Last week the Nobel Prize in Physics was awarded to Alain Aspect, John F. Clauser, and Aton Zeilinger, for their work in testing quantum entanglement, essentially validating that quantum mechanics is correct about the phenomenon, and eliminating, or at least profoundly minimizing, any possible loopholes.
Of course this set off a lot of physicists discussing entanglement, and led to the inevitable arguments about what it means. One early effort I liked was a Twitter thread by Adam Becker, another was a Big Think article by Adam Frank. Frank’s overall thesis is that quantum physics forces weird choices on us.
It’s often said in the popular press that quantum entanglement forces us to give up locality, to accept “spooky action at a distance”. That is one option. But as Becker points on in his thread, and Sabine Hossenfelder in her own Twitter comments, there are others. Rather than give up local dynamics, we could accept superdeterminism, the idea that unlikely correlations are causally set in the early universe, or that some form of retrocausality, where the experimental setup has effects on, or at least constrains, the earlier evolution of the particles that will be measured.
Or, rather than add anything to the theory to explain what’s happening, we could simply accept the mathematical structure of quantum theory for what it is, along with all the consequences. Because doing this results in the infamous many-worlds scenario, most people reject it out of hand.
But I think when weighing these options (and others), we should remember about how we got here. When Albert Einstein and his collaborators first identified entanglement in 1935 in the famous (infamous?) EPR paradox paper, the purpose wasn’t really to just recognize a feature of quantum mechanics. It was to identify something so absurd and ridiculous that it could not possibly be true, and so demonstrate that quantum theory had to be incomplete. Erwin Schrödinger’s famous cat thought experiment followed shortly afterward with the same sentiment.
Einstein and his co-authors reportedly took heat in the scientific community for speculating about something untestable and metaphysical. Today we know that a couple of decades later John Stewart Bell figured out a way to test whether Einstein or quantum theory was correct. The Nobel is going to the experimentalists who over the decades made it happen with increasing precision and completeness.
Richard Feynman reportedly dinged philosophy because no philosopher even conceived of the possibility of quantum weirdness before the data forced it on us. But it’s worth noting that neither did theoretical physicists, and some, like Einstein, never accepted that quantum theory is the whole story.
All of which, it seems to me, is something we should consider when evaluating scientific or philosophical possibilities. It’s very easy to reject propositions we dislike, that just don’t accord with our preconceptions of how reality works. But if there is a logical chain of reasoning for the proposition, and we can’t identify where in that chain things are going off track, then we should remember all the similar rejections made throughout the history of science that turned out to be wrong.
Of course, that doesn’t mean we should accept the proposition as true without evidence. It’s an uncomfortable fact of life that there are a lot of scientific and philosophical propositions which we can’t yet dismiss, but also can’t take as reliable knowledge. And it’s very easy to fool ourselves that a proposition we want to be true is the best explanation, when there may be simpler or less exotic options.
I don’t know any way to avoid the two extremes here, other than to force ourselves to explain the logic for propositions we think are true, and find specific logical issues with the ones we don’t. And be willing to change our mind when the reasoning or evidence warrants it.
But maybe I’m missing something?
SelfAwarePatterns 
To quote Jim Al-Khalili – ‘This gets to the very heart of Bell’s idea (theorem) 1964 ..If we start playing and I win as many as I lose then Einstein was right..the dealer is just a trickster with a slight of hand. But what if I lose, then there is no sensible explanation…I’m forced to accept at the fundamental level, reality is truly unknowable.’ Bell reduced this idea into an equation about what seems unanswerable. A decade later, experiments were conducted to see if Einstein or Bohr were correct and based on the results Bohr was. Einstein’s version of reality cannot be true. It has been proven. The two entangled photons properties couldn’t have been set from the beginning, but only come into existence when we measure them. Photons only become real when we observe them. According to Jim Al-Khalili.
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The idea that photons only come into existence when measured is another one of those options. Whether it involves non-locality depends on how you feel about the other guy’s measurement of the partner particle. If the two of you measure at the same time, and that brings each particle into existence, and they’re entangled and so correlated, then we have non-locality. Of course you could go the Carlo Rovelli route and say that my measurement doesn’t exist for you until you get the results. Either way, it’s a bonkers view of reality, like all the other options.
