On Thu, May 31, 2012 at 2:09 PM, Bruno Marchal <marc...@ulb.ac.be> wrote:

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> > On 31 May 2012, at 18:29, Jason Resch wrote: > > > > On Wed, May 30, 2012 at 3:27 AM, Bruno Marchal <marc...@ulb.ac.be> wrote: > >> >> On 29 May 2012, at 22:26, Jason Resch wrote: >> >> >> >> On Tue, May 29, 2012 at 12:55 PM, Bruno Marchal <marc...@ulb.ac.be>wrote: >> >>> >>> To see this the following thought experience can help. Some guy won a >>> price consisting in visiting Mars by teleportation. But his state law >>> forbid annihilation of human. So he made a teleportation to Mars without >>> annihilation. The version of Mars is very happy, and the version of earth >>> complained, and so try again and again, and again ... You are the observer, >>> and from your point of view, you can of course only see the guy who got the >>> feeling to be infinitely unlucky, as if P = 1/2, staying on earth for n >>> experience has probability 1/2^n (that the Harry Potter experience). >>> Assuming the infinite iteration, the guy as a probability near one to go >>> quickly on Mars. >>> >>> >> Bruno, >> >> Thanks for your very detailed reply in the other thread, I intend to get >> back to it later, but I had a strange thought while reading about the above >> experiment that I wanted to clear up. >> >> You mentioned that the probability of remaining on Earth is (1/2)^n, >> where n is the number of teleportations. >> >> >> Not really. I pretend that this is the relative probability inferred by >> the person in front of you. But he is wrong of course. Each time the >> probability is 1/2, but his experience is "harry-Potter-like". >> >> >> >> >> I can see clearly that the probability of remaining on earth after the >> first teleportation is 50%, but as the teleportations continue, does it >> remain 50%? >> >> >> Yes. >> >> >> >> Let's say that N = 5, therefore there are 5 copies on Mars, and 1 copy on >> earth. Wouldn't the probability of remaining on Earth be equal to 1/6th? >> >> >> You cannot use absolute sampling. I don't think it makes any sense. >> >> >> >> >> While I can see it this way, I can also shift my perspective so that I >> see the probability as 1/32 (since each time the teleport button is >> pressed, I split in two). It is easier for me to see how this works in >> quantum mechanics under the following experiment: >> >> I choose 5 different electrons and measure the spin on the y-axis, the >> probability that I measure all 5 to be in the up state is 1 in 32 (as I >> have caused 5 splittings), >> >> >> OK. >> >> >> but what if the experiment is: measure the spin states of up to 5 >> electrons, but stop once you find one in the up state. >> >> >> That is a different protocol. The one above is the one corresponding to >> the earth/mars experience. >> >> >> >> In this case it seems there are 6 copies of me, with the following >> records: >> >> 1. D >> 2. DU >> 3. DDU >> 4. DDDU >> 5. DDDDU >> 6. DDDDD >> >> However, not all of these copies should have the same measure. The way >> I see it is they have the following probabilities: >> >> 1. D (1/2) >> 2. DU (1/4) >> 3. DDU (1/8) >> 4. DDDU (1/16) >> 5. DDDDU (1/32) >> 6. DDDDD (1/32) >> >> I suppose what is bothering me is that in the Mars transporter >> experiment, it seems the end result (having 1 copy on earth, and 5 copies >> on mars) is no different from the case where the transporter creates all 5 >> copies on Mars at once. >> >> >> This is ambiguous. >> > > > What I mean is me stepping into the teleporter 5 times, with the net > result being 1 copy on Earth and 5 copies on Mars, seems just like stepping > into the teleporter once, and the teleporter then creating 5 copies (with > delay) on Mars. > > Like the diagram on step 4 of UDA: > > http://iridia.ulb.ac.be/~marchal/publications/SANE2004MARCHAL_fichiers/image012.gif > > Except there is no annihilation on Earth, and there are 4 copies created > with delay on Mars (instead of one with delay). > > When stepping into the teleporter once, and having 5 copies created on > Mars (with various delays between each one being produced) is the > probability of remaining on Earth 1/6th? > > > Yes. > That would be a good idea to enhance the probability to be the one, or a > one, finding himself of mars. But again, the guy on earth will be in front > of the "looser", even if you multiply by 20. billions your delayed copies > on mars. > > > > Is the difference with the iterated example receiving the knowledge that > the other copy made it to Mars before stepping into the Teleporter again? > > > I don't understand the sentence. It looks like what is the difference > between 24. > I apologize for not being clear. There are two different experiments I am contrasting: 1. A person steps into a teleporter, and 5 copies (with varying delays) are reproduced on Mars. 2. A person steps into a teleporter, and a duplicate is created on Mars. To increase the chance of subjectively finding himself on Mars, he does it again (when he fails) and the copy on Earth does so 5 times before giving up. For experiment 1, you and I seem to agree that subjectively, that person person has a 1 in 6 chance of experiencing a continued presence on earth, and a 5/6 chance of finding himself on mars. For experiment 2, I believe you suggested there is a 1 in 32 (subjective chance) of going through this exercise and not having the subjective experience of ending up on Mars. Have I understood this correctly thus far? If so, what accounts for these different subjective probabilities? How can it be that there is a 31/32 chance of finding oneself on mars if there are just 5 copies there? I hope I have been clear enough. Thanks again. Jason > > In this thought experience you were supposed to be an external observer on > earth, not the candidate doing the duplication. > In your diary, you will always write things like, "he try to multiply the > copy on mars, push on the button and told me "this fails again". > > -- You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to everything-list@googlegroups.com. To unsubscribe from this group, send email to everything-list+unsubscr...@googlegroups.com. 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