Russell Standish writes:

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[quoting Norman Samish]

> Suppose we take ten apparently identical ball bearings and put stickerson> each with the identifiers "1" through "10." We leave the room where the > balls with stickers are, and a robot removes the stickers and mixes the> balls up so that we don't which ball is which. However, the robotremembers> which sticker belongs on which ball. We come back into the room andpick> one ball at random to destroy by melting it in an electric furnace. Ifat> this point we ask "What is the probability that the destroyed ball isball> '3'?" we can truthfully answer "My memory tells me that the destroyedball> has a one in ten probability of being '3.' " >> However, by reviewing the robot's record we can see that "6" was, infact,> the one destroyed. >> Does this mean that the quantum wave functions of all ten ballscollapsed at> the moment we viewed the record and observed what happened to "6"? Ordid> the wave function never exist, since the robot's record always showedthe> identity of the destroyed ball, irrespective of whether a human observed > this identity or not? Yes and no. In a 3rd person description of the situation, the Multiverse has decohered into 10 distinct universes at the moment the robot decides which ball it picks up. What about the 1st person description? According to the interpretation I follow, the observer is in fact superposed over all 10 branches, and only collapses into a single branch the moment the observer becomes aware of the robot's record. A more conventional physics interpretation would have the conscious observer as belonging to a definite branch since the Multiverse decohered, but not knowing which. I understand that David Deutsch holds this interpretation, for example. There is certainly no 3rd person experiment that can be done to distinguish between these two interpretations, and the only 1st person experiment I can think of relates to tests of quantum immortality. I find it hard to believe the "no cul-de-sac" conjecture would hold in the latter case.

`If you accept that it makes no first person difference whether there is one`

`or many instantiations of the same observer moment - that it is all one`

`observer moment - then it becomes meaningless to ask whether the observer`

`belongs to just one or to a superposition of all of the instantiations. How`

`would QTI distinguish between the two interpretations?`

--Stathis Papaioannou _________________________________________________________________

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