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One thing I can’t figure out is the following. The wave function is complex (has real and imaginary parts). When we interpret a solution of Schrodinger’s equation that is a wave function, we just takes its amplitude (square root of the sum of the squares of the real and imaginary parts), and this is the probability of a particle being at that point in spacetime. But what about the phase of the complex number? Does that not act as a hidden variable? Does it ever have a physical effect, or only indirectly via its effect on solutions of Schrodinger’s equation at other times and places. Does it have a role in entanglement?
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From what I’ve read the phase is part of the formalism, so not hidden. I pulled this quote from my post on Alyssa Ney’s book on wave function realism.
. https://selfawarepatterns.com/2022/01/16/the-benefits-of-wave-function-realism/
That said, my ability to talk intelligently about the mathematics is very limited, even less so today than when I made that post. Sorry! You actually might get a lot out of Ney’s book.
I will say this. You won’t find any special “entanglement variables” in the mathematics. (I looked for that early on, eventually finding my way to Schrödinger’s paper where he coined the term.) The thing that becomes obvious in the math is that entanglement is just correlations tracked across the dimensions of wave function. It wouldn’t be any different from classical correlation if it weren’t for wave function collapse and the fact that all portions of the wave function covering the entangled particles collapse to the correct correlated values.
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I know I’m way out of my water in this discussion. Still, as I understand, Aspect, Clauser, and Zeilinger won the Nobel because they proved that hidden variables could not be involved in quantum entanglement over vast distances, thus forcing our theories of local reality to give up the ghost finally. It seems to me that the direction QM is moving toward with non-local reality is that space (or spacetime) is not empty, but is filled to the brim with one or more fields, of which particles and their anti-particles are temporary perturbations, entangled particles in superposition can be separated across unlimited distances and measurement of one collapses both particles instantaneously (implying that the speed of causality can be faster than the speed of light). I read somewhere recently that Einstein did not say C was an absolute speed limit, but that it was possible for some things to travel faster than light, but things traveling below the speed of light could not ramp up their speed to faster than light. Maybe causality can go faster than light speed.
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On what the experiments showed, it’s complicated and contentious. But if we accept Bell’s assumptions (one result, statistical independence) then his theorem and these experiments rule out any local hidden variable theories. Non-local hidden variable theories remain compatible the theorem and results. Interestingly, Bell himself was a fan of pilot-wave theory (a non-local hidden variable approach), and his motivation for his theorem was reportedly to try to support it.
Of course, if we throw either of those assumptions under the bus, then other options become available. Sabine Hossenfelder and other superdetermminists are keen to dismiss statistical independence. Everettians inherently dismiss the one result assumption.
Einstein’s chief beef with quantum physics, at least by 1935, was the non-locality, which implies that, at least for normal matter and energy, he saw c as a fundamental limit. People sometimes talk about things like tachyons, but there’s not really any observations indicating their existence, just the manipulation of equations that show they could be possible, and those manipulations require things like imaginary mass.
Exceeding c, if it’s possible, would likely need an entirely new physics. The thing is, any new physics has to explain everything the old physics did and more, a tall order.
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The bartender says “Get out! We don’t serve faster than light particles here!”
So, two tachyons walk into a bar …
*
[sorry, is all I got]
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Why did the tachyon cross the road?
Because it was on the other side.
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>”to force ourselves to explain the logic for propositions we think are true.”
I like that very much.
But what does that mean? Does it mean laying out the propositions’ theory and facts or arguments supporting it? Or should we, in addition to that, provide a story of how the author worked out his way to this proposition? If the latter, do you know any examples in the history of science (not limited to quantum physics or even just physics) when such a story helped convince scientists or the audience? I know that there are several cases in the history of science when authors came to the right conclusions starting from the wrong assumptions.
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Thanks Victor.
