<huge snip>
>>
>>The key point is, what would count as a
>>'context' for a context-dependent URI? Consider
>>this scenario. You, sitting at your computer,
>>use a URi to browse an interesting website, and
>>you send me an email telling me about it and
>>citing the URI. I then, sitting at my computer,
>>two days later on the other side of the planet,
>>type that URI into my browser. We expect that
>>we will see the same website: but what do our
>>two contexts have in common? It might be almost
>>nothing: the times, places, browsers,
>>countries, users, OSs, maybe even cultural and
>>linguistic settings, can be completely
>>different. It is inherent to the Web that the
>>contexts of publication and of use of a URI can
>>be arbitrarily different and far apart on every
>>dimension, yet the URI is supposed to retain
>>its meaning.
>
>Unless my relative ignorance is blinding me to
>something obvious, we seem to be thinking of two
>different things. (01)
Possibly :-) (02)
> I am not thinking of the *uniqueness* part
>changing with the context, so that a URI-access
>produces two different sites, I'm thinking of
>the ontological classification of what is there. (03)
Hmm. But how can one and the same site have many
different ontological classifications? (04)
>To explain what I mean, here is an example: that
>of a fingerprint. Fingerprints have for some
>time been used to identify suspects in criminal
>investigations. A human fingerprint is
>considered unique, except in the case of
>identical twins. It would seem to be an adequate
>identifier or *name* for a person. But it might
>also be used for many other references. A
>gruesome example, after an airliner crash, a
>fingerprint could be used to identify a finger,
>or a hand, or an arm. On the other end of the
>scale, that same fingerprint could be used to
>identify my nuclear family, since no other
>family can possibly have a member with the same
>fingerprint. For the same reason, it could be
>used to identify a football team, a nation, or a
>species. It is a unique, distinguishing
>characteristic all right - of many, many things.
>By itself, it is not clear which of these things
>a fingerprint names. (05)
None of them. A fingerprint isn't a name at all.
I think you have a misleading analogy/example
here. Names aren't forensic evidence for their
referents. The relationship (of reference)
between a name and its referent is essentially
arbitrary, a linguistic/social convention. (06)
> Each occurrence of the same identical
>fingerprint, which belongs to one and only one
>person, might then have a different referent. (07)
No, I think fingerprints don't have referents at
all. Unless someone invents a 'language of
fingerprints', but I haven't seen such a thing
ever proposed. (08)
>The person doesn't change - but what his
>fingerprint denotes in the context of its
>occurrence does. So it is with a name (in
>context) or a URI: The time-varying set of
>representations of the resource doesn't change,
>but *what it is* may vary. (09)
But that is exactly what CL denies about names
(and the TAG about URIs). Under appropriate
http-200 circumstances, a URI denotes what it
accesses. Which is unique, right? And under the
REST model, a resource (in current jargon:
information resource) *is* a function from times
to webarch:representations. So *what it is*
cannot vary, by definition, as a basic
Web-architecture requirement. (010)
>Take the Moby Dick web-site URI example. In one
>context, say a group of network admins, an
>occurrence of that URI may denote the bit stream
>encoding itself, perhaps a certain section of
>the bit stream has the same signature as a well
>known virus. (011)
Why is it required that the URI *denote* the bit
stream? Would it not be better to be explicit
about the distinction between the resource and
the bitstream, and keep their names distinct?
Human discourse often muddles referents in this
kind of contextual way, but that is probably
because human languages are under great pressure
to reduce the usage of valuable bandwidth, and
human brains can function very will with contexts
of various kinds. Computer languages have no such
bandwidth constraint, but have no provision for
being sensitive to context, and benefit greatly
from being somewhat pedantic about reference. (012)
>In another context, that of the web-site admin,
>another occurrence of the URI may denote that
>particular on-line version of the novel Moby
>Dick, for it may contain punctuation errors that
>need to be corrected. In yet another context,
>that of a literature professor, an occurrence of
>the URI denotes the entire phenomenon of Moby
>Dick, the great American classic, translated in
>many languages, subject of many articles. This
>is how each occurrence of a URI could have a
>different referent, even though each user GETs
>'representations' of one single 'resource'. (013)
Well, yes, one could try to make such a story
work. I have in the past argued for that kind of
approach myself:
http://www.ibiblio.org/hhalpin/irw2006/presentations/HayesSlides.pdf
But, ironically, the presence of the semantic web
itself makes this impractical, since ontology
reasoners will rapidly come to invalid
conclusions. Take your example, and suppose that
these three users all express themselves using
SWeb ontologies and wish to communicate. The
second may have asserted that (014)
_:x rdf:type GrammarCheck:SyntaxError13 .
