RE: Measure, madness, and Max

From: Jacques M Mallah <>
Date: Wed, 20 Jan 1999 14:13:49 -0500

On Mon, 18 Jan 1999 wrote:
> I disagree with the reasoning of Jacques Mallah regarding quantum suicide.
> Jacques claims that in a Many-Worlds universe, someone has no reason
> to expect the results of a suicide attempt to be different from what
> they would be if there were just one world. I and many other people
> argue, instead, that in a MW universe, suicide would eliminate you from
> some successor "branches", but that you would go on living in others.
> Since you cannot experience your own nonexistence, those successor
> branches where you do not exist are irrelevant to you (just as are
> branches where all life is impossible). Your personal experience is
> that the suicide never works.
> (Of course this prediction is completely different from in a single-world
> model, where the outcome would be that you continue to remain alive in
> the single world with some probability, or that you completely cease to
> exist, forever and completely.)

        In the single world model, since you cannot experience your own
nonexistance, you personal experience is that the suicide never works.
However, if it really did, all of your measure will be in the region of
time before the suicide.
        If the universe is large enough, "you" will continue to have a
reduced measure after that time in the sense that beings similar to you
will continue to exist. The MWI case is just the same as the infinite
universe limit of that.
        But just as I would want to avoid my measure going to zero, for
the exact same reason I would want to avoid any reduction in my measure.
The only exception is if I didn't place a positive value on my future self
or 'selves'.

> There are a number of points on which I believe we can agree:
> - When you attempt a quantum suicide, you remain alive in some
> branches but die in others.


> - The measure of those branches of the world in which you are alive
> afterwards is less than the measure of the branch in which you
> attempted the suicide.


> - In some branches where there are continuations of your present
> existence, you live forever. However the measure of these branches
> is very small.


> These depend implicitly on a certain flavor of the MWI, to wit:

        Huh? It only depends on any MWI or uniform infinite universe

> Jacques also makes another point, which I find somewhat questionable but
> which may be valid:
> - Our current conscious experiences can be taken to be "typical" in
> that they are drawn randomly from the set of all of "our" conscious
> experiences, over all the universes.
> I question this for a couple of reasons:
> - This is similar in flavor to the Carter-Leslie "Doomsday" argument which
> says that we are typical specimens from the entire history of our race,
> and hence the human race is likely going to die out in a few hundred
> years. This argument is not at all well accepted among philosophers.

        Yes. Though don't forget, the a priori expectation can be
modified in the usual Bayesian way if we have additional information to
narrow down our case more specifically.

> - In the MWI example, it's not clear whether I should be a random sample
> among all instances of "me", or perhaps I should be a random sample
> among all conscious observers in all the universes, human, alien, or
> other. It seems harder to draw conclusions in the latter case.

        It is the latter. Indeed the first case would require a formal
definition of 'you' and some reason why nature should respect such

> Jacques has suggested that if you were going to live forever, this last
> argument would predict that you would already find yourself very old
> (exactly what is predicted with regard to the human race in the Doomsday
> argument). However if we assume that the measure of those branches in
> which you live forever is small (as it almost surely would be), then
> in fact the observation that you are relatively young is consistent with
> there being branches where you will live forever.

        Exactly! Which is why there is no quantum immortality in any
meaningful sense.

                         - - - - - - -
              Jacques Mallah (
       Graduate Student / Many Worlder / Devil's Advocate
"I know what no one else knows" - 'Runaway Train', Soul Asylum
            My URL:
Received on Wed Jan 20 1999 - 11:18:24 PST

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