The story of how someone conceived of their proposition is frequently interesting and compelling, but I think it’s a mistake to see it as essential to a defense of the proposition. Often people stumble on the right idea for the wrong reasons, or the wrong idea for the best of reasons. It doesn’t seem like the lineage of the idea can protect it if it can’t hold up on its own. Astronomers once had valid reasons for thinking there were crystalline celestial spheres. But while it’s understandable that they came to that conclusion, it’s not an idea that withstood Tycho Brahe’s observations, much less the telescopic ones which followed.
So yeah, when I say we should force ourselves to explain the logic, the story of how we came to that conclusion is optional, and may well be irrelevant. Of course, people frequently find testimonials more convincing that straight logical reasoning, but that’s more about our psychology than the propositions themselves, I think.
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Well said, Mike. Reality, or at least the parts that are not familiar to us in everyday life, is weird. But then, when you think about where our sense of normalcy comes from, it’s not so surprising that other stuff is weird.
I think the so called retrocausality option deserves more attention than it usually gets – or as you rightly rephrased it, that later events can constrain earlier ones. I kinda doubt that this actually yields a variation on superdeterminism that is simple and elegant, but I’d like someone to try.
Nothing says you can’t deny more than one of Bell’s assumptions, also. Lev Vaidman rejects single outcome, and subscribes to retrocausality, which seems to conflict with the independence assumption.
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Thanks Paul.
Yeah, still struggling with the retrocausality / future constraining past thing. I get time symmetry at the microphysical but can’t see how that gets us there. Things still have to work in both directions. It seems like something has to be added to make it work. But I remain open that I could be missing something. And I’m onboard with people exploring it.
The biggest issue I see with ditching independence is I don’t really see the motivation, at least aside from wanting to make superdeterminism work. While ditching one unique outcome seems like just accepting the consequences of quantum theory. Doesn’t mean it’s right, only that we have reasons other than just wanting many-worlds to be true.
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I’m not sure what you mean by “Things still have to work in both directions.” Maybe the Wiki article on Two-state vector formalism will help. Or the first reference therein. On the other hand, if your worry is how Alice and Bob’s detectors are aligned for the same spin axis, that would all be about past-to-future macro level causality, where they make a plan together before going to their separate locations.
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Thanks. I don’t have access to the first cited paper. Not that I’d be likely to make heads or tails of it anyway. 🙂 But I think this snippet gives me the gist.
“In the example of the double-slit experiment, the first state vector evolves from the electron leaving its source, the second state vector evolves backwards from the final location of the electron on the detection screen, and the combination of forwards and backwards evolving state vectors determines what occurs when the electron passes the slits.”
I can see it as a conceivable solution to the measurement problem, but it still seems like we’re adding assumption to the formalism. But maybe I’d see it differently if I could read (and understand) the full theory.
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Yes I think there may be added assumptions, namely the descriptors of the final state. If you’re trying to avoid Everett’s result and insist on a single outcome for something like a pair of spin measurements, then you need both the initial and final state to pick that one true result out.
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To the contrary: It pays to remember that reality is fundamental. It is our interpretation of that reality that is absurd not the other way around…..
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You might be right. But to someone attached to their particular interpretation, it seems like it’s the other way around. And when a proposition seems absurd, we can’t be sure which side we’re on.
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“And when a proposition seems absurd, we can’t be sure which side we’re on.”
Sure we can, all one has to do is ask oneself this: Does that proposition apply “universally” to all physical systems without exceptions, or does it exclude some? If it excludes some physical systems then the proposition is absurd.
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That might make sense for a proposition about fundamental physics, but as we go up in levels of organization, it seems problematic. Is it unreasonable to note that biological processes don’t apply to rocks, or stars? Or that only certain types of systems implement the game Tetris?
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Your essay was titled: “It pays to remember that reality is absurd”. Sticking to the focal point of the essay which is fundamental physics; reality is not absurd, it is our interpretation of that reality that is absurd. So to answer your question: yes, it is not unreasonable to note that biological processes do not apply to rocks, or stars, or that only certain types of systems implement the game Tetris.
