[HN Gopher] Does Superdeterminism Save Quantum Mechanics?
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Does Superdeterminism Save Quantum Mechanics?
Author : nsoonhui
Score : 31 points
Date : 2021-12-19 01:15 UTC (21 hours ago)
(HTM) web link (backreaction.blogspot.com)
(TXT) w3m dump (backreaction.blogspot.com)
| d--b wrote:
| I can't agree more with the OP about free will and stuff. The
| main problem of superdeternimism though is that it both explains
| everything and nothing. It's like giving up.
| midjji wrote:
| Exactly so, its an interesting philosophical idea,but its by
| definition invalidates the scientific method, and all forms of
| meaningful reason. The correct answer to the question of if you
| are dreaming a dream from which you could never wake up isnt
| perhaps that explains why my math doesnt make sense, its: by
| premise that can not matter.
| astrange wrote:
| The explanation of superdeterminism she gives here isn't a
| "full" superdeterministic theory (nothing actually happens over
| time, there are no physics, the universe is just a movie being
| played back, etc) and she does say it only applies at the
| quantum level. So there's still room for science.
| midjji wrote:
| Just means she hasn't thought of the inevitable consequences.
| Besides, the paradox she is resolving isn't a paradox, she
| just does not understand the answer in standard QM.
| 6gvONxR4sf7o wrote:
| Superdeterminism needs some kind of simplicity, for lack of a
| better word. To take her vaccine trial analogy further, imagine
| that you randomly assign a group of 100 people to a treatment and
| control cell (50-50). It _could_ happen that all 50 people in the
| control cell just happened to be the 50 most a priori healthy
| people in the group. But it's extremely unlikely. Following the
| analogy, superdeterminism says it happens anyways. But the level
| of coincidence involved invokes such an absurdly _complex_ series
| of coincidences, that your coin flip comes up heads on these
| particular people, that occam's razor might as well spontaneously
| cease to exist.
|
| Are there any superdeterministic theories that maintain the level
| of simplicity that the universe is posited to have without it?
| Strilanc wrote:
| From watching the video and reading one of the papers, I get the
| sense that the theory being described doesn't work in the usual
| way. For example, reading the paper it talks about "future
| inputs" determining what happens, which seems impossible if you
| need to have the entire state specified for each time slice
| without need to reference other time slices. Instead of having a
| specific state for time t, and being able to evolve it
| forward/backward to other times, it is instead applying
| constraints across spacetime?
|
| In principle, allowing yourself that kind of flexibility could be
| enough to model quantum mechanics. But I'm not sure why I'd want
| to do it that way instead of the existing ways. It's not
| particularly philosophically appealing to me, and objectively
| speaking it looks like they don't yet have a concrete
| mathematical model that actually reproduces quantum mechanics.
| But maybe I'm just ignorant of the latter part's existence.
| SuoDuanDao wrote:
| I'm no expert in this field, but aren't the existing
| assumptions around time being independent at the slice we want
| to take a major reason why QM and General Relativity can't be
| reconciled? If so, that would seem like a good reason to look
| at alternative ideas in this space.
| superdetermined wrote:
| As a complete layman, Sabine Hossenfelder's description here
| about Quantum Mechanics and Super Determinism is exactly that
| explanation that I came up with that made the most sense to me
| way back in college. And I have noticed that the idea of Super
| Determinism really bothers people on some fundamental level that
| I never really understood.
| graycat wrote:
| Uh, the OP frequently mentions "statistical independence", and I
| am uncomfortable with that: _Independence_ is a property of a set
| of more than one random variable and is defined in _probability_
| , often used in _statistics_ but not defined in _statistics_.
| There is a polished, elegant, and thorough treatment of such
| independence, including of uncountably infinite sets of random
| variables, in J. Neveu, _Mathematical Foundations of the Calculus
| of Probability_.
| kgwgk wrote:
| I guess the whole field of statistical mechanics would make you
| uncomfortable.
| PeterWhittaker wrote:
| In the context of Bell's Theorem, statistical independence is
| understood to mean that, if extant, hidden variables are not
| correlated with how measurements are being performed.
|
| Bell's Theorem is only correct if this assumption holds.
| Hossenfelder is arguing that the assumption is incorrect: that
| Bell's Theorem is incorrect precisely because there ARE hidden
| variables and that these ARE correlated with measurement
| settings.
|
| She also argues that all mentions of free will in all related
| discussions are meaningless red herrings that have distracted
| physicists from properly interpreting Bell's Theorem and
| observed violation of Bell's Inequality.
|
| Superdeterminism, arguably misnamed, simply argues that QM is
| deterministic, where Bell and others have argued it is not.
| graycat wrote:
| At least for now, I'm willing to f'get about issues of "free
| will".
|
| Thanks, I will keep trying to make sense out of Bell's work.
|
| I keep getting stuck trying to read quantum mechanics: One
| place was the claim that the wave functions form a Hilbert
| space. Nope: As I read in W. Rudin, _Real and Complex
| Analysis_ , a _Hilbert space_ is a complete inner product
| space where _complete_ means that every Cauchy convergent
| sequence is convergent. Well, while the wave functions are
| likely points in a suitable Hilbert space, they can 't be
| complete, e.g., they can converge to a point in the space,
| i.e., a function, that is not continuous and, thus, not
| differentiable in contradiction to the assumption that all
| wave functions are differentiable. I admit that this is a
| small point, but I was trying to take quantum mechanics
| seriously and be careful.
|
| Closer to the OP, another place I got stuck was in the
| approaches of physics to _independent_ and _uncorrelated_ :
| In probability theory those two are not the same: For two
| real valued random variables, independence implies
| uncorrelated. As in W. Feller, in the case of two real valued
| random variables with joint Gaussian probability density
| function, uncorrelated implies independence. Generally,
| however, uncorrelated does not imply independence.
| Independence is a much stronger property than uncorrelated.
| Maybe eventually I will figure out what physics means by
| "uncorrelated", especially for Bell's work.
|
| To me, we can take the Ace of Hearts and the Ace of Spades,
| shuffle them, and deal them out, face down, one each to Bob
| and Sally. Bob can go a light year away. Sally then looks at
| her card and knows right away, nothing faster than the speed
| of light needed, what Bob's card is.
|
| We know all the associated probability distributions for Bob
| and Sally. And we know that as soon as the cards are dealt
| what each of Bob and Sally have is _determined_ -- so far
| unknown but still _determined_.
|
| I'm guessing that this Bob-Sally _thought experiment_ may
| have something to do with _entanglement_ , the EPR (Einstein,
| Podolsky, Rosen) paradox, "spooky action at a distance",
| _collapse_ of quantum mechanics wave functions, and Bell 's
| results -- but I need to keep studying.
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