- #51
heusdens
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vanesch said:
Or we can assume a higher dimension, in which the two observations are not spatially distantiated, but very close to each other.
Bell experiment would somehow prove non-locality and information FTL?
- Thread starter heusdens
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Or we can assume a higher dimension, in which the two observations are not spatially distantiated, but very close to each other.
- #52
heusdens
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What to conclude from this QM paradox?
One of the points to look for in the intepretation of this seemingly paradoxical quantum nature is that ordinary (formal) logic does not perform very well on quantum events.
Sometimes this notions is established as a distinction between classical logic and "quantum mechanical" logic, a new logic that can deal with the nature of quantum mechanics.
It is however worthwhile noticing that philosophers/logicians smelled something "fishy" about formal logic long before these physical discoveries were made.
Most noticable philosophical progress was made by Hegel, who saw the contradictions of formal logic and sublated formal logic into a system of dialectics which both overcomes and maintaints formal logic.
Quantum mechanics has used this to their advantage.
See for example:
http://www.marx.org/reference/archive/hegel/help/mean05.htm
One of the logic rules that are not tennable in quantum mechanics is the law of excluded middle. The statement that an object either has property A or has not property A, is in quantum mechanics no longer tennable.
But also the law of identity, which merely says that an object/entity equals itself, has also problems when related to nature, since if it were to be assumed that the law of identity is applied always, it would mean no change whatsoever could take place in which something changes into something else. Everything would be motionless and without change.
If the strict rules of formal logic were to be applied, it could only be used in abstract and formal thought, not to the real world.
One of the points to look for in the intepretation of this seemingly paradoxical quantum nature is that ordinary (formal) logic does not perform very well on quantum events.
Sometimes this notions is established as a distinction between classical logic and "quantum mechanical" logic, a new logic that can deal with the nature of quantum mechanics.
It is however worthwhile noticing that philosophers/logicians smelled something "fishy" about formal logic long before these physical discoveries were made.
Most noticable philosophical progress was made by Hegel, who saw the contradictions of formal logic and sublated formal logic into a system of dialectics which both overcomes and maintaints formal logic.
Quantum mechanics has used this to their advantage.
See for example:
http://www.marx.org/reference/archive/hegel/help/mean05.htm
One of the logic rules that are not tennable in quantum mechanics is the law of excluded middle. The statement that an object either has property A or has not property A, is in quantum mechanics no longer tennable.
But also the law of identity, which merely says that an object/entity equals itself, has also problems when related to nature, since if it were to be assumed that the law of identity is applied always, it would mean no change whatsoever could take place in which something changes into something else. Everything would be motionless and without change.
If the strict rules of formal logic were to be applied, it could only be used in abstract and formal thought, not to the real world.
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- #53
CarlB
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Dear heusdens,
You might try the first half of this article, as it discusses a version of the problem that really illustrates well the problem:
http://arxiv.org/abs/quant-ph/9510002
Every time I read papers like the one I just link in, I am reminded again just how weired "The World" is. It makes one want to explore alternatives to explain the quantum weirdness. There are various attempts. The one you've just mentioned seems to be brought up regularly by amateurs, but they can never get the equations to work with it, and so I doubt that it goes anywhere. But faith is what keeps people trying new (or old) ideas, in the face of odds that they are most certainly deluded, and it is faith that will someday solve these problems.
What these experiments do show is that QM is not joking around when they talk about the quantum states not being determined before you make the measurement. This is really the way it has to be.
Once you accept this by looking at stuff like the GHZ experiment, you have gained important insight. The insight is that in understanding a QM experiment, you simply cannot suppose that things are predetermined. And this insight is important because now you can go back and look at the experiment that Feynman said was the fundamental mystery of QM, the two slit experiment. And the two slit experiment is a lot simpler to understand than these other experiments.
When you take a class in QFT, you end up learning how to add up large numbers of things called Feynman diagrams. Intuitively, I always thought of each diagram as an alternative path for the experiment. I realize that other people think of it as just perturbation theory or whatever. But I like to imagine that there is a physical reality behind a calculation, a reason for why the calculation works, an ontology.
The most common ontological explanation for the weirdness is the MWI, which I find revolting. The idea is that the universe splits at each of the places where a measurement is made, and somehow only splits are allowed are ones that are consistent with the calculations, more or less.
