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Re: Role of URI and HTTP in Linked Data

From: David Booth <david@dbooth.org>
Date: Wed, 17 Nov 2010 18:41:37 -0500
To: Pat Hayes <phayes@ihmc.us>
Cc: Jiří Procházka <ojirio@gmail.com>, nathan@webr3.org, public-lod@w3.org
Message-ID: <1290037297.8901.10697.camel@dbooth-laptop>
On Thu, 2010-11-11 at 12:59 -0600, Pat Hayes wrote:
> On Nov 11, 2010, at 8:00 AM, David Booth wrote:
> > On Thu, 2010-11-11 at 07:23 +0100, Jiří Procházka wrote:
> > [ . . . ]
> >> I think it is flawed trying to enforce "URI == 1 thing" 
> > 
> > Exactly right.  The "URI == 1 thing" notion is myth #1 in "Resource
> > Identity and Semantic Extensions: Making Sense of Ambiguity":
> > http://dbooth.org/2010/ambiguity/paper.html#myth1 
> > It is a good *goal*, but it is inherently unachievable. 
> Well, no, careful. It is unachievable IF the only means we have to pin
> down a referent is to describe it. 

Okay, I should have said it is inherently unachievable in the vast
majority of cases.  :)

> But that isn't the only way we have. 
> In the 'real' world of ordinary language we often have the possibility
> of ostention. Q: "What do you mean by 'froogle'?"  A: "This, here in
> my hand, this is a froogle"  spoken while brandishing a teaspoon, say,
> leads to the hypothesis that 'froogle' means teaspoon, or at any rate
> some category which overlaps teaspoons. Arguably, this is at the root
> of how we learn language in the first place. (After all, if Quine were
> right about the indeterminacy of translation - 'gavagai' and all that
> - then it would be *impossible* to learn a language; and yet we all do
> it.) 
> What http-range-14 does can be seen as allowing conventional HTTP
> GETting to be a form of ostention. If an http: IRI succeeds in GETting
> a representation of something with a 200 code attached, then that's
> the Web saying, in effect, A: "What I mean by <IRI> is this thing
> here"  while it - the Web - is doing the closest it can GET to
> brandishing something, ie delivering you a Web awww:representation of
> it. 

Hmm, that's an interesting view.  I kind of like it.

> (The question "What do you mean by <IRI>?" was your GET request, by
> the way, and a 303 response is the Web saying "I have no idea.")

Actually, a 303 response would be the Web saying "I don't know, but that
resource over there might have information about it".
> Since the identification performed by HTTP GET is indeed unambiguous
> and unique, just as holding and waving a teaspoon is, this really does
> succeed in unambiguously identifying something. [ . . .]

Hold on, I think you're overreaching here.  I don't think the teaspoon
was unambiguously identified in any absolute sense.  It may have been
unambiguous *enough* for the task at hand.  But later training may be
needed to disambiguate the froogle from 90% of other teaspoon-like
things when I need to do a task that depends on a finer distinction.  

Similarly with a web page, the degree of identification that you get
from an HTTP 200 response may be ambiguous enough for *some*
applications, but there may be other applications that need to
distinguish between the-web-page-as-intellectual-property versus
the-web-page-as-a-bit-stream-generator.  After all, they may have
totally different custodians.

In the world of RDF, I think the notion of ambiguity is only meaningful
in a relative sense -- relative to a particular application -- not
absolute.  Is the identity of the resource unambiguous *enough* for a
particular application?  That's what matters.  And what's unambiguous to
one application may be ambiguous to another application that requires
finer distinctions.

David Booth, Ph.D.
Cleveland Clinic (contractor)

Opinions expressed herein are those of the author and do not necessarily
reflect those of Cleveland Clinic.
Received on Wednesday, 17 November 2010 23:42:07 UTC

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