Why is superdeterminism not the universally accepted explanation of nonlocality?

[jadrian]

from my thinking nonlocality and entanglement are never a problem because in a totally determinstic universe, the information about what is going to be instantaneously tranferred from a to b is already known to the universe. we may not be in block time but the universe acts as if it were. this is the first thing I've come across that agrees with my resolution of instantaneous info transfer.

even tho i personally believe that entanglement is basicly a zero sum static, and it is essentually noneffectual on the universe, just something we have to live with, but does not violate relativity because the information does not have any effect on anything anywhere. why is this not mainstream? do most people want to live in an undetermined future, thinking its closer to free will?

 

[lugita15]

It is true that Bell's theorem as such does not rule out the possibility local superdeterministic hidden variable theory. But there are solid reasons why people do not rush to embrace a superdeterministic explanation.

First of all, such an explanation would be in some sense "conspiratorial" - it would mean that all the particles in the universe are secretly working together, each particle acting in just the right way as to make it seem as if local realism is false even though it is really true. So for instance, if you decide which way to orient your polarizer based on throwing dice (or some more sophisticated pseudorandom number generator), the motion of the dice in principle can be predicted from the initial conditions of the dice and all the air molecules. So all the air molecules were working together to turn the die in just the right way so that the right number would show up. And the air molecules could be affected by the time a person sneezed, which could be affected by something they ate. So the laws of the universe made the person choose just the right food so as to make him sneeze at the right time to make the air molecules turn the die in just the right way so that the polarizer will be turned to the exact orientation the universe wants. You can see that this sounds less like a scientific theory and more like a religious explanation - you have a God who is controlling all the little details of the universe in order to make the statistics of quantum entanglement experiments come out just right.

Second of all, there's a reason why the Bohmian interpretation, which is a nonlocal realist interpretation, gets respect and superdeterminism does not (even though both are arguably "conspiratorial" to varying degrees). In the case of Bohmian mechanics, we actually have a fully developed mathematical theory which predicts all the phenomena of (nonrelativistic) quantum mechanics. In the case of superdeterminism, however, we just have a vague hope of the possibility of a scientific theory. There are some people like Gerard t'Hooft who have tried to create a "proof of concept" superdeterministic theory, just to show that it is possible for a local realist theory to exploit the superdeterminism loophole to Bell's theorem. But until there's an explanation that actually shows exactly how the particles of the universe are conducting this grand "conspiracy", there will probably be continued skepticism from the scientific community.

 

[Zarqon]

Maybe a bit simple way of putting, but the short answer to your question is that not everyone thinks non-locality needs an explanation! On the contrary, it can rather be considered as an answer. If we ask how can our entangled results be explained, then non-locality is a part of one answer to this.

As for your interpretational arguments, it's hard to say much since you seemed to have formed your view on it already. My personal view on interpreting it all, is that I try to keep my beliefs as close to measured reality as possible. For example, we currently measure both random and non-local phenomena, and even though there may exist explanations to these that are deterministic, we still need to be able to explain the random, non-local measurement results in the end. This means that the possible deterministic background contribute with nothing, and may therefore just as well be omitted from our theory.

To put it shortly, when left with nothing else to go on, it's better to "believe" that the universe is actually as we see it (random and non-local) rather than to invent longer explanations.

 

[lugita15]

Maybe a bit simple way of putting, but the short answer to your question is that not everyone thinks non-locality needs an explanation! On the contrary, it can rather be considered as an answer. If we ask how can our entangled results be explained, then non-locality is a part of one answer to this.

As for your interpretational arguments, it's hard to say much since you seemed to have formed your view on it already. My personal view on interpreting it all, is that I try to keep my beliefs as close to measured reality as possible. For example, we currently measure both random and non-local phenomena, and even though there may exist explanations to these that are deterministic, we still need to be able to explain the random, non-local measurement results in the end. This means that the possible deterministic background contribute with nothing, and may therefore just as well be omitted from our theory.

To put it shortly, when left with nothing else to go on, it's better to "believe" that the universe is actually as we see it (random and non-local) rather than to invent longer explanations.

If you were a pure pragmatist, then wouldn't you assume that if you measured a particle to have a certain property, that it had that property before you measured it? Like if you see a dollar bill lying on the road, don't you assume that it was lying there before you saw it?

Now that kind of naive noncontextual realism, although as a pragmatist you may be naturally led to it, runs into some difficulties if you apply it to the spin observable, because the Kochen-Specker theorem states roughly that any theory of spin that reproduces the predictions of quantum mechanics must be contextual, i.e. dependent on how you measured it. (Of course, if you're a superdeterminist that doesn't mean much to you, because you don't believe there is any free choice of how you choose to measure, so you would think a Kochen-Specker tests are a fraud for the same reason you would think Bell tests are a fraud.) I wonder, is there an analogous result like Kochen-Specker for the position observable? I suspect it would be problematic for Bohmian mechanics if there was, because part of the reason Bohmians think spin is "fake" is because of the Kochen-Specker theorem. Would they similarly think position is "fake", or is position too foundational for Bohmian mechanics?

 

[jadrian]

It is true that Bell's theorem as such does not rule out the possibility local superdeterministic hidden variable theory. But there are solid reasons why people do not rush to embrace a superdeterministic explanation.