The second most common is probably Bohmian mechanics, for which I find little motivation. The idea is that quantum objects are composed of a wave and a particle. The particle suffers a force that is determined by the wave. The wave can be calculated without knowing exactly where the particle. To know how to move, the particle only needs to know the shape of the wave in the region which it travels through.
In these experiments, the weird results come from interactions between the waves of the two (or three) moving quantum thingies. So the Bohmian mechanics say that the waves are just what you'd expect for interacting waves. And the particles just surf on the waves.
To me, the Bohmian interpretation implies that the wave must be present before the particle shows up. That is, the wave effects the path of the particle, but the particle does not effect the flow of the wave. To me this is very suggestive, and it calls into question the meaning of the word "event" in relativity.
In relativity, an "event" is something that happens at a particular point in space at a particular time. That would seem to be compatible with the "particle" definitions, but it is not compatible with the wave. The conclusion of a lot of physicists is therefore that the wave is not a part of reality, it's just the technique we use for calculating the interactions of particles.
I prefer to think of the wave as a part of reality, but to place it in the future (of the observer of the event), the future where the moving finger of fate has not yet written. As the finger moves, the particle advances. The wave is the stress that's present on spacetime before the finger of fate reaches that particular time.
Now the two slit experiment is fully understandable with light treated as a wave. It is only mysterious when it thought of as a particle experiment, how does the particle go through both slits? If you look at it from the "moving finger of fate" point of view, the little chunk of spacetime where the event takes place exists some minutes, hours and probably days before the actual experiment.
The event already exists, but its result is not yet determined. The particles, however, exist in the past and already their presence in the past influences the future, that chunk of spacetime is influenced by them, and it is deformed or stressed by the approaching presence of the particles. Engineers (and heavy equipment operators) know that the equations of stress and strain can be written as differential equations. Applied to a 4-D object like spacetime, the differential equations become wave equations, the same sort of things that define QM waves.
Before the particle actually shows up, it presumably induces stresses in all the places where it could go, and that is why we cannot assign a predetermined result to the experiments. It is only when the actual choice of the hand of fate is made that the experiment completes. At that time, fate makes the choice for the particle, and its stresses on the roads not taken fall to zero, while the stresses on the roads yet to take are subtly altered (which is sort of an issue with the Bohmian explanation).
This kind of ontology avoids the problem with spooky action at a distance, and the issues of a whole universe splitting up in unimaginably large numbers of measurements simultaneously. There's still only one universe, but at any given position of the finger of fate, the events of that universe are divided up into the things still to come (where stresses act like waves), and the things that have been written, (where the passages are written in particle tracks).
The weirdness of QM is sufficiently strong that you can start arguments among even people who know a great deal about it. I can't imagine a better hobby than trying to understand it.
You might try the first half of this article, as it discusses a version of the problem that really illustrates well the problem:
http://arxiv.org/abs/quant-ph/9510002
heusdens said:
Every time I read papers like the one I just link in, I am reminded again just how weired "The World" is. It makes one want to explore alternatives to explain the quantum weirdness. There are various attempts. The one you've just mentioned seems to be brought up regularly by amateurs, but they can never get the equations to work with it, and so I doubt that it goes anywhere. But faith is what keeps people trying new (or old) ideas, in the face of odds that they are most certainly deluded, and it is faith that will someday solve these problems.
What these experiments do show is that QM is not joking around when they talk about the quantum states not being determined before you make the measurement. This is really the way it has to be.
Once you accept this by looking at stuff like the GHZ experiment, you have gained important insight. The insight is that in understanding a QM experiment, you simply cannot suppose that things are predetermined. And this insight is important because now you can go back and look at the experiment that Feynman said was the fundamental mystery of QM, the two slit experiment. And the two slit experiment is a lot simpler to understand than these other experiments.
When you take a class in QFT, you end up learning how to add up large numbers of things called Feynman diagrams. Intuitively, I always thought of each diagram as an alternative path for the experiment. I realize that other people think of it as just perturbation theory or whatever. But I like to imagine that there is a physical reality behind a calculation, a reason for why the calculation works, an ontology.
The most common ontological explanation for the weirdness is the MWI, which I find revolting. The idea is that the universe splits at each of the places where a measurement is made, and somehow only splits are allowed are ones that are consistent with the calculations, more or less.