_:x :containedIn :TheURI . (015)
The third may have concluded that (016)
:TheURI dc:Author "Herman_Melville"^^xsd:string . (017)
If they now communicate using SWeb protocols,
they can both conclude that Herman Melville was
guilty of making spelling mistakes. If the first
joins in, they can all conclude that Herman
Melville was the author of a well known virus.
Similarly, ambiguity between a website home page
and its author (the archetypical case for the
http-range-14 discussion) rapidly leads to such
nonsensical conclusions that people are their own
dc:authors, or that their home pages are created
on their birthday. (018)
One reaction to this is to denigrate the lack of
context-sensitivity in current Web
communications. But another is to simply accept
that the open, global nature of the Web makes it
essential to presume that Web names -
URIreferences - are transparent (every occurrence
of them have the same meaning) and to write
ontologies accordingly. The cost of the former -
a complete re-design of the entire apparatus of
Web logic along lines that are yet to be
researched - seems to greatly exceed that of the
latter, which really amounts simply to following
a certain discipline in inventing URI references.
At any rate, like it or not, this is how the SWeb
is evolving. (019)
Pat (020)
>
>John Black
>www.kashori.com
>
>>>>>even if different from other uses, all while
>>>>>HTTP returns the same object for the same
>>>>>URI.
>>>>
>>>>Here you touch on a delicate point. IMO,
>>>>there is indeed an important conceptual
>>>>distinction to be made between the
>>>>relationships of naming or reference, on the
>>>>one hand, and 'accessing' or 'identifying' on
>>>>the other, and many of the W3C discussions
>>>>fail to make this distinction and so are
>>>>hopelessly muddled. The http-range-14
>>>>decision can be summarized as: when a Web
>>>>object returns a 200 response code, the URI
>>>>which accessed it (ie the GETing of which
>>>>resulted in the code being returned) must
>>>>also be understood as denoting it. This is
>>>>highly intuitive, so much so that many folk
>>>>take it as so obvious as to not need saying,
>>>>but it does need to be said, as it is by no
>>>>means necessary.
>>>
>>>And again, doesn't it need to be pounded into RDF and OWL somehow?
>>
>>Thats exactly what the http-range-14 decision is trying to do.
>>
>>Pat
>>
>>>
>>>>
>>>>Pat
>>>>
>>>>>
>>>>>(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.)
>>>>>
>>>>>John Black
>>>>>www.kashori.com
>>>>
>>>>
>>>>--
>>>>---------------------------------------------------------------------
>>>>IHMC (850)434 8903 or (650)494 3973 home
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>>>>FL 32502 (850)291 0667 cell
>>>>phayesAT-SIGNihmc.us http://www.ihmc.us/users/phayes
>>
>>
>>--
>>---------------------------------------------------------------------
>>IHMC (850)434 8903 or (650)494 3973 home
>>40 South Alcaniz St. (850)202 4416 office
>>Pensacola (850)202 4440 fax
>>FL 32502 (850)291 0667 cell
>>phayesAT-SIGNihmc.us http://www.ihmc.us/users/phayes (021)
--
---------------------------------------------------------------------
IHMC (850)434 8903 or (650)494 3973 home
40 South Alcaniz St. (850)202 4416 office
Pensacola (850)202 4440 fax
FL 32502 (850)291 0667 cell
phayesAT-SIGNihmc.us http://www.ihmc.us/users/phayes (022)
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