I Is Free Will a Foundational Assumption in Quantum Theory?

  • #101
A. Neumaier said:
Do you really think that a child is not free in its decisions just because we can predict that it will say yes when it is asked whether it likes to have ice cream?

We we should distinguish between "free will" as a sensation of a conscious being along the lines of "I decide to... " versus the properties of the underlying physical processes that implement this sensation. Do the physical processes that implement the sensation of free will differ in some fundamental way from the physical processes that implement the weather or the behavior of insects?
 
Physics news on Phys.org
  • #102
For me, it would be a huge surprise if it is ever shown that biological systems, and concretely neural systems, follow laws independent of the laws of physics.

As far as I know, there is currently not a single hint that points in that direction.
 
  • #103
DarMM said:
I don't think so. Since one simply has a Boolean algebra of propositions the events can be considered to occur independent of the device, with the device simply recording them with some small disturbance to both. All observables "mesh" correctly to be considered random variables on one sample space of outcomes.

Do you have a reference for this?
A classical universe has no probability - everything is deterministic. It just has particles with time-dependent positions and momenta - no observers or detectors, unless these are introduced through a Heidelberg cut.
Only the latter introduces probability - quite in the spirit of Heisenberg.

I don't know a single paper dealing with the classical measurement problem - the question how a detector subsystem of a large classical chaotic system can acquire information about a disjoint subsystem to be measured.

This would be the classical analogy of the quantum measurement situation, and has a lot of the features of the latter.

A classical event would be something happening to the measured system that is approximated by something happening in the detector. This introduces probability in an otherwise deterministic classical universe.
 
Last edited:
  • #104
mattt said:
For me, it would be a huge surprise if it is ever shown that biological systems, and concretely neural systems, follow laws independent of the laws of physics.

As far as I know, there is currently not a single hint that points in that direction.
The Emperor's new Mind? Not sure, read it some 10 years back -- didnt even finish it iirc.
 
  • #105
A. Neumaier said:
A classical universe has no probability - everything is deterministic.

This can't be the case.

This would mean there's some mechanism that knows the Experimenter's choice prior to measurement and this would go against all of the evidence like the Free Will Theorem which states:

Given the axioms, if the two experimenters in question are free to make choices about what measurements to take, then the results of the measurements cannot be determined by anything previous to the experiments.

The Axioms are:

  1. Fin: There is a maximal speed for propagation of information (not necessarily the speed of light). This assumption rests upon causality.
  2. Spin: The squared spin component of certain elementary particles of spin one, taken in three orthogonal directions, will be a permutation of (1,1,0).
  3. Twin: It is possible to "entangle" two elementary particles and separate them by a significant distance, so that they have the same squared spin results if measured in parallel directions. This is a consequence of quantum entanglement, but full entanglement is not necessary for the twin axiom to hold (entanglement is sufficient but not necessary).
Free Will Theorem

There would have to be some hidden variable mechanism that would transmit information faster than light to quantum system being measured and that system would be determined by this hidden variable mechanism prior to measurement and that goes against everything that has been observed. Here's some experiments.

The Big Bell Test which closed the freedom of choice loophole.

Challenging local realism with human choices

A Bell test is a randomized trial that compares experimental observations against the philosophical worldview of local realism1, in which the properties of the physical world are independent of our observation of them and no signal travels faster than light. A Bell test requires spatially distributed entanglement, fast and high-efficiency detection and unpredictable measurement settings2,3. Although technology can satisfy the first two of these requirements4,5,6,7, the use of physical devices to choose settings in a Bell test involves making assumptions about the physics that one aims to test. Bell himself noted this weakness in using physical setting choices and argued that human ‘free will’ could be used rigorously to ensure unpredictability in Bell tests8. Here we report a set of local-realism tests using human choices, which avoids assumptions about predictability in physics. We recruited about 100,000 human participants to play an online video game that incentivizes fast, sustained input of unpredictable selections and illustrates Bell-test methodology9. The participants generated 97,347,490 binary choices, which were directed via a scalable web platform to 12 laboratories on five continents, where 13 experiments tested local realism using photons5,6, single atoms7, atomic ensembles10 and superconducting devices11. Over a 12-hour period on 30 November 2016, participants worldwide provided a sustained data flow of over 1,000 bits per second to the experiments, which used different human-generated data to choose each measurement setting. The observed correlations strongly contradict local realism and other realistic positions in bipartite and tripartite12 scenarios. Project outcomes include closing the ‘freedom-of-choice loophole’ (the possibility that the setting choices are influenced by ‘hidden variables’ to correlate with the particle properties13), the utilization of video-game methods14 for rapid collection of human-generated randomness, and the use of networking techniques for global participation in experimental science.

https://www.nature.com/articles/s41586-018-0085-3

Here's 2 more:

Experimental rejection of observer-independence in the quantum world

The scientific method relies on facts, established through repeated measurements and agreed upon universally, independently of who observed them. In quantum mechanics, the objectivity of observations is not so clear, most dramatically exposed in Eugene Wigner's eponymous thought experiment where two observers can experience fundamentally different realities. While observer-independence has long remained inaccessible to empirical investigation, recent no-go-theorems construct an extended Wigner's friend scenario with four entangled observers that allows us to put it to the test. In a state-of-the-art 6-photon experiment, we here realize this extended Wigner's friend scenario, experimentally violating the associated Bell-type inequality by 5 standard deviations. This result lends considerable strength to interpretations of quantum theory already set in an observer-dependent framework and demands for revision of those which are not.
https://arxiv.org/abs/1902.05080

Wheeler's delayed-choice gedanken experiment with a single atom

The wave–particle dual nature of light and matter and the fact that the choice of measurement determines which one of these two seemingly incompatible behaviours we observe are examples of the counterintuitive features of quantum mechanics. They are illustrated by Wheeler’s famous ‘delayed-choice’ experiment1, recently demonstrated in a single-photon experiment2. Here, we use a single ultracold metastable helium atom in a Mach–Zehnder interferometer to create an atomic analogue of Wheeler’s original proposal. Our experiment confirms Bohr’s view that it does not make sense to ascribe the wave or particle behaviour to a massive particle before the measurement takes place1. This result is encouraging for current work towards entanglement and Bell’s theorem tests in macroscopic systems of massive particles.

https://arxiv.org/abs/1902.05080

So everything can't be deterministic. The freedom of choice of the Experimenter has to be totally free unless there's some faster than light hidden variable that determines the outcomes of quantum systems prior to a measurement occurring.
 