The second most common is probably Bohmian mechanics, for which I find little motivation. The idea is that quantum objects are composed of a wave and a particle. The particle suffers a force that is determined by the wave. The wave can be calculated without knowing exactly where the particle. To know how to move, the particle only needs to know the shape of the wave in the region which it travels through.
In these experiments, the weird results come from interactions between the waves of the two (or three) moving quantum thingies. So the Bohmian mechanics say that the waves are just what you'd expect for interacting waves. And the particles just surf on the waves.
To me, the Bohmian interpretation implies that the wave must be present before the particle shows up. That is, the wave effects the path of the particle, but the particle does not effect the flow of the wave. To me this is very suggestive, and it calls into question the meaning of the word "event" in relativity.
In relativity, an "event" is something that happens at a particular point in space at a particular time. That would seem to be compatible with the "particle" definitions, but it is not compatible with the wave. The conclusion of a lot of physicists is therefore that the wave is not a part of reality, it's just the technique we use for calculating the interactions of particles.
I prefer to think of the wave as a part of reality, but to place it in the future (of the observer of the event), the future where the moving finger of fate has not yet written. As the finger moves, the particle advances. The wave is the stress that's present on spacetime before the finger of fate reaches that particular time.
Now the two slit experiment is fully understandable with light treated as a wave. It is only mysterious when it thought of as a particle experiment, how does the particle go through both slits? If you look at it from the "moving finger of fate" point of view, the little chunk of spacetime where the event takes place exists some minutes, hours and probably days before the actual experiment.
The event already exists, but its result is not yet determined. The particles, however, exist in the past and already their presence in the past influences the future, that chunk of spacetime is influenced by them, and it is deformed or stressed by the approaching presence of the particles. Engineers (and heavy equipment operators) know that the equations of stress and strain can be written as differential equations. Applied to a 4-D object like spacetime, the differential equations become wave equations, the same sort of things that define QM waves.
Before the particle actually shows up, it presumably induces stresses in all the places where it could go, and that is why we cannot assign a predetermined result to the experiments. It is only when the actual choice of the hand of fate is made that the experiment completes. At that time, fate makes the choice for the particle, and its stresses on the roads not taken fall to zero, while the stresses on the roads yet to take are subtly altered (which is sort of an issue with the Bohmian explanation).
This kind of ontology avoids the problem with spooky action at a distance, and the issues of a whole universe splitting up in unimaginably large numbers of measurements simultaneously. There's still only one universe, but at any given position of the finger of fate, the events of that universe are divided up into the things still to come (where stresses act like waves), and the things that have been written, (where the passages are written in particle tracks).
The weirdness of QM is sufficiently strong that you can start arguments among even people who know a great deal about it. I can't imagine a better hobby than trying to understand it.
- #54
jtbell
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CarlB said:
As evidence, observe the fact that the longest threads in this forum are invariably about the interpretation of quantum mechanics, not about the predictions that it makes for physical observables.
- #55
heusdens
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heusdens said:
I don't know if this will fit the descriptions, but let us assume we design the experiment in another way. We use the initial descriptions of the experiment, but now add to it that the "dice" we used is not in a fixed position, but instead it is rotating around it's axis (let's asume it is a vertical axis, from top to bottom).
That means, that some of the measurements get "blurred". It just means, the outcome is not settled, or unkown. Instead of a property of either it is (TRUE), or it isn't (FALSE), we then get the outcome that the property is unknown/undefined (NULL).
It is then rather easy to get outcomes which don't fit statistically the Bell inequality.
The property values are as follows:
True: 1,2,3
False: 4,5,6
Null: blurred
For example, let's describe the properties as follows:
A: Number we see from the top
B: Number we see from the side (which might be blurred)
C: Number we see from the bottom
It would then be relatively easy to have outcomes that violate the inequality:
N (A, ~B) + N (B, ~C) >= N (A, ~C)
- #56
heusdens
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vanesch said:
That are good questions, and that is of course the problem. Since, realistically seen, there are not singular objects anywhere. Neither the electron for example is a singular object, there are always other particles involved. So, it is very difficult to extract singular objects.
- #57
DrChinese
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heusdens said:
Good try, but that does not fit the actual facts!
