Re: Travelling to a different universe

From: Saibal Mitra <>
Date: Wed, 26 Dec 2001 15:26:26 +0100

Bruno wrote:
> Saibal Mitra wrote:
> > Now there exists a class of universes, with a very low measure, in
> >which the laws of physics are such that I am guaranteed to win. The
> >probability that I find myself in such a universe will have increased
> >substantially after each experiment. After a few years I will be sure to
> >live in such a universe. It would be easy to check, all I would have to
> >is to buy a ticket and see if I have won without using the suicide
> Just do the computation. At each suicide you will survive in the nearer
> world from the one you left. That is: the more normal world
> relatively to you.
> Of course you will be sure that you live in such a universe, but you will
> be wrong. If you stop to use the suicide machine you will stop winning
> (unless you are using explicitely the suicide machine for filtering just
> a world where you win without suicide machine, but then that is an another
> experiment).
> Look at the iteration 64 times of simple self-duplication WM. Among
> the 2^64 resulting person, one will believe ending up always at W, but
> if you iterate *again* 32 times you know that this one will have 2^32 - 1
> descendant knowing that the expection was wrong, and only one
> believing (more and more) having been magically linked to Washington.

There is a selection effect by the very use of the suicide machine. In the
usual WM experiment this doesn't occur, so let's modify it slightly.

First I measure the z-component of a spin particle is measured 1000 times
in succesion. Provided I don't find 1000 times spin up I will perform the
usual WM experiment, otherwise I will only make copies that end up in

Suppose you use the suicide machine to select W ten thousand times in a row,
what would the probability be that I had found 1000 times spin up?

Received on Wed Dec 26 2001 - 06:28:14 PST

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