  • #106
Quantum Alchemy said:
This can't be the case.

Note that @A. Neumaier said a classical universe. The Spin and Twin axioms of the Free Will Theorem would not hold in a classical universe; they are quantum assumptions.
 
  • #107
PeterDonis said:
Note that @A. Neumaier said a classical universe. The Spin and Twin axioms of the Free Will Theorem would not hold in a classical universe; they are quantum assumptions.

Yes they would hold and this is stated by Kochen and Conway in their lectures. This has to be the case or there would need to be some mechanism that transmits information faster than light and that determines the Experimenters choice. Here's an example:

Say you have an entangled particle pair and one particle goes to Alice in lab A and the other particle goes to Bob in lab B. There's not any information in the brain or anywhere else that can determine the choices between Alice and Bob.

They can get together and say Alice will carry out her measurement before Bob or Vice Versa. They can also say a random number generator will determine who will carry out there measurement first. If it's a 1 then Alice will carry out her measurement at 1 and Bob at 1:01. If the RNG is an 0, then Bob will carry out his measurement at 1.

The Big Bell Test which I listed earlier shows that these would have to be free choices carried out by Bob and Alice. It says this at the end of the Abstract.

Project outcomes include closing the ‘freedom-of-choice loophole’ (the possibility that the setting choices are influenced by ‘hidden variables’ to correlate with the particle properties13), the utilization of video-game methods14 for rapid collection of human-generated randomness, and the use of networking techniques for global participation in experimental science.

As far as I'm concerned, Determinism isn't Scientific, it's a Philosophy. There's no evidence of any mechanism in the brain or any mechanism anywhere that can determine the choice of the Experimenter prior to carrying out a measurement.
 
  • #108
Quantum Alchemy said:
Yes they would hold and this is stated by Kochen and Conway in their lectures.

Where do they say the Spin and Twin axioms hold in classical physics? Please give a specific paper, section, and page number.

Quantum Alchemy said:
Here's an example

You don't need to explain how EPR experiments work; we all know that. You need to back up your claim about the Spin and Twin axioms holding in classical physics.
 
  • #109
The physics we know today today is too rudimentary to derive anything of significance for this topic. Hyerarchy and emergence of new features(top down causation) play a big role in how quantum superpositions can manifest as atoms, molecules, chemicals, materials, biological systems, conscious entities able to process information, social phenomenons and self awareness. Other planets may be more simple but this one is home to molecules as big as 200 billion atoms. And complexity comes with new useful features. Somehow this universe is too survivable to be an accident. Due to parsimony one would hardly expect such an extraordinary myriad of new properties that can combine and lead to such a long chain of hyerarchial structures and ultimately conscious thought and free will, but probably 1 or 2 different mundane basic ingredients. Why is this possible? https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3262299/
 
  • #110
PeterDonis said:
Where do they say the Spin and Twin axioms hold in classical physics? Please give a specific paper, section, and page number.

Here you go:

These are excerpts from the paper The Strong Free Will Theorem by Kochen and Conway that refute Determinism.

The TWIN Axiom: For twinned spin 1 particles, suppose experimenter A performs a triple experiment of measuring the squared spin component of particle a in three orthogonal directions x, y, z, while experimenter B measures the twinned particle b in one direction, w. Then if w happens to be in the same direction as one of x, y, z, experimenter B’s measurement will necessarily yield the same answer as the corresponding measurement by A.

The MIN Axiom: Assume that the experiments performed by A and B are space-like separated. Then experimenter B can freely choose anyone of the 33 particular directions w, and a’s response is independent of this choice. Similarly and independently, A can freely choose anyone of the 40 triples x, y, z, and b’s response is independent of that choice. 4 It is the experimenters’ free will that allows the free and independent choices of x, y, z and w. But in one inertial frame – call it the “A-first” frame – B’s experiment will only happen some time later than A’s, and so a’s response cannot, by temporal causality, be affected by B’s later choice of w. In a B-first frame, the situation is reversed, justifying the final part of MIN. (We shall discuss the meaning of the term “independent” more fully in the Appendix.)

Here's the coup de grace:

Some readers may object to our use of the term “free will” to describe the indeterminism of particle responses. Our provocative ascription of free will to elementary particles is deliberate, since our theorem asserts that if experimenters have a certain freedom, then particles have exactly the same kind of freedom. Indeed, it is natural to suppose that this latter freedom is the ultimate explanation of our own.

The tension between human free will and physical determinism has a long history. Long ago, Lucretius made his otherwise deterministic particles “swerve” unpredictably to allow for free will. It was largely the great success of deterministic classical physics that led to the adoption of determinism by so many philosophers and scientists, particularly those in fields remote from current physics. (This remark also applies to “compatibalism,” a now 8 unnecessary attempt to allow for human free will in a deterministic world.)

