Why is superdeterminism not the universally accepted explanation of nonlocality?

[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.

 

[jadrian]

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.

yeah but how can you POSSIBLY rule out that a and d did not interact in the past.

 

[jadrian]

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.

exactly

also again who has proof that a and d could not have interacted in the past

 

[jadrian]

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.

SPECIALLY SET? CAUSALITY SPECIALLY SETS EVERYTHING OTHERWISE THERE WOULDNT BE CAUSALITY!

 

[jadrian]

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.

I think you view superdeterminism as a way AROUND bells tests. I think superdeterminsm makes bells tests look like an absolute waste of time.

 

[jadrian]

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. .

.

local copy? information isn't copied! i can't punch a wall without breaking my knuckles! me punching the wall might put a dent in it and that dent represents some info i transferred to the wall. the wall didnt store the full information of the event! the wall had just as much info transfer to my hand! what makes you think all the information about this event would get stored in the wall and my knuckles as if we made a xerox of every bit of information in every particle in the wall and every particle in my hand and this info gets stored forever in the wall and in my hand? how do causal interactions give you the philosophy that every particle is storing all other particles information? its only storing a finite amount of information it obtained from events which happened to it in the past!

the universe as a whole contains all this information AND IF YOU HYPOTHETICALLY HAD ALL THE INFORMATION IN THE UNIVERSE YOU WOULD KNOW EXACTLY WHAT WILL HAPPEN IN THE FUTURE WITH DEFINED DETERMINISM AND ABSOLUTE CERTAINTY. AND SINCE ALL THE INFORMATION IN THE UNIVERSE EXISTS, THE FUTURE WILL HAPPEN WITH DEFINED DETERMINISM., even tho it is impossible to obtain all this information.

why is this such a hard pill to swallow, unless you believe in free will? if i could hypothetically rewind time like a videotape, and re perform an electrons position measurement, i would get the exact same result! otherwise we would have to regard the past as undetermined at a given location.

doesnt anybody find the free will assumption of the copenhagen interpretation to be hysterical?

 

[IttyBittyBit]

jadrian, speaking in all caps does not assist in getting your point across. I'm trying to defend your viewpoint, don't make me look like an idiot for doing so.

 

[jadrian]

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.

assumption? it should be trivial! the past is defined but the future you suppose isnt?

take this example. the word "could've", HAS NO MEANING, and should be abolished from the english language. maybe if they did that, the next generation of scientists would be all over superdeterminism, as opposed to free will, santa, the tooth fairy etc...

 

[jadrian]

jadrian, speaking in all caps does not assist in getting your point across. I'm trying to defend your viewpoint, don't make me look like an idiot for doing so.

sorry i just don't understand how these concepts are not blatantly obvious to people.

 

[jadrian]

Occam's razor makes it hard to justify invoking a conspiratorial explanation like superdeterminism.
No, a lot of work is not being done on superdeterminism.

occams razor should lead you to a deterministic viewpoint. its so simple.
even in your experiment with entanglement a and b and particles c and d, can you prove that information had not been transmitted between a and d in the history of the universe?

 

[jadrian]

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

speaking of conspiratorial, this experiment could never theoretically be carried out, seeing as your large distance statements imply that a and d are outside each others lightcones. and as we came from a singularity according to bbt, at what point since the big bang did causality cease to exist? because noncausality is the only way i can think of particles a and d having never interacted in some form.