals:isBeingReadAtLocation _:here .
> (then you go on to make assertions about _:you and _:here.)
> where <> is the URI for the document itself, and _:you and _:here are
> bnodes.  Like this, an application isn't going to make the mistake that
> the same person is the "I" of every document.  Here it says "someone is
> reading the document", and just when the applications understands
> indexicals:isBeingReadBy it can say "Oh, and _:you is actually me!".
> (I'm not positive that that actually solves every problem, but it seems
> to be a step in the right direction.)


Harry Halpin,  University of Edinburgh 6B522426

Received on Monday, 18 December 2006 19:52:53 UTC