X-Message-Number: 14137
Date: Fri, 21 Jul 2000 15:14:47 -0700
From: Mike Perry <>
Subject: Identity Issues Raised By Ettinger (and Others)

Bob Ettinger,  #14128, says
>If we "survive," then in the remote future we will probably have scarcely 
>anything in common with our present selves.

One important thing I hope to have in common with my present self is a
serious interest in history, which will also include personal history. I
will be interested in past versions of myself, including the one that is
typing this message right now. (By the time you read this, it will be a
"past" version, albeit a recent one.)  I don't see that thought as
far-fetched or unrealistic. Historians, paleontologists and so on are
interested in the past, even the distant past when our human forebears were
much more primitive than we of today. I have read somewhere that we are
apparently descended from a ribbonlike creature, an inch or so in length,
that lived maybe 500 to 550 million years ago. (This creature is actually
the ancestor of all vertebrates, but that includes us.)  I find that
fascinating. In the remote future the being I develop into may find myself
of today, relatively speaking, much like that small creature is, relative to
where I am now. With one presumed difference, that the future me will be
able to *recall being that creature*--to me that itself is a fascinating
prospect that I today very strongly hope will come to pass. In other words,
I hope and expect to find enjoyment, even in the remote future, in recalling
from time to time where I've come from and what events led up to where I may
be at the time of recall. So I don't see much problem with losing the sense
of self, even if I develop into something far beyond the present level--I
would go so far as to say that the more I develop *in the right way*, the
*more* I will appreciate and value the past versions of myself--though
certainly not just these. But for all this, memories, really just a type of
historical record, are clearly important.

>Mike Perry--and many scientists, prominently including Frank Tipler--believe 
>that "indistinguishable" systems are identical in every meaningful way. In 
>the least controversial case, they point out, two atoms of the same kind, in 
>the same quantum state, are indistinguishable, even in principle, hence must 
>not have separate identities. 
>Again I take issue with this. "Same quantum state" can be a tricky and 
>misleading label. If (say) two atoms are widely separated in space, then they 
>ARE distinguishable both in principle and in practice. (Look at a track in a 
>cloud chamber.) (In addition, of course, a FULL designation of "quantum 
>state" for any system is beyond our current knowledge, and might even have to 
>account for the complete history of the cosmos, if interacting systems remain 

One thing worth pointing out here is is that the quantum state is affected
by measurement. Sure, a measurement "proves" that you have two particles
that are separate and distinct. But in making that measurement, you have
also put them in different quantum states. When the states are the same, the
behavior of the total system is such that you have to treat them as identical.

Mike Perry

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