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Re: [VM,ALL] Revised scope statement

From: Thomas Baker <thomas.baker@bi.fhg.de>
Date: Thu, 17 Jun 2004 15:53:06 +0200
To: Bernard Vatant <bernard.vatant@mondeca.com>
Cc: SW Best Practices <public-swbp-wg@w3.org>
Message-ID: <20040617135306.GB1648@Octavius>

On Thu, Jun 17, 2004 at 02:54:43PM +0200, Bernard Vatant wrote:
> > To my way of thinking, this semantic context is different from
> > the identification context per se.  If a URI identifying a
> > term is backed up by policies and explanations formulated by
> > the coiners and maintainers of that URI, then to me that URI
> > is not simply a "bare identifier".  Rather, the maintainers
> > are be establishing for that URI an "identification context".
> 
> Interesting. Seems that you have clear ideas about this distinction between identification
> and semantic context(s).
> I'd be curious to see this expanded in the details (where the devil is hiding, as usual).
> Does the identification context includes the application context? (e.g. scope of use,
> protocols ...)

I don't think the identification context necessarily includes
information about intended scope and use.  For Dublin Core,
the documented identification context is the DCMI Namespace
Policy [1], perhaps in conjunction with DCMI Grammatical
Principles [2] -- in all, just six pages of text.  One could
elaborate on scope of use, etc, but my instinct would be to
leave such choices up to the authors of the identifier policy
(or namespace policy).

I certainly get the point about devil in the details.
It reminds me of IEEE/LOM discussions about how to identify
the notion of Title given that in the LOM model, a Title
within the General hierarchy is not exactly the same as a
title within the Metadata hierarchy.  I.e., URIs of the form:

    http://ltsc.ieee.org/LOM/Title

implies a flat namespace, whereas

    http://ltsc.ieee.org/LOM/General/Title
    http://ltsc.ieee.org/LOM/Metadata/Title

seemed to lose the notion that they are both "Title", while
URIs such as

    http://ltsc.ieee.org/LOM/GeneralTitle
    http://ltsc.ieee.org/LOM/MetadataTitle

seem to imply a change of labels in LOM's standard base
schema conceptual definition (see [3], Section 7.1).
(This particular discussion must be out-of-date by now but
serves to make a point.)

But if we agree that "Semantic Web" is about enabling re-use
and citation -- or at any rate _sensible_ re-use and citation
(do we agree on that?) -- then a maintenance community would
have to address this problem anyway.  In my opinion, the
point is to encourage people to articulate the assumptions
according to which they have identified terms.

[1] http://dublincore.org/documents/dcmi-namespace/
[2] http://dublincore.org/usage/documents/principles/
[3] http://www.dlib.org/dlib/july03/baker/07baker.html

> People misusing language does not prevent dictionaries and grammars to be useful :)

Yes - very good analogy.  And dictionaries are useful even
if it is true that words take on different nuances from the
sentences within which they are embedded.

> > > IOW, relationships between identification and contextual definition are tricky to
> > > entangle, and setting generic term identification valid for *any* context seems very
> > > difficult (read : barely possible).
> >
> > In my understanding, the whole idea of Semantic Web is
> > based on the notion of citing and reusing and recombining
> > and referencing and repurposing and merging data from a
> > diversity of sources, and it is well recognized that doing
> > so can in principle violate the semantic intent of the
> > source data.  To question whether it ever makes sense to use
> > terms independently of their application context would seem
> > to question the very idea of Semantic Web.
> 
> I disagree on that. Relativity of identification (what an URI identifies depends on the
> application context) is questioning the SW idea iff one assumes the SW is bound to be a
> single, univocal, application context. If this latter assumption is part of the SW
> definition, well, yes, I'm questioning it strongly, because I think it's plainly
> unsustainable. But if the SW, like the plain Web, is bound to be composed of many, more or
> less orthogonal, application contexts, then there is no contradiction between the SW idea
> and the relativity of identification.

I don't think I disagree with what I take to be the intent
of your words (got that?) - it's just that "identification"
doesn't seem like the right word.  Maybe I'm being too literal,
but to me, a URI identifies a term and that's that -- rather
like a URI identifying a word.  And whether that word is being
used sensibly in the context of a sentence (the semantic
context) is beyond the scope of the identification context
of the word per se.

At any rate, I strongly agree that the SW, like the world in
general (not just the plain Web), is bound to be composed of
many orthogonal contexts.

> > I don't think
> > that is what you are saying, but I do think one can and must
> > distinguish between how maintainers "make sense" for a term
> > (which I see as largely out of scope for the VM note) and
> > what simply establishes identity and makes terms referencable
> > by others, "sensibly" or not.
> 
> What (simply?) establishes identity is identifier + application context.

I understand you to be saying that the URI "X" identifies
something different in the context of Application A and in
Application B, in other words:

    The thing identified by URI "X" in Application A is not the
    same as the thing identified by URI "X" in Application B.

I'm not sure I understand...

Tom

-- 
Dr. Thomas Baker                        Thomas.Baker@izb.fraunhofer.de
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Received on Thursday, 17 June 2004 09:52:04 UTC

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