The absurdity of our interpretation of fundamental physics is what is in question. For example: asserting that as a singular system such as the physical brain can be both an objective system as well as a subjective system at the same time is absurd. This so-called anomaly occurs no where else in the known universe. That is of course, unless one chooses to reject the insurmountable evidence of fundamental physics and default to some form of dualism to explain the anomaly.
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First Cause,
I very much agree that it doesn’t pay to remember that reality is absurd. Perhaps it’s absurd if it functions magically, though my strong naturalism doesn’t permit me to entertain that notion more than hypothetically. If anything I’d say it pays to remember that people often believe absurd things. So yes, I was unsettled by the title of this post at first. When read I didn’t find the theme to reflect that title however — the post seemed reasonable to me.
Earlier this year I reviewed a draft of philosopher Eric Schwitzgebel’s coming “Weirdness of the World” book for him. Though the “weird” term seems much less doubtable than the “absurd” term, consider Schwitzgebel’s way of differentiating between “weird” and “bizarre”. While both may be strange, bizarre things have reason to be believed while weird things do not. So from here I had to press him about why he’d use a title for his book which suggests that the world is “weird”, or strange in ways that aren’t validated, when he might just as easily use the “bizarre” term and so reference justified strangeness? I doubt he’ll drop the weirdness title however, and indeed, I consider many of the ideas that he discusses to lack justification. So perhaps the title fits in that sense. If it were my book however I’d probably reference the weirdness of beliefs rather than the actual world. To me the world seems epistemically weird and ontologically bizarre, though could only be absurd by means of otherworldly magic.
“For example: asserting that as a singular system such as the physical brain can be both an objective system as well as a subjective system at the same time is absurd. This so-called anomaly occurs no where else in the known universe. That is of course, unless one chooses to reject the insurmountable evidence of fundamental physics and default to some form of dualism to explain the anomaly.”
Consider this explanation for that anomaly. The brain’s neurons and synapses operate the body as a relatively standard form of computer, though it also tends to produce a subjective experiencer that doesn’t exist as “brain” itself, but rather as an electromagnetic product of certain brain function. The thought is that there’s a kind of synchrony by which neurons can fire that produce an EM field which exists as the conscious experiencer of existence. Furthermore it’s theorized that when such a phenomenal thinker decides to act, that these elements of the EM field feedback to the brain by means of ephaptic coupling which engages associated muscles as instructed.
I wonder if you have any questions or comments about this natural rather than supernatural way of addressing the anomaly that you’ve mentioned?
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Eric,
First Cause is Lee; I’ve chosen a pseudonym because I’m tired of seeing my name plastered all over the internet.
For the record; I find those self-appointed academics and their disciples who promote functionalism to be a disingenuous group. Their claim to fame is based solely upon bashing dualism without offering a viable alternative to the dualism architecture.
I really don’t have much to contribute anymore, so good luck my friend…..
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Eric,
It’s worth mentioning for the sake of posterity that human beings seem incapable of being objective. For example: the theists project their own experience of mind onto a fundamental reality with their rendition of a God; the idealists project their own experience of consciousness onto a fundamental reality with their version of universal consciousness and equally, scientists project their own experience of being able to hold all possibilities in a superposition until an intellectual measurement is made unto a fundamental reality with the so-called wave-function and the Schrodinger equation.
Talk about absurd notions; it’s absolutely absurd to project our own experience onto a fundamental reality. Our grounding metaphysics is to blame and that foundation is SOM.
Go figure eh??????
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I don’t blame you for taking a pseudonym Lee. Your name seems unusual enough for a deranged person to perhaps look you up and maybe even cause you some trouble. For blogging I went with a pseudonym from day one so I might at least pretend I’m not quite that accessible to such a person. But thanks for letting me know.
You don’t like functionalism? I thought you were into a priori truth. Don’t you realize that functionalism is true by definition?
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Absolutely. Even physicists are subject to the bias, if you could call it that, for common sense. Anyone can see the world is flat, otherwise you’d just fall off.
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Physicists are definitely human, even ones who accept that reality is stranger than can be imagined. It’s one thing to accept it in the abstract, but much harder when it ends up trodding on our own convictions.
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