"Shut up and calculate"

[gen x]

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?
What do you think of Gerard opinion that every single particle follow some for human still unknown deterministic rules and probability only comes from our incomplete knowledge?

​

 

[javisot]

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

The only people who can resolve your question are the authors of those statements themselves.

If by "complete" we mean describing everything that can be described regarding quantum effects, then it is complete. If by "complete" we mean describing absolutely everything, then it is not complete. Only the author himself knows what he intends to say.

What do you think of Gerard opinion that every single particle follow some for human still unknown deterministic rules and probability only comes from our incomplete knowledge?

I think it is easier said than proven.

 

[Matterwave]

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?

There's commonly two things people flag when making such statements, but as has already been pointed out, only the authors of those statements can tell you what they actually mean.

1. Lack of quantum gravity. There's as-yet no unified quantum theory of gravity.
2. Open questions in Quantum foundations, most prominently, the measurement problem.

Talk about the latter usually belongs better in the quantum interpretations subforum. Discussion of the former might belong more in Beyond the Standard Model.

 

[gen x]

The only people who can resolve your question are the authors of those statements themselves.

Here I try to understand his views

 

[FactChecker]

Here I try to understand his views

In the first few minutes (t=5:30): "The real world isn't probabilistic. It's only probabilistic if you don't have all information."
That is a common belief and one that Einstein had. IMO, it shows a limitation of a human to accept that the real world might just be intrinsically probabilistic in some things. Einstein famously said "God does not play dice." Does that assume God would be intimidated or confused by probabilities?
I think this is a philosophical (religious?) objection, but I am certainly not qualified to argue with Einstein.

 

[Demystifier]

The standard QM postulates that the non-deterministic aspect of QM is described by the collapse postulate, and that this postulate only needs to be applied at the measurement. The measurement itself is a macroscopic notion, related to the interaction with the macroscopic measuring apparatus with many degrees of freedom. This already suggests that quantum randomness only appears when there are many uncontrollable degrees of freedom, namely, that randomness is an artifact of the lack of knowledge about those degrees of freedom. In other words, this suggests that quantum systems are, at the fundamental microscopic level, intrinsically deterministic. Otherwise, the microscopic equations themselves would be probabilistic (which they are not, the Schrodinger equation is deterministic), without a need to appeal to the vague notion of measurement to see where the randomness come from.

 

[pines-demon]

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?
What do you think of Gerard opinion that every single particle follow some for human still unknown deterministic rules and probability only comes from our incomplete knowledge?

​

This is low effort. Have you looked at why 't Hooft says that? Can you cite a specific text or video? In PF we request users to provide sources and a little deep read before starting a discussion in order to provide a better conversation.

Also can a mod change the title to "Views of 't Hoof on incompleteness of quantum mechanics" or something like that.

 

[gen x]

This is low effort. Have you looked at why 't Hooft says that? Can you cite a specific text or video? In PF we request users to provide sources and a little deep read before starting a discussion in order to provide a better conversation.

Also can a mod change the title to "Views of 't Hoof on incompleteness of quantum mechanics" or something like that.

Look at video at my post #4

 

[gen x]

In the first few minutes (t=5:30): "The real world isn't probabilistic. It's only probabilistic if you don't have all information."

You don't agree with this opinion?

If that say some member from this forum, moderators will ban him immediately.

 

[gen x]

Interesting part is at 46:40 where he comment Bell theorem.

 

[Sagittarius A-Star]

This already suggests that quantum randomness only appears when there are many uncontrollable degrees of freedom, namely, that randomness is an artifact of the lack of knowledge about those degrees of freedom. In other words, this suggests that quantum systems are, at the fundamental microscopic level, intrinsically deterministic.

Please consider a 1 photon double-slit experiment, which is symmetric regarding left/right. If a photon is detected on the left side of the photographic plate, how can a deterministic process in a symmetric setup create an asymmetric result?

 

[Demystifier]

Please consider a 1 photon double-slit experiment, which is symmetric regarding left/right. If a photon is detected on the left side of the photographic plate, how can a deterministic process in a symmetric setup create an asymmetric result?