First of all, such an explanation would be in some sense "conspiratorial" - it would mean that all the particles in the universe are secretly working together, each particle acting in just the right way as to make it seem as if local realism is false even though it is really true. So for instance, if you decide which way to orient your polarizer based on throwing dice (or some more sophisticated pseudorandom number generator), the motion of the dice in principle can be predicted from the initial conditions of the dice and all the air molecules. So all the air molecules were working together to turn the die in just the right way so that the right number would show up. And the air molecules could be affected by the time a person sneezed, which could be affected by something they ate. So the laws of the universe made the person choose just the right food so as to make him sneeze at the right time to make the air molecules turn the die in just the right way so that the polarizer will be turned to the exact orientation the universe wants. You can see that this sounds less like a scientific theory and more like a religious explanation - you have a God who is controlling all the little details of the universe in order to make the statistics of quantum entanglement experiments come out just right.

Second of all, there's a reason why the Bohmian interpretation, which is a nonlocal realist interpretation, gets respect and superdeterminism does not (even though both are arguably "conspiratorial" to varying degrees). In the case of Bohmian mechanics, we actually have a fully developed mathematical theory which predicts all the phenomena of (nonrelativistic) quantum mechanics. In the case of superdeterminism, however, we just have a vague hope of the possibility of a scientific theory. There are some people like Gerard t'Hooft who have tried to create a "proof of concept" superdeterministic theory, just to show that it is possible for a local realist theory to exploit the superdeterminism loophole to Bell's theorem. But until there's an explanation that actually shows exactly how the particles of the universe are conducting this grand "conspiracy", there will probably be continued skepticism from the scientific community.

i have no idea what makes you think that superdeterminism is conspiratorial. i don't understand why superdeterminism is not the fundamental pillar that all science is built on. your dice analogy only seems to prove my point.

but when you say your view of superdeterminism as "the laws of the universe made the person choose just the right food so as to make him sneeze at the right time to make the air molecules turn the die in just the right way so that the polarizer will be turned to the exact orientation the universe wants. You can see that this sounds less like a scientific theory and more like a religious explanation - you have a God who is controlling all the little details of the universe in order to make the statistics of quantum entanglement experiments come out just right.", you just seem to be incapable of accepting the possibility that the future is a 100 percent consequence of the events preceding it.

do you believe in free will or something?

 

[kith]

In principle, I don't think superdeterminism is less valid than standard interpretations. One has to realize, that the freedom to chose initial conditions ("free will") is an axiom in QM.

The problem is that if you drop this axiom, I can't think of a way how to apply the scientific method in a meaningful way. Since the mainstream is doing science, I don't think he will ever embrace such an interpretation.

So philosophically, I think, it stands on equal footing with standard interpretations. But for actually doing science, one has to assume at least some kind of "effective" freedom in choosing initial conditions.

 

[jadrian]

It is true that Bell's theorem as such does not rule out the possibility local superdeterministic hidden variable theory. But there are solid reasons why people do not rush to embrace a superdeterministic explanation.

First of all, such an explanation would be in some sense "conspiratorial" - it would mean that all the particles in the universe are secretly working together, each particle acting in just the right way as to make it seem as if local realism is false even though it is really true. So for instance, if you decide which way to orient your polarizer based on throwing dice (or some more sophisticated pseudorandom number generator), the motion of the dice in principle can be predicted from the initial conditions of the dice and all the air molecules. So all the air molecules were working together to turn the die in just the right way so that the right number would show up. And the air molecules could be affected by the time a person sneezed, which could be affected by something they ate. So the laws of the universe made the person choose just the right food so as to make him sneeze at the right time to make the air molecules turn the die in just the right way so that the polarizer will be turned to the exact orientation the universe wants. You can see that this sounds less like a scientific theory and more like a religious explanation - you have a God who is controlling all the little details of the universe in order to make the statistics of quantum entanglement experiments come out just right.

Second of all, there's a reason why the Bohmian interpretation, which is a nonlocal realist interpretation, gets respect and superdeterminism does not (even though both are arguably "conspiratorial" to varying degrees). In the case of Bohmian mechanics, we actually have a fully developed mathematical theory which predicts all the phenomena of (nonrelativistic) quantum mechanics. In the case of superdeterminism, however, we just have a vague hope of the possibility of a scientific theory. There are some people like Gerard t'Hooft who have tried to create a "proof of concept" superdeterministic theory, just to show that it is possible for a local realist theory to exploit the superdeterminism loophole to Bell's theorem. But until there's an explanation that actually shows exactly how the particles of the universe are conducting this grand "conspiracy", there will probably be continued skepticism from the scientific community.

also, since entanglement must always originate locally, the info transfer between entangled particles is never going to be faster than c, therefore nonlocality is not an issue in superdeterminism and neither are hidden variables if I am correct. instantaneous info transfer will not violate relativity because of this.

 

[jadrian]

also, since entanglement must always originate locally, the info transfer between entangled particles is never going to be faster than c, therefore nonlocality is not an issue in superdeterminism and neither are hidden variables if I am correct. instantaneous info transfer will not violate relativity because of this.

or information theory for that matter

 

[Demystifier]

i have no idea what makes you think that superdeterminism is conspiratorial. i don't understand why superdeterminism is not the fundamental pillar that all science is built on. your dice analogy only seems to prove my point.

but when you say your view of superdeterminism as "the laws of the universe made the person choose just the right food so as to make him sneeze at the right time to make the air molecules turn the die in just the right way so that the polarizer will be turned to the exact orientation the universe wants. You can see that this sounds less like a scientific theory and more like a religious explanation - you have a God who is controlling all the little details of the universe in order to make the statistics of quantum entanglement experiments come out just right.", you just seem to be incapable of accepting the possibility that the future is a 100 percent consequence of the events preceding it.

do you believe in free will or something?

