Gerard 't Hooft on the incompleteness of quantum mechanics

[PeterDonis]

It's completely normal to have different viewpoints on a topic that can't be proven today.

Yes, that's quite true.

I want to listen to people opinion why Gerard is right or wrong..

What you say above is just as true of this. Gerard is giving his opinion. Others have different opinions. And we have no way today of testing any of them.

 

[PeterDonis]

both statements say the same thing.

No, they don't. I already explained how the two things are different in Bohmian mechanics, in posts #54 and #57. You even quoted where I explicitly said that Bohmian mechanics has no randomness in its formalism and explained why. Please read those posts again. I don't think you have fully grasped what they're saying.

 

[Sagittarius A-Star]

But just as plausibly it is evidence that there are asymmetries in the initial conditions that are too small to detect - our hypothetical coin-flipping machine doesn’t start the coin in a vertical position, it starts it as close to vertical as we can.

I think this is called spontaneous symmetry breaking.

 

[Matterwave]

I want to listen to people opinion why Gerard is right or wrong..

I have not looked into Gerard's cellular automata theory, however, I already gave my view of him pulling the super determinism escape hatch to Bell's theorem in post #22.

But perhaps a few more comments in different rhetoric to make the point sharper.

Yes, super determinism is a logically consistent escape hatch; however, one should know what one is buying and what one is paying for it by pulling said escape hatch.

The conclusion that Bell would reach given violations of his inequalities would be that the world is fundamentally non-local. Gerard wants to avoid this conclusion so he pulls the super determinism escape hatch. He buys a local world, but he pays by committing to none of our experimental procedures can be freely chosen, using any conceivable scheme, in a way that does not make the statistics of the measurement outcomes confirm the predictions of quantum mechanics. Peter and others made a few more follow on remarks on what else is being committed to.

One should note that pulling an escape hatch doesn't automatically give you a new theory or interpretation. It is simply a denial of a given assumption.

I don't know whether Gerard's cellular automata theory actually builds a consistent bridge to super determinism in a way that bypasses Bell.

 

[javisot]

We don't know that. That's an assumption, which may be true, or may be wrong.

Correct me if I'm wrong, Demystifier. In BM, evolution is deterministic: if we knew the wave function and the initial configuration of all particles exactly, the equations would determine their subsequent evolution. However, this does not imply that we can know all those initial conditions or predict experimental results with arbitrary precision. For BM, the UP is just as important as it is for any other interpretation, right?

 

[PeterDonis]

the UP

...is not really about "randomness". It's about the consequences of having non-commuting observables. "Non-commuting" does not mean "randomness". It means that changing the order in which you measure the different observables changes the results. It's unfortunate that most treatments aren't clear about this.

It's also unfortunate that most treatments focus on the specific case of position and momentum, which have a continuous spectrum; it's actually the latter that makes the non-commutation of those observables look like "randomness" in the sense of enforcing a minimum spread in phase space. But spin observables about different spin axes also don't commute, and the consequence of their non-commutation looks the same mathematically if you're just looking at the operator equations for the commutators--but those observables have a discrete spectrum, so there is no "uncertainty principle" for them in the usual sense. But there is certainly still "uncertainty" involved in that changing the order of measurements changes the results.

All of this is independent of any interpretation, so Bohmian mechanics of course includes it. But the way Bohmian mechanics explains it is very different from the way other interpretations do.

 

[Matterwave]

By the way, has Gerard actually put out a (peer reviewed) paper on his cellular automata theory? Or is it just in the domain of YouTube videos atm?

 

[Sagittarius A-Star]

By the way, has Gerard actually put out a (peer reviewed) paper on his cellular automata theory? Or is it just in the domain of YouTube videos atm?

I found this:

https://arxiv.org/abs/1405.1548

https://www.amazon.com/Cellular-Aut...s-Fundamental/dp/3319823140?tag=pfamazon01-20

 

[javisot]

All of this is independent of any interpretation, so Bohmian mechanics of course includes it. But the way Bohmian mechanics explains it is very different from the way other interpretations do.

