Re: experimentation

From: Hal Finney <>
Date: Wed, 11 Feb 1998 21:23:58 -0800

Wei Dai, <>, writes:
> Max Tegmark's Many Worlds paper (quant-ph/9709032) gives an experiment
> called quantum suicide for testing the Many Worlds Interpretation.

Committing suicide is pretty scary. But if uploading and/or mind
duplication is possible, it's not so bad. Make a copy of your mind.
Arguably you can expect beforehand to find that you are one of the two
copies with equal probability. Now, flip a coin to choose one, and that
copy pushes a button to make itself stop. This is less frightening
because you would only be giving up a few seconds of unique experience.

If many-worlds is true, then I think the copy who pushes the button will
find himself continuing to live. Either the part of the program which
is supposed to make him stop fails, or something else strange happens.

Of course this is only convincing to the one who is selected to try it.
You can repeat it a number of times and expect to be the selected one
eventually (or can you?).

Does this seem like a convincing test?

> It
> seems possible a variant of this experiment could be used to test the idea
> that all universes exist (is there a shorter name for this idea?).

You would have to assume that your same mind could exist in another
universe. But this is not just another Everett world, it is conceivably
a completely different universe, with totally different properties. Maybe
it is two-dimensional or maybe there is no such thing as distance. It
would seem questionable whether your mind could really exist for any
length of time in such a different universe.

It would seem that the other universe would have to be only a little
different from our own, so different that you can't notice the difference.

> Basicly the experimenter reduces the measure of his personal continuation
> in this universe sufficiently so that his mostly likely continuation is in
> another universe. This would involve setting up a suicide device that is
> almost certain to succeed in this universe but not as likely to succeed in
> another. However, this experiment is even less practical than quantum
> suicide since constructing such a reliable suicide device (I guess failure
> probability must be much smaller than 2^-100) would be nearly impossible.

How about if you set up the device so that it was deterministic but
fired based on some measurement of physical properties. Take something
like the speed of light, and set up a system to measure it with more
and more accuracy. Prepare your suicide device to kill you unless the
initially unknown digits of the speed turn out to have some special value.

If all universes exist and there are a range of speeds of light in universes
where you live, then you will stay alive because in some universe there is
an instance of you where light has that special speed. But if only the
one universe exists and the speed of light has some fixed value, then
chances are you will die.

Received on Wed Feb 11 1998 - 22:22:33 PST

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