Arguments Against Superdeterminism

[denisv]

In order to believe that physical determinism poses a threat to free will, you also have to believe that laws of nature are equivalent to inviolable prescriptions. Although proponents of such a view may not consciously believe in a Prescriber, they still persevere with the view that laws of nature 'are' prescriptions.

However, if one adopts a view that natural laws are descriptive, the problem of free will disappears. In this view, all the choices made by conscious beings are not forced upon them by the laws of nature. Rather, Indeed, it is the reverse. The laws of nature are the true descriptions of the world. For example, although it is true that you cannot 'violate' a law of nature, it is not because laws of nature 'force' you to behave as such, but because the laws are true descriptions of what we do or have done.

So, inviolable prescriptions vs. inviolable descriptions, the objective difference being...?

 

[Fra]

So, inviolable prescriptions vs. inviolable descriptions, the objective difference being...?

I didn't get comptons point either.

Here is another personal view of this.

IMHO, the whole motivation for physical law is neither invioable prescriptions nor inv. descriptions. It's used in predictive strategies, inferred from nature by evolutionary processes. The utility of a rule to infere the future from the current, is justified with a context where sometime depends on this rule, and there can be variation and selection.

Thus the justification of any rule of inference, is that it does in fact exists in nature since this rule has a self-preserving trait. This doesn't mean that bad inferences are banned, it's just that they not like make it through the competition.

So my view of physical law, is that it is a rule for helping inference of the future, given the present, and thus rule has been formed in the past. It is manifested in the microstructure of matter around us. The laws of physics are IMHO mplicit in the makeup of matter. Thus, the microstructure and interaction properties of matter ENCODE physically, a view of law. If you consider this matter indefinitely stable in all ways, then so ar the laws. But if the evolving material content is not in equilibrium, then the encoded laws are still evolving IMO.

Thus to me, a law is effectively a state, but due to information capacity constraints, there is no embedding state space. So we can not apply ordinary statistics to these states. Only a evolving logic like in biology would work.

The information capacity constraint, is the exploit I imagine to turn this into predctions. If you ponder how possibly encodable distinguishable laws scale with the complexit of matter, then the _observable_ (ie. inferrable) laws of physics are bound to get simpler (ie. unification).

That might provide a somewhat unique starting point, and then see how new laws emerge as the "symmetry" if we call it that is broken by the observers growing larger and larger.

/Fredrik

 

[WaveJumper]

We are large groups of (mainly) quarks and electrons.

No, that's a rather narrow and misleading view. Life is an emergent property of quarks and electrons. There is very Big difference between a dead person and an alive person, though they are made up of the same quarks and electrons.

I didn't say that "everything is an illusion".

Without free-will, everything is an illusion.

How exactly our brain works is not a QM question. On the other hand I have seen no evidence that the brain should deserve a different treatment than any other object.

Why didn't you say consciousness instead of brain? Brain is not consciousness, though they are obviously related.

We try to explain the world around us because we are genetically programmed to do so (it enhances survival).

This explanation, along with all explanations of anything are completely senseless in a superdeterministic universe.

Evolution does not require that mutations are fundamentally random (unpredictable in principle). The term "random mutation" refers to our lack of knowledge regarding the exact conditions at the time that mutation occurred. So there is no conflict between a deterministic universe and evolution.

True, but if you posit that everything is a consequence of a pre-determined configuration of exteremely low entropy at the Big Bang, it raises more questions than it answers.

Those questions can be also put in a probabilistic universe. The fact that some quantum events might be unpredictable do not explain any of your above questions therefore I think they have no relevance to our topic. Give me a good account of how "our personal subjective experience of reality" appears in a universe that is not superedetrministic.

How about "Free will(and Life) is an emergent property in our universe, because there are infinite number of universes".

The existent evidence pointed me into that direction. I don't think it was "pre-programmed". It could be predicted by someone with infinite knowledge but this is different.

I think your idea is radical(that's generelly a good thing when applied to reality), but it degrades science, understanding, knowledge and logic and as such is absurd. If free will is an illusion, how is your theory not another illusion/delusion?

 

[Demystifier]

Well I'm probably as stubbron in my radical solipsism as you are with deterministic realism

Well, I wouldn't call myself stubborn, but yes, that is my preferred viewpoint, especially the realism.

