on Wed. Dec. 26, 2007 at 7:30 PM, Pat Hayes wrote:
[snip] (01)
JB>>Reminds me of a question I keep having with regard to URIs in the
>>Web Architecture. There doesn't seem to be any attempt to distinguish
>>between each occurrence (I sometimes call it an utterance) of a URI and
>>its establishment.
>
PH> Indeed, there is not. On the contrary, there is an insistence that no
> such distinction be made. To make it is an architectural error. That is
> the whole point of URIs, if you think about what they are mostly used for.
> If your browser, in its context, were to interpret a URI differently from
> the website it identifies, in its context, then the entire Web would stop
> working.
>
>> And in fact, it seems to be argued often that this is by design and
>> intentional, yet nowhere is are there methods for dealing with what seems
>> to be inevitable contextual differences between each occurrence of a URI.
>
> That is exactly the point. There should not be any such contextual
> differences. The CL logic is designed to eliminate them. If they, as you
> say, 'inevitable', then the Web must be broken. But on the whole it seems
> to work reasonably well.
>
>>In other words, it sounds like IKL aims for the same goal
>
> IKL and CL are similar in this aspect, of having globally transparent
> meanings for names.
>
>> but includes some machinery for achieving it, while the Web Architecture
>> claims that it is so by engineering design.
>
> Well, URIs on the Web have a dual aspect: they provide access to
> "information resources" (for the meaning of this jargon, go to the W3C)
> and they also are used in RDF and OWL to *denote* arbitrary things. The
> relationships between these two roles are subtle and controversial, and
> not always described very clearly. But certainly, both the Web
> architecture and the CL logic assume that names denote uniformly, not
> differently in different 'local contexts'. (02)
I just came across this in Tarski's 1944 paper, The Semantic Conception of
Truth: "...the fundamental conventions regarding the use of any language
require that in any utterance we make about an object it is the name of the
object which must be employed, and not the object itself. In consequence, if
we wish to say something about a sentence, for example, that it is true, we
must use the name of this sentence, and not the sentence itself." This
reminds me of my objection (due partly to my understanding of your own
arguments about it) to the current attempts to describe the relationship
between those two roles. For I think the same could be said about the object
that is accessed by using a URI utterance in an HTTP system. To say of a web
document that it is an information resource, for example, it is the name of
the object (the URI) which must be employed, and not the object itself. What
the current version of the web architecture seems to be saying is that web
objects, as opposed to everything else, say what they are themselves. In
other words, to make utterances about a web object, you use the web object
itself (including the 200 OK), and not its name. This would be like
insisting that, when talking about a car, you had to insert the car itself
in your speech somehow, as the subject of all propositions about it. This,
of course, would seem to have the great advantage that everyone would always
be referring to the same car - unambiguously - regardless of any local
context. But actually, I think this is an illusion. Objects can't insert
themselves into ontological categories. Agents use names to put categories
around objects like cars or web documents for particular purposes. The
universe just exists, agents say what objects are by using language. So I
don't agree it would break the web for each utterance of the name (URI
occurrence) of some web object to be used for any useful purpose, even if
different from other uses, all while HTTP returns the same object for the
same URI. (03)
(But even as I try to wrap this up and hit the send button, I see problems
with this. For example, the fly (object) buzzing around in front of the frog
reflects light that physical changes the frogs vision transducers in a
distinct, fly-like way. When the frog processes this as a fly, that is, when
the frog's brain puts it in the 'dinner' category, it appears very much like
it is the very essence of the fly, the fly's fly-ness that does so. Any frog
that arbitrarily put it in the 'mate' category, for example, would lead a
very short life.) (04)
John Black
www.kashori.com (05)
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