> I might still occasionally face accidents where I had 
> to be very lucky to survive, but the lower the probability there is of

> surviving a particular type of accident, the less likely I am to
> experience events leading up to such an accident.

So if someone is on a cliff about to commit suicide, from his
perspective, he will probably find he can't go through with it?  In fact
will a suicidal person find that nothing tends to go wrong in his life
(because if it did he would want to commit suicide)?  The more suicidal
he is the better!  Or perhaps there is a vanishingly small probability
of finding yourself so easily depressed even though it is not
unreasonable to come across other people that are.  But if the tendency
to be suicidal is inherited in the genes can it be that this is
anticipatory as well?  Of course at the time you inherit your genes you
aren't conscious.

- David


-----Original Message-----
From: Jesse Mazer [mailto:[EMAIL PROTECTED] 
Sent: Wednesday, 12 November 2003 5:34 PM
To: [EMAIL PROTECTED]
Subject: "Last-minute" vs. "anticipatory" quantum immortality

>From: Bruno Marchal <[EMAIL PROTECTED]>
>To: [EMAIL PROTECTED]
>Subject: Re: Fw: Quantum accident survivor
>Date: Sat, 08 Nov 2003 15:56:31 +0100
>
>At 14:36 07/11/03 -0800, Hal Finney wrote:
>
>snip
>
>
>>Well, I do believe in continuity of consciousness, modulo the issues
>>of measure.  That is, I think some continuations would be more likely
to
>>be experienced than others.  For example, if you started up 9
computers
>>each running one copy of me (all running the same program so they stay
>>in sync), and one computer running a different copy of me, my current
>>theory is that I would expect to experience the first version with 90%
>>probability.
>
>
>Almost OK, but perhaps false if you put *the measure* on the (infinite)
>computations going through those states. I mean, if the 9 computers
>running one copy of you just stop (in some absolute way I ask you to 
>conceive for
>the benefit of the argument), and if the one computer running the
>different copy, instead of stopping, is multiplied eventually into many
>self-distinguishable copies of you, then putting the measure on the 
>histories should
>make you expect to experience (and memorized) the second version more 
>probably.
>
>It is the idea I like to summarize in the following diagram:
>
>\        /                     |      |
>   \    /                       |      |
>     \/               =        |      |
>      |                         |      |
>      |                         |      |
>
>That is, it is like a "future" bifurcation enhances your present
measure.
>It is why I think comp confirms Deutsch idea that QM branching is
really
>QM differentiation. What do you think? I mean, do you conceive that the
>measure could be put only on the "maximal" possible computations?
>
>Bruno

This is an important point which I think people often miss about the
QTI. It 
is sometimes spoken of as if the QTI only goes into effect at the moment
you 
are about to die (and thus have no successor observer-moment), which
would 
often require some fantastically improbable escape, like quantum
tunneling 
away from a nearby nuclear explosion. But if later bifurcations can
effect 
the first-person probability of earlier ones, this need not be the case.

Consider this thought experiment. Two presidential candidates, let's say

Wesley Clark and George W. Bush, are going to be running against each
other 
in the presidential election. Two months before the election, I step
into a 
machine that destructively scans me and recreates two copies in
different 
locations--one copy will appear in a room with a portrait of George W.
on 
the wall, the other copy will appear in a room with a portrait of Wesley

Clark. The usual interpretation of first-person probabilities is that,
all 
other things being equal, as the scanner begins to activate I should
expect 
a 50% chance that the next thing I see will be the portrait of George W.

appearing before me, and a 50% chance that it will be Wesley Clark.

But suppose all other things are *not* equal--an additional part of the 
plan, which I have agreed to, is that following the election, the copy
who 
appeared in the room with the winning candidate will be duplicated 999 
times, while the copy who appeared in the room with the losing candidate

will not experience any further duplications. Thus, at any time after
the 
election, 999 out of 1000 versions of me who are "descended" from the 
original who first stepped into the duplication machine two months
before 
the election will remember appearing in the room with the candidate who 
ended up winning, while only 1 out of 1000 will remember appearing in
the 
room with the losing candidate.

The "last minute" theory of quantum immortality is based on the idea
that 
first-person probabilities are based solely on the observer-moments that

qualify as immediate successors to my current observer-moment, and this
idea 
suggests that as I step into the duplication machine two months before
the 
election, I should expect a 50% chance of appearing in the room with the

portrait of the candidate who goes on to win the election. But as Bruno 
suggests, an alternate theory is that later bifurcations should be taken
to 
influence the first-person probabilities of earlier bifurcations--under
this 
"anticipatory" theory, I should expect only a 1 out of 1000 chance that
I 
will appear in the room with the portrait of the losing candidate. This 
would lead to a weird sort of "first-person precognition", where after
the 
duplication but before the election, I'd have good reason to believe
(from a 
first-person point of view) that I could predict the outcome with a high

probability of being right. But this kind of prediction would be useless

from a third-person point of view, since all outside observers would see
two 
symmetrical copies who both seem equally certain that their candidate
will 
be the winner. Of course this is not much stranger than the basic
quantum 
immortality idea that if I am in some dangerous accident, most
third-person 
observers will see me end up dead, while I have a close to 100% chance
of 
surviving from a first-person POV.

Applied to quantum immortality, this "anticipatory" idea suggests it
would 
not be as if the universe is allowing events to go any which way right
up 
until something is about to kill me, and then it steps in with some 
miraculous coincidence which saves me; instead, it would be more like
the 
universe would constantly be nudging the my first-person probabilities
in 
favor of branches where I don't face any dangerous accidents which
require 
"miracles" in the first place. Of course since this would just be a 
probabilistic effect, I might still occasionally face accidents where I
had 
to be very lucky to survive, but the lower the probability there is of 
surviving a particular type of accident, the less likely I am to
experience 
events leading up to such an accident.

Jesse Mazer

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