Do you think Gerard goes further than BM? I mean, BM respects the UP (he treats it differently, but he respects it). Gerard seems to deny the UP, therefore, he concludes "QM is wrong".

 

[iste]

By random, do you mean pseudo-random?

No, you can have a process with trajectories that move randomly but at the ensemble-level it is described by the probability density function evolving deterministically. The deterministic Schrodinger evolution is arguably analogous to the deterministic Fokker-Planck evolution which can describe random dynamical systems.

 

[PeterDonis]

Do you think Gerard goes further than BM?

His model is certainly different from BM, and he appears to be relying on superdeterminism to reproduce the predictions of standard QM, which BM does not.

Gerard seems to deny the UP

I'm not sure about that. As far as I can tell, his model still allows for us to have uncertainty about measurement results because we don't know the precise state of the underlying superdeterministic degrees of freedom (the "cellular automaton" in his model). And it doesn't seem like his model denies that there can be non-commuting observables.

 

[FactChecker]

Yes, super determinism is a logically consistent escape hatch; however, one should know what one is buying and what one is paying for it by pulling said escape hatch.

One should note that pulling an escape hatch doesn't automatically give you a new theory or interpretation. It is simply a denial of a given assumption.

I like that very much. One can always say the apparent random behavior is really the result of astonishingly detailed deterministic behavior that only a super being can fathom. That is an "escape hatch"which is always available. But IMO, at some point, Occam's razor makes me prefer (personal opinion) believing that there is some intrinsic, fundamental randomness rather than following ad hoc ("Rube Goldberg"?) explanations of results.

I think this is the choice we are presented with in trying to explain the results of Bell's Theorem tests. We can not say the results are due to correlations in the experimenter's minds (I think Gerard implies this) unless we can explain why the results are repeatable by different experimenters.

PS. I must admit that I am no more than a casual amateur on this subject, if that.

 

[Demystifier]

Correct me if I'm wrong, Demystifier. In BM, evolution is deterministic: if we knew the wave function and the initial configuration of all particles exactly, the equations would determine their subsequent evolution. However, this does not imply that we can know all those initial conditions or predict experimental results with arbitrary precision. For BM, the UP is just as important as it is for any other interpretation, right?

Yes, at the practical level, that's correct. But at the conceptual level, the origin of UP is explained somewhat differently.

In my opinion, the important principle of QM is not uncertainty but contextuality. This means that measurement changes the system and influences its properties. The so called "uncertainty" is just one of manifestations of contextuality. As @PeterDonis said, uncertainty does not necessarily need to be interpreted as fundamental non-determinism.

 

[PeroK]

I explain why I think free will is just illusion.

Everything is an "illusion" depending on how you define it. "Gravity is an illusion"; "time is an illusion"; "mass is an illusion" ... Such statements ultimately make no meaningful contribution to knowledge. All that matters, vis-a-vis free will, is what we are capable of doing and what we are not capable of doing. The words you use to describe that are arbitrary.

Quotes from Einstein, Spinoza, Schopenhauer, Penrose,Hawkings, Green, Sapolsky
etc etc I just use as example that I am not alone.

The problem is what happens when one Nobel laureate says one thing and another says the opposite? There is no philosophical unanimity among geniuses or Nobel laureates.

I want to listen to people opinion why Gerard is right or wrong..

I don't know whether he is right or wrong. I just gave my opinion. It's interesting that you find this frustrating (that I should defy the wisdom of a Nobel laureate) and then emphasise that you believe I have no free will!

 

[Lord Jestocost]

Why today so many world-class physicists(so no pseudo or charlatans physicists), even some Nobel price like genius Gerard 't Hooft talk about quantum physics as incomplete, wrong etc?

Is a physical theory such as quantum theory incomplete simply because it cannot answer some questions that appear “reasonable” from the classical point of view?

 

[gen x]

I just gave my opinion. It's interesting that you find this frustrating (that I should defy the wisdom of a Nobel laureate) and then emphasise that you believe I have no free will!