The reason is that there is NO "blurring" (regardless of how you define it) and there are apparently NO null values (regardless of how you define it).
Imagine the case where we measure the polarization of two entangled photons at angle settings of 0, 120 and 240, but the measurements are random on each side. We ALWAYS get agreement when the angle settings are the same, so how is there blurring or null values? On the other hand, when the settings are different we have a violation of Bell's Inequality as the values should be the same at least 1/3 of the time, but are actually the same only 1/4 of the time.
In other words: the violation of Bell's Inequality that you have above is not explainable when you also consider the perfect correlations.
- #58
vanesch
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heusdens said:
Again, you've found a setup which has nothing to do with the original setup, and moreover for which your "Bell inequality" is erroneously written down. Indeed, for a Bell inequality, we have to sum over a TOTAL PARTITION of the B-outcome. So, your B-outcome can now have 3 possible values:
"true", "false","blurred". You have to cut this set in two parts, and then apply the Bell inequality to that, because THAT is what happens in a true EPR experiment. Then you have:
N(A,B=~(true or false)) + N(B=(true or false),~C) >= N(A,~C) and that won't be violated (as are all the other inequalities resulting from other subdivisions of the outcomes at B).
So you didn't construct a system with a "Bell inequality violation" because the inequality you wrote down wasn't a Bell inequality.
- #59
heusdens
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Yes, but the fact is if there is a separate measurement of all 3 properties A,B,C and only true or false values and I put that in a table, the bell inequality will hold no matter what the experiment is.
I could even create a table of any combination of A,B, C without an experiment, and always the inequality comes out.
The quantum variant of the measurement, holds to the fact that 'somehow' individual properties are being measured, while they are not. We only measure the constructs N (A, ~B), N (B, ~C) and N (A, ~C), and they may deviate from the inequality. That is why the inequality can be broken.
If we would rearrange that into:
A' = P (A, ~B)
B' = P (B, ~C)
C' = P (A, ~C)
Then the inequality will still hold.
I could even create a table of any combination of A,B, C without an experiment, and always the inequality comes out.
The quantum variant of the measurement, holds to the fact that 'somehow' individual properties are being measured, while they are not. We only measure the constructs N (A, ~B), N (B, ~C) and N (A, ~C), and they may deviate from the inequality. That is why the inequality can be broken.
If we would rearrange that into:
A' = P (A, ~B)
B' = P (B, ~C)
C' = P (A, ~C)
Then the inequality will still hold.
- #60
wm
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Clarifying realism and locality
Dear Doc: Given that there are differing ''brands'' of realism and locality (including Einstein realism, Bell locality; variously defined), would you mind defining the realism and the locality that you say we cannot logically stay with?
That is, could we have the definitions implicit in your reply above? Thus:
For DrC, realism is ...
For DrC, locality is ...
Thanks, wm
DrChinese said:
Dear Doc: Given that there are differing ''brands'' of realism and locality (including Einstein realism, Bell locality; variously defined), would you mind defining the realism and the locality that you say we cannot logically stay with?
That is, could we have the definitions implicit in your reply above? Thus:
For DrC, realism is ...
For DrC, locality is ...
Thanks, wm
- #61
heusdens
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vanesch said:
http://www.upscale.utoronto.ca/GeneralInterest/Harrison/BellsTheorem/BellsTheorem.html
That page I got the equation from, and to my knowledge that is correct.
It says it doesn't matter what the population is, we just inspect three distinct properties A,B,C (which can be dependend properties) with at least two possible outcomes.
- #62
DrChinese
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heusdens said:
The Inequality does NOT hold. That is the issue.
On the other hand, there are "prefect" correlations at ANY angle setting. That is the evidence that makes one suspect that there IS reality to the values at any angle setting. EPR created a definition of such "elements of reality", because the value of one entangled particle could be predicted without disturbing the other.
- #63
DrChinese
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wm said:
I use the definitions generally associated with Einstein for both.
For DrC, Realism = "A particle must have a separate reality independent of the measurements. That is: an electron has spin, location and so forth even when it is not being measured." -Einstein. (In effect, that reality is observer independent.)
For DrC, Locality = Signals/information/causal influences/force carriers cannot propagate faster than c.
