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Re: [ontolog-forum] An Ultra High Level Ontology - ISO15926 & Fly in the

To: "'[ontolog-forum] '" <ontolog-forum@xxxxxxxxxxxxxxxx>
From: "Chris Partridge" <mail@xxxxxxxxxxxxxxxxxx>
Date: Wed, 11 Feb 2009 19:23:35 -0000
Message-id: <004e01c98c7e$3c20f2d0$b462d870$@net>
Hi Pat,    (01)

I think someone (you?) may be working under different premises here.    (02)

> That isn't what 'extensional' means. Everything would be a lot easier
> if y'all used the terminology properly.     (03)

Properly? Is there an agreed definition???? Where? What is PatH's
Ian's use is extremely common. See e.g.
BTW the list has just had a long discussion of this point, where the various
senses were pointed out.    (04)

> But why do you think that
> strict extensionality (in your sense, here) is so desirable? What is
> the advantage to all this extensional rigor?     (05)

As Ian has said, it is the elusive grail of a criterion of identity - two
things are the same if ... etc.    (06)

> Seems on the face of
> things that there can be more than one way to describe a given piece
> of space/time, eg the famous example of a vase being also a chunk of
> plastic, yet having properties (like, being a vase) that the chunk of
> plastic doesn't have.    (07)

Plastic or clay - well, I suppose clay is a bit passť.
And maybe the issue is that the type vase and the type chunk of plastic/clay
have different properties - rather than a specific token.     (08)

Or the famous example of the Ship of Theseus, or the practical example of a
pump's tag and serial number or a military person and their rank or posting.
All these are used as standard arguments for a 4D *extensional* approach.
The reason 4D is important is that in all the cases above, being
co-extensive merely at a point in time (3D) is too strong and gives false
positives.    (09)

> So why does data integration require extensionality (in your sense,
> here)?    (010)

If system A talks about a person (tag) and system B talks about a posting
(serial number), then one can use the criterion of identity to determine
whether they are talking about the same thing. Matthew can give you examples
of commercial systems which assumed an identity between tag and serial
number of things such as pumps which had the consequence you can imagine. I
have had engineers tell me that it was extremely useful to have a simple
explanation - one they can easily grasp - as to why these are different.
There is a paper I wrote when at LOA (or LADSEB) (i.e. long ago) that
includes this point. www.loa-cnr.it/Papers/ladseb_tr04-02.pdf . (In case Ed
asks, there was no need for talk about characteristics etc.) If you want to
say these are very odd engineers, I'll let you take that point up with them.    (011)

Chris    (012)

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