
David Bohm, Quantum Mechanics and Enlightenment - jonbaer
https://blogs.scientificamerican.com/cross-check/david-bohm-quantum-mechanics-and-enlightenment/
======
rimher
Great video that showcases the Pilot Wave idea:
[https://youtu.be/WIyTZDHuarQ](https://youtu.be/WIyTZDHuarQ)

I really do hope that we can find a way to make sense of everything in
Physics, but Bohm's description of the infinite in the article is rather
fascinating. Maybe there's no way out after all

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kkylin
The (completely classical) fluids "experiment on television" mentioned in this
article is presumably something like this (which is really cool if you haven't
seen it before):

    
    
      https://www.youtube.com/watch?v=QcBpDVzBPMk
    

Said experiments starts about 40 seconds in. A bit more info here:
[https://en.wikipedia.org/wiki/Stokes_flow#Properties](https://en.wikipedia.org/wiki/Stokes_flow#Properties)

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raverbashing
IMHO the Copenhagen interpretation should have been taken as "this is the best
we can come up right now" (instead of an "all-in") and while the original
Bohmian mechanics do have some issues it does sound like they threw the baby
out with the bathwater.

(In the end the most successfully interpretation has been the "shut up and do
the math" one, but the interpretations help us find unexplored and
contradictory sides of the theory and hopefully help to find new experimental
possibilities)

~~~
mnl
Maybe the bad idea is insisting in having a classical physics pictorical
interpretation when there's no reason why there should be one. At some point
having just Maths is the more reasonable outlook.

~~~
naasking
> Maybe the bad idea is insisting in having a classical physics pictorical
> interpretation when there's no reason why there should be one

Actually there is a reason: we see classic physics with our own two eyes every
day. We know classical physics exists at the macroscopic level, and so a
theory that simply explains the transition from microscopic to macroscopic
physics and how this works.

This transition is unbelievably simple in Bohmian mechanics, since in
principle, it's just classical physics with an extra term to account for
quantum influences. The picture isn't nearly so simple for many other
interpretations.

~~~
mnl
We think we see classical physics, but this micro/macro divide is not that
clear-cut. It's more like a convenient textbook classification. For instance
you can build a very macro magnet which is not classical physics at all, you
can't explain ferromagnetism without QM. Why don't we fall through the floor?
that's not classical. Chemistry makes no sense without QM either. A classical
world, albeit nice and easy to mirror with mental images involving
differential equations of continuous stuff would fall to pieces.

I like Bohm's book on Quantum Physics, but the pilot wave theory... well it
doesn't explain anything new and the only problems it might solve are related
to prejudices. Besides, the nature of that duplicity is never explained (and
very ugly), so you're trading the ignorance you don't like for the one you
like. In this kind of situations just go for the more simple and consistent
theory as the only thing that matters is measurements.

(There's also the problem of getting to some form of QFT with it. Bell has
written about this elsewhere, it's not pretty but I'm sure somebody has
arrived to a working model by now.)

~~~
westoncb
You're statements attempt to negate the GP's claim that the macro is classical
by saying that the micro is not classical. But that's the whole larger
question we're trying to answer here, so asserting an answer in one direction
(micro is not classical) as a reply to some sub-point ends the possibility of
a reasonable discussion.

If there is a formulation of quantum mechanics which retains classical
determinism, then just because it coheres so well with the behavior of
everything we have _directly_ observed (insofar as that's possible through the
intermediaries of our senses) so far, it should be given a good amount of
attention.

> but the pilot wave theory... well it doesn't explain anything new and the
> only problems it might solve are related to prejudices.

It can only be considered a prejudice if you're already pre-decided that non-
classical physical descriptions are necessary before attempting to evaluate
pilot wave theory. You're saying the prejudice is against non-classical
behavior, right? Just put yourself in the shoes for a moment of a person
judging (the modern formulations of) these theories, but at a point in time
before any of them had a reputation (in an alternate history I mean). Would it
be a prejudice to select from among essentially equivalent (predictive power)
theories the one which doesn't force us to leave the then reigning classical
paradigm?

If Pilot Wave theory and the more established quantum theories have comparable
predictive power, but pilot wave theory can do the same thing without
introducing new classes of behavior never observed at the macro level, then
that's a point in its favor via Occam's Razor if nothing else.

~~~
mnl
No, I'm actually saying that everything is QM, and yet for some phenomena you
can use instead of that some effective theories called classical physics, that
have these nice properties of needing just calculus and vector analysis and
being easy to draw. That, and they having been discovered before more
explanatory theories make them very popular, but it doesn't mean the world is
actually separated in domains. Usually physics is taught in terms of micro and
macro descriptions, the macro applies to those situations likely to be
adequately characterized by classical physics, but that's because Planck's
constant is really small, not because there's such a thing as a classical
world. Hence for macroscopical everyday stuff classical physics usually works
reasonably well, but even there, right in front of you there are very obvious
phenomena that can't be explained with classical physics.

About the pilot wave theory, well it came after the standard formulation of
QM, so people didn't choose between them, and it's quite a patchwork that
brings its own complications. Apparently as it includes classical trajectories
some people love it, ignoring that you put by hand the actual QM wavefunction
to make it work, then you fix things to get the old stuff back. I find all
that weirder than standard QM.

~~~
westoncb
> No, I'm actually saying that everything is QM

I assumed that's what you're saying. I'm familiar with the viewpoint that
classical physics is a pragmatic approximation to QM for macro phenomena.