 

[ueit]

Right back at you! Your entire argument seems to be that "it's possible" that the configuration of things at the Big Bang were arranged so that the seemingly "free" choice of polarizer settings in a Bell experiment are somehow pre-arranged (despite efforts to "randomize" them) just to preserve the expected correlations. While I certainly don't believe that the choice of polarizer settings for Alice and Bob are "free" in any ultimate (contra-causal) sense, until you produce a real physical explanation as to why those choices are not at least proximately "free" (and thus statistically independent), the claim is rather empty.

The way a SD theory might explain entanglement has nothing to do with a specific configuration at the Big-Bang. The correlations are not a result of fine-tuning of the original conditions but a result of source-detector interaction. The mechanism is as follows:

1. The detector is described by some particle configuration (it doesn't matter what, no conspirational fine-tuning required).
2. Each particle has an associated classical-like local field. This field is not one of the known fields (EM, weak, etc.) but those fields are assumed to arise as an effective description of the assumed fundamental field. This field has also infinite range so that it can communicate the particle configuration anywhere, at light speed.
3. A particle is only emitted when the detectors' field has a certain, "favorable", value, corresponding to a certain detector configuration.
4. The properties of the emitted particle is a function of the above field.

The result of the above proposed mechanism, both the properties of the emitted particle (spin for example), and the future detector configuration depend on the detector's configuration in the past, therefore they cannot be assumed to be statistical independent, hence the possible violation of Bell's inequalities by a local theory.

 

[octelcogopod]

The only problem I can see that could argue against superdeterminism is consciousness.
If we were talking about anything else in the world I would have no problem believing that they were all things controlled by the quantum forces.
I do however see a gap between quarks and electrons, and qualia.
So far there has been no way to bridge the mental with the physical, and if you think about it, it becomes increasingly harder to do so.
This is not a question about free will (although it's related) but rather how the subjective conscious states can emerge from physical matter and energy.
You can measure and scrutinize the brain all you want, but never are you able to capture the actual subjective experience.
And the only way to do so seems to be to translate neuron relations into known subjective states, if we were able to know every possible neuron configuration. But even in that scenario the magical property of the consciousness is gone.

Consciousness is not just a property of the brain, it is a property of the senses, and the environment around those senses perceive.
But if superdeterminism was true, we should be able to pick up this experience directly in the brain, because the brain would have to be the carrier of all such information.
There's also the free will question of course. If superdeterminism is true, how can we make a choice? No matter on what level the choice is, I can choose to pick up the apple or not, so that would mean deterministic events would control all my emotions and thoughts, but how could I be aware then? Am I really aware?

 

[ueit]

You are arguing both sides of the same argument! Either a) electroweak theory is accurate, and there is no room for SD in it currently; or b) SD is completely outside our current Physics.

I pointed out that a) contradicts your hypothesis. So clearly SD is outside of what we know. That makes it 100% as speculative as the existence of God, so where is the science in any of this?

1. Please substantiate your first statement (a). Where exactly did you provide evidence for your assertion that electroweak theory is incompatible with SD ?

 

[DrChinese]

1. Please substantiate your first statement (a). Where exactly did you provide evidence for your assertion that electroweak theory is incompatible with SD ?

Read any of the Weinberg/Salaam work and follow-on work, and you will see that there is no mention of a superdeterministic mechanism. Yet there would need to be for there to be a violation of Bell Inequalities when the angle setting is determined by radioactive decay (i.e. randomly as far as we know). The mechanism you propose (which is not really a specific proposal at all) requires that either the electromagnetic properties are "right" for emission, which requires that the source knows the detector settings in advance. But they won't be selected until AFTER the photon pair is in flight.

I really must point out that anyone can postulate a non-falsifiable hypothesis (which is completely useless in all respects) regarding any existing physical theory. Hey, maybe oranges are really tiny solar systems but they simply act like edible fruit due to superdeterminism!

Why don't you own up to the true purpose of your question, which I believe is to find a back-handed way to keep local realism in play? If you were serious about superdeterminism per se, you would start by looking for evidence IN FAVOR of SD (of course there is none currently) rather than asking for evidence AGAINST (as you have done).