I already write in post #59 that I respect different opinions, because I know human "neurons fire differently", so we can't do anything about it. I am a prisoner of my own neural wiring.
I don't know who is right, but we agree that there is only one truth.

 

[gen x]

@gen x : You don't agree with this opinion?

I don't know if this is true, but I find it logical, because I see in my macroworld deterministic events all the time. If I a throw apple, it will fall down to the ground, it will not land in every random place in this universe, if I push on brake pedal, car will decelerate, it will not accelerate or fly to Jupiter etc etc. So everything happened with cause and effect. Nothing happen without reason.

You're ignoring the key point: what determines these things?

Nature laws?

What determine that ball in river travel downstream, not upstream?

Processes that are random on small scales can still produce predictable results on larger scales, so things can still be "deterministic enough" at the level of our brains and bodies to allow us to have the kind of free will I described above.

How in finite time random 0 and 1 can produce useful software?

 

[PeroK]

I don't know if this is true, but I find it logical, because I see in my macroworld deterministic events all the time. If I a throw apple, it will fall down to the ground, it will not land in every random place in this universe, if I push on brake pedal, car will decelerate, it will not accelerate or fly to Jupiter etc etc. So everything happened with cause and effect. Nothing happen without reason.

We live in very different worlds. I see chaos and probabilities everywhere. You look at the world of falling apples and human-made machines and regular shapes and say "everything is like that". And you choose to disregard the chaotic and fractal elements of nature. The weather, the stock market, human endeavour appears probabilistic. If you had enough information, you say, you could predict everything in advance. Just as surely as you know the difference between the brake and accelerator pedals. There is a Paris masters tennis tournament coming up. Where is the information that you need to predict the winner now? Every atom of every tennis player for a start. Really? What if a player has a car crash? Then you need every atom of every other person that a player may come into contact with in the next few weeks. Not to mention the weather, and pretty much everything else.

Then, you say, this must apply to atoms themselves. They can't be probabilistic because your car is a well-designed machine. But, perhaps, atoms do behave probabilistically - and only their sheer number washes out these probabilities when it comes to macroscopic systems such as your car.

Physics is about investigating these questions. You must be prepared for the microscopic world to be different from the macroscopic world. And that the atom might not be a mini-solar system. Or, a molecule just like a motor car.

 

[FactChecker]

I don't know if this is true, but I find it logical, because I see in my macroworld deterministic events all the time. If I a throw apple, it will fall down to the ground, it will not land in every random place in this universe, if I push on brake pedal, car will decelerate, it will not accelerate or fly to Jupiter etc etc.

These are examples of infinitesimal probability that are not worth considering.
Also, I find Gerard's objection to the experiments regarding Bell's Theorem to be stretching the imagination. He resorts to the possibility that the experimenter's brains provide correlations that distort the results. I guess this is supposed to apply to every experimenter who repeated the experiments in various ways.

 

[gen x]

I have not looked into Gerard's cellular automata theory,

If you had enough information, you say, you could predict everything in advance. Just as surely as you know the difference between the brake and accelerator pedals. There is a Paris masters tennis tournament coming up. Where is the information that you need to predict the winner now? Every atom of every tennis player for a start. Really? What if a player has a car crash? Then you need every atom of every other person that a player may come into contact with in the next few weeks. Not to mention the weather, and pretty much everything else.

Yes, by Gerard,Einstein and others determinists car crash is predetermined as well, just like every single particle in the universe.

 

[FactChecker]

Yes, by Gerard,Einstein and others determinists car crash is predetermined as well, just like every single particle in the universe.

So we have a choice:
1) QM, which is astoundingly successful in giving us a pattern of probabilities, if not an exact prediction for any single event.
2) CORRECTED, Super Determinism, which says we need to know everything about every particle and force field in the universe before we can make certain predictions.

Make your choice (assuming you believe your choice is not predetermined.)

 

[PeterDonis]

Nature laws?

Those are part of it, but there are an infinite number of solutions to those laws. So something else has to pick out just one of those solutions to be the one we actually observe. The something else is usually described as initial conditions.

How in finite time random 0 and 1 can produce useful software?

