Re: Quantum accident survivor

From: Saibal Mitra <>
Date: Mon, 10 Nov 2003 16:01:27 +0100

There are some problems with this as Eric has pointed out.

The best way to define identity, i.m.o., would be to say that a program is a
SAS having an identity. If that SAS experience the outcome of an experiment,
it's program will be changed by the mere fact it has acquired the memory of
the outcome of the experiment. So the identity has changed because the
program has changed. Programs are what some of us call ''observer moments''.

----- Oorspronkelijk bericht -----
Van: "David Barrett-Lennard" <>
Aan: <>
Verzonden: Monday, November 10, 2003 08:39 AM
Onderwerp: RE: Quantum accident survivor

> I'm trying to define "identity"...
> Let's write x~y if SAS's x and y (possibly in different universes) have
> the same identity. I propose that this relation must be reflexive,
> symmetric and transitive. This neatly partitions all SAS's into
> equivalence classes, and we have no ambiguity working out whether any
> two SAS's across the multi-verse have the same identity.
> Consider an SAS x that splits into x1, x2 (in child universes under
> MWI). We assume x~x1 and x~x2. By symmetry and transitivity we deduce
> x1~x2. So this definition of identity is maintained across independent
> child universes.
> This is at odds with the following concept of identity...
> > I am, for all practical purposes, one
> > and only one specific configuration of atoms in a specific
> > universe. I could never say that ' I ' is ALL the copies, since I
> > NEVER experience what the other copies experience
> It seems necessary to distinguish between a definition of identity and
> the set of memories within an SAS at a given moment.
> Is it possible that over long periods of time, the environment can
> affect an SAS to such an extent that SAS's in different universe that
> are suppose to have the same identity actually have very little in
> common?
> What happens if we "splice" two SAS's (including their memories)?
> It seems to me that the concept of identity is not fundamental to
> physics. It's useful for classification purposes as long as one doesn't
> stretch it too far and expose its lack of precision.
> This reminds me of the problem of defining the word "species". Although
> a useful concept for zoologists it is not well defined. For example
> there are cases where (animals in region) A can mate with B, B can mate
> with C, but A can't mate with C.
> - David
Received on Mon Nov 10 2003 - 10:03:53 PST

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