----- Oorspronkelijk bericht ----- Van: "Stathis Papaioannou" <[EMAIL PROTECTED]> Aan: <[EMAIL PROTECTED]> CC: <[EMAIL PROTECTED]>; <everything-list@eskimo.com> 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 it > > > >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 drawn > > > >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 have > > > 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 an > >arbitrary > >large number of suicide experiments) with probability 1. > > > >But if you use the a priori probability distribution then you see that you > >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 me > typing this email is practically zero, considering all the other versions of > me and all the other objects in the multiverse. Another way of looking at it > 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. Saibal