under my umbrella
"I would like to know whether it is likely to rain tomorrow. However, when I ask an Everett follower, all she will tell me in direct response to my question is that `it will rain and it won't rain.'
Nevertheless, she is willing to tell me whether or not it is rational for me to take an umbrella. I suppose that if she tells me that it would be highly irrational for me to take an umbrella, I can take the hint and deduce that it is very unlikely to rain.
However, there does seem something wrong with the fact that she is not allowed to say this directly."
Robert Wald reviewed Many Worlds?: Everett, Quantum Theory, and Reality
Subscribe to:
Post Comments (Atom)
5 comments:
So what would an Everett follower say about the rationality of trying to resolve the foundational issues of quantum mechanics?
If I remember correctly, John Bell was the first to point out that the many worlds would contain several histories with all crucial quantum experiments failing.
And without the Born probabilities we cannot even be sure that they would be unlikely...
Same would be true for relativity etc., there could be worlds where e.g. neutrinos are faster than light ...hmmm...
wait a second...
btw the real argument against Wallace et al. is that in the many worlds you never really make a decision: you will take the umbrella and you will not take it.
Unless you can show that umbrella-rain and no umbrella-no rain worlds are somehow more likely than umbrella - no rain and no umbrella - rain worlds you have gained nothing ...
... but this means that you are back to square one of the Born rule puzzle imho.
In my opinion one should go with the Everett interpretation but add the Born rule about the probability that I find myself in a particular world.
I think this is exactly equivalent to the good old Copenhagen interpretation (just replace 'find myself in' with 'collapse to').
Therefore your proposal suffers from the same issues. E.g. assuming that you are made from electrons, photons etc. (but no magic "mind stuff")
one would expect that the physical process of 'finding yourself' in one of the worlds is described itself by quantum theory.
But unitary quantum evolution cannot pick one world out from all the others...
Post a Comment