Although, as we show in [1], determinism may formally be shown to be consistent, there is no longer any evidence that supports it, in view of the fact that classical physics has been superseded by quantum mechanics, a non-deterministic theory. The import of the free will theorem is that it is not only current quantum theory, but the world itself that is nondeterministic, so that no future theory can return us to a clockwork universe.


https://arxiv.org/pdf/0807.3286.pdf

I also listed other experiments that support what I'm saying including the Big Bell Test. There's no evidence to support determinism. It's not scientific in any way as shown by Conway and Kochen in the Strong Free Will Theorem.
 
  • #111
Quantum Alchemy said:
These are excerpts from the paper The Strong Free Will Theorem by Kochen and Conway that refute Determinism.

There is currently nothing that can refute Determinism, given that our best Physics Theories of today, admit deterministic interpretations.

...classical physics has been superseded by quantum mechanics, a non-deterministic theory. The import of the free will theorem is that it is not only current quantum theory, but the world itself that is nondeterministic...


That is not correct. Quantum Mechanics admits several deterministic interpretations. Quantum field Theory too.
 
Last edited:
  • Like
Likes Delta2
  • #112
By the way, I have never felt that I have free will in the sense that other people say they feel they have free will. I can try to formulate an a posteriori explanation of my thoughts and my feelings, but they are only guesses, because we don't have access to the exact neural processes that give rise to thoughts and feelings arising in consciousness.
 
  • #113
mattt said:
There is currently nothing that can refute Determinism, given that our best Physics Theories of today, admit deterministic interpretations.
That is not correct. Quantum Mechanics admits several deterministic interpretations. Quantum field Theory too.

This isn't the case. There's nothing that reduces probabilities to 1 outside of a measurement. QM is inherently in-deterministic.

When you look at QFT, the standard formulation is in terms of the S-Matrix. So when you apply the S Matrix to the state you can only ask questions like what's the probability that this vector describes...

So the probability distribution or the outcomes that can occur are deterministic but the outcomes that do occur are not.

This would be like saying, the outcomes for a pair of dice are deterministic. You can only roll a 2-12 no matter how many times you roll the dice. Each roll is random and we can only talk about the outcomes of each roll in terms of probability. For instance, you're likely to see a 7 more than a 2 as you keep rolling the dice because there's more ways for a 7 to be rolled.

There's nothing in QFT or any formulation of QM that reduces the probabilities that can occur to 1. So either it's 2 outcomes or maybe 10^500 but never just 1. This is the inherent in-determinism you can't avoid in QM. This is based on things like the Strong Free Will Theorem, the Big Bell Test and more. I've listed experiments to support what I'm saying and I haven't seen anything that refutes it.

Again, you can only get a probability distribution. So 52 cards are deterministic. 2-12 on a dice are deterministic. There's 2,598,960 poker hands that can occur and that's deterministic. Knowing this, we can calculate what probabilities can occur with certainty. We can't calculate who will get dealt what hands in a poker game or what number you will roll in a dice game no more than we can calculate if you're going to measure spin up or spin down.

So it's inherently in-deterministic and you can never reduce the outcomes to 1.
 
  • Like
Likes Lord Jestocost
  • #114
Quantum Alchemy said:
This isn't the case. There's nothing that reduces probabilities to 1 outside of a measurement. QM is inherently in-deterministic.

When you look at QFT, the standard formulation is in terms of the S-Matrix. So when you apply the S Matrix to the state you can only ask questions like what's the probability that this vector describes...

So the probability distribution or the outcomes that can occur are deterministic but the outcomes that do occur are not.

This would be like saying, the outcomes for a pair of dice are deterministic. You can only roll a 2-12 no matter how many times you roll the dice. Each roll is random and we can only talk about the outcomes of each roll in terms of probability. For instance, you're likely to see a 7 more than a 2 as you keep rolling the dice because there's more ways for a 7 to be rolled.

There's nothing in QFT or any formulation of QM that reduces the probabilities that can occur to 1. So either it's 2 outcomes or maybe 10^500 but never just 1. This is the inherent in-determinism you can't avoid in QM. This is based on things like the Strong Free Will Theorem, the Big Bell Test and more. I've listed experiments to support what I'm saying and I haven't seen anything that refutes it.

Again, you can only get a probability distribution. So 52 cards are deterministic. 2-12 on a dice are deterministic. There's 2,598,960 poker hands that can occur and that's deterministic. Knowing this, we can calculate what probabilities can occur with certainty. We can't calculate who will get dealt what hands in a poker game or what number you will roll in a dice game no more than we can calculate if you're going to measure spin up or spin down.

So it's inherently in-deterministic and you can never reduce the outcomes to 1.

What is deterministic or not, is the model we use, and Quantum field Theory, as a model of reality (the best one we have currently), in the Thermal Interpretation (for example), is completely deterministic.
 
  • Like
Likes PeroK
  • #115
But is emergent determinism the same as the determinism observed on the macro scale? Without making unwarranted assumptions, the micro world is fundamentally interministic and non realistic. All these so called interpretations rely on assumptions that fail in experiments(see the Wigner's friend experiment from March 2019). Einstein was a proponent of this line of reasoning and was forced to concede defeat.
 
  • #116
EPR said:
Without making unwarranted assumptions, the micro world is fundamentally interministic

That's not correct. We have both deterministic and non-deterministic equally valid models of fundamental physics.

EPR said:
.All these so called interpretations rely on assumptions that fail in experiments

No experiment can favor one interpretation over another (if they are actually interpretations).
 
  • Like
Likes AndreasC
  • #117
mattt said:
That's not correct. We have both deterministic and non-deterministic equally valid models of fundamental physics.
Are the deterministic interpretations known to fully work with QFT? Genuine question. My understanding was that Bohmian Mechanics hasn't been successfully generalized, due to the Reeh-Schlieder theorem there are issues with understanding MWI branching and the Thermal Interpretation relies on certain as of yet unproven conjectures.
 