A coin is symmetric regarding heads/tails. How can a deterministic process in a symmetric setup create an asymmetric result?

 

[PeroK]

Where is the evidence for determinism in the real world? There is none. The laws of physics may be deterministic, but that's a model of the real world. There is no reason to believe that deterministic laws of physics are ultimately a complete model.

Where is the evidence that "all the information" actually exists? Theoretically or hypothetically you may postulate complete information for the state of a complex system. E.g. a human being. But, where is the evidence for this information? Where is it? If it doesn't exist, then you can't say what is the case if you knew it all.

It's not the coin that is probabilistic. It's the person tossing the coin; and, perhaps, the environment. You might toss a coin in a storm or on a small boat in a rough sea.

Finally, even if all the information exists, if it's infinite, then we cannot know it all. E.g. a single real number may require an infinite amount of information to be described.

Even with a full deterministic set of laws of physics, the real world could still be unpredictable, because all the information cannot be input to the model. Then the outcomes are probabilistic.

Or, to sum this up: omniscience may be theoretically impossible.

 

[martinbn]

The standard QM postulates that the non-deterministic aspect of QM is described by the collapse postulate, and that this postulate only needs to be applied at the measurement. The measurement itself is a macroscopic notion, related to the interaction with the macroscopic measuring apparatus with many degrees of freedom. This already suggests that quantum randomness only appears when there are many uncontrollable degrees of freedom, namely, that randomness is an artifact of the lack of knowledge about those degrees of freedom. In other words, this suggests that quantum systems are, at the fundamental microscopic level, intrinsically deterministic. Otherwise, the microscopic equations themselves would be probabilistic (which they are not, the Schrodinger equation is deterministic), without a need to appeal to the vague notion of measurement to see where the randomness come from.

But QT can also handle particle decay, no measrument, no macroscopic devices.

 

[Herman Trivilino]

What do you think of Gerard opinion that every single particle follow some for human still unknown deterministic rules and probability only comes from our incomplete knowledge?

I think this argument has been going on since the formation of quantum physics crystallized in the 1920's. Alain Aspect et. al. made seminal contributions in the 1970's that, depending on your opinion, either largely refuted it or significantly changed the way it is supported.

I think it's metaphysics.

 

[Demystifier]

But QT can also handle particle decay, no measrument, no macroscopic devices.

That's not really true. The decay also rests on the collapse postulate and on decoherence with the environment. In fact, if decoherence is sufficiently strong, then the decay can be slowed down by the quantum Zeno effect. I was writing more about this in https://arxiv.org/abs/2010.07575 Sec. 4.3.

 

[Demystifier]

Where is the evidence for determinism in the real world?

In coherent unitary evolution of quantum states prior to measurement.

There is none.

There is a lot of evidence that the state is correctly described by the deterministic Schrodinger equation, without the probabilistic collapse, prior to measurement.

The laws of physics may be deterministic, but that's a model of the real world.

Agreed.

There is no reason to believe that deterministic laws of physics are ultimately a complete model.

Maybe, but there is also no reason to believe the opposite, that probabilistic laws of physics are ultimately a complete model.

 

[FactChecker]

In the first few minutes (t=5:30): "The real world isn't probabilistic. It's only probabilistic if you don't have all information."

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

As a mathematician, I had to accept the limitations of logic implied by Gödel's incompleteness theorems.
In physics, I am willing to accept that the human race is not, and never will be, in a position to know everything necessary to say physics is completely deterministic.
So I don't think that question will ever be answered.

 

[Sagittarius A-Star]

A coin is symmetric regarding heads/tails.

Yes, but the initial condition of the system is not symmetric, because one side is up before the coin is thrown.
There exists a "same-side-bias" of 50.8%.

Source:
https://www.mpi.nl/publications/ite...-same-side-they-started-evidence-350757-flips

Where could the asymmetric result in a spatial symmetric 1 photon double-slit experiment come from, without real randomness?

 

[pines-demon]

Look at video at my post #4

Did you watch it? what did you find worth discussing? There is something specific you don't understand?

