From: christophe delriviere (darkmichet@bigfoot.com)
Date: Fri Nov 20 1998 - 20:17:05 MST
Eugene Leitl wrote:
> Randall Randall writes:
>
> > The very language you use betrays the assumption that they
> > are not, in fact, identical. To wit, "positions" is plural,
> > and perfect identity would require that they have an identical
> > position, no?
>
> Hang language. Can you give me a measurement procedure how you are
> supposed to distinguish between these copies if your observation of
> their spacetime trajectories is interrupted? Space itself isn't
> labelled, nor are system's particles.
We could, for example, guess by their previous respective positions and
what we know of their respective environments some properties they will
respectively have after the interruption of the observation of their
space-time trajectories. couldn't we? of course i can't imagine an
universal way to distinguish, the way to distinguish is dependent of the
configuration of the system. I didn't say here there will not exist
situations in witch distinction is impossible, i say there exist plenty
of situations where we could easily distinguish between the two brains.
example :
for the demo, we consider we really could have true identical copies of
a brain at a same time.
system : our universe including a brain1 and a brain2.
brain1=brain2.
(concept of identity without considering the respective positions of the
brains)
Consider brain1 is separated by (10c * 1 second) of brain2.
(c= light speed in meter/second)
Say the interruption of observation of their space-time trajectories is
of 1 second.
*
By witch physical process can you exchange (in 1 second) the two brains
who where truly identical at the beginning of the interruption of the
observation of their space-time trajectories ? As far as i know, i think
it's impossible. If you think it's possible and you can provide facts,
then i agree with you.
*
we could thus be able to distinguish between these two brains after the
interruption of the observation of their space-time trajectories.
Respective positions of the two brains, even if they are truly identical
(without position concept) at the beginning, do matter.
> I'd presume otherwise identical objects is indistinguishable, since
> space is rotationally and translationally invariant. (It's actually
> not enantioinvariant, but you'll find that out if you look _very_
I fail to understand the point... how can two macro objects be truly
identical at quantum level? by chance?Space is very probably
rotationally and translationally invariant, but the universe is not
empty and what happen in a place at a certain time doesn't necessary
happen in another place at the same time, so there is variations of the
*macro* properties of the universe in function of the position relative
to an arbitrary object.
I think the identity concept you are claiming for is very useful in
quantum mechanics, but doesn't apply for a macro object like a human
brain. Perhaps i'm not correcty understanding what you are asking for or
i'm fooling myself, but if you are able to prove me that position
doesn't matter, i will be in debt to you.
delriviere
christophe
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