 

[Doc Al]

The way a SD theory might explain entanglement has nothing to do with a specific configuration at the Big-Bang. The correlations are not a result of fine-tuning of the original conditions but a result of source-detector interaction. The mechanism is as follows:

1. The detector is described by some particle configuration (it doesn't matter what, no conspirational fine-tuning required).
2. Each particle has an associated classical-like local field. This field is not one of the known fields (EM, weak, etc.) but those fields are assumed to arise as an effective description of the assumed fundamental field. This field has also infinite range so that it can communicate the particle configuration anywhere, at light speed.
3. A particle is only emitted when the detectors' field has a certain, "favorable", value, corresponding to a certain detector configuration.
4. The properties of the emitted particle is a function of the above field.

The result of the above proposed mechanism, both the properties of the emitted particle (spin for example), and the future detector configuration depend on the detector's configuration in the past, therefore they cannot be assumed to be statistical independent, hence the possible violation of Bell's inequalities by a local theory.

(1) I see no justification in your model for your statement that future detector positions depend on past detector positions. I don't see anything in your model that prevents detector positions from being chosen "randomly", determined perhaps by the polarization of some cosmic microwave background photon.

(2) If I understand your model properly, it satisfies Bell's locality conditions and thus cannot agree with experiment in all situations. Even if the "field" from the detector communicates with and influences the emission of the particles, the actual detector positions can be randomly chosen at the very last instant (as in double delayed choice experiments) just before the already-emitted particles reach the detectors.

 

[ThomasT]

The way a SD theory might explain entanglement has nothing to do with a specific configuration at the Big-Bang. The correlations are not a result of fine-tuning of the original conditions but a result of source-detector interaction.

The correlation is between the angular difference of the crossed polarizers and the rate of joint detection. The detectors placed after the polarizers are always both set the same. The polarizer settings are varied. So, I assume that by detector you mean polarizer.

Keeping that in mind:

The mechanism is as follows:

1. The detector is described by some particle configuration (it doesn't matter what, no conspirational fine-tuning required).
2. Each particle has an associated classical-like local field. This field is not one of the known fields (EM, weak, etc.) but those fields are assumed to arise as an effective description of the assumed fundamental field. This field has also infinite range so that it can communicate the particle configuration anywhere, at light speed.
3. A particle is only emitted when the detectors' field has a certain, "favorable", value, corresponding to a certain detector configuration.

What about when the polarizer settings are varied while the particles are in flight?

4. The properties of the emitted particle is a function of the above field.

If this were true, then wouldn't it be possible to predict the sequences (and not just the rates) of both individual and joint detections?

The result of the above proposed mechanism, both the properties of the emitted particle (spin for example), and the future detector configuration depend on the detector's configuration in the past, therefore they cannot be assumed to be statistical independent ...

They're dependent due to the pairing process, which is based on the assumption that the polarizers are analyzing the same (or a related) property wrt any given pair of detection attributes. The problem is that it's unknown where the relationship between the entangled particles is produced. The standard assumption is that it's happening via the emission process, and that everything is happening according to the principle of locality via transmissions less than or equal to c. But the precise qualitative charactaristics of the emitted disturbances is unknown. So, standard qm can't give a realist, or explicitly local, account. However, from optics, and the conservation laws, and the known statistical dependencies, etc., standard qm gives an accurate statistical account of the joint state in a nonfactorable form -- which doesn't rule out the possibilities of locality, or nonlocality, or ftl transmissions. And, locality and light speed limit remain the defacto standard assumptions.

... hence the possible violation of Bell's inequalities by a local theory.

I think that the Aspect experiment with time-varying analyzers, as well as the demonstrated independence between polarizer orientation and individual detection in every Bell experiment, make your proposal unacceptable.

 

[ueit]

No, that's a rather narrow and misleading view. Life is an emergent property of quarks and electrons. There is very Big difference between a dead person and an alive person, though they are made up of the same quarks and electrons.

The "big" difference boils down to a difference in the particle configuration, nothing else. Do you have evidence for the existence of something else?

Without free-will, everything is an illusion.

I don't see how this follows.

Why didn't you say consciousness instead of brain? Brain is not consciousness, though they are obviously related.

Consciousness is an emergent, macroscopic property of the particle configuration of the brain. It has no relevance at fundamental level.

