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Re: Clarifying what a URL identifies (Four Uses of a URL)

From: Michael Mealling <michael@neonym.net>
Date: 21 Jan 2003 15:25:42 -0500
To: Miles Sabin <miles@milessabin.com>
Cc: www-tag@w3.org
Message-Id: <1043180742.25349.142.camel@blackdell.neonym.net>

On Tue, 2003-01-21 at 15:13, Miles Sabin wrote:
> Michael Mealling wrote,
> > Its not a fallacy. Its merely insufficient when you are within some
> > system's set of semantics that requires that function. URIs exist
> > outside any set of semantics you may require for the time being.
> > Since they do and the only information that exists across contexts is
> > that a URI identifies a Resource and two URIs identify two Resources,
> > etc then your statement and Tim's is still orthogonal. The
> > httpRange-14 problem is not a problem with URIs, its a problem with
> > the context that contains "the HTTP protocol, the 'http:' URI scheme,
> > XML, HTML and web browsers". If you're not in that particular context
> > then there isn't a problem. Thus the problem isn't with URIs but how
> > they're being used in that context. Not everyone is using the same
> > context....
> 
> I'm afraid I don't think works very well.

It works well for the Internet. That' doesn't mean is solves all of your
problems for you...

> 
> On the one hand you're saying that a URI identifies a Resource across 
> contexts. 

No. I'm saying that URIs and Resource exist regardless of contexts.

> On the other you're saying that a URI is always used in a 
> given context, and that contexts can vary, so the effects of use might 
> vary correspondingly.

It depends on how sloppy your context is with its URIs. If a context
says that URIs can be anything and you go redefining and adding stuff
that's inconsistent then, yea, your effects will varry correspondingly.

> That's not flat out inconsistent ... tho' it would be if we agree that 
> meaning (ie. the referent) is determined by use ... but it certainly 
> looks like a very unstable position.

Its not. What you're doing is trying to assume some part of the
infrastructure has more meaning than it really has and when that meaning
your trying to attach is inconsistent you then blame the infrastructure
compoenent instead of the sloppy application of meaning.

Take IP addresses for example, some people attach some meaning to where
the physical location of the entity that registered that network block
and then use that to apply 'geophysical' semantics to some end node.
Within that system the 'use' is consistent but the view of the world is
skewed because all of the users of AOL end up living in Northern
Virginia. The problem isn't that IP addresses are incorrect and need to
be fixed. Its that a context was misapplied in a way that assumed that
the underlying identifier agreed with that context. I.e. its a layer
violation....

If you're context gets easily confused and can't handle "URIs as simple
identifiers and nothing else" then you should be using something more
than URIs (URIs plus RDF) to help you along. But other applications
don't need that because they don't have concepts such as documents,
links, headers, representations, etc. They get along just fine with what
URIs give them and they generally don't try and violate the naming
layers....

-MM

-MM
Received on Tuesday, 21 January 2003 15:28:19 GMT

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