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Re: Possible new issue: Things with and without identity?

From: Miles Sabin <miles@milessabin.com>
Date: Tue, 10 Sep 2002 00:17:42 +0100
To: uri@w3.org, rest-discuss@yahoogroups.com
Message-Id: <200209100017.42827.miles@milessabin.com>

Stephen Cranefield wrote,
> Miles Sabin <miles@milessabin.com> wrote:
> > At issue is the first sentence of the informal definition of
> > resource in RFC 2396 1.1,
> >
> >   A resource can be anything that has identity.
> >
> > "that has identity" is redundant because *everything* has identity
> > in the only reasonably straightforward understanding of identity,
> > ie. the logical truth in all but the most obscure formal systems
> > that,
> >
> >   (Vx) x = x
>
> A discussion of the philosophical notion of identity can be found in:
>
> Guarino, Nicola and Chris Welty. 2000. Identity, Unity, and
> Individuality: Towards a formal toolkit for ontological analysis. In,
> Horn, W. ed., Proceedings of ECAI-2000: The European Conference on
> Artificial Intelligence. pp. 219-223. Berlin: IOS Press. August, 2000
> http://www.ladseb.pd.cnr.it/infor/Ontology/Papers/LADSEB02-2000.pdf

It's an interesting enough paper, but it's about unity, integrity and 
persistence of physical objects rather than identity. And that's a good 
thing, because their theory appears to be expressed in terms of 
first-order predicate calculus with identity initially, then later a 
simple first-order mereology and set theory, both of which presuppose 
identity: so if it really was supposed to be a theory of identity it'd 
be hopelessly circular. There are formal systems around which don't 
take identity as a primitive, but, like I said, they're somewhat 
obscure.

That said, if the qualifier in RFC 2396 said something like,

  A resource can be anything that is integrated (for some value of
  "integrated")

it would at least be adding something non-trivial. But I'd strongly 
advise against going down that route. Integrity is a slippery enough 
concept for physical objects (eg. it's extremely difficult to 
distinguish is-attached-to from is-part-of without running into all 
kinds of awkward edge cases) never mind the kind of electronic 
artifacts which are RFC 2396's primary (tho' maybe not exclusive) 
concern.

There's also a brief discussion of the relation between stuffs and 
things, but that's irrelevant here: RFC 2396 talks about things from 
the outset, so individuation is already presupposed.

Cheers,


Miles
Received on Monday, 9 September 2002 19:18:20 UTC

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