  • #118
A. Neumaier said:
This would be the classical analogy of the quantum measurement situation, and has a lot of the features of the latter.

A classical event would be something happening to the measured system that is approximated by something happening in the detector. This introduces probability in an otherwise determinstic classical universe.
That's the point though. In the classical case we can consider the imprint in the device as some kind of approximation of an event that occurred in the system. This is because all random variables in the classical case can be considered as functions on a space of outcomes. Thus we have some notion of the events of microsystem when no external system is present to register them.

In quantum theory viewed as a probability theory, due to the non-Boolean structure, we do not. Some device must be present to define the outcome space. The external system is a crucial aspect of defining the events unlike in the classical case where we can consider there to be events independent of the external system, with the external system simply recording them with some hopefully small error.

A recent paper by Janas, Cuffaro, Janssen (https://arxiv.org/abs/1910.10688) puts it well:
Quantum mechanics is about probabilities. The kinematical framework of the theory is probabilistic in the sense that the state specification of a given system yields, in general, only the probability that a selected observable will take on a particular value when we query the system concerning it. Quantum mechanics’ kinematical framework is also non-Boolean: The Boolean algebras corresponding to the individual observables associated with a given system cannot be embedded into a global Boolean algebra comprising them all, and thus the values of these observables cannot (at least not straightforwardly) be taken to represent the properties possessed by that system in advance of their determination through measurement. It is in this latter—non-Boolean—aspect of the probabilistic quantum-kinematical framework that its departure from classicality can most essentially be located.
The profound problem of measurement stems, rather, from the fact that of the many classical probability distributions that are implicit in the quantum state description, the one that emerges in a given scenario is always conditional upon the choice that we make from among the many possible measurements performable on the system. In other words it is the—in part physical and in large part philosophical—problem to account for the fact that, owing to the nature of the non-Boolean kinematical structure of quantum mechanics, only some of the classical possibility distributions implicit in the quantum state are actualized in the context of a given measurement, and moreover which of them are actualized is always conditional upon that measurement context.
Given a particular measurement context, quantum mechanics provides us with all of the resources we need in order to account for the dynamics of the measurement interaction between the system of interest and measurement device, and through this account we explain why a particular classical probability distribution is applicable given that measurement context, despite the non-classical nature of the quantum state description. Quantum mechanics does not tell you, however, which of the many possible measurements on a system you should apply in a given case. From the point of view of the theory the choices you make or do not make are up to you.
So quantum theory provides a stochastic description of a system-external system interaction when supplied with a choice of external system, but it is intrinsically incapable of modelling that choice of external system. Moreover this is a feature of any non-Kolmogorovian probability theory.
 
  • Like
Likes mattt
  • #119
DarMM said:
Are the deterministic interpretations known to fully work with QFT? Genuine question. My understanding was that Bohmian Mechanics hasn't been successfully generalized, due to the Reeh-Schlieder theorem there are issues with understanding MWI branching and the Thermal Interpretation relies on certain as of yet unproven conjectures.
The standard source for Bohmian bosonic field theory

Bohm.D., Hiley, B.J., Kaloyerou, P.N. (1987). An ontological basis for the quantum theory, Phys. Reports 144(6), 321-375

For bosons, it considers mainly the scalar field, but this is the key. For the gauge fields, I would simply reuse the scheme for scalar fields and throw away gauge symmetry as unimportant. It is necessary for renormalizability? So what, anyway I have to care only about effective field theory, and what remains on large distances from a general vector field are the renormalizable parts, thus, the gauge-invariant parts. So, this seems nothing one would have to care about if one defines the theory resp. its Bohmian version.

For fermions, the Dürr group favors the particle ontology.

I would prefer to use a construction that gives fermions out of bosonic fields. To such a construction you can, then, apply the scheme above.

I know one such construction, given in arxiv:0908.0591. It starts with a scalar field with a degenerated vacuum regularized on a 3D lattice. This gives for low energies a ##\mathbb{Z}_2## valued field together with a much more massive scalar field. The ##\mathbb{Z}_2## valued field has in each point already a fermionic character, but the operators for different of different points do not commute. But to transform this into a fermionic operator algebra is also quite standard, all one needs is to define some order. Some quite strange order is constructed on the lattice, and the resulting lattice equations become, via a doubling effect, in the large distance limit the equations of two Dirac fermions.
 
  • #120
mattt said:
That's not correct. We have both deterministic and non-deterministic equally valid models of fundamental physics.
No experiment can favor one interpretation over another (if they are actually interpretations).
These local hidden variable theories aka determinism have gone out of favour since the ever growing efficency of the experimental setups has eliminated more than 99% of loopholes of Bell tests(if memory serves me right). All in favour of quantum mechanics in its orthodox form. With non-local deterministic models, it's impossible to do physics as results start to precede causes. Not many proponents of this line of reasoning.
 
  • #121
EPR said:
These local hidden variable theories aka determinism have gone out of favour since the ever growing efficency of the experimental setups has eliminated more than 99% of loopholes of Bell tests ...
So what if there are deterministic interpretations that violate Einstein causality (named "nonlocal" even if they are local but with higher maximal speed of information transfer)?
 
  • #122
Elias1960 said:
So what if there are deterministic interpretations that violate Einstein causality (named "nonlocal" even if they are local but with higher maximal speed of information transfer)?

This is specultaive. Relativity already showed that there is no observer independent object length or mass, distance, time, etc. so the concept of immaliable space is weakened if not downright eliminated. I don't think it makes sense to treat space as something fundamental - there are good indications that it is not. It’s very likely not a deep feature of reality.
Why are there nonlocal correleations in 4D spacetime?
 
