Many-Worlds-Interpretation: reintegration?

[bbbl67]

Now, the MWI makes all kinds of predictions about universes splitting apart as quantum fluctuations cause particles to take different paths. So if there are many paths a particle can take from point A to point B, the universe splits apart into many universes, does that imply that once the particle has reached point B (whichever possible paths it took), that the universe reintegrates into a single universe again?

Does this also imply that the universe doesn't split apart in its entirety, just in local causally-connected regions, before reintegrating?

 

[PeterDonis]

Now, the MWI makes all kinds of predictions about universes splitting apart as quantum fluctuations cause particles to take different paths.

No, that's not what the MWI says. Only different macroscopic measurement results cause "splitting" of worlds (which is a misleading description anyway). In an experiment like the double slit, where the particle can take multiple paths to reach a particular spot on the screen where a detection is observed, there is no "splitting" in the MWI because of those multiple paths.

does that imply that once the particle has reached point B (whichever possible paths it took), that the universe reintegrates into a single universe again?

No, because there was no "splitting" in the first place. See above.

 

[bbbl67]

No, that's not what the MWI says. Only different macroscopic measurement results cause "splitting" of worlds (which is a misleading description anyway). In an experiment like the double slit, where the particle can take multiple paths to reach a particular spot on the screen where a detection is observed, there is no "splitting" in the MWI because of those multiple paths.
No, because there was no "splitting" in the first place. See above.

So does the MWI predict any splitting at all?

 

[PeterDonis]

does the MWI predict any splitting at all?

I already answered this in post #2, in the second sentence in what you quoted.