Original Message -----
From: "Saibal Mitra" <[EMAIL PROTECTED]>
To: "Stathis Papaioannou" <[EMAIL PROTECTED]>
Subject: Re: Many Pasts? Not according to QM...
Date: Fri, 27 May 2005 14:29:07 +0200
> ----- Oorspronkelijk bericht -----
> Van: "Stathis Papaioannou" <[EMAIL PROTECTED]>
> Aan: <[EMAIL PROTECTED]>
> CC: <[EMAIL PROTECTED]>;
> Verzonden: Friday, May 27, 2005 01:44 AM
> Onderwerp: Re: Many Pasts? Not according to QM...
> > Saibal Mitra wrote:
> > >Quoting Stathis Papaioannou <[EMAIL PROTECTED]>:
> > >
> > > > On 25th May 2005 Saibal Mitra wrote:
> > > >
> > > > >One of the arguments in favor of the observer moment picture is that
> > > > >solves Tegmark's quantum suicide paradox. If you start with a set of
> > >all
> > > > >possible observer moments on which a measure is defined (which can be
> > > > >calculated in principle using the laws of physics), then the paradox
> > > > never
> > > > >arises. At any moment you can think of yourself as being randomly
> > > > >from
> > > > >the set of all possible observer moments. The observer moment who has
> > > > >survived the suicide experiment time after time after time has a very
> > > > very
> > > > >very low measure.
> > > >
> > > > I'm not sure what you mean by "the paradox never arises" here. You
> > > > said
> > > > in the past that although you initially believed in QTI, you later
> > >realised
> > > >
> > > > that it could not possibly be true (sorry if I am misquoting you, this
> > >is
> > > > from memory). Or are you distinguishing between QTI and QS?
> > > >
> > >That's correct. In both QTI and QS one assumes conditional probabilities.
> > >You just
> > >throw away the branches in which you don't survive and then you conclude
> > >that you
> > >continue to survive into the infinitely far future (or after performing
> > >arbitrary
> > >large number of suicide experiments) with probability 1.
> > >
> > >But if you use the a priori probability distribution then you see that
> > >the measure
> > >of versions of you that survive into the far future is almost zero.
> > What does "the measure of versions of you that survive into the far future
> > is almost zero" actually mean? The measure of this particular version of
> > typing this email is practically zero, considering all the other versions
> > me and all the other objects in the multiverse. Another way of looking at
> > is that I am dead in a lot more places and times than I am alive. And yet
> > undeniably, here I am! Reality trumps probability every time.
> You have to consider the huge number of alternative states you could be in.
> 1) Consider an observer moment that has experienced a lot of things. These
> experiences are encoded by n bits. Suppose that these experiences were more
> or less random. Then we can conclude that there are 2^n OMs that all have a
> probability proportional to 2^(-n). The probability that you are one of
> these OMs isn't small at all!
> 2) Considering perforing n suicide experiments, each with 50% survival
> probability. The n bits have registered the fact that you have survived the
> n suicide experiments. The probability of experiencing that is 2^(-n). The
> 2^(n) -1 alternate states are all unconscious.
> So, even though each of the states in 1 is as likely as the single state in
> 2, the probability that you'll find yourself alive in 1 is vastly more
> likely than in 2. This is actually similar to why you never see a mixture of
> two gases spontaneously unmix. Even though all states are equally likely,
> there are far fewer unmixed states than mixed ones.
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