This explanation, along with all explanations of anything are completely senseless in a superdeterministic universe.

How is a fundamentally probabilistic universe different in this aspect?

True, but if you posit that everything is a consequence of a pre-determined configuration of exteremely low entropy at the Big Bang, it raises more questions than it answers.

Those questions being...?

How about "Free will(and Life) is an emergent property in our universe, because there are infinite number of universes".

I do not see how this answers what I've asked you:

"Give me a good account of how "our personal subjective experience of reality" appears in a universe that is not superedetrministic."?

How does the number of universes change anything?

I think your idea is radical(that's generelly a good thing when applied to reality), but it degrades science, understanding, knowledge and logic and as such is absurd. If free will is an illusion, how is your theory not another illusion/delusion?

Free will is an assumption we make, not an empirical observation. The fact that this particular assumption is wrong does not imply that our direct observations are delusional.

 

[ueit]

Read any of the Weinberg/Salaam work and follow-on work, and you will see that there is no mention of a superdeterministic mechanism. Yet there would need to be for there to be a violation of Bell Inequalities when the angle setting is determined by radioactive decay (i.e. randomly as far as we know). The mechanism you propose (which is not really a specific proposal at all) requires that either the electromagnetic properties are "right" for emission, which requires that the source knows the detector settings in advance. But they won't be selected until AFTER the photon pair is in flight.

Look, tell me which of the following assumptions you find incompatible with the papers you refer to:

1. Each particle (electron, quark, neutrino, etc.) has a well defined trajectory.
2. Each particle is accompanied by an infinite range, local field.
3. The trajectory of each particle is determined by the structure of this field.

I really must point out that anyone can postulate a non-falsifiable hypothesis (which is completely useless in all respects) regarding any existing physical theory. Hey, maybe oranges are really tiny solar systems but they simply act like edible fruit due to superdeterminism!

SD refers to a class of possible theories (like the class of non-local theories like BM or GRW), it is not a unique theory. Therefore it is too soon to say if those theories are falsifiable or not. I see no a-priori reason to assert that they are not. I see no relevance of your "orange" analogy to SD. SD does not claim that we are deluded. Our observations are correct. SD only imposes some additional constraints on what experimental results are possible to be observed.

Why don't you own up to the true purpose of your question, which I believe is to find a back-handed way to keep local realism in play? If you were serious about superdeterminism per se, you would start by looking for evidence IN FAVOR of SD (of course there is none currently) rather than asking for evidence AGAINST (as you have done).

SD is usually dismissed because of various reasons ('t Hooft is an exception). For now I want to evaluate how strong the arguments against the idea are. Also, I do find EPR experiments as pointing towards SD because the other explanations are very close to a belief in god as you have mentioned (non-locality, unfalsifiable many worlds, etc). While SD may seem counter-intuitive it doesn't contradict (at least in an obvious way) no well established scientific result.

 

[WaveJumper]

The "big" difference boils down to a difference in the particle configuration, nothing else. Do you have evidence for the existence of something else?

I think you have misunderstood my statement. I said that a particluar particle configuration does not mean a living entity. This same configuration can also mean a dead entity(person, animal, etc.). It's not only the configuration that is at play, in fact it's the configuration that causes the emergence of a totally New phenomenon - that of Life. It's still a mistery what it really is that causes a particluar dumb quantum particles configuration to "come alive". Your guess that this emergent phenomenon is a deterministic process is a speculative unfalsifiable guess.

I don't see how this follows.

If every event in the universe is pre-determined by an awful long chain of reactions(incl. your free will), how can we ever know anything for sure? There may be no universe at all, how would we tell if a deterministic process isn't causing us hallucinations of an objectively existent universe? We can't say anything with certainty about anything. We can only say - "A deterministic process is causing/forcing us to believe there is A, B or C".

Consciousness is an emergent, macroscopic property of the particle configuration of the brain. It has no relevance at fundamental level.

What do you mean by "fundamental level"? There are good arguments to believe that at the most fundamental level, something and nothing are one and the same and that all known concepts from our experience are squeezed into non-existence.

How is a fundamentally probabilistic universe different in this aspect?

True randomness(whatever that is) is a pre-requisite for probabalistic genetic occurences. I don't think our observations point to there being a particlular chain of events in the past that lead to particular genetic mutations.