Interesting part is at 46:40 where he comment Bell theorem.

What did you find interesting about it?

 

[Nugatory]

Where could the asymmetric result in a spatial symmetric 1 photon double-slit experiment come from, without real randomness?

From an unknown asymmetry in the initial conditions, perhaps. The coin flipping experiment you cite in #19 notes the effect of a known asymmetry. We could develop a coin-flipping machine that starts the coin in a vertical position to eliminate that known asymmetry, and in principle we could eliminate all other detectable asymmetries in the initial conditions.

But suppose we still have asymmetric results? Perhaps that is evidence of “real”randomness? 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 don’t think that it is possible to experimentally distinguish “real” randomness from incomplete knowledge of the initial conditions.

 

[Matterwave]

Interesting part is at 46:40 where he comment Bell theorem.

It seems t' Hooft is appealing to a known loophole in Bell's theorem, that of "super determinism". It is true that Bell relied on a condition of statistical independence of the "hidden variable" from Alice and Bob's measurement settings. So if you deny that assumption you can bypass the conclusion of "the world is non-locally causal" that Bell came to (denying that assumption is often called "super determinism"). This is the position that Sabine Hossenfelder also takes.

But one should understand what that assumption actually entails. It is a rather weak assumption that, if rejected, seems to make our "doing of science" rather difficult. The assumption needed is that the probability distribution of the hidden variables does not depend on the measurement settings: $\rho(\lambda|a,b)=\rho(\lambda)$ (conditioning doesn't matter). We make use of assumptions like this quite often when doing science. For example, when assuming we can create randomized control studies.

When we set up any experiment, we have to control for irrelevant variables. Variables that we think will only add noise to our experimental results. This procedure becomes dubious in super determinism since in principle you need to know literally everything in the past light cone of the measurement event.

 

[PeterDonis]

in principle you need to know literally everything in the past light cone of the measurement event.

Not only that, but the things in the past light cone that you need to know could be events whose past light cones themselves do not overlap, i.e., there is no way for those events to themselves have any common cause in their own common past. Which means that for those events to be correlated, which they would have to be in order to make superdeterminism work, the initial conditions of potentially our entire observable universe would have had to be fine-tuned very precisely, in order to make it seem like our laws of physics are the laws of QM, when actually they are some completely different classical-style deterministic theory, that just happens to have precisely tuned initial conditions to mislead us so completely about what the laws actually are.

 

[Matterwave]

Not only that, but the things in the past light cone that you need to know could be events whose past light cones themselves do not overlap, i.e., there is no way for those events to themselves have any common cause in their own common past.

Inflation to the rescue?

Which means that for those events to be correlated, which they would have to be in order to make superdeterminism work, the initial conditions of potentially our entire observable universe would have had to be fine-tuned very precisely, in order to make it seem like our laws of physics are the laws of QM, when actually they are some completely different classical-style deterministic theory, that just happens to have precisely tuned initial conditions to mislead us so completely about what the laws actually are.

Yeah I agree that super determinism does seem somewhat (or quite) conspiratorial.

 

[FactChecker]

Interesting part is at 46:40 where he comment Bell theorem.

He believes that everything we do, in fact everything that happens anywhere, has been determined by the past.

Bell's Theorem is violated in tests that get random inputs (he would argue they are not random) from star systems many lightyears apart. I find it hard to believe that random sequences from opposite sides of the galaxy are correlated in a devious way. And I think that either source is a sequence without strong time correlations.
If that is his strongest argument, I am not convinced.

 

[javisot]

A coin is symmetric regarding heads/tails. How can a deterministic process in a symmetric setup create an asymmetric result?

No, no existing coin offers a 50%-50% split with infinite precision.

If you’re talking about a theoretical coin, then yes. But even then, you would have to flip the coin an infinite number of times to confirm that it landed on heads 50% of the time and on tails 50% of the time, in accordance with the law of large numbers.

 

[ohwilleke]

Even if QM were fundamentally deterministic, and I agree that there is experimental evidence suggesting that pre-collapse that the probabilistic description may be "real", it is necessarily at least "chaotic" in the mathematical sense that outcomes are sensitive to initial conditions so close to each other than we have no way to measure the differences between initial conditions large predict materially and measurably different outcomes.

