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saturn comments on Stupid Questions Open Thread - Less Wrong Discussion

42 Post author: Costanza 29 December 2011 11:23PM

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Comment author: [deleted] 30 December 2011 12:29:00AM 15 points [-]

Well, hmmm. I wonder if this qualifies as "stupid".

Could someone help me summarize the evidence for MWI in the quantum physics sequence? I tried once, and only came up with 1) the fact that collapse postulates are "not nice" (i.e., nonlinear, nonlocal, and so on) and 2) the fact of decoherence. However, the following quote from Many Worlds, One Best Guess (emphasis added):

The debate should already be over. It should have been over fifty years ago. The state of evidence is too lopsided to justify further argument. There is no balance in this issue. There is no rational controversy to teach. The laws of probability theory are laws, not suggestions; there is no flexibility in the best guess given this evidence. Our children will look back at the fact that we were STILL ARGUING about this in the early 21st-century, and correctly deduce that we were nuts.

Is there other evidence as well, then? 1) seems depressingly weak, and as for 2)...

As was mentioned in Decoherence is Falsifiable and Testable, and brought up in the comments, the existence of so-called "microscopic decoherence" (which we have evidence for) is independent from so-called "macroscopic decoherence" (which -- as far as I know, and I would like to be wrong about this -- we do not have empirical evidence for). Macroscopic decoherence seems to imply MWI, but the evidence given in the decoherence subsequence deals only with microscopic decoherence.

I would rather not have this devolve into a debate on MWI and friends -- EY above to the contrary, I don't think we can classify that question as a "stupid" one. I'm focused entirely in EY's argument for MWI and possible improvements that can be made to it.

Comment author: saturn 30 December 2011 12:43:33AM 2 points [-]
Comment author: shminux 30 December 2011 01:08:27AM -1 points [-]

Actually, this is evidence for making a classical object behave in a quantum way, which seems like the opposite of decoherence.

Comment author: saturn 30 December 2011 01:35:12AM 2 points [-]

I don't understand your point. How would you demonstrate macroscopic decoherence without creating a coherent object which then decoheres?

Comment author: Manfred 30 December 2011 06:39:29AM *  0 points [-]

The interpretations of quantum mechanics that this sort of experiment tests are not all of the same ones as the ones Eliezer argues against. You can have "one world" interpretations that appear exactly identical to many-worlds, and indeed that's pretty typical.

Maybe I should have written this in reply to the original post.