Those questions being...?

If you are putting forward the Simulation Argument, do say so. I find it rather thought provoking and i think it makes much more sense than a "bare" superdeterministic universe that has no first cause. If you had said from the onset that that's what you believe, i think your worldview would have met even more recognition(but maybe that's just me).

I do not see how this answers what I've asked you:

"Give me a good account of how "our personal subjective experience of reality" appears in a universe that is not superedetrministic."?

True Randomness in the quantum vacuum. Wait infinity. Infinity is a long time. Vacuum fluctuations come and go, constantly creating particle-antiparticle pairs. Occasionally whole atoms are created. emember, you have infinity on your side. After 10^5678 "years" - there goes BOOM, a giant quantum fluctuation gives birth to a whole universe like ours(Bolzmann brains). This of course pre-supposes the existence of a spacelike medium. It sounds somewhat abstract, but what we perceive as reality is already abstract enough.

How does the number of universes change anything?

It's the existence of true randomness that counts. Infinite universes, or infinite random quantum fluctuations(some of which create whole atoms and are theorized to be able to create even universes) all rely on randomness as a pre-requsite.

Free will is an assumption we make, not an empirical observation.

How can we make the assumption that we have free-will if we don't have the free-will to make assumptions? This is circular reasoning, not much different than the liar's paradox - The liar said - "I am a liar".

Generally speaking, it sounds like you have the virtual reality argument in mind. If it is so, i have nothing against it, as i see reasons to believe that this might be plausible.

The fact that this particular assumption is wrong does not imply that our direct observations are delusional.

How are we not delusional? We believe we are making our own choices, we believe we live our own lives in our own ways, we believe we are not "pre-programmed" cause-effect robots. How is this not a delusion in a Superdeterministic universe?


I am surprised you didn't invoke the block view of the universe(as per GR) and its all-at-once existence of past, present and future. You could make a strong case on determinism there.

 

[ThomasT]

ueit, I'm still not sure what the distinguishing characteristics of a superdeterministic theory are.

Anyway, here's a good article by Ghirardi for those who haven't read it:

http://plato.stanford.edu/entries/qm-collapse/

 

[SW VandeCarr]

If arguments against SD are wanted, it seems one the most obvious is that it negates the concepts of entropy and information. SD would imply the entropy of any system anywhere at any time is zero since there is never any objective uncertainty as to a system's state or evolution. Then we are dealing with subjective uncertainty only. However subjective uncertainty would also be predetermined, as our "subjective" state is also a function of a system with zero entropy. (Note: I'm using 'subjective' and 'objective' as if there were a fundamental difference. However,I agree with others here that our notion of 'objectivity' is related to issues of consistency and clarity of descriptions).

EDIT: What happens to "the arrow of time" if thermodynamic entropy is always zero?

 

[ueit]

The correlation is between the angular difference of the crossed polarizers and the rate of joint detection. The detectors placed after the polarizers are always both set the same. The polarizer settings are varied. So, I assume that by detector you mean polarizer.

By "detector" I mean the device or group of devices that measure the spin. It might be polarizer + photon detector, or a Stern-Gerlach device or something else. What is important is that the "detector" also includes whatever is used to change its orientation (be it an electric engine, a human, a monkey pressing a button, etc.). Everything that has a contribution to the decision regarding the measurement axis is included in the generic name of "detector".

What about when the polarizer settings are varied while the particles are in flight?

As I have said, "a particle is only emitted when the detectors' field has a certain, "favorable", value, corresponding to a certain detector configuration." Because the evolution of the detector is deterministic, its future orientation is "fixed". The "change" while the particle is in flight is nothing but the detector's deterministic evolution which is "known" by the particle since emission. In other words, you cannot "fool" the particle. The particle "knows" what will happen because it knows the value of the field in the past + deterministic evolution law.

If this were true, then wouldn't it be possible to predict the sequences (and not just the rates) of both individual and joint detections?

Sure, but only if you know the exact value of the field at particle's place.

I think that the Aspect experiment with time-varying analyzers, as well as the demonstrated independence between polarizer orientation and individual detection in every Bell experiment, make your proposal unacceptable.

It doesn't, see above.

