Re: Quantum Immortality and Information Flow

From: Bruno Marchal <marchal.domain.name.hidden>
Date: Fri, 9 Dec 2005 19:04:19 +0100

Le 08-déc.-05, à 22:21, George Levy a écrit :


> Bruno Marchal wrote:
>>
>> Le 05-déc.-05, à 02:46, Saibal Mitra a écrit :
>>
>>
>>> I still think that if you double everything and then annihilate only
>>> the
>>> doubled person, the probability will be 1.
>>
>>
>>
>> Actually I agree with this.
>>
>>
>
> So far we have been talking about splitting universes and people.
> Let's consider the case where two branches of the universe merge.



Of course this is the an hard and interesting question ... I would say
that Everett, Deutsch, Hartle somehow answer it in the quantum realm. I
would say that empirically or "apparently", at the bottom there is
neither elimination of information, nor duplication of information.
Irreversibility and non cloning.
I believe comp entails this too. Got evidence from the interview with
the Lobian Machine, but also from some intuitive way to put (first
person) measure on the computational histories generated by the UD.





> In other words, two different paths eventually happen to become
> identical -

At the bottom I don't think this can happens. Like Deutch I think that
both bifurcation and fusion are really differentiation and
dedifferentiation by *apparent* lack of memory.

Remember Y = II If you "bifurcate" I think you just grow
the measure on your past. If you fuse consistently you don't change the
measure. To be sure I have also different arguments in favor of an
increase of measure when you fuse (loosing memory makes greater your
possible histories, like substracting equations in a system of
equations augments the possible number of solutions (the Galois
connection).
All this is very difficult, that I think we should take benefit of
Godel, Lob, Solovay and the discovery of the (modal) logic of
self-reference G and G* to ask the opinion of a universal machine ...



> Of course when this happens all their branching futures also become
> identical.

This is not so obvious. You should define a notion of identity for the
branches, path, etc.



> Would you say that such a double branch has double the measure of a
> single branch even though the two branches are totally
> indistinguishable? How can you possibly assert that any branch is
> single, double, or a bundle composed of any number of identical
> individual branches?

Indeed, how? And from which point of view?


Bruno

http://iridia.ulb.ac.be/~marchal/
Received on Fri Dec 09 2005 - 13:55:21 PST

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