Jadrian, I think that you have misunderstood what is meant by "superdeterminism" in the context of avoiding nonlocality of QM. In this context, superdeterminism is NOT merely the idea that everything is deterministic, i.e., that future is completely determined by the past. If superdeterminism was only that, then it could not avoid nonlocality. Instead, superdeterminism is much more. It is the idea that
1. Future is completely determined by the past.
AND
2. The past (i.e., initial conditions) is not arbitrary, but is fine tuned so that in the future we see correlations between distant object which never mutually interacted.

Superdeterminism is not popular due to the property 2 (not 1). It is this second property (not the first) which makes it conspiratorial.

 

[Zarqon]

If you were a pure pragmatist, then wouldn't you assume that if you measured a particle to have a certain property, that it had that property before you measured it? Like if you see a dollar bill lying on the road, don't you assume that it was lying there before you saw it?

Now that kind of naive noncontextual realism, although as a pragmatist you may be naturally led to it, runs into some difficulties if you apply it to the spin observable, because the Kochen-Specker theorem states roughly that any theory of spin that reproduces the predictions of quantum mechanics must be contextual, i.e. dependent on how you measured it. (Of course, if you're a superdeterminist that doesn't mean much to you, because you don't believe there is any free choice of how you choose to measure, so you would think a Kochen-Specker tests are a fraud for the same reason you would think Bell tests are a fraud.) I wonder, is there an analogous result like Kochen-Specker for the position observable? I suspect it would be problematic for Bohmian mechanics if there was, because part of the reason Bohmians think spin is "fake" is because of the Kochen-Specker theorem. Would they similarly think position is "fake", or is position too foundational for Bohmian mechanics?

It's important to make a distinction between a measurement result and what is "really" there. Just because a measured result is clearly contextual does not mean we can exclude realism!

This is because your measurement apparatus changes the "real" state. To follow up on your dollar bill analogy, if you used a paper shredder as a measurement tool for detecting the bill and watch the output of it, then you could state that there must have been some form of dollar bill before but you don't necessarily see it as "really" was when it was lying on the road. But that does not mean it wasn't "really" there, it only means you have limited your range of answers to how you ask questions/what measurement you do. i.e. you measurements are contextual, but realism might still be valid.

Similarly, in quantum mechanics, your output answers are often very limited. For example, measuring a superposition state in the computational basis (0 and 1), you can only get 0 or 1 as answer, and even measuring multiple times will not allow you to ascertain the "real" underlying state. Nevertheless, a superposition state can be said to be a "real" state, because it is even possible to draw a figure of the electron distribution of that particular superposition state! (or whatever system you used). That electron distribution will be different from both the 0 and the 1 state's distributions, and smarter measuring devices can allow you to determine it more precisely (don't shred you dollar).

 

[Demystifier]

If you were a pure pragmatist, then wouldn't you assume that if you measured a particle to have a certain property, that it had that property before you measured it? Like if you see a dollar bill lying on the road, don't you assume that it was lying there before you saw it?

Now that kind of naive noncontextual realism, although as a pragmatist you may be naturally led to it, runs into some difficulties if you apply it to the spin observable, because the Kochen-Specker theorem states roughly that any theory of spin that reproduces the predictions of quantum mechanics must be contextual, i.e. dependent on how you measured it. (Of course, if you're a superdeterminist that doesn't mean much to you, because you don't believe there is any free choice of how you choose to measure, so you would think a Kochen-Specker tests are a fraud for the same reason you would think Bell tests are a fraud.) I wonder, is there an analogous result like Kochen-Specker for the position observable? I suspect it would be problematic for Bohmian mechanics if there was, because part of the reason Bohmians think spin is "fake" is because of the Kochen-Specker theorem. Would they similarly think position is "fake", or is position too foundational for Bohmian mechanics?

There is one big difference between spin and position. Spin consists of 3 observables (corresponding to 3 directions in space) which do NOT commute with each other, while position consists of 3 observables which DO commute with each other. The Kochen-Specker theorem applies to any observables which do not commute with each other, so it doesn't apply to the position observable.

 

[lugita15]

i have no idea what makes you think that superdeterminism is conspiratorial. i don't understand why superdeterminism is not the fundamental pillar that all science is built on. your dice analogy only seems to prove my point.

but when you say your view of superdeterminism as "the laws of the universe made the person choose just the right food so as to make him sneeze at the right time to make the air molecules turn the die in just the right way so that the polarizer will be turned to the exact orientation the universe wants. You can see that this sounds less like a scientific theory and more like a religious explanation - you have a God who is controlling all the little details of the universe in order to make the statistics of quantum entanglement experiments come out just right.", you just seem to be incapable of accepting the possibility that the future is a 100 percent consequence of the events preceding it.

do you believe in free will or something?

I'm not talking about free will and I'm not rejecting determinism out of hand. All I'm saying is that in order for a local deterministic theory to exploit the superdeterminism loophole to Bell's theorem, it seems that it has to possesses some properties that many would consider to be strange for a scientific theory to have. The conspiratorial nature is one of them: you have to assume that all the particles in the universe are doing just the right actions which will make local determinism seem false even though it is really true. And it seems pretty hard to come up with a theory that assigns to these particles exactly these "right actions", although as I mentioned earlier there has been some promising work in this direction by Nobel prize-winner Gerard t'Hooft and others.

 

[lugita15]

In principle, I don't think superdeterminism is less valid than standard interpretations. One has to realize, that the freedom to chose initial conditions ("free will") is an axiom in QM.

The problem is that if you drop this axiom, I can't think of a way how to apply the scientific method in a meaningful way. Since the mainstream is doing science, I don't think he will ever embrace such an interpretation.

So philosophically, I think, it stands on equal footing with standard interpretations. But for actually doing science, one has to assume at least some kind of "effective" freedom in choosing initial conditions.