 

[ueit]

ueit, I'm still not sure what the distinguishing characteristics of a superdeterministic theory are.

See my answer above.

Anyway, here's a good article by Ghirardi for those who haven't read it:

http://plato.stanford.edu/entries/qm-collapse/

Thanks!

 

[Doc Al]

By "detector" I mean the device or group of devices that measure the spin. It might be polarizer + photon detector, or a Stern-Gerlach device or something else. What is important is that the "detector" also includes whatever is used to change its orientation (be it an electric engine, a human, a monkey pressing a button, etc.). Everything that has a contribution to the decision regarding the measurement axis is included in the generic name of "detector".

Including the polarization of the cosmic microwave background photon that was used to "choose" the detector setting, right?

As I have said, "a particle is only emitted when the detectors' field has a certain, "favorable", value, corresponding to a certain detector configuration." Because the evolution of the detector is deterministic, its future orientation is "fixed". The "change" while the particle is in flight is nothing but the detector's deterministic evolution which is "known" by the particle since emission. In other words, you cannot "fool" the particle. The particle "knows" what will happen because it knows the value of the field in the past + deterministic evolution law.

So basically the emitter knows the state of the entire universe and thus certainly can predict the detector settings at any future time and choose to emit or not emit particles accordingly. Good one! Of course the detector is no dummy--it also knows the state of the entire universe and can predict the behavior of the emitter and act accordingly. (I assume the behavior of the emitter is just as deterministic as is that of the detector.)

All I see is some vague handwaving that somehow everything works out in the end. Where is the physics?

 

[ueit]

Including the polarization of the cosmic microwave background photon that was used to "choose" the detector setting, right?

Right.

So basically the emitter knows the state of the entire universe and thus certainly can predict the detector settings at any future time and choose to emit or not emit particles accordingly.

Indeed.

Good one! Of course the detector is no dummy--it also knows the state of the entire universe and can predict the behavior of the emitter and act accordingly. (I assume the behavior of the emitter is just as deterministic as is that of the detector.)

Sure, but as we are not interested in the particles emitted from detectors I've let them out.

All I see is some vague handwaving that somehow everything works out in the end. Where is the physics?

Can you show that there is something inconsistent in the above assumptions? Can you show mathematically that such a behavior is not possible? If you can, it is great. Rejecting a possible mechanism is good science. But maybe, such a mechanism works and leads to testable predictions (for example one may find out that only a small class of fields lead to predictions that are consistent with QM).

 

[Doc Al]

Can you show that there is something inconsistent in the above assumptions? Can you show mathematically that such a behavior is not possible? If you can, it is great. Rejecting a possible mechanism is good science. But maybe, such a mechanism works and leads to testable predictions (for example one may find out that only a small class of fields lead to predictions that are consistent with QM).

I stated up front that it's "possible" (meaning: not immediately self-contradictory), as I think Bell did as well. So what? It's also "possible" that you (and all of PF) are just a figment of my imagination.

You have not provided or described any mechanism. What experiment would you propose to falsify your proposed "mechanism"? To get anywhere, you need a specific physical mechanism.

 

[ueit]

I stated up front that it's "possible" (meaning: not immediately self-contradictory), as I think Bell did as well. So what? It's also "possible" that you (and all of PF) are just a figment of my imagination.

You have not provided or described any mechanism. What experiment would you propose to falsify your proposed "mechanism"? To get anywhere, you need a specific physical mechanism.

In order to falsify the mechanism one should propose a clear mathematical structure. I am not able to propose it. But if you want a "cheap" example of a SD theory just take Bohm's interpretation, as it is, and replace in the equation the instantaneous, "present" particle distribution with a past distribution so that locality is observed. The "present" distribution is then "predicted" by the particle from the past one.

It would be more interesting to find a formulation that is not such obviously ad-hoc, but for the time being I was only interested if there are well formulated arguments against SD.

 

[ueit]

If arguments against SD are wanted, it seems one the most obvious is that it negates the concepts of entropy and information. SD would imply the entropy of any system anywhere at any time is zero since there is never any objective uncertainty as to a system's state or evolution. Then we are dealing with subjective uncertainty only. However subjective uncertainty would also be predetermined, as our "subjective" state is also a function of a system with zero entropy. (Note: I'm using 'subjective' and 'objective' as if there were a fundamental difference. However,I agree with others here that our notion of 'objectivity' is related to issues of consistency and clarity of descriptions).

