mitchell_porter2 comments on Many Worlds, One Best Guess - Less Wrong

12 Post author: Eliezer_Yudkowsky 11 May 2008 08:32AM

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Comment author: mitchell_porter2 12 May 2008 07:00:47AM 1 point [-]

So far, we're still implicitly in a framework where there's time evolution, so I have described ways of implementing the many worlds vision in that framework. I am a little hesitant to preempt your next step (after all, I don't know what idiosyncratic spin you may put on things), but nonetheless: Suppose we adopt the "timeless" perspective. The wavefunction of the universe is a standing wave in configuration space; it does not undergo time evolution. My first option means nothing, because now we just have a static association of amplitudes with configurations. The second option is Barbour's - disconnected "time capsules" - only now there isn't even a question of linking up the time capsules of one moment with the time capsules of the next, because there's only one timeless moment throughout configuration space. I don't know if the third option is still viable or not; you can still compute the phase gradients of the standing wave according to the Bohmian law of motion, but I don't know about the properties of the resulting trajectories.

There may be a problem for mangled worlds peculiar to Barbour's model; there are no dynamics, therefore no mangling in any dynamical sense. You will have to come up with a nondynamical notion of decoherence too.