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Re: [ontolog-forum] Time representation

To: "[ontolog-forum]" <ontolog-forum@xxxxxxxxxxxxxxxx>
From: "John F. Sowa" <sowa@xxxxxxxxxxx>
Date: Sat, 26 Jan 2008 09:38:51 -0500
Message-id: <479B45FB.9040208@xxxxxxxxxxx>
Pat and Chris P.,    (01)

I sympathize with Pat in criticizing vague notions such as
'fruitfulness' and I sympathize with Chris in the feeling
that there is something useful about the idea.    (02)

But for the definition of ontology, I believe that there is
a precise definition that is *identical* for both philosophical
ontologies and IT ontologies.    (03)

CP>> Jonathon Lowe (a philosopher I recall you meeting) has a
 >> technical definition of ontology as "the set of things whose
 >> existence is acknowledged by a particular theory or system
 >> of thought." (E. J. Lowe, The Oxford Companion to Philosophy)    (04)

PH> He is clearly using the word in its philosophical sense, not its
 > IT sense. Nobody in this forum is doing philosophical ontology.    (05)

I have no idea what distinction Pat is trying to draw, but I
would say that Lowe's definition contains an error that makes
it unsuitable for *both* philosophy and IT.    (06)

The mistake is in the word 'set', which should be replaced by
the word 'type'.  For example, Boeing might want to design a
new type of airplane, say the 797.  Since no instances of that
type exist, the set of all 797s is empty.  In fact, it must
remain empty from the time the plans are being discussed up
to the time that the first 797 rolls off the assembly line.    (07)

CP>> And saying that the financial markets are volatile, and new
 >> instruments are going to arise (whose details we do not know)
 >> - and how we plan for that. At some level, we are saying that
 >> we cannot foresee what is going to happen.    (08)

PH> Right. So how is it possible to plan for something that you
 > cannot forsee, other than in a general sense trying to stay alert?    (09)

That's another reason why the word 'type', not 'set', belongs
in the definition.  It's impossible to make statements about
a clearly defined set of things in the future, and the word
'unforeseen' raises all sorts of misleading issues.  But it is
appropriate to talk about types of events, such as disasters,
recessions, or political events that could affect the markets.    (010)

I'll admit that it is possible to talk about sets rather than types,
*provided that* sets are treated as mathematical abstractions that
are not tied to any particular time or place.  In that case, it would
be possible to talk about a set S of entities that might exist at
some point in the future.  But I would still prefer the word 'type'
in the definition of 'ontology', because it does not limit the
ontology to a specific point or region in space-time.    (011)

With that qualification, I don't see any reason why there would
or should be any difference whatever between a philosophical
ontology and an IT ontology.  If anything, I would say that
a philosophical ontology should *include* an IT ontology as
a special case.    (012)

John    (013)


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