Last edited:
  • #123
'Einstein never got very far. Even today there are almost as many contending ideas for a quantum theory of gravity as scientists working on the topic. The disputes obscure an important truth: the competing approaches all say space is derived from something deeper—an idea that breaks with 2,500 years of scientific and philosophical understanding.'

https://www.scientificamerican.com/article/what-is-spacetime/
 
  • #124
I think Free Will only exists in a closed environment where no other factors can be introduced. Otherwise you are subject to outside influences. But life just isn't like that. In the game of Othello the black disk will remain black unless someone or something flips one and then all in it's path will flip at same time. Leaving no free will. There are so many outside factors that it makes it hard to imagine Free Will realistically. We are all pushed along and carried with the flow of everyday life. If you were to stop life would continue washing over you like waves. I suppose life is deffinately a force to be reckoned with for indeed time waits for no man. I suppose this is why Jesus claimed that some seed would fall between the cracks or be eaten by birds or burned by the sun while others would flourish in rich fertile soil.
 
  • #125
EPR said:
This is specultaive. Relativity already showed that there is no observer independent object length or mass, distance, time, etc. so the concept of immaliable space is weakened if not downright eliminated. I don't think it makes sense to treat space as something fundamental - there are good indications that it is not.
This is also speculative. There is the straightforward, initial interpretation of relativity, where the ether distorts clocks and rulers and in this way prevents the measurement of absolute time and absolute distances, but they nonetheless exist. This interpretation can be extended to gravity too, with harmonic coordinates as the straightforward candidates for the Cartesian coordinates of the background and absolute time. Nothing in quantum theory suggests that this would have to be abandoned for the quantization of gravity.
EPR said:
The disputes obscure an important truth: the competing approaches all say space is derived from something deeper—an idea that breaks with 2,500 years of scientific and philosophical understanding.'
And it does it without any serious justification, simply based on GR metaphysics (not physics) being fashionable.

To justify proposals to reject such old common sense notions like the existence of space and time, one needs a serious justification. Extraordinary claims require extraordinary evidence. This extraordinary evidence would have to contain something close to impossibility theorems for theories with classical space and time. At least there should be quite obvious serious problems for any theory with classical space and time, with no plausible chance to solve them. This is certainly not the actual situation. Such theories exist, have been published, they follow a straightforward path known already by Lorentz. Simply not liking them because a curved spacetime is sort of more fascinating is not enough, but nothing better has been proposed yet against them.
 
Last edited:
  • #126
Demystifier said:
In the Bell theorem, the "free will" assumption is really the assumption that there is no correlation between the choices of which observable will be measured on different subsystems. So yes, it is an assumption of the Bell theorem, but it is not directly related to the usual psychological notion of free will.
Just another question on this point, to see if I can understand it better.

Would the choices of which observable to be measured require a common cause in order to be considered correlated? Is that the position essentially what superdeterminism implies/requires?
 
  • #127
Lynch101 said:
Would the choices of which observable to be measured require a common cause in order to be considered correlated? Is that the position essentially what superdeterminism implies/requires?
No, in superdeterminism correlations do not need any explanation at all. Which makes it so attractive for the tobacco industry. I would guess their lobbyists have never heard about it, else they would use the fact that "in modern physics, superdeterminism is considered and discussed as a serious possibility", with reference to this thread, to show that the correlation between smoking and lung cancer proves nothing, and that all those who require some common cause explanation are simply retrogrades, comparable to ether freaks, who are unable to grasp modern physics.
 
  • Like
Likes PeroK
  • #128
Quantum Alchemy said:
These are excerpts from the paper The Strong Free Will Theorem by Kochen and Conway that refute Determinism

None of this supports your claim that the axioms hold in classical physics. The whole context of all those papers is quantum physics.

Quantum Alchemy said:
There's no evidence to support determinism.

Which is irrelevant to the point I am making, that since we know our actual universe is quantum, not classical, the fact that determinism does not appear to hold in our actual universe (assuming that is true) does not in any way mean that classical physics is not deterministic. So your response to @A. Neumaier was wrong, as I said.
 
  • Like
Likes bhobba
  • #129
Demystifier said:
Just had a quick read of that paper Demystifier. My understanding of it is probably gone awry somwhere but the following lines jumped out at me:

Closed timelike curves said:
“free will” (FW) – the ability of experimentalists to make free choices of initial conditions – is merely an illusion. As a consequence, by entangling a part of brain (responsible for the illusion of FW)
...
one should be aware that the assumption of FW plays an important role in the derivation of the Bell theorem
...
Some implications of this assumption in QM have been discussed in [1, 2] (see also [3, 4, 5] for critiques)

I scanned the referenced papers 3 & 4 and have read read through #5. It sounds to me like all of them except #5 advocate for the common sense notion of Free Will and pretty explicitly state that it is a fundamental axiom of Bell's theorem. The only paper that appears to argue for an alternative interpretation of "Free Will" in the manner you mentioned in post #2 is paper #5 ON THE FREE-WILL POSTULATE IN QUANTUM MECHANICS by Gerard 't Hooft who is the foremost proponent of Superdeterminism.

In that paper 't Hoofty outlines the role of "Free Will" in Bell's theorem. Is this an accurate characterisation?
t Hooft said:
A class of very important questions arose when John Bell formulated his famous inequalities[1]. Indeed, when one attempts to construct models that visualize what might be going on in a quantum mechanical process, one finds that deterministic interpretations usually lead to predictions that would obey his inequalities, while it is well understood that quantum mechanical predictions violate them. In attempts to get into grips with this situation, and to derive its consequences for deterministic theories, the concept of “free will” was introduced. Basically, it assumes that any ‘observer’ has the freedom, at all times and all places, to choose, at will, what variables to observe and measure. Clashes with Bell’s inequalities arise as soon as the observer is allowed to choose between sets of observables that are mutually non commuting.
 
