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I have no idea what a many-worlds person would say about time asymmetry. Would they postulate a kind of splitting-of-worlds at the moment of measurement? In whi

I have no idea what a many-worlds person would say about time asymmetry. Would they postulate a kind of splitting-of-worlds at the moment of measurement? In which case this sounds time-asymmetric to me.

gizmo686 10y ago
There is no splitting-of-worlds in many-worlds. The central idea behind many worlds is that the concept of "measurement" is extraneous and can be removed. When to particles interact on a quantum level, they become entangled. The behaviour of this entanglement is well understood and accurately described by pretty simple (but potentially counter-intuitive) math. Our best description of these systems involves them being in a superposition of many states. We have also observed in experiments these superimposed states turn back into pure states, in exactly the way we would expect from the time reversible equations governing quantom mechanics. The idea behind many-worlds is that "measurement" is just a bunch of these quantom interactions. In theory, we could reverse these interactions in the same way we could reverse them at a two particle level. In practice, this never happens because it is the same idea as the Earth shooting out a giant asteroid. Theoretically possible as the time reverse of an asteriod hitting Earth, but massively improbable.
- mathgenius 10y ago
  > The central idea behind many worlds is that the concept of "measurement" is extraneous and can be removed. Well obviously I need to read more about MWI because this just looks like standard quantum physics to me. Or perhaps "Church of the larger Hilbert space". Is it just saying superposition of states looks like "many worlds"? This looks to me like a non-interpretation interpretation.
- jessaustin 10y ago
  There is no splitting-of-worlds in many-worlds. TIL the many-worlds interpretation is actually the many-worlds many-interpretations. That's so meta!

gizmo686 10y ago

There is no splitting-of-worlds in many-worlds. The central idea behind many worlds is that the concept of "measurement" is extraneous and can be removed. When to particles interact on a quantum level, they become entangled. The behaviour of this entanglement is well understood and accurately described by pretty simple (but potentially counter-intuitive) math. Our best description of these systems involves them being in a superposition of many states. We have also observed in experiments these superimposed states turn back into pure states, in exactly the way we would expect from the time reversible equations governing quantom mechanics. The idea behind many-worlds is that "measurement" is just a bunch of these quantom interactions. In theory, we could reverse these interactions in the same way we could reverse them at a two particle level. In practice, this never happens because it is the same idea as the Earth shooting out a giant asteroid. Theoretically possible as the time reverse of an asteriod hitting Earth, but massively improbable.

mathgenius 10y ago
> The central idea behind many worlds is that the concept of "measurement" is extraneous and can be removed. Well obviously I need to read more about MWI because this just looks like standard quantum physics to me. Or perhaps "Church of the larger Hilbert space". Is it just saying superposition of states looks like "many worlds"? This looks to me like a non-interpretation interpretation.
jessaustin 10y ago
There is no splitting-of-worlds in many-worlds. TIL the many-worlds interpretation is actually the many-worlds many-interpretations. That's so meta!