From: Rafal Smigrodzki (rafal@smigrodzki.org)
Date: Thu Feb 13 2003 - 16:26:58 MST
Damien wrote:
> Serafino says:
>
> [Me trimming desperately:]
>
>> Yes, maybe there are many different MWI.
>>
>> I.e. there is one MWI assuming that quantum objects, detectors,
>> observers, etc., are simply *split* between the various branches.
>
>> There is another MWI assuming that particles, observers, and
>> instruments, are *multiplied*.
>
>>> Tegmark argues that universes join as well as branch. We may have
>>> multiple pasts as well as multiple futures.
>>
>> Yes, this seems similar to Feynman paths.
>
> Around this point my brain usually makes a clicking sound and
> reboots. I *think* I can see what's going on (yes, like everyone here
> I've read *Q.E.D.*) until I try to correlate it all. Just to take one
> simple point:
>
> The Feynman account of least action is (so to speak) that every action
> occurs multiply and simultaneously, with destructive and constructive
> interference obliterating the less likely or more energy-hungry
> trajectories and reinforcing the least-energy path.
>
> I've never understood what exactly is meant to be doing all this
> interference (the wave aspect of the quantum universe, apparently,
> whatever that means), or virtual particles, or handwaving in Hilbert
> space, but once we move to a MWI *there's no way the superposed
> alternatives can all be REAL*.
>
> In olde worlde quantum physics, they weren't kinda really real to
> start with; what is real, what is concretized and instantiated, is
> their compounded and mutual interaction. (Right?) In Copenhagen,
> there is only one Real World; the many worlds blur together like many
> photographs of faces to form the One Common True Bland Face of
> Reality. In Deutschean MW, `shadow' particles from all the adjacent
> worlds somehow mess with trajectories of measurable, detectable
> particles.
>
> But wait! Here's this great swathe of possible paths, all of them
> taken, each of them the trajectory native to its own idiosyncratic
> world--but what *we* *here* experience is (almost) always that one
> goddam minimal action path. This looks wildly inconsistent with MW to
> me. (Of course it might be that in the MW manifold there is an a
> priori high p value for the least action path, so any observer is
> almost always in such a world--but that just establishes by fiat what
> is meant to be explained.
>
> Any takers?
### Let me guess: the measure of universes close to the minimal action path
is much greater than the measure of universes diverging from it
significantly?
There is a Damien who always wins the lottery :-)
Rafal
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