I never said they could. Instead of putting words in my mouth, you could have asked me for examples of what I was talking about. One such example would be: the random motions of individual molecules in a gas produce, macroscopically, predictable responses of the gas's thermodynamic variables to changes in conditions.

 

[Matterwave]

I know what cellular automata are, I just have not read Gerard's theory.

You do not have interest in engaging in any other points I made? Only in showing me this YouTube video?

 

[Matterwave]

2) Determinism, which says we need to know everything about every particle and force field in the universe before we can make certain predictions.

Note that determinism and super determinism are not the same thing. There's a reason they have different names since not all determinists commit to the premises of super determinism. Within determinism there's different camps, and we could consider super determinists a subset.

 

[PeterDonis]

Determinism, which says we need to know everything about every particle and force field in the universe before we can make certain predictions.

Not everywhere in the universe, only in the past light cone of the event you're trying to predict. At least, that's the case in any deterministic theory that is consistent with relativity. (Bohmian Mechanics is an interesting case, since on its face it is non-relativistic and the pilot wave updates instantaneously everywhere in the universe--but some proponents, like @Demystifier, have proposed relativistic versions of it. The no signaling theorem means that QM itself can't violate relativity in this way.)

 

[FactChecker]

Note that determinism and super determinism are not the same thing. There's a reason they have different names since not all determinists commit to the premises of super determinism. Within determinism there's different camps, and we could consider super determinists a subset.

Thanks for the correction. I'll correct my post.

 

[Sambuco]

For those interested, there is a very recent paper (from two weeks ago) that analyzes how many derivations of the Born rule, which start from the other non-probabilistic postulates, require the introduction of additional postulates that, in one way or another, possess intrinsic probabilistic properties.

Lucas.

 

[pines-demon]

I explain why I think free will is just illusion.
Quotes from Einstein, Spinoza, Schopenhauer, Penrose,Hawkings, Green, Sapolsky
etc etc I just use as example that I am not alone.

Sure but it is not who said it that matters, it is the argument. "Authorities" can be right for the wrong reasons.

I want to listen to people opinion why Gerard is right or wrong..

Sure but that is too vague of a post. As nothing was defined clearly most users are going into tangents that have no relation to 't Hooft's work.

 

[Demystifier]

2) CORRECTED, Super Determinism, which says we need to know everything about every particle and force field in the universe before we can make certain predictions.

That's also true for determinism. The difference between determinism and superdeterminism is the following: Determinism postulates deterministic equations of motion, while superdeterminisim, in addition, postulates also a law for the initial conditions. In QM, the idea of superdeterminism (as opposed to mere determinism as in Bohmian mechanics) is to get rid of the need of nonlocal instantaneous action at a distance, by postulating a special law for initial conditions that can explain correlations violating Bell inequalities.

 

[PeroK]

That's also true for determinism. The difference between determinism and superdeterminism is the following: Determinism postulates deterministic equations of motion, while superdeterminisim, in addition, postulates also a law for the initial conditions. In QM, the idea of superdeterminism (as opposed to mere determinism as in Bohmian mechanics) is to get rid of the need of nonlocal instantaneous action at a distance, by postulating a special law for initial conditions that can explain correlations violating Bell inequalities.

Here's an analogy. Determinism would say that the outcome of every soccer match is predetermined. Or, at least, that the outcome follows deterministic laws. Two soccer matches in two countries, however, would be independent systems.

Superdeterminism additionally produces otherwise inexplicable correlations between soccer matches. For example, Glasgow Celtic's results in Scotland might be exactly correlated with Bayern Munich's in Germany.

This is the point that the superdeterminists try to sweep under the carpet. That the initial conditions conspire to produce otherwise inexplicable but experimentally repeatable correlations between seemingly independent events. And, not only that, but these correlations are precisely those that would convince some of us that QM is an appropriate theory of nature. Whereas, as Scott Aaronson points out, the superdeterminists believe that nature is leading us astray by making it look like QM is correct. And, equally critically, that these otherwise inexplicable correlations extend to nothing except those experiments that support QM.