Free will is not an axiom of quantum mechanics; where did you get that idea? But it is true that the Copenhagen interpretation is compatible with the idea that the experimenter has free will (although it is also compatible with radical rejections of counterfactual definiteness where it becomes meaningless to even consider the possibility that the experimenter could have done something other than what they actually did).

As for your second point, that "effective" freedom of initial conditions is necessary for science, yes, it's difficult to see how the scientific method can proceed if the initial conditions of all experiments have such large systematic biases as required by superdeterminism.

 

[lugita15]

also, since entanglement must always originate locally, the info transfer between entangled particles is never going to be faster than c, therefore nonlocality is not an issue in superdeterminism and neither are hidden variables if I am correct. instantaneous info transfer will not violate relativity because of this.

I never said that nonlocality or violations of relativity are issues for superdeterminism.

 

[lugita15]

There is one big difference between spin and position. Spin consists of 3 observables (corresponding to 3 directions in space) which do NOT commute with each other, while position consists of 3 observables which DO commute with each other. The Kochen-Specker theorem applies to any observables which do not commute with each other, so it doesn't apply to the position observable.

Demystifier, let's call the conclusion of the Kochen-Specker theorem "fakeness". If you have a set of noncommuting observables, does Kochen-Specker state that all of them are fake, or just that just at least one of them must be fake? The reason I'm asking is that position and momentum are non-commuting.

On an unrelated note, doesn't Bohmian mechanics suffer from its own fine-tuning problems, namely that the universe got into just the right state that comports with the Born rule? I think this is a somewhat odd issue for BM, because decoherence can easily explain why the Born rule seems correct in practice. Why can't this explanation be carried over into BM, which anyway utilizes decoherence in its reduction of quantum uncertainty to classical uncertainty?

 

[jadrian]

Jadrian, I think that you have misunderstood what is meant by "superdeterminism" in the context of avoiding nonlocality of QM. In this context, superdeterminism is NOT merely the idea that everything is deterministic, i.e., that future is completely determined by the past. If superdeterminism was only that, then it could not avoid nonlocality. Instead, superdeterminism is much more. It is the idea that
1. Future is completely determined by the past.
AND
2. The past (i.e., initial conditions) is not arbitrary, but is fine tuned so that in the future we see correlations between distant object which never mutually interacted.

Superdeterminism is not popular due to the property 2 (not 1). It is this second property (not the first) which makes it conspiratorial.

why is 2 even necessary
and initial conditions should have interacted at some point correct?
i don't see any problem with nonlocality because it can never beat c to the finish

 

[jadrian]

It's important to make a distinction between a measurement result and what is "really" there. Just because a measured result is clearly contextual does not mean we can exclude realism!

This is because your measurement apparatus changes the "real" state. To follow up on your dollar bill analogy, if you used a paper shredder as a measurement tool for detecting the bill and watch the output of it, then you could state that there must have been some form of dollar bill before but you don't necessarily see it as "really" was when it was lying on the road. But that does not mean it wasn't "really" there, it only means you have limited your range of answers to how you ask questions/what measurement you do. i.e. you measurements are contextual, but realism might still be valid.

Similarly, in quantum mechanics, your output answers are often very limited. For example, measuring a superposition state in the computational basis (0 and 1), you can only get 0 or 1 as answer, and even measuring multiple times will not allow you to ascertain the "real" underlying state. Nevertheless, a superposition state can be said to be a "real" state, because it is even possible to draw a figure of the electron distribution of that particular superposition state! (or whatever system you used). That electron distribution will be different from both the 0 and the 1 state's distributions, and smarter measuring devices can allow you to determine it more precisely (don't shred you dollar).

could you give a simpler explanation of the superposition?

 

[kith]

Free will is not an axiom of quantum mechanics; where did you get that idea?

My bad, I intended to write "the Copenhagen interpretation".

But it is true that the Copenhagen interpretation is compatible with the idea that the experimenter has free will (although it is also compatible with radical rejections of counterfactual definiteness where it becomes meaningless to even consider the possibility that the experimenter could have done something other than what they actually did).

In the CI, measurements involve the freedom to choose what's being measured. If the measurements themselfs are to be explained by (quantum mechanical) laws, I think we let go of the CI.

 

[jadrian]

how about nonlocal superdeterminism? is that falsifiable?
i really don't see why part 2 is necessary at all

 

[jadrian]

My bad, I intended to write "the Copenhagen interpretation".

In the CI, measurements involve the freedom to choose what's being measured. If the measurements themselfs are to be explained by (quantum mechanical) laws, I think we let go of the CI.

imo we have the illusion that we are choosing, i don't know how anybody could embrace ci. do they think they could have done measurements any differently than they did them? lol

 

[jadrian]

how about nonlocal superdeterminism? is that falsifiable?
i really don't see why part 2 is necessary at all

couldnt you view nonlocality as shortcutting the universe/ wormholing it through entanglement?

nonlocality does not violate relativity because entanglement has to start at a local level, so why is nonlocality such an issue?

 

[kith]

imo we have the illusion that we are choosing, i don't know how anybody could embrace ci. do they think they could have done measurements any differently than they did them? lol

Just out of curiosity: how do you decide what to do in a given situation? ;-)

 

[DrChinese]

why is this not mainstream?

Because it is not a theory, it is more akin to a religious concept. No different than saying God waits for us to do Bell tests, and then makes the results look like QM is nonlocal.

An actual superdeterministic theory, on the other hand, would feature elements which are (easily) falsifiable. For example: if particles are to have certain correlations, the elements for determining those correlations are present in every particle everywhere. There are other requirements as well.

