Re: Many worlds theory of immortality

From: Jesse Mazer <>
Date: Fri, 15 Apr 2005 17:52:04 -0400

Saibal Mitra wrote:

>I more or less agree with Jesse. But I would say that the measure of
>similarity should also be an absolute measure that multiplied with the
>absolute measure defines a new effective absolute measure for a given
>Given the absolute measure you can define effective conditional
>probabilities, except in cases where branches lead to death. In these
>the ''conditional probability'' of there being a next experience at all
>would be less than 1.

Would you apply the same logic to copying a mind within a single universe
that you would to the splitting of worlds in the MWI? If so, consider the
thought-experiment I suggested in my post at --

>But you should no more expect to end up in a branch where you died than in
>a branch where you were never born in the first place. Consider, instead of
>a branching multiverse, a Star-Trek-style transporter/duplicator in a
>single universe, which can deconstruct you and reconstruct exact copies
>atom-by-atom in distant locations (assuming the error introduced by the
>uncertainty principle is too small to make a difference--if you don't want
>to grant that, you could also assume this is all happening within a
>deterministic computer simulation and that you are really an A.I.). To use
>Bruno Marchal's example, suppose this duplicator recreates two identical
>copies of you, one in Washington and one in Moscow. As you step into the
>chamber, if you believe continuity of consciousness is "real" in some sense
>and that it's meaningful to talk about the probabilities of different
>possible next experiences, it would probably make sense to predict from a
>first-person-point of view that you have about a 50% chance of finding
>yourself in Moscow and a 50% chance of finding yourself in Washington.
>On the other hand, suppose only a single reconstruction will be performed
>in Washington--then by the same logic, you would probably predict the
>probability of finding yourself in Washington is close to 100%, barring a
>freak accident. OK, so now go back to the scenario where you're supposed to
>be recreated in both Washington and Moscow, except assume that at the last
>moment there's a power failure in Moscow and the recreator machine fails to
>activate. Surely this is no different from the scenario where you were only
>supposed to be recreated in Washington--the fact that they *intended* to
>duplicate you in Moscow shouldn't make any difference, all that matters is
>that they didn't. But now look at another variation on the scenario, where
>the Moscow machine malfunctions and recreates your body missing the head. I
>don't think it makes sense to say you have a 50% chance of being "killed"
>in this scenario--your brain is where your consciousness comes from, and
>since it wasn't duplicated this is really no different from the scenario
>where the Moscow machine failed to activate entirely. In fact, any
>malfunction in the Moscow machine which leads to a duplicate that
>permanently lacks consciousness should be treated the same way as a
>scenario where I was only supposed to be recreated in Washington, in terms
>of the subjective probabilities. Extending this to the idea of natural
>duplication due to different branches of a splitting multiverse, the
>probability should always be 100% that my next experience is one of a
>universe where I have not been killed.

So if the machine accidentally creates a copy of me missing a head, do you
agree that doesn't lessen the probability that I will continue to have
conscious experiences, that in this case I could be confident I'd end up as
the other copy that was created with head intact? If so, is this any
different from a situation where someone is shooting at me, and there is a
branch of the multiverse where my head gets blown off and another where the
bullet misses?

Received on Fri Apr 15 2005 - 17:55:39 PDT

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