  • #130
Quantum Alchemy said:
Again, you can only get a probability distribution. So 52 cards are deterministic. 2-12 on a dice are deterministic. We can't calculate ... what number you will roll in a dice game...

So it's inherently in-deterministic and you can never reduce the outcomes to 1.
Apologies, this will probably seem like an incredibly basic question, but would it not be possible to predict what number you will roll in a dice game if you knew nearly all of the material information. If you were watching an impossibly high definition video and slowed it right down so that you could see the force that the die was being thrown, the angle it leaves the hand, the trajectory, couples with the relevant information about the air, the firmness of the table, etc. etc. If all of this was known, wouldn't it be possible to predict the roll of a die?

Apologies if it is somewhat off-topic and basic.
 
  • #131
Elias1960 said:
No, in superdeterminism correlations do not need any explanation at all. Which makes it so attractive for the tobacco industry. I would guess their lobbyists have never heard about it, else they would use the fact that "in modern physics, superdeterminism is considered and discussed as a serious possibility", with reference to this thread, to show that the correlation between smoking and lung cancer proves nothing, and that all those who require some common cause explanation are simply retrogrades, comparable to ether freaks, who are unable to grasp modern physics.
If the choices of which observable to be measured had a common cause would they be correlated?
 
  • #132
Lynch101 said:
would it not be possible to predict what number you will roll in a dice game if you knew nearly all of the material information

It would depend on how sensitive the result of the roll was to the exact initial conditions, and how accurately you could measure those initial conditions.
 
  • Like
Likes bhobba and Lynch101
  • #133
Quantum Alchemy said:
you can only get a probability distribution. So 52 cards are deterministic. 2-12 on a dice are deterministic. There's 2,598,960 poker hands that can occur and that's deterministic. Knowing this, we can calculate what probabilities can occur with certainty. We can't calculate who will get dealt what hands in a poker game or what number you will roll in a dice game no more than we can calculate if you're going to measure spin up or spin down.

These claims about macroscopic processes like shuffling cards, rolling dice, etc., are not necessarily true, because it's highly likely that quantum indeterminacy does not play any role in the outcome, unlike the case of, say, a Stern-Gerlach measurement of a particle's spin. It's entirely possible that, for example, the process of die rolling is insensitive enough to its exact initial conditions that an accurate enough measurement of those initial conditions could allow us to predict the result.
 
  • Like
Likes bhobba
  • #134
Elias1960 said:
This is also speculative. There is the straightforward, initial interpretation of relativity, where the ether distorts clocks and rulers and in this way prevents the measurement of absolute time and absolute distances, but they nonetheless exist. This interpretation can be extended to gravity too, with harmonic coordinates as the straightforward candidates for the Cartesian coordinates of the background and absolute time. Nothing in quantum theory suggests that this would have to be abandoned for the quantization of gravity.

And it does it without any serious justification, simply based on GR metaphysics (not physics) being fashionable.

To justify proposals to reject such old common sense notions like the existence of space and time, one needs a serious justification. Extraordinary claims require extraordinary evidence. This extraordinary evidence would have to contain something close to impossibility theorems for theories with classical space and time. At least there should be quite obvious serious problems for any theory with classical space and time, with no plausible chance to solve them. This is certainly not the actual situation. Such theories exist, have been published, they follow a straightforward path known already by Lorentz. Simply not liking them because a curved spacetime is sort of more fascinating is not enough, but nothing better has been proposed yet against them.
The aether theory was discredited decades ago by experiment. Science is not bound by pedestrian common sense. The world would appear flat, and some still contend that it is, based on common sense.

None of the mainstream approaches to quantum gravity are treating space as fundamental.
 
Last edited:
  • #135
It was not "the ether", but a large group of particular ether theories, which have been empirically falsified by various experiments. The Lorentz ether, which is essentially nothing but a name for SR with a preferred frame, was, together with SR in the spacetime interpretation, not among them.

The Einstein equations of GR also allow for a generalization of the Lorentz ether to gravity, with harmonic coordinates defining the preferred coordinates. So, the generalization to relativistic gravity is also unproblematic, and gives a theory with some minor differences (not allowing wormholes and causal loops) but otherwise indistinguishable from GR. Feel free to provide here the evidence against this interpretation of the GR equations.

Then, I have in no way suggested that science should be bound by common sense. But if something is in conflict with common sense, this is an extraordinary claim, thus, requires extraordinary evidence. This evidence was provided against flat Earth theory.

Moreover, it is not fair against common sense to claim that flat Earth theory is required by common sense. Spherical Earth is easy enough given what we see about Sun, moon, and planets that it was sufficient for the Ancient Greeks to find it.
 
  • #136
Elias1960 said:
The Einstein equations of GR also allow for a generalization of the Lorentz ether to gravity, with harmonic coordinates defining the preferred coordinates.

Can you give a reference for this theory?
 
  • #137
PeterDonis said:
Can you give a reference for this theory?
arxiv:gr-qc/0205035

What I reference here as the interpretation of the Einstein equations would be the limit ##\Xi,\Upsilon \to 0## of the equations of that theory.
 
  • #138
Lynch101 said:
Is the freedom of the mind the fundamental assumption in QM then and in what sense would you say that "the mind" is free?

No its not. The entire mathematical machinery of QM is also needed and how you derive that from free will beats me. Even defining free will - well philosophers haven't solved that one. I know the history of how it entered discussions about QM and its now generally accepted it was a mistake by the great Von-Neumann - not the only one he made in QM either.

