George Levy wrote: (complete message below) >This illustrates the difference in the observations. Observing a spark >with no detonation has a probability of 0.25 for a third person observer >but 0.33 for a first person observer.

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I agree, at least intuitively, with your reasoning. But as you perhaps remember Jacques Mallah trapped me in some intuitive probability reasoning, and that motivated me more for my arithmetical translation. Unfortunately this has led only to the definition of the particular case of probability one. Still, it is striking that such probability has some important quantum features. Most of the time I agree with your reasoning, although I cannot say I am sure (but then I am sure of nothing!). Some of your dream comments are very nice, but I am very far of being able to ask the sound machine (through G or G*) what she thinks about that. But it is interesting having different approach leading to similar propositions. >The spark itself is neither a >first nor third person event. It is in-between. But this, I'm not sure I understand. Could you elaborate a little bit? Is there a relationship with the first *plural* person, which makes possible some intermediaries between the 1 and 3 person? Bruno Original message: >In my opinion, the concept of first person and third person perspective >is really a special case of a continuum. > >A first person observation of an event occurs when the event is 100% >coupled with the continued existence of the observer. >A third person observation of an event occurs when the coupling between >the event and the observer's existence is 0%. >A continuum of possibilities exists between the two. In Tegmark suicide >experiment for example, the observation of the very preliminary phase of >the experiment is third person. The observation of the non-explosion of >the pack of dynamite is first person. > >Modifying that experiment slightly, let's say that the detonation of the >deadly explosive is intended if a quantum coin lands tail. Let's say the >the mechanism operates in two steps in rapid non-observable succession >with the following probabilities:. >1) A 50% chance p1 that the electrical circuit fires, which is a >function of the outcome states of the coin. If or when the circuit fires >it generates a visible spark intended to trigger the explosive. >2) A 50% chance p2 that the chemical responds to the spark and >detonates. (because it is (quantum?) wet for example) > >Here is the Third Person Perspective: > >Coin Head - Probability = (1-p1) = 0.50 > >Coin Tail => Spark => Non Detonation; Probability = (1-p1)(1-p2) = >0.25 > >Coin Tail => Spark => Detonation; Probability = (1-p1)p2 = 0.25 > > >The third person probability of live outcome is (1-p1) + (1-p1)(1-p2) = >0.75 > > > >The First Person Perspective is obtained by normalizing the third person >probabilities such that the sum of the live outcomes equals 1. > >Coin Head => Probability = (1-p1)/((1-p1) + (1-p1)(1-p2)) = 0.50/0.75 = >0.67 > >Coin Tail => Spark => Non Detonation; Probability = (1-p1)(1-p2)/((1-p1) >+ (1-p1)(1-p2)) = 0.33 > >Coin Tail => Spark => Detonation; Probability = 0.0 > > >This illustrates the difference in the observations. Observing a spark >with no detonation has a probability of 0.25 for a third person observer >but 0.33 for a first person observer. The spark itself is neither a >first nor third person event. It is in-between.