While some disagree, I believe these definitions map to the definitions Bell intended in his original paper, especially that of Reality. So to me, this is also Bell realism (i.e. they are equivalent). Bell realism is expressed mathematically as the idea that a particle has simultaneous definite spin or polarization values - independent of their actual measurement - at 3 or more angle settings; and that those values have probability of occurring that are in the range from 0 to 100%.
- #64
ianbell
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Worth pointing out here that since in the standard EPR experiment the observations are considered as spacially separated rather than timelike sepertied events, it is meaningless to speak of Alice making her measurement "before" Bob makes his as there will be some observers who percieve Bob's measurement as occurring first.
- #65
heusdens
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DrChinese said:
Have you calculated that?
Can you give a numerical proof of it too?
Yes, of course there is reality to it, only we don't know what reality.
- #66
vanesch
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heusdens said:
You've got it.
YES. That's the whole point. So indeed, there is NO INDIVIDUAL QUANTITY that seems to correspond to each of the physical objects at the two remote experimenters. That's the whole point of the Bell inequalities. IF there were such a quantity (a "hidden variable") then there is only one possibility: that is that the hidden variable for the quantity to be measured is CHANGING at Bob's when Alice (very far away) is doing her measurement on an OTHER object (the famous action-at-a-distance).
So we are confronted with the puzzling point that:
1) Bob is doing a measurement on some object and Alice is doing some measurement on another object
2) What they measure is seemingly NOT a property of the object they measure (because if it were, you agree that the inequality should come out)
3) nevertheless, they find perfect anti-correlations !
BTW, that's why no "classical analogy" of such a violation can be set up. You cannot think of any classical system in which we:
1) measure the set of objects N(A,~B), ... and violate the inequalities
2) have perfect anti-correlations.
You can easily find setups where ONLY 1) or ONLY 2) is satisfied (that's what people often do and think they found the "solution"), but both together, doesn't work classically (unless you allow for long ropes between Alice and Bob...).
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- #67
vanesch
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heusdens said:
Even that is not true. We have a *theory* which gives us these predictions. It is not as if we found this empirically and had no clue how it happened. We HAVE a theory which predicts exactly this behaviour, and it is called quantum theory.
- #68
heusdens
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vanesch said:
Yes, I thought that! We misassume something about propertyness in the quantum cases.
But then it could be claimed that - when redefining 'property' as follows:
A' = P(a, ~b)
B' = P(b, ~c)
C' = P(a, ~c)
the inequality:
P(A', ~B') + P(B', ~C') >= P(A', ~C')
still holds?
- #69
DrChinese
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heusdens said:
1. I see now that you were trying to create a new inequality with your "prime" designation. There is no purpose to following that further until your provide some meaning to what this is supposed to represent.
2. Well, you can say there is reality to it, but there may not be the simple Einsteinian reality that is commonly discussed. So when you say "reality", what do YOU mean? Are there simultaneous definite values at all angle settings regardless of the act of measurement? (If so, you must be a believer in the non-local branch of Bell's Theorem.)
- #70
heusdens
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DrChinese said:
1.
The question was wether these *new properties* (derived from the old ones) conflict with the inequality or not. My guess is, they do not conflict, but I haven't calculated them.
2.
The question of meaning does not only apply to my new definition, but also to the already used old meaning. What in fact are Bob and Alice measuring in the first place? What is it in *that* definition that gives it meaning?
In fact, meaning, is a subjective term of some sort. What does it mean for a certain phenomena to have a certain property?
Is there intrinsic meaning in any of the phenomena of nature or any property we can define?
What does it mean for an object to have mass, speed, charge, spin, etc.?
In my point of view, both Alice and Bob just collect meaningless data. Only after they compare each others note, we can extract some meaning out if it.
[ note: compare this for example to a question like what is the value of a dollar. Some people tend to think that a dollar has some intrinsic property, we call value, although in fact we can only measure the value of a dollar or any other currency as an exchange value, that is the relative value of a dollar as compared to another currency. There is nothing in the dollar, or any other currency, that make it have some intrinsic property of value. ]
In the perspective of relativity the term *simultanious* is a very observer dependend term. In what frame of reference and in what configuration of the set up are you asking this?
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- #71
heusdens
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vanesch said:
Yeah!
As I showed, and using the proper definitions of "property" and "outcome" and other requirements under which the Bell Inequality is defined, my argument is that you do not even have to do a measurement, since the inequality comes out in any case. That is, because it is only bound to logic itself.