EDIT: What happens to "the arrow of time" if thermodynamic entropy is always zero?

Are you saying that a classical gas, composed of molecules with strict deterministic behavior would not obey the laws of thermodynamics?

 

[SW VandeCarr]

Are you saying that a classical gas, composed of molecules with strict deterministic behavior would not obey the laws of thermodynamics?

I'm making a reductio ad absurdum argument. If SD is true, then all events occur with probability one. If you plug p=1 into the Shannon equation (which differs from the Boltzmann entropy equation only by the choice of the constant) you get zero entropy. A block universe under SD (as I understand SD) is completely defined at all space-time points. Therefore its entropy would be zero everywhere all the time. The universe exists in just one possible state.

http://en.wikipedia.org/wiki/Boltzmann_entropy

EDIT:http://en.wikipedia.org/wiki/Entropy_(statistical_thermodynamics)

I'm posting these links, not because I don't think most people on this thread know what I'm talking about, but because some might not, and I just want to be specific regarding what I'm talking about.

 

[Count Iblis]

I'm making a reductio ad absurdum argument. If SD is true, then all events occur with probability one. If you plug p=1 into the Shannon equation (which differs from the Boltzmann entropy equation only by the choice of the constant) you get zero entropy. A block universe under SD (as I understand SD) is completely defined at all space-time points. Therefore its entropy would be zero everywhere all the time. The universe exists in just one possible state.

http://en.wikipedia.org/wiki/Boltzmann_entropy

This is the fine grained entropy, not the coarse grained entropy used in thermodynamics. The fine grained entropy is always zero, even in "ordinary physics".

 

[SW VandeCarr]

This is the fine grained entropy, not the coarse grained entropy used in thermodynamics. The fine grained entropy is always zero, even in "ordinary physics".

Just a short response for now. What kind of entropy does the equation I cited (S_{B}) describe? If it's the "fine grained" entropy and it's always zero, what good is it?

 

[ThomasT]

By "detector" I mean the device or group of devices that measure the spin. It might be polarizer + photon detector, or a Stern-Gerlach device or something else. What is important is that the "detector" also includes whatever is used to change its orientation (be it an electric engine, a human, a monkey pressing a button, etc.). Everything that has a contribution to the decision regarding the measurement axis is included in the generic name of "detector".

Using the standard referents for emitter, polarizer, and detector, in a simple optical Bell test setup involving emitter, 2 polarizers, and 2 detectors it's pretty easy to demonstrate that the polarizer settings aren't determined by the detector settings, or by the emitter, or by anything else in the design protocol except "whatever is used to change" the polarizer settings.

It's been demonstrated that the method that's used to change the polarizer settings, and whether it's a randomized process or not, isn't important wrt joint detection rate. What is important is the settings that are associated with the detection attributes via the pairing process -- not how the settings themselves were generated.

As I have said, "a particle is only emitted when the detectors' field has a certain, "favorable", value, corresponding to a certain detector configuration." Because the evolution of the detector is deterministic, its future orientation is "fixed". The "change" while the particle is in flight is nothing but the detector's deterministic evolution which is "known" by the particle since emission. In other words, you cannot "fool" the particle. The particle "knows" what will happen because it knows the value of the field in the past + deterministic evolution law.

It's already well established that detector orientations don't trigger emissions -- and changing the settings while the emissions are in flight has no observable effect on the correlations. If you want to say that these in-flight changes are having some (hidden) effect, then either there are some sort of nonlocal hidden variable(s) involved, or, as you suggest, there's some sort of heretofor unknown, and undetectable, local field that's determining the correlations. Your suggestion seems as contrived as the nonlocal models -- as well as somewhat incoherent wrt what's already known (ie., wrt working models). Anyway, flesh out the details of it, submit it to the appropriate forum, and maybe somebody who knows more than I do will agree with your approach.

I still don't know what the distinguishing characteristics of a superdeterministic theory are. Can you give a general definition of superdeterminism that differentiates it from determinism? If not, then you're OP is just asking for (conclusive or definitive) arguments against the assumption of determinism. There aren't any. So, the assumption that the deep reality of Nature is deterministic remains the defacto standard assumption underlying all physical science. It isn't mentioned simply because it doesn't have to be. It's generally taken for granted -- not dismissed.

