On 2 Sep 2009, at 09:40 , Henry S. Thompson wrote:

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> C. M. Sperberg-McQueen writes:
>
>> The record would not be complete without someone observing
>> that it also has the disadvantage that if the domain name
>> registration for [your committee] ever lapses, there is no
>> guarantee that the new owner will refrain from assigning
>> a new meaning to http://[your committee]/namespaces/xxx
>
> For sure.
>
> But be careful using this as an argument in favour of using URNs or
> some other URI scheme -- If you don't care about dereferencing, it
> doesn't matter that http://[your committee]/namespaces/xxx doesn't
> dereference today, and might dereference misleadingly in some
> relatively unlikely future.  If you _do_ care, then the mechanisms put
> in place to support dereferencing of e.g. URNs will almost certainly
> be vulnerable to the same human-originating failure modes.

The meaning of some identifiers is given in a way that
guarantees permanence of the meaning assigned.  If URLs
mean things by virtue of the actions and/or intentions of
their owners (which is what I understand the TAG's story
to be), then when the owner changes, the meaning is
necessarily subject to change.

The difference at issue is not whether, when you dereference
something, you get something 'misleading' or not.  The
issue is whether the prescribed methods for determinining
the denotation of an identifier guarantee stability of
denotation over time or not.

On the account offered in your email, the system of using
URLs as long-lived identifiers seems to depend on (a) the
proposition that a URL has a given meaning just when the
owner of the relevant domain assigns it that meaning, and
(b) the proposition that a URL has a given meaning
whenever we feel like interpreting that way, regardless
of the actions of the owner of the relevant domain.

The TAG may have no trouble reconciling those two
propositions; I confess that to me, they just look like
a contradiction at the heart of the TAG's edifice.

-- 
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* C. M. Sperberg-McQueen, Black Mesa Technologies LLC
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