You could just fill an arbitrary table of outcomes, without doing actual measurements.
That is even true for QM experiment outcomes, just by redefining "property" as I did, then also the inequality is not broken.
So, in other words, the paradoxes which arise, are just based on how we made our choice of defining "property" and "outcome" for this experiment.
We can do that, at the cost of sacrificing logic itself.
Or we can redefine them, so that they do not conflict with logic.
Yet, in doing so, we create another stumbling paradox regarding our underlying understanding of physical theory, in which we can't understand it anymore. The method we can invent to circumvent that, seems worse then the cure.
So, wether one chooses for one, or the other, we will always get a contradiction.
For conventional logic, this situation is not satisfyable and unrepairable.
It is especially for that reason that we need a "better tool" as formal logic, and which is a tool which both overcomes and maintains the formal logic, which is the tool of dialectics.
Surprisingly, dialectics has been already developed, amongst others by Hegel, many years before physics run into this experimentally. But for some reason, physics never adapted this tool.
Perhaps therefore physics has some problems in understanding the universe, and runs sometimes in deep problems, for example in the field of cosmology and other physics theories, have great difficulty in explaining the universe as it is. Physics and physics theory does not yet grasp that at the very bottom of nature we stumble on unsolvable contradictions, and every method to fix that contradiction, new and worse contradictions arise in other fields.
[ The issue of the "beginning" of the world/universe or the finity/infinity of the world, are examples in which the methods of physics and physical theory stumble on contradictions.
(and please note that wether or not the world is finite in time/space or infinite, are both contradictions).
String theory development, and M theory, are examples on how physics tries to come up with a solution, and in doing so, creates an unimaginable world of higher dimensions and unseen particles, and in fact creates a world of it's own in pure mathematical abstract terms. The way they are created (as mathematical constructs) are not even in principle falsifiable.
We can NEVER detect (not even in theory) higher dimensions, and NEVER detect strings.
This in itself is not yet a reason to reject them (as neither can we see or detect gravity directly, yet we know it's effects, and can do measurements that can be predicted by theory), as long as the theory can make predictions that can be falsified. ]
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- #72
heusdens
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DrChinese said:
The second one, locality, has never been disproved, and if relativity is true, this must be the case.
The first however, realism, defines "things" to have 'intrinsic' properties, independend of other things.
I find that at least problematic, and also even in theory unprovable.
As a macro world example: there is nothing intrinsic in a dollar that makes it have value, there is only exchange value, so a relative value between different currencies.
I would guess that the micro world can only be approached in similar ways.
A measurement of a "property" is always comparing things with other things.
Measuring a mass, is a relative property of a thing, when compared to a "standard" thing, etc.
- #73
JesseM
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(again, please note that the word is spelled 'independent') This talk about "things" and "properties" is probably not necessary when discussing Bell's theorem--we could instead think in terms of events and their causal relations. Suppose two experiments measure a pair of entangled particles, and find that whenever they measure their spin along the same axis, they always get opposite spins. Instead of bothering with whether the electrons are "things" with a preexisting property of having certain spins, we can just think in terms of three events--the events of the two measurements, and the event of the pair's creation at some point in space between the experimenters. We can explain the correlation in causal terms either by saying one measurement-event causes the other measurement to come out opposite--superluminal causation--or we can try to explain it by saying that the event of the particles' creation determined in advance what result would be found if each particle was later measured on a given axis, in such a way that it is always determined that measurements on the same axis will yield opposite results. Since the event of the particles' creation lies in the past light-cone of both measurement-events, there would be no violation of locality if this were the case. What the violation of Bell's inequality shows is that this second strategy can't work.heusdens said:
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- #74
wm
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Clarification please
Clarification please: Finding this to be a very productive thread, I believe some of the helpful statements by supporters of Bell's theorem are readily rebutted. So the clarification that I seek is this:
1. Some of the BT supporters statements are already rebutted on my personal website (and more could be added), but I understand that it is not permitted to cite my site on PF because it is seen to be ''independent research''.
2. Do I understand the situation correctly? AND SO: Do I need to reproduce my arguments afresh and in full here without any reference whatsoever to my site?
3. PS: The ''independent research'' section of PF appears unsuited to my work because my site is frequently updated in response to correspondence, etc.