Thanks
Bill
 
  • Like
Likes Lynch101
  • #139
PeterDonis said:
Can you give a reference for this theory?

It's GLET developed by Ilja Schmelzer who occasionally posts here:
https://ilja-schmelzer.de/gravity/
Its been around for a while but hasn't really taken off in any way. That doesn't make it wrong of course - but its definitely a backwater. Yes its limit is LET, but that does not change the fact the aether is superfluous in SR - SR follows from basic symmetries of inertial frames and the POR. LET was not proven wrong - simply superseded by something simpler in its assumptions, with those assumptions having direct experimental support, which the aether does not.

Thanks
Bill
 
Last edited:
  • Like
Likes weirdoguy
  • #140
Quantum Alchemy said:
This would mean there's some mechanism that knows the Experimenter's choice

That is a logical absurdity. Determinism and choice are mutually contradictory. Determinism means initial conditions determine everything - the concept of choice does not exist. What we do know is chaos does exist so in practical terms it is impossible to predict everything even if the world is deterministic. We can never know initial conditions with exact accuracy and those inaccuracies grow to the point all we can predict is probabilities just like if it was probabilistic in the first place.

I still have zero idea how to even define free will. It looks like one of those concepts such as reality we have an intuitive idea of, but pinning down exactly has not been possible.

The free will theorem is based on assumptions of dubious validity - eg 'There is a maximal speed for propagation of information (not necessarily the speed of light). This assumption rests upon causality.' It does not rest on causality eg Newtonian gravity is a deterministic theory that is causal yet the speed of propagation is infinite. Move an object and all other objects are affected instantaneously. But even more basic is although called the free will theorem, it does not depend on any assumption of free will as generally intuitively understood, or directly support any conclusion about free will.

To be blunt in my view the theorem is simply semantics about a not generally accepted definition of what free will is proving something absurd - electrons having free will. All that shows is the concept of free will used in the theorem is not a reasonable way to look at it.

Thanks
Bill
 
Last edited:
  • Like
Likes Lord Jestocost
  • #141
DarMM said:
That's the point though. In the classical case we can consider the imprint in the device as some kind of approximation of an event that occurred in the system. This is because all random variables in the classical case can be considered as functions on a space of outcomes. Thus we have some notion of the events of microsystem when no external system is present to register them.
Not really. We have measurement results (aka events) only after we specify what in the classical universe is the measurement device and how it is supposed to measure which system of interest. This is external to the Laplacian description of the universe by positions and momenta. Thus measurement theory in a classical universe needs as much externals (i.e., the Heisenberg cut) as measurement theory in a quantum universe.
The properties of the underlying probability theory are secondary to that.

DarMM said:
So quantum theory provides a stochastic description of a system-external system interaction when supplied with a choice of external system, but it is intrinsically incapable of modelling that choice of external system. Moreover this is a feature of any non-Kolmogorovian probability theory.
This statement is interpretation dependent. For example, it does not hold in the thermal interpretation, where modeling both system and external system is done inside the quantum universe.
 
Last edited:
  • #142
A. Neumaier said:
Not really. We have measurement results (aka events) only after we specify what in the classical universe is the measurement device and how it is supposed to measure which system of interest. This is external to the Lapalcian description of the universe by positions and momenta. Thus measurement theory in a classical universe needs as much externals (i.e., the Heisenberg cut) as measurement theory in a quantum universe.
The properties of the underlying probability theory are secondary to that.
Do you have a reference for this?

Yes defining the measured system and measuring system split is required for a measurement theory. However since all properties of the measured system have a single Boolean algebra the device events can be seen to be approximate recordings of events occurring in the system alone. In Quantum Theory there are no events for the system alone, you can't consider the measurement result to be an approximation of some property, even a randomly driven one, in the system alone. The idea that the underlying probability theory is irrelevant seems hard to support to me in this case. It's the underlying probability theory that drives results like contextuality that utterly change the notion of measurement for most authors.

A. Neumaier said:
This statement is interpretation dependent. For example, it does not hold in the thermal interpretation, where modeling both system and external system is done inside the quantum universe.
Yes of course, I indicated this initially that I was speaking of QM viewed as a probability theory not the quantum state viewed as a real wave or some such representational view.
 
  • #143
DarMM said:
Do you have a reference for this?
No. But this needs no reference as it is obvious. Indeed classical multiparticle dynamics is chaotic but deterministic, and has no intrinsic notion of one part measuring another. So something must be added from the outside to talk about any of probability or measurement.
DarMM said:
Yes defining the measured system and measuring system split is required for a measurement theory. However since all properties of the measured system have a single Boolean algebra the device events can be seen to be approximate recordings of events occurring in the system alone.
Not in a classical universe. Nothing about the measured system can be considered to be recorded even approximately unless you specify what recording a property of the measured system means in terms of the measuring system. You still need to specify an outcome space, but even what is an outcome - neither exists in the Laplacian universe by itself.
DarMM said:
I was speaking of QM viewed as a probability theory not the quantum state viewed as a real wave or some such representational view.
QM is not primarily a probability theory but a dynamical theory of Nature. Reducing it to noncommutative probability theory (a mathematical discipline) means abstracting from the real content, eliminating all physics. It is analogous to reducing classical mechanics to Kolmogorov probability theory. In both cases, little is left of the substance.
 
  • #144
Lynch101 said:
Apologies, this will probably seem like an incredibly basic question, but would it not be possible to predict what number you will roll in a dice game if you knew nearly all of the material information. If you were watching an impossibly high definition video and slowed it right down so that you could see the force that the die was being thrown, the angle it leaves the hand, the trajectory, couples with the relevant information about the air, the firmness of the table, etc. etc. If all of this was known, wouldn't it be possible to predict the roll of a die?