Further: superdeterminism equally explains the results of all experiments everywhere, such as gravity, electromagnetism, etc. Why pull it out for Bell tests only?

I personally do not believe there is any element of this concept, in its current form, which belongs under the heading of science.

 

[jadrian]

Just out of curiosity: how do you decide what to do in a given situation? ;-)

everything that occurs in my body is a chemical reaction. all the chemical reactions are mediated/controlled via enzymes which are produced in quantities resulting in positive and negative feedback chemical reactions which ultimately react with dna as the homeostatic instruction manual.

my brain has developed partly through instinctual developments from my dna ie arachnophobia, and partly as a response to my environment, always ultimately controlled by dna which grows our brain into a tool to cope with a complex environment, always looking out for its survival, and eventual reproduction, not because the genes goal is reproduction, but because our genes are replications of genes that had a proclivity to reproduce. do you know why jealosy is one of the strongest and most violence producing emotion? its because our dna has strongly embedded in our brains development a defense against somebody else impregnating your reproductive partner with other than your genes, resulting in your genetic death if you do not reproduce because of foreign adultery.

my choices are the end result of a causal continuum of millions of neural interactions, ultimately leading me to make the best decision in the interest of my genes. why does a male preying mantis let itself get eaten by the female after mating? because the added nutrition to the female will result in a more favorable genetic outcome (more eggs with its genes inside) than running away.

we are exercising our brains on a website because of complex psychological reasons that ultimately benefit our many aspects that could be considered in the genes interest.

why am i writing this post? because my self sustaining chemical reaction has effectively directed me to do it for reasons you can ask an evolutionary minded psychologist.

the chemical reactions that occur in my body and brrain are fundamentally indistinguishable from a burning flame or pouring acid into a buffer solution.

so to think that there is somebody behind the wheel in my brain calling the shots is an infantile notion. i have no more choice than any other chemical reaction that we would regard as nonliving.

let me ask you a question. Do you think you are alive?

 

[lugita15]

why is 2 even necessary

Because if you do not include 2 then your deterministic theory will contradict the results of Bell test experiments.

and initial conditions should have interacted at some point correct?
i don't see any problem with nonlocality because it can never beat c to the finish

Yes, no one is suggesting that nonlocality is a problem for superdeterminism.

 

[lugita15]

If the measurements themselfs are to be explained by (quantum mechanical) laws, I think we let go of the CI.

It's true, if measurement decisions were based on the quantum state of the experimenter, that would be decoherence, not Copenhagen. But you can have a view where the wavefunctions of the particles under observation collapse probabilistically, but where the experimenter and his measuring device are governed by classical, deterministic laws. This sharp division of the classical world and the quantum world was at the heart of the historical Copenhagen interpretation, even though modern Copenhagen people aren't quite so bold.

 

[Demystifier]

Because if you do not include 2 then your deterministic theory will contradict the results of Bell test experiments.

Exactly!

 

[Demystifier]

Demystifier, let's call the conclusion of the Kochen-Specker theorem "fakeness". If you have a set of noncommuting observables, does Kochen-Specker state that all of them are fake, or just that just at least one of them must be fake? The reason I'm asking is that position and momentum are non-commuting.

KC theorem says that, if you have a set of noncommuting observables, then at most one of them can be genuine (i.e., not fake).

On an unrelated note, doesn't Bohmian mechanics suffer from its own fine-tuning problems, namely that the universe got into just the right state that comports with the Born rule? I think this is a somewhat odd issue for BM, because decoherence can easily explain why the Born rule seems correct in practice. Why can't this explanation be carried over into BM, which anyway utilizes decoherence in its reduction of quantum uncertainty to classical uncertainty?

First, I don't see how decoherence explain the Born rule, and I would be very happy if you could explain it to me or give a reference where it is explained.

Second, BM can explain the Born rule for positions, without postulating it and without using decoherence. See e.g.
http://xxx.lanl.gov/abs/quant-ph/0403034
and Ref. [16] therein.

Third, BM can explain the Born rule for other observables by combining the Born rule for positions with the theory of decoherence.

 

[jadrian]

Because if you do not include 2 then your deterministic theory will contradict the results of Bell test experiments.
Yes, no one is suggesting that nonlocality is a problem for superdeterminism.

well wouldn't non arbitrary initial conditions be consistent with a determinist view? i don't see how the initial conditions need to be special, as their evolution can be traced back intuitively through determinism.

in simple terms what is so special about the initial conditions?

 

[Demystifier]

well wouldn't non arbitrary initial conditions be consistent with a determinist view?

They would, but they would not be consistent with predictions of quantum mechanics.

 

[Demystifier]

in simple terms what is so special about the initial conditions?

The correct question is what is so special about the predictions of quantum mechanics. Loosely speaking, the answer is that the predictions are such that they cannot be explained by a local deterministic theory, except for special initial conditions.

 

[Delta Kilo]

I'll play devil's advocate:

Regarding point 2 (initial conditions conspiring to make Bell experiment to come out true), there is another possible view of it: imagine a frozen block universe where everything - past present and future - is predetermined. Presumably laws of physics constrain it to be a solution of some fancy PDE. Lets' say some symmetry condition in this galactic equation implies that Bell results for entangled particles come out as they do. So the rest of the universe would just have to "bend around" it. The effect would propagate from the point outwards in all directions - left, right, past, future - so when we look at it from our "arrow of time" point of view it would look as if initial conditions have been fine-tuned to achieve the results.

Of course all of the above is just wishful thinking. There is not a shred of evidence to support this point of view.

