xml-dev - Identity

[John Cowan <cowan@locke.ccil.org>]

David Brownell, in a message I've unfortunately purged, thinks
that identity is a hard concept.

Actually, it isn't.   What's hard is *determining* identity.
It took the human race millennia to determine the identity of
the evening star with the morning star (they are identical
with each other and with the planet Venus).  The labels he calls
"extrinsic" are an attempt to bypass this problem.

Other difficulties with identity are not truly with identity,
but with what counts as an object.  Are you identical with yourself
ten years ago?  At the level of memory, almost certainly;
at the level of atoms, no (most of our atoms turn over in 6-12 months;
iron is retained for several years).

And don't try to dispense with identity, either, or you find you
can't even count things.  To say "There are five sheep in that field"
is to say "There exists a sheep, A, in the field, and ... and
there exists a sheep, E, in the field, and A is not identical with
B, C, D, or E, and B is not identical ..., and D is not identical with E."
We can count sheep (real sheep) only because we have identity
criteria for sheep.

-- 
John Cowan					cowan@ccil.org
		e'osai ko sarji la lojban.

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