 

[SW VandeCarr]

I still don't know what the distinguishing characteristics of a superdeterministic theory are. Can you give a general definition of superdeterminism that differentiates it from determinism? If not, then you're OP is just asking for (conclusive or definitive) arguments against the assumption of determinism. There aren't any. So, the assumption that the deep reality of Nature is deterministic remains the defacto standard assumption underlying all physical science. It isn't mentioned simply because it doesn't have to be. It's generally taken for granted -- not dismissed.

I don't know how SD is defined either. Perhaps you can address my concerns stated in post 53. I'm basing my argument on Boltzmann entropy.

 

[ThomasT]

I don't know how SD is defined either. Perhaps you can address my concerns stated in post 53. I'm basing my argument on Boltzmann entropy.

Since we're not sure exactly what ueit means by superdeterminism, let's assume for the moment that it's just an emphatic form of the term determinism (equivalent to saying that Nature is absolutely deterministic or really really deterministic, which is equivalent to the standard meaning of determinism).

If arguments against SD are wanted, it seems one the most obvious is that it negates the concepts of entropy and information.

Determinism is an assumption about the underlying nature of the reality that we observe. It's a given as far as physical science's search for fundamental, as well as emergent, dynamical laws.

It isn't obvious to me, and I don't understandl, how the assumption of determinism "negates the concepts of entropy and information".

As I've mentioned, afaik, there are no (and I don't think there can be any) definitive or conclusive arguments against determinism. Entropy might be irrelevant for this, and our information seems to support the assumption of determinism.

Maybe I just don't understand your argument. So, if you could lay it out, step by step, that might help.

 

[ueit]

I don't know how SD is defined either. Perhaps you can address my concerns stated in post 53. I'm basing my argument on Boltzmann entropy.

As ThomasT says, there is no difference between superdeterminism and determinism. However, classical deterministic theories can work with free, external parameters because either there is no long-range field (billiard balls) either the field vanishes with distance (classical EM and gravitational fields). The distinctive characteristic of SD (as I propose it) is that such a separation observer-observed is not possible because the interaction between distant particles never becomes negligible. It is a quantitative, not qualitative difference. The closest analogous would be a system (galaxy) of black holes in general relativity. In order to model the trajectory of one BH you need to know the distribution of all other BH-s.

Regarding your argument, AFAIK a reversible system has a constant entropy. If our universe is SD then it has a constant entropy. However we cannot measure the entropy of the universe, only of a part of it. But this part is not reversible because the interactions with the environment are not taken into account, therefore the entropy may increase.

 

[SW VandeCarr]

Maybe I just don't understand your argument. So, if you could lay it out, step by step, that might help.

The basic argument is fairly straightforward. Entropy, both in the Shannon IT context and in the Gibbs thermodynamic context, is a logarithmic function of probabilities The Gibbs entropy equation:

S=-k\sum_{i}p_{i}lnp_{i}

The probabilities are based on the number of states in which a system can exist. For example a sequence of ten fair coin tosses has 1024 possible states, each state having an equal probability of 1/1024. In thermodynamics, we're talking about the macrostate of a system as a composition of N microstates. The model of the evolution of a thermodynamic system is a Markov process involving the transition probabilities from one state to another.

Given this background, if you assume SD, I'm arguing that there is just one state in which a system can exist at any point in time. The whole notion of a probability becomes irrelevant as an objective concept. Entropy is a function of the number of possible states in which a system can exist. If there is only one state, entropy is equal to zero. Moreover, since the evolution of a system is strictly determined, there is no Markov process.

In the coin toss example, the ten toss sequence is predetermined. There is only one possible outcome before the coin is actually tossed. At best we an only talk about subjective entropy: that is, our uncertainty as to the outcome. This is what SD says. Now, if you take this one step further and ask what subjective uncertainty actually is, it's a state of a system, the system being our brain and the state of knowledge represented in the brain. That's my reductio ad absurdum. We only imagine there are multiple possible outcomes. In reality (under SD) there is only one possible outcome and probabilities have no objective meaning. How can we talk about the entropy of the universe increasing when there is no objective entropy?