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Re: [ontolog-forum] What is the role of an upper level ontology?

To: ontolog-forum@xxxxxxxxxxxxxxxx
From: John F Sowa <sowa@xxxxxxxxxxx>
Date: Sat, 18 May 2013 19:29:50 -0400
Message-id: <51980EEE.3040807@xxxxxxxxxxx>
On 5/18/2013 6:30 PM, William Frank wrote:
> a thread that runs through many philosophers and logicians, for
> millennia, to the present day:
> x is the same as y
> is not meaningful in itself, in that it lacks the context of a qualifier
> T, where T is a type of thing, so that the full expression is
> x is the same T as y.    (01)

That is the basis for saying that each category must have specific
"identity criteria" for determining whether a claim of identity is true.    (02)

> I apologize if I am missing something that has happened since
> I learned these basics.    (03)

The issues have been debated since antiquity.  The classic example is
the Ship of Theseus, every part of which has been replaced.  Is it still
"the same ship".  If not, at which point did it stop being the same.    (04)

The US army allowed soldiers to request replacement parts for their
rifles, but they solved the identity question by fiat:  any part could
be replaced, except the stock.  If the stock was damaged, the soldier
had to turn it in and request a new rifle.    (05)

You can keep multiplying those issues endlessly.  The identity criteria
for humans seem fairly clear.  DNA is fairly good, except for identical
twins.  But as genetic engineering progresses, those issues are
becoming blurred.  How do you count Siamese twins who are too closely
connected to make surgery practical?    (06)

But when you get to other species, things get more and more blurry.
When you see "two" mushrooms close to one another in the woods,
they are almost certainly two "fruiting bodies" of the same fungus.    (07)

Sometimes a single fungus covering many acres can be "the same"
individual.  But what if they construct a highway through the woods?
Will that break turn "one fungus" into two?  Biologists have performed
experiments:  there are criteria for distinguishing "one fungus" from
"two fungi".  But those separated parts pass the test for being one.    (08)

Most plants and many animals can be cut in parts, which can regenerate
to form completely new individuals.  The line between colonies of many
single-celled living things and "metazoa" consisting of multiple cells
is blurry.    (09)

When you get to artifacts like ships, houses, etc., all bets are off.    (010)

The examples can be and have been multiplied and debated for millennia.
I consider identity conditions useful, fallible, and not fundamental.    (011)

John    (012)

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