[ExI] Bergson and Einstein are still debating the nature of time and change
Stuart LaForge
avant at sollegro.com
Sat Nov 30 04:53:45 UTC 2019
Quoting BillK:
> On Wed, 27 Nov 2019 at 21:43, Stuart LaForge via extropy-chat
> <extropy-chat at lists.extropy.org> wrote:
>>
>>
>> I don't see decoherence as being any more necessary than collapse in
>> Everett's MWI. If one posits the existence of all possible Everett
>> branches, all completely superdetermined, the result would be
>> indistinguishable from what we observe. With all randomness
>> attributable completely to our ignorance of which of the infinite
>> Everett branches we reside in. This view also seems to corroborate the
>> Wheeler-Dewitt equation which implies that the total energy and
>> information of the multiverse as a whole is unchanging and therefore
>> cannot be said to experience time at all.
>> ---
> <big snip>
>
>
> Quantum Bayesianism claims that MWI is meaningless.
> Quote:
> The Many Worlds Interpretation just boils down to this: Whenever a
> coin is tossed (or any process occurs) the world splits. But who would
> know the difference if that were not true? What does this vision have
> to do with any of the details of physics?
> ----------------------
To be honest, the notion that the universe splits asunder every time a
coin is flipped, initially made me strongly dislike MWI because
universe-splitting seemed a very unphysical process as bad as, if not
worse than, wave-function collapse. But that is before I started
investigating quantum gravity and wanting to merge QM and GR. Once GR
comes into the picture and time becomes geometrized into a space-time
manifold, one realizes that nothing splits or collapses. All the
universes are all already there a piori.
If one spatially clusters the universes by similarity to one another,
the resulting model or structure of the multiverse looks like an
infinite fractal tree, with uncountable Everett branches splitting off
into further branch universes of increasing specificity until one gets
down to the twigs; a picture reminiscent of Yggdrasil the World-Tree
of Norse mythology. Any particular path from trunk to twig tracing out
the unique history of a informationally-distinct universe.
Perhaps this super-deterministic interpretation of MWI is sufficiently
different from Everett's original vision so as to have its own name
but calling it MWI suffices for me. The point is that Everett's model
of QM lends itself well to the 3+1 geometry of general relativity.
None of the so-called epistemic interpretations of QM like Copenhagen
or QBism can boast this GR-coziness (hairy mathematical details like
renormalization aside).
The critic's allegation that classical versions of MWI could exist as
there is nothing inherently quantum mechanical about the model,
actually underscore the most valuable feature of MWI. And that is that
a single visualization tool or interpretation of physics can bridge
the quantum mechanical realm of subatomic processes with the
inter-galactic realm of cosmological processes. In that regard, MWI is
more a model of the physics of probabilistic phenomena on all scales
rather than a narrow interpretation of QM.
However, the Yggdrasil picture gained by clustering universes by
informational similarity is a useful tool for concept visualization
but the actual multiverse need not be so well organized. Quantum
entanglement enables quantum systems to evolve unitarily no matter how
far apart they are. And there seems to be more space in the multiverse
than anything else. Because information seems to be non-local, a
universe that is identical to ours except for one crucial detail (one
atom out of place for example) need not be our nearest neighboring
universe in space but instead lie countless trillions of Hubble radii
away.
Yet a single bit of Shannon information can nonetheless bridge that
unfathomable gap. Just like there is only one number 3 that
simultaneously exists wherever there are three of anything.
> <https://en.wikipedia.org/wiki/Quantum_Bayesianism>
> <https://www.discovermagazine.com/the-sciences/quantum-physics-is-no-more-mysterious-than-crossing-the-street>
>
> Interesting?
QBism is a valid interpretation of QM. It uses all the same maths and
leads to the same answers. However, it suffers from the same problems
that Copenhagen and other epistemic interpretations suffer from. For
one thing, it places undue importance on consciousness by way of
subjective observation of probabilities in the evolution of quantum
systems. Somehow abstract probabilities must become concrete
actualities in quantum systems.
In such epistemic interpretations for example, the moon is a fuzzy
mass of probability amplitudes until the moment you glance at it, then
it snaps to attention as a real object in the present moment located
precisely where you see it. Then when you look away, it relaxes once
again into a fuzzy mess of abstract data.
It seems to violate the Copernican principle that the moon should
dance at the whim of mere monkeys and that seems like a slippery slope
to solipsism.
In ontological interpretations of QM, such as MWI however, the moon is
always there and in every possible phase and position while it is we
precious observers that may or may not be there to witness it.
I suppose in the end, it boils down to matter of taste. Which
intuition about the world do you cherish more? Realism or locality?
For my part, I choose realism. If the present moment is real, then all
of space is real. There is so much space out there that we don't know
if it is infinite or not. Furthermore it is expanding due to dark
energy with the farthest parts receding faster than light. That means
that almost all of space is causally disconnected from us. That means
that there is room out there for all possible pasts, presents, and
futures to be real yet completely unobserved.
If the number three can exist wherever threeness is manifest, Why
cannot Einstein exist wherever Einsteiness is manifest?
Stuart LaForge
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