PPS: Given the permitted discussion so far, I do not believe that my ideas fall under the Forum Rule: ''Poorly formulated personal theories, unfounded challenges of mainstream science, and overt crackpottery will not be tolerated anywhere on the site.''
Thanks, wm
Clarification please: Finding this to be a very productive thread, I believe some of the helpful statements by supporters of Bell's theorem are readily rebutted. So the clarification that I seek is this:
1. Some of the BT supporters statements are already rebutted on my personal website (and more could be added), but I understand that it is not permitted to cite my site on PF because it is seen to be ''independent research''.
2. Do I understand the situation correctly? AND SO: Do I need to reproduce my arguments afresh and in full here without any reference whatsoever to my site?
3. PS: The ''independent research'' section of PF appears unsuited to my work because my site is frequently updated in response to correspondence, etc.
PPS: Given the permitted discussion so far, I do not believe that my ideas fall under the Forum Rule: ''Poorly formulated personal theories, unfounded challenges of mainstream science, and overt crackpottery will not be tolerated anywhere on the site.''
Thanks, wm
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- #75
heusdens
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JesseM said:
The logic of the whole experiment is that the individual measurements, don't relate to any specific property we can define as such, but only if we combine the results, we can actually state something and relate it so some kind of property.
Another way of looking at this (as an analogy). Suppose a single source sending two signals to two observers. Both observers measure nothing but random values.
But when we combine both signals (for example by subtracting respective values) then suddenly we get a clear signal, a message or whatever.
What before seems meaningless bytes of information, now becomes something with meaning, a message or something.
If we look at it this way, it becomes more obvious what we are talking about.
- #76
heusdens
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http://www.chronon.org/Articles/localreal.html
In the above case, the explenation given seems invalid to me.
First, the stream of particles sent out has both the property of being random (all polarization directions are equally possible, as can be seen when we inspect only one detector) and not random (somehow the polarization directions between both detectors, do correlate, which can be seen if their polarization direction is the same).
If both detectors are in the same line up (effective angle is zero), there is 100% correlation between both measurements.
We might think what happens if we increase the angle (yet again, we speak here of the effective angle between both detector settings, each individual setting is irrelevant, which seems plausible because that would just be the equivalence of having the source turn at an angle, which makes no difference since the polarization directions are random), that is that we will find less corelation.
First we notice that this is just a slight reduction of the correlation, which might be explained because when the effective angle is zero, we do not only find photons that exactly match that angle, but also photons that deviate a little bit, although the same number at every side.
Notice that for a photon the polarization filter is a big gap, which gives some tolerance for not perfectly lined up polarization directions of photons. This means we find less correlated photons, and introduce more of the randomness.
However, above a certain range, the correlation gets completely lost, that is we get total randomness.
I don't see why this would not be a good explenation of the above mentioned experiment. Although it could be tested by using different sized polarization filters.
And a different anology would be to see this as the broadcasting of a radio signal between a reciever and a sender. If sender and receiver have the same frequency we get a clear signal. If one or both sender and reciever have a different frequence, the signal gets less clear (more random), until at a certain frequence difference, we get only noise (total random signal).
In the above case, the explenation given seems invalid to me.
First, the stream of particles sent out has both the property of being random (all polarization directions are equally possible, as can be seen when we inspect only one detector) and not random (somehow the polarization directions between both detectors, do correlate, which can be seen if their polarization direction is the same).
If both detectors are in the same line up (effective angle is zero), there is 100% correlation between both measurements.
We might think what happens if we increase the angle (yet again, we speak here of the effective angle between both detector settings, each individual setting is irrelevant, which seems plausible because that would just be the equivalence of having the source turn at an angle, which makes no difference since the polarization directions are random), that is that we will find less corelation.
First we notice that this is just a slight reduction of the correlation, which might be explained because when the effective angle is zero, we do not only find photons that exactly match that angle, but also photons that deviate a little bit, although the same number at every side.
Notice that for a photon the polarization filter is a big gap, which gives some tolerance for not perfectly lined up polarization directions of photons. This means we find less correlated photons, and introduce more of the randomness.
However, above a certain range, the correlation gets completely lost, that is we get total randomness.
I don't see why this would not be a good explenation of the above mentioned experiment. Although it could be tested by using different sized polarization filters.
