# Re: The Nature of Contingency: Quantum Physics as Modal Realism

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On 5/3/2022 4:40 AM, smitra wrote:
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```On 28-04-2022 02:14, Brent Meeker wrote:
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```On 4/27/2022 2:00 PM, smitra wrote:

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```If you agree, and are prepared,
with me, to throw out Everett, then we agree, and there is nothing

more to be argued about (at least, until you present some
different
complete theory).
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```I'm open to the idea that QM itself may only be an approximation to
a more fundamental theory. The arguments in favor of no collapse are
strong arguments but you then do get this issue with probability
is that I  don't see it as a fatal inconsistency that would prove
the MWI to be wrong. Probabilities for the different branches do not
have to be equal. But that doesn't mean that this looks to be a
rather unnatural feature of the theory. This suggests that a more
fundamental theory exists from which one could derive quantum
mechanics with its formalism involving amplitudes and the Born rule
as an approximation.
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If there are probabilities attached to the branches, then Gleason's
theorem shows that the probabilities must satisfy the Born rule.  So I
don't seen any inconsistency in simply saying they are probabilities
of measurement results,  that's Copenhagen.  But if they are
probabilities of results that implies that some things happen and
others don't...other wise what does "probability" mean and what use is
it as an empirical concept?  That brings back the original problem of
CI, where and how is this happening defined?

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If there are 3 copies of an observer and 2 experience outcome A and 1 experiences outcome B then the probability of the observer experiencing outcome B is 1/3.
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That doesn't even parse.  There is no THE observer.  The probability of any one of the three experiencing B is 1/3.  The Borel set is AAB, ABA, BAA.
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Here we should note that the personal identity of an observer is determined by all the information in the brain and is therefore different from the different outcomes. So, we always have (slightly) different observers observing different things, which is not all that different from starting with 3 different people of whom 2 experience outcome A and 1 experiences outcome B.
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In which case you  have to say that if I choose one of the three persons with equal probability, the probability of that I choose the one who experienced B is 1/3.  The the Borel set is the set of choices...not the set of persons.
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Brent

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```
Saibal

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```Brent

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