 

[jadrian]

I'll play devil's advocate:

Regarding point 2 (initial conditions conspiring to make Bell experiment to come out true), there is another possible view of it: imagine a frozen block universe where everything - past present and future - is predetermined. Presumably laws of physics constrain it to be a solution of some fancy PDE. Lets' say some symmetry condition in this galactic equation implies that Bell results for entangled particles come out as they do. So the rest of the universe would just have to "bend around" it. The effect would propagate from the point outwards in all directions - left, right, past, future - so when we look at it from our "arrow of time" point of view it would look as if initial conditions have been fine-tuned to achieve the results.

Of course all of the above is just wishful thinking. There is not a shred of evidence to support this point of view.

im not sure whether your defending or attacking determinism.

but block time is more of a model to represent all the past and all the future together.

but since space and time were created in an evolving fashiion, its obvious that we cannot reverse time. however, hypothetically if our brains operated at the speed of light, (you would have to ignore relativity i know) then you would see the universe as frozen. and since time can't really be viewed as moving at a constant speed, you can just as well regard a picosecond as lasting trillions of years, when intuitively viewed from the human perception of time.

this is why a fly is so hard to catch, and why to a rock, time passes incredibly fast if you think of it as having a lifespan.

 

[jadrian]

except for special initial conditions.

that was my question what are special initial conditions?

 

[jadrian]

They would, but they would not be consistent with predictions of quantum mechanics.

but isn't superdeterminism unfalsified by qm predictions?

 

[jadrian]

everything that occurs in my body is a chemical reaction. all the chemical reactions are mediated/controlled via enzymes which are produced in quantities resulting in positive and negative feedback chemical reactions which ultimately react with dna as the homeostatic instruction manual.

my brain has developed partly through instinctual developments from my dna ie arachnophobia, and partly as a response to my environment, always ultimately controlled by dna which grows our brain into a tool to cope with a complex environment, always looking out for its survival, and eventual reproduction, not because the genes goal is reproduction, but because our genes are replications of genes that had a proclivity to reproduce. do you know why jealosy is one of the strongest and most violence producing emotion? its because our dna has strongly embedded in our brains development a defense against somebody else impregnating your reproductive partner with other than your genes, resulting in your genetic death if you do not reproduce because of foreign adultery.

my choices are the end result of a causal continuum of millions of neural interactions, ultimately leading me to make the best decision in the interest of my genes. why does a male preying mantis let itself get eaten by the female after mating? because the added nutrition to the female will result in a more favorable genetic outcome (more eggs with its genes inside) than running away.

we are exercising our brains on a website because of complex psychological reasons that ultimately benefit our many aspects that could be considered in the genes interest.

why am i writing this post? because my self sustaining chemical reaction has effectively directed me to do it for reasons you can ask an evolutionary minded psychologist.

the chemical reactions that occur in my body and brrain are fundamentally indistinguishable from a burning flame or pouring acid into a buffer solution.

so to think that there is somebody behind the wheel in my brain calling the shots is an infantile notion. i have no more choice than any other chemical reaction that we would regard as nonliving.

let me ask you a question. Do you think you are alive?

and kith, I am sorry. i don't take pleasure in telling people the adult version of there is no santa clause, unless they ask for it.

 

[DrChinese]

but isn't superdeterminism unfalsified by qm predictions?

I don't think this question makes sense as written. Could you rephrase?

 

[lugita15]

that was my question what are special initial conditions?

OK, let me give you an example of why you need special initial conditions.

In a deterministic theory, in order to predict the current behavior of any object, you need to know the initial conditions of the object, as well as the deterministic laws of the universe. In Newtonian mechanics, for example, you need to know the positions and velocities of all the particles at time t=0, and then F=ma will tell you the behavior of the particles at all later times.

Now let's consider what a local deterministic explanation of entanglement would look like. Let particles A and B be an entangled pair of photons, which are separated by a great distance and then sent through polarization detectors. We also have particles C and D: C tells the experimenter what angle he should set the polarizer that measures A, and D tells the experimenter how to set the polarizer that measures B. You can think of C and D as neurons in the brains of the experimenters if you like.

Now we find experimentally that the behavior of particle A through its measurement device is strongly correlated with the angle at which B's measurement device is set. And that angle is determined by particle D. So we have a correlation between the behavior of particles A and D.

But particles A and D are separated by such a large distance, so they cannot communicate with each other to coordinate their behavior (unless you have a nonlocal theory like Bohmian mechanics which allow undetectable faster-than-light signalling between particles). So a local determinist has to conclude that A and D are correlated not based on a current relationship between the present states of A and D, which would be impossible, but based on a past relationship of the initial states of A and D.

This is what we mean by special initial conditions: A and D seemingly have nothing to do with each other. After all, it is A and B that were in the entangled state, and yet somehow we have to conclude that the initial conditions of A and D had to be specially set so that a correlation between A and D would be observed in the future. And instead of just D, we can have a large number of particles D1, D2, D3,... which together determine the measurement setting, so the initial state of particle A had to have been set based on the initial states of all these particles. And in the real world, almost all particles in the universe are interacting in some way with almost all other particles, so really the setting of measurement device depends on almost everything in the universe, from which we conclude that the initial conditions of the whole universe were specially set so that the right kind of correlation would be displayed billions of years later between particle A and the measuring device.

This is why superdeterminism is called "conspiratorial". That doesn't mean it's wrong, it just has some issues which make it rather difficult to construct a viable superdeterministic theory, but let me repeat that some potential first steps toward such a theory have already been taken by a few people.

 

[DrChinese]

...This is why superdeterminism is called "conspiratorial". That doesn't mean it's wrong, it just has some issues which make it rather difficult to construct a viable superdeterministic theory, but let me repeat that some potential first steps toward such a theory have already been taken by a few people.