Apologies if it is somewhat off-topic and basic.
The difficulty is not to "predict" the role of the die after it's been thrown, but before it's been thrown!
 
  • #145
PeterDonis said:
These claims about macroscopic processes like shuffling cards, rolling dice, etc., are not necessarily true, because it's highly likely that quantum indeterminacy does not play any role in the outcome, unlike the case of, say, a Stern-Gerlach measurement of a particle's spin. It's entirely possible that, for example, the process of die rolling is insensitive enough to its exact initial conditions that an accurate enough measurement of those initial conditions could allow us to predict the result.
It depends what you mean by initial conditions. You might claim to be able to predict whether a penalty in a soccer match is scored or not. But, if you wait to see which way the ball is kicked and which way the goalkeeper is moving, I don't consider that removes the fundamental uncertainty.
 
  • #146
Lynch101 said:
If the choices of which observable to be measured had a common cause would they be correlated?
Not necessarily. For example, you could generate a sequence from the digits of ππ and another sequence from the digits of ee.
These two sequences of digits would be uncorrelated, even though they are completely determined in advance.

PS for further insight into the difference between indeterminacy and randomness look up the definition of "normal number".
 
  • #147
A. Neumaier said:
No. But this needs no reference as it is obvious.
...
QM is not primarily a probability theory but a dynamical theory of Nature. Reducing it to noncommutative probability theory
The point here isn't to say that QM is nothing but noncommutative probability theory, obviously there is much more to it than that. However it is the non-Boolean nature of the underlying probability that changes the notion of measurement in the theory, by introducing issues like contextuality. I do not consider it "obvious" that these seismic shifts in the ability to perform property assignment due to the non-Boolean structure cause no difference in the notion of measurement.

A. Neumaier said:
Nothing about the measured system can be considered to be recorded even approximately unless you specify what recording a property of the measured system means in terms of the measuring system. You still need to specify an outcome space, but even what is an outcome - neither exists in the Laplacian universe by itself.
Again this goes against most of what I've read where by in a classical theory one can consider there to be events in the absence of devices and measuring systems.
 
  • #148
bhobba said:
Even defining free will - well philosophers haven't solved that one.

Exactly. Nevertheless, regarding the "freedom of choice", there is an interesting point of view.

Hans Primas in „Hidden Determinism, Probability, and Time’s Arrow“ (Section 10 Experimental Science Requires Freedom of Action):

"At present the problem of how free will relates to physics seems to be intractable since no known physical theory deals with consciousness or free will. Fortunately, the topic at issue here is a much simpler one. It is neither our experience of personal freedom, nor the question whether the idea of freedom could be an illusion, nor whether we are responsible for our actions. The topic here is that the framework of experimental science requires a freedom of action in the material world as a constitutive presupposition. In this way “freedom” refers to actions in a material domain which are not governed by deterministic first principles of physics.

To get a clearer idea of what is essential in this argument we recall that the most consequential accomplishment by Isaac Newton was his insight that the laws of nature have to be separated from initial conditions. The initial conditions are not accounted for by first principles of physics, they are assumed to be “given”. In experimental physics it is always taken for granted that the experimenter has the freedom to choose these initial condition, and to repeat his experiment at any particular instant. To deny this freedom of action is to deny the possibility of experimental science.

In other words, we assume that the physical system under investigation is governed by strictly deterministic or probabilistic laws. On the other hand, we also have to assume that the experimentalist stands out of these natural laws. The traditional assumption of theoretical physics that the basic deterministic laws are universally and globally valid for all matter thus entails a pragmatic contradiction between theory and practice. A globally deterministic physics is impossible.“

[PDF]Hidden Determinism, Probability, and Time's Arrow - Core
 
  • Like
Likes Lynch101
  • #149
DarMM said:
this goes against most of what I've read where by in a classical theory one can consider there to be events in the absence of devices and measuring systems.
This is just because, as I had already mentioned, nobody ever really addressed the classical version of the quantum measurement problem. Instead it is simply assumed that the measuring device somehow acquires the measurement value, in principle with arbitrary accuracy and without backreaction to the system measured. This is a Platonic notion of measurement, looking into God's cards so to say. In this case you may say that the events are the properties of the collection of trajectories of the particles making up the system measured. You (like everyone else in the past) are treating classical mechanics exclusively from this Platonic perspective, while you consider quantum mechanics on a different footing, e.g., by allowing for microscopic descriptions of the measuring device, or even a hierarchy of these. This gives a distorted picture of the classical vs. quantum theme.

But for a system consisting of a few interacting atoms it is impossible to measure (from within a classical universe) most of these properties as if they were unobserved, as the coupling to the measuring device distorts the trajectories as in the quantum case. This proves that classical measurement is nontrivial. Realistic measurement in a classical universe would have to consider how some observable of a classical microscopically described measuring device acquires a value correlated with some property of the observed system. The outcome space is then the range of that observable - which is not necessarily that of the property considered. Thus one needs considerable extra structure...
 
  • Like
Likes akvadrako
  • #150
Lord Jestocost said:
In experimental physics it is always taken for granted that the experimenter has the freedom to choose these initial condition, and to repeat his experiment at any particular instant. To deny this freedom of action is to deny the possibility of experimental science.
No. Part of experimental physics is to figure out which part of the initial condition can be manipulated in such a way that desired experiments are possible. Often this is the most difficult aspect of an experiment. Calibration experiments (such as various kinds of quantum tomography) are even set up to discover the initial conditions of a source through appropriate measurements.
 
  • Like
Likes Lynch101
Back
Top