Plenty of systems that we routinely model as stochastic (i.e. probabilistic) and random are ultimately deterministic at a level not directly influenced to a meaningful degree by quantum uncertainties: coin flips, drawing lots, rock-paper-scissors, statistical thermodynamics, weather in the medium term time horizon (several days to several weeks out), genetic mutations, the mixing of genes that happen in sexual reproduction, stock market behavior, epidemiology, etc.

So, there is nothing unusual about treating a system that is fundamentally deterministic as if it were stochastic for purposes of practical applications in a wide range of circumstances. Indeed, this reality probably (as used for this word in this sentence expressing lack of knowledge rather than a probabilistic process) has a lot to do with our psychological drive to find a deeper deterministic explanations, even when we have nothing by psychological inclinations to support the believe that QM has a deterministic basis.

Coming up with a deterministic model that accurately reproduces both pre-collapse experimental effects and entanglement effects (particularly transferred entanglement effects), probably isn't impossible, but it is very hard, at a minimum --> that is without allowing for either retro-causality, or non-local effects that have no mediator.

Retro-causality (i.e. that a cause can trace along a world line of particles that have contact interactions with each other both forward and backward in time) is probably the easiest sacrifice to make, IMHO, to reproduce entanglement phenomena in a deterministic but mathematically chaotic model of quantum mechanics, at least from a model building and conceptual perspective, without disturbing other important features of our QM models. But, it has been pretty powerfully demonstrated over the last century or so that you can't cling to all of the foundational assumptions applied to systems that are well described by classical mechanics if you want to have a model that reflects what the mathematics of QM produces in a way that is exquisitely accurate. You have to sacrifice locality or causality or "reality" (a somewhat technical term of art in this context) or determinism, or more of than one of them, if you are going to get a model that works.

This still leaves the measurement problem and how to shoehorn the observed differences between non-collapsing unmeasured systems and collapsing measured systems in a deterministic model.

I'm not aware of any very intuitively satisfying resolutions to that (i.e. to why physical things should act differently when they are measured than when they are not measured), which is why "shut up and calculate" has become kind of the default "QM interpretation", if you can call it that, even though it doesn't really express any opinion on an underlying mechanism that produces the mathematical behavior that QM tells us it should when we calculate it.

To some extent, "shut up and calculate" comes with the hidden agenda of trying to change your intuition about phenomena that are outside the non-instrumentally assisted observational experience of either us, or our evolutionary ancestors, that gave rise to our intuitions about how the universe ought to act in the first place. Calculate enough, and you'll develop an intuition about how systems where QM behavior matters behave without the "crutch" of having to associate it with one of the leading QM interpretations.

 

[Matterwave]

No, no existing coin offers a 50%-50% split with infinite precision.

If you’re talking about a theoretical coin, then yes. But even then, you would have to flip the coin an infinite number of times to confirm that it landed on heads 50% of the time and on tails 50% of the time, in accordance with the law of large numbers.

Although true, what is the point being made here? This seems to be pointing out an issue with the frequentist view of probability.

No Bell test has ever produced an infinite number of samples. No experiment has ever produced an infinite-sigma result.

 

[FactChecker]

My two cents:
The insistence that nothing is random is purely because we are not used to that in our macro-existance. But it implies that every decision we have ever made, from what pie you ate a year ago to which shoe to tie first on your birthday next year, was determined before our Grandparents were born.
Personally, I find that less acceptable than believing some subparticle behavior might be random.
Given the practical success of QM, it is a heavy lift to convince me otherwise.
IMO, this is a philosophical question.
To each his own.

 

[iste]

Otherwise, the microscopic equations themselves would be probabilistic (which they are not, the Schrodinger equation is deterministic), without a need to appeal to the vague notion of measurement to see where the randomness come from.

But random processes can also be described eith a deterministic time-evolution so I don't think the fact Schrodinger evolution is deterministic necessarily indicates anything.