Maybe someone is working on it, but that would pretty much be a waste of time. The entire point would be to replicate the predictions of QM.

On the other hand, the obstacles are enormous. I like your example. Once you see that your C and D could be anything (and in fact different) - radioactive decay, coin tosses, arrival time of photons from the moon, etc. - you realize the magnitude of the conspiracy.

And, like any conspiracy, it is impossible to disprove. Really, it is a ridiculous premise and I see no scientific merit in it. Although there are plenty of scientists who acknowledge it as viable conceptually, I doubt there are many who give it more than a second thought.

 

[lugita15]

Maybe someone is working on it, but that would pretty much be a waste of time.

No one's doing serious work on it; I was just talking about some basic proof-of-concept stuff from Gerard t'Hooft and a few others.

On the other hand, the obstacles are enormous. I like your example. Once you see that your C and D could be anything (and in fact different) - radioactive decay, coin tosses, arrival time of photons from the moon, etc. - you realize the magnitude of the conspiracy.

As I mentioned in my post, you can argue that all the particles in the universe would have to be involved in the conspiracy, because pretty much everything in the universe is interacting with everything else, be it gravitationally, electromagnetically, etc.

 

[lugita15]

First, I don't see how decoherence explain the Born rule, and I would be very happy if you could explain it to me or give a reference where it is explained.

The derivation of the Born rule is an important topic in the decoherence literature. Here's a typical reference:
http://arxiv.org/abs/quant-ph/0405161

 

[IttyBittyBit]

Wow, a great deal of unwarranted hostility towards jadrian in this thread, even from people like DrChinese whom I (used to) have a great deal of respect for.

It is true that superdeterminism is more of a viewpoint than a scientific theory --- but then so is the idea that all matter is made up of vibrating strings a la string theory. The latter is unfalsifiable as well (string theory can be reformulated in terms of branes to yield the exact same results) but it still serves as a useful guide for research.

Superdeterminism is a perfectly valid approach to things. Superdeterministic hidden variable theories (many of which are falsifiable) should be investigated more, I think.

Superdeterminism is only conspiratory if you don't understand it. If we were to build a set of toy Universes, some of them based on superdeterministic theories and others not, and the latter ones tended to match our Universe more closely, then it would be reasonable to conclude that the Universe is not superdeterministic and that any superdeterministic explanation would have to be conspiratory. However, such a study has never been undertaken and there is little evidence at the moment to support one position or the other.

It seems that the willingness of many people in this thread to discount superdeterminism offhand speaks more to an attempt to cling on to neo-vitalistic notions of free will than actual interest in science.

 

[DrChinese]

Wow, a great deal of unwarranted hostility towards jadrian in this thread, even from people like DrChinese whom I (used to) have a great deal of respect for.

It is true that superdeterminism is more of a viewpoint than a scientific theory --- but then so is the idea that all matter is made up of vibrating strings a la string theory. The latter is unfalsifiable as well (string theory can be reformulated in terms of branes to yield the exact same results) but it still serves as a useful guide for research.

Superdeterminism is a perfectly valid approach to things. Superdeterministic hidden variable theories (many of which are falsifiable) should be investigated more, I think.

Superdeterminism is only conspiratory if you don't understand it. If we were to build a set of toy Universes, some of them based on superdeterministic theories and others not, and the latter ones tended to match our Universe more closely, then it would be reasonable to conclude that the Universe is not superdeterministic and that any superdeterministic explanation would have to be conspiratory. However, such a study has never been undertaken and there is little evidence at the moment to support one position or the other.

It seems that the willingness of many people in this thread to discount superdeterminism offhand speaks more to an attempt to cling on to neo-vitalistic notions of free will than actual interest in science.

I certainly hope jadrian does not feel any hostility from me, that would be the last thing I would want. He asked why superdeterminism is not universally accepted, so I thought I was answering the question. It is not taken too seriously, please don't blame me personally for that.

As I have said before many times, there are no extent superdeterministic candidate theories that I know about. Yes, I have seen a few papers from well known scientists (Gerard 't Hooft cones to mind) discussing the matter, but none of them put forth anything really specific to rebut, and none have gained much traction.

 

[DrChinese]

No one's doing serious work on it; I was just talking about some basic proof-of-concept stuff from Gerard t'Hooft and a few others.
As I mentioned in my post, you can argue that all the particles in the universe would have to be involved in the conspiracy, because pretty much everything in the universe is interacting with everything else, be it gravitationally, electromagnetically, etc.

Yeah, that's all I had seen as well.

As you say, after a while you realize that every single particle in the universe would need to carry a local copy of all the information regarding every other particle as well. Plus a lot more information, I think, to handle the large number of possible Bell tests that could be performed.

The entire direction then takes on the attributes of an ad hoc theory, which immediately means no novel predictions will likely be forthcoming (that's what happens when you go into ad hoc mode). So I would say the outlook is bleek in terms of future prospects, and further that most scientists share this view in one way or another.

 

[juanrga]

from my thinking nonlocality and entanglement are never a problem because in a totally determinstic universe, the information about what is going to be instantaneously tranferred from a to b is already known to the universe. we may not be in block time but the universe acts as if it were. this is the first thing I've come across that agrees with my resolution of instantaneous info transfer.

even tho i personally believe that entanglement is basicly a zero sum static, and it is essentually noneffectual on the universe, just something we have to live with, but does not violate relativity because the information does not have any effect on anything anywhere. why is this not mainstream? do most people want to live in an undetermined future, thinking its closer to free will?

First, since that nonlocality and entanglement are perfectly compatible with a non-deterministic viewpoint, the problem does not even exists.

