On 10 October 2013 12:25, chris peck <chris_peck...@hotmail.com> wrote: > Hi Bruno > >>> I don't see why. There is a chance of 1/2 to feel oneself in M, and of >>> 1/2 to feel oneself in W, but the probability is 1 (assuming comp, the >>> protocol, etc.) to find oneself alive. > > This begs the question. And the probability of finding oneself alive is 1 in > both your view and mine. > >>> P(W v M) = P(W) + P(M) as W and M are disjoint incompatible (first >>> person) events. > > That they are disjoint is fine. And they are incompatible only insofar as no > person, Bruno-Helsinki, Bruno-Washington or Bruno-Moscow, in the experiment > will experience both simultaneously. But Bruno-Helsinki will experience each > outcome. > > Whats missing here is a discussion about what conditions are required in > order to induce a feeling of subjective uncertainty in Bruno-Helsinki. I > think what is required is some ignorance over the details of the situation, > but there are none. Bruno-Helsinki knows all there is to know about the > situation that is relevant. > > He knows that in his future there will be two 'copies' of him; one in > Moscow, one in Washington. By 'yes doctor' he knows that both these 'copies' > are related to him in a manner that preserves identity in exactly the same > way. There will be no sense in which Bruno-Washington is more Bruno-Helsinki > than Bruno-Moscow. That is the essence of 'yes doctor'. So, at the point in > time when Bruno-Helsinki is asked what he expects to see, there are no other > relevant facts. Consequently there is no room for subjective uncertainty. > > It would therefore be absurd of Bruno-Helsinki to assign a probability of > 50% to either outcome. It would be like saying only one of the future > Bruno's shares a relationship of identity with him. This is why I say your > analysis violates the yes doctor axiom. > > This can be contrasted with a response from either of the copies when asked > the same question. If asked before opening their eyes, both Bruno-Washington > and Bruno-Moscow are ignorant of their location. Ofcourse, apart from the > fact that asking the question at this point is far too late for > Bruno-Helsinki, this is not a relevent fact for him. Because he has no doubt > that an identity maintaining version of him will be in each location. > > I have to admit, what with you being a professor and all that, I did begin > to feel like I was going mad. Luckily, the other day I found a paper by > Hillary Greaves "Understanding Deutcsh's Probability in a Deterministic > Multiverse". Section 4.1 discusses subjective uncertainty in a generalized > setting and argues for the exact same conclusions I have been reaching just > intuitively. This doesn't make either of us right or wrong, but it gives me > confidence to know that subjective uncertainty is not a foregone conclusion > as I sometimes have felt it has been presented on this list. It is an > analysis that has been peer reviewed and deemed worthy of publishing and > warrants more than the hand waving scoffs some academics here have been > offering. > > All the best
When I toss a coin, I expect to see either heads or tails but not both, and in fact I see heads or tails but not both. In a multiverse, versions of me will see both heads and tails. Should I therefore conclude that I don't live in a multiverse? -- Stathis Papaioannou -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