> About the pilot wave theory, well it came after the standard formulation of
> QM, so people didn't choose between them

Of course. I was posing a hypothetical to demonstrate an error the argument
you were making (assuming the conclusion as part of your argument).

> ignoring that you put by hand the actual QM wavefunction to make it work,
> then you fix things to get the old stuff back. I find all that weirder than
> standard QM.

I may be missing something here, and I haven't looked into the calculational
details of pilot wave theory, but my understanding is that the same
probabilities you ordinarily deal with in QM exist, but they are used to
signify lack of knowledge of the observer of the state of the system (rather
than saying that the system is literally in an indefinite state), so it makes
sense that the wavefunction machinery would still be present, but used in a
different way.

------
a_d
Kip Thorne here [1] agrees with one aspect of Bohm’s philosophy (not Physics)
—- he posits that theories that explain nature’s laws with more and more
precision are like Matryoshka Dolls (Greeks->Newton->Einstein->String
Theory->{??}), where each new layer improves on the predictions of the
previous one —- and at one point in the discussion, he says this could go on
until infinity.

(Regardless, this is a great interview to watch if you are interested in
physics)

In similar vein, here is Eric Weinstein [2] talking about why we can’t find
the theory of everything — and has similarly...kooky...ideas as Bohm. He is
short-String theory ([https://www.edge.org/response-
detail/25547](https://www.edge.org/response-detail/25547)). His main critique
comes from the demands that the theory starts imposing about wanting 11 or 26
dimensions.

All this in some level is super exciting and suspenseful, as I do believe
Physics is on the cusp of a “new big idea from a lone genius” type revolution,
that might push things forward!

[1]
[https://www.youtube.com/playlist?list=PLFJr3pJl27pItxUFeZlx9...](https://www.youtube.com/playlist?list=PLFJr3pJl27pItxUFeZlx98GQzl-5UBroJ)

[2] [https://youtu.be/Yw88utUCx9M](https://youtu.be/Yw88utUCx9M)

~~~
catawbasam
'Kooky' seems a bit dismissive, especially as applied to thinkers of this
caliber.

~~~
dominotw
Maybe something to do with him hanging out with Jiddu Krisnamurthi for decades
( before falling out). Joking aside, I did enjoy the conversations between the
two that some kind soul uploaded to youtube couple of yrs ago.

~~~
samratjp
Were you perhaps referring to this
[https://www.youtube.com/watch?v=SqYCFRzqNoA&list=PL1n30s-LKu...](https://www.youtube.com/watch?v=SqYCFRzqNoA&list=PL1n30s-LKus4MyNuceRoFAes5teZS_guW)?
I love this series and highly recommend it to anyone interested in either of
them or in Non-duality.

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axilmar
My apologies for the seemingly unrelated comment, but I do not understand why
'spooky action at a distance' has to be 'action at a distance' and not photons
getting entangled when created.

I.e. why couldn't it be that a pair of photons are generated with their
properties already in such state that, when measured, a correlation is
present? the photons don't communicate, they are already in the appropriate
state when measured.

~~~
jostylr
That is what Bell's work showed is not possible. The inequality he derived
assumes the values already exist and then proves that a certain inequality for
the predictions must be satisfied. This is without specifying the actual
theory, just simply that the values already exist in the right correlations.
Experiments has proven that the inequality is violated. Thus, the properties
cannot be determined beforehand. So either there is a connection that is,
essentially, faster than light, or the results of the experiments do not
become finalized until compared (that is, the researchers first reading the
results exist in a multi-state, allowing for various outcomes yet to be
determined [this is what the many worlds view basically is] ).

[http://www.scholarpedia.org/article/Bell%27s_theorem#Bell.27...](http://www.scholarpedia.org/article/Bell%27s_theorem#Bell.27s_inequality_theorem)

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amai
In contrast to what the article says, Einstein didn’t think Bohm had a
sensible theory.

In a letter to Max Born he wrote about Bohm’s theory: “That way seems too
cheap to me.”

[https://en.m.wikiquote.org/wiki/De_Broglie–Bohm_theory](https://en.m.wikiquote.org/wiki/De_Broglie–Bohm_theory)

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okket
The articles says Bohm's ideas "remain influential". Are there any examples in
recent Physics where this is the case?

~~~
naasking
Various no-go theorems were formulated due to looking into this question. For
instance, the very first no-go theorem, Bell's theorem, was published because
Bell was such a big fan of Bohmian mechanics.

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mapcars
>For him, truth-seeking was not a game, it was a dreadful, impossible,
necessary task. Bohm was desperate to know, to discover the secret of
everything, but he knew it wasn’t attainable, not for any mortal being. No one
gets out of the fish tank alive.

This is a very, very big question. Its a little pity he didn't meet Sadhguru.

~~~
dwarman
"not a game" \- well, he certainly hid this well behind a playful and
enthusiastic way of teaching, as when he was our Props of Matter lecturing
prof at Birkbeck College in the early 70's. And very effective too, not that I
followed the Physics path beyond that (the siren call of computers was
stronger for me).

------
SidiousL
I didn't read the article but, in case you don't know quantum mechanics, I
should tell you that the vast majority of people who study such things think
that Bohm's theory is plain wrong.

I should also say that it is not taught in schools, papers about it are not
published in serious journals and the field is just not an active field of
research. It's quite likely that all the people trying to develop this idea
are crackpots.