Second, from a theoretical point of view determinism arises when one consider a certain kind of simple systems as the traditionally studied in physics.

Third, the assumption that universe is deterministic is outside the scope of science.

 

[IttyBittyBit]

You say that every particle must have a 'local copy' of the states of all the particles in the Universe. First of all, I don't see why this is taken to mean that superdeterminism must be wrong. Certainly, this is a much more reasonable assumption than the multiverse interpretation that every particle is associated with not one, but a huge number of different copies of the Universe (possibly several after each single measurement).

Second, if the digital physics hypothesis is true, and the entire Universe is being run on a big computer in some alien's backyard shed, this is actually exactly the kind of thing that you would expect. In a sequential computer simulation, when calculating the trajectory of any particle we have access to the states of all the other particles (i.e. a sequential digital universe must be nonlocal).

Going back to toy universes, it is actually quite impossible to create toy Universes that are not superdeterministic, unless randomness is injected from the outside. However, if the Universe itself is superdeterministic, then this is impossible as well!

A lot of the misunderstanding concerning superdeterminism stems from the fact that people do not pause to consider its full implications. If the Universe were superdeterministic, then the action of human beings would be deterministic, and of course counterfactual definiteness wouldn't be true. This is natural and what you'd expect, and if this were not the case it would be strange.

Of course, these are all philosophical arguments, and we should not spend too much time dwelling on them. This goes for arguments in support of superdeterminism as well as those against it.

What frightens me is that there is a lot of talent being steered away from hidden variable theory research, just because of these empty philosophical arguments. However, the good news is that a lot of work is being done. Take a look at: http://www.sciencedirect.com/science/article/pii/S037015730500147X (available on arXiv: http://arxiv.org/abs/quant-ph/0701071 - 500 references!) That's from 2005, there has been more work done since then.

 

[lugita15]

Second, if the digital physics hypothesis is true, and the entire Universe is being run on a big computer in some alien's backyard shed, this is actually exactly the kind of thing that you would expect. In a sequential computer simulation, when calculating the trajectory of any particle we have access to the states of all the other particles (i.e. a sequential digital universe must be nonlocal).

No, you can easily create a digital universe in which particles don't have access to nonlocal information.

Going back to toy universes, it is actually quite impossible to create toy Universes that are not superdeterministic, unless randomness is injected from the outside. However, if the Universe itself is superdeterministic, then this is impossible as well!

It's true that no computer program in a deterministic universe can be non-deterministic. But not all deterministic theories have to be superdeterministic. In a superdeterministic theory, all the particles in the universe are conspiring to create the appearance of nonlocal correlations. That's not a common property of theories.

A lot of the misunderstanding concerning superdeterminism stems from the fact that people do not pause to consider its full implications. If the Universe were superdeterministic, then the action of human beings would be deterministic, and of course counterfactual definiteness wouldn't be true.

Yes, superdeterminism obviates the need for counterfactual definiteness; that is the whole reason why there is a no-conspiracy condition in Bell's theorem, and why there is a superdeterminism loophole in the first place. I don't think there is much misunderstanding about that point. But the reason that superdeterminism is not generally embraced, even among people who don't believe that humans have free will, is because it's natural to take nonlocal correlations at face value, and Occam's razor makes it hard to justify invoking a conspiratorial explanation like superdeterminism.

What frightens me is that there is a lot of talent being steered away from hidden variable theory research, just because of these empty philosophical arguments. However, the good news is that a lot of work is being done. Take a look at: http://www.sciencedirect.com/science/article/pii/S037015730500147X (available on arXiv: http://arxiv.org/abs/quant-ph/0701071 - 500 references!) That's from 2005, there has been more work done since then.

No, a lot of work is not being done on superdeterminism.

 

[IttyBittyBit]

I certainly hope jadrian does not feel any hostility from me, that would be the last thing I would want.

He posted a question and you replied, immediately equating his (perfectly legitimate) line of thought with religious belief.

Of course, you did answer the question, and I have found your posts so far to be insightful, so I apologize if I have misunderstood.

It's true that no computer program in a deterministic universe can be non-deterministic. But not all deterministic theories have to be superdeterministic. In a superdeterministic theory, all the particles in the universe are conspiring to create the appearance of nonlocal correlations. That's not a common property of theories.

I specifically meant toy universes that model our own Universe. Sorry if I wasn't clear about that.

Yes, superdeterminism obviates the need for counterfactual definiteness; that is the whole reason why there is a no-conspiracy condition in Bell's theorem, and why there is a superdeterminism loophole in the first place. I don't think there is much misunderstanding about that point. But the reason that superdeterminism is not generally embraced, even among people who don't believe that humans have free will, is because it's natural to take nonlocal correlations at face value, and Occam's razor makes it hard to justify invoking a conspiratorial explanation like superdeterminism.

Occam's razor does not apply here. It would only apply if there was a non-deterministic theory that could explain as much as a deterministic theory could and was simpler. There is no such theory as of yet; entanglement makes it difficult. All alternative resolutions to the EPR paradox make more assumptions than superdeterminism does. Why discount the one viewpoint that is intuitive and makes sense, in favor of other viewpoints that offer no increased predictive power and make more strange assumptions?

No, a lot of work is not being done on superdeterminism.

What are you trying to say?

 

[lugita15]

Occam's razor does not apply here. It would only apply if there was a non-deterministic theory that could explain as much as a deterministic theory could and was simpler.

It's called Quantum Mechanics.

 

[IttyBittyBit]

It's called Quantum Mechanics.

I don't think you fully appreciate the EPR paradox.

At any rate, this discussion is becoming far too philosophical for my tastes so I see no point in continuing it.