And a different anology would be to see this as the broadcasting of a radio signal between a reciever and a sender. If sender and receiver have the same frequency we get a clear signal. If one or both sender and reciever have a different frequence, the signal gets less clear (more random), until at a certain frequence difference, we get only noise (total random signal).
- #77
JesseM
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Thinking in terms of a source sending signals to two observers is indeed a good way of understanding the strangeness of the fact that the inequalities are violated. Suppose we have two people, Alice and Bob, connected to computer terminals at distant location. At a certain moment, each of them has the option to type "A", "B", or "C"--the monitor will then show either a + or a -. They have no idea how the computer picks which symbol to display on each trial--it could be based on a signal from a source, it could be based on a random selection made after the button is pressed, it could be based on some physical experiment in the next room, they don't know. After multiple trials they get together and compare results. They find that on every trial where they both hit the same letter, they get opposite symbols. In this case, the version of Bell inequality given on this page, which is based on the assumption that a common source had sent each computer a signal or object which would predetermine its answer to each possible letter they chose, with the three predetermined answers being opposite for the two of them (so if one's predetermined answers are A+ B- C-, the other's predetermined answers must be A- B- C+), would imply the following:heusdens said:
Number(Alice types A, gets +; Bob types B, gets +) plus Number(Alice types B, gets +; Bob types C, gets +) is greater than or equal to Number(Alice types A, gets +; Bob types C, gets +).
Likewise, the alternate inequality which I mentioned in my earlier post about scratch lotto cards would imply that when Alice and Bob pick different letters, the probability of them getting opposite results (one sees a + and the other sees a -) must be greater than or equal to 1/3.
If the computers are hooked up to devices which measure the spins of entangled photons on 3 possible axes depending on which letter is typed, and return a + or - depending on the spin found, then it will be possible to insure that either or both of these inequalities are violated. However, I would claim that if we lived in a classical universe which obeyed locality, it would be impossible to violate either inequality and still ensure that Alice and Bob always get opposite answers when they type the same letter. No matter what possible setup you think up, you can never ever replicate this "trick" using only classical signals and devices. Do you agree?
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- #78
DrChinese
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heusdens said:
Einstein, and Bell, understood that the specific property we purport to give meaning to is as follows: If the outcome of Bob can be predicted with certainty, then there must be an element of reality associated with it. In fact, the outcome of Bob can easily (by way of direct actual experiment, using suitably shaped fiber optics) be predicted with certainty simply by first looking at the outcome of Alice.
This is what we learned from EPR: that the Heisenberg Uncertainty Principle (if correct) implies that the reality of Bob's outcome is dependent on how we measure Alice. Actual experiments would likely have satisfied Einstein as to his definition of "elements of reality", since they were designed with this in mind. Some folks call this "naive realism" but I consider that an insult to Einstein.
- #79
vanesch
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heusdens said:
Indeed, up to one single detail. When you "fill in your table", you are filling in the properties which could be potentially measured. That is, when you fill in the table which tells you: up - up - down for the potential measurements in the a-direction, the b-direction and the c-direction, you are assuming that there EXISTS a UNIQUE answer for each of these measurements, independent of the fact whether they are being done or not. In other words, you assume that there is a property of the thing to be measured, that can determine the outcome of these measurements. Otherwise your table wouldn't make sense.
Well, this is what doesn't work in quantum theory. In the same way as you cannot say that a particle HAS a specific position and HAS a specific momentum (whether or not we KNOW it) in quantum mechanics, in the same way you are not supposed to say that there IS a specific outcome potentially present for the a-direction, the b-direction and the c-direction.
So it is not "logic itself" which makes the Bell inequality hold, it is logic, plus the assumption that there is a property that determines the potential outcome for each of the 3 potential measurements associated to each of the two objects. Why did we consider this potential outcome in the first place ? Because of the perfect anti-correlations. It is the evident explanation that comes to mind when you have perfect anti-correlations: it is that the outcome is already "predetermined" in the objects (thanks to their common origin). Well, turns out that this is not so in quantum theory.
So what is puzzling in QM is not so much the violation of the Bell inequalities themselves, but rather their violation together with the perfect anti-correlations. The violations seem to indicate that the "table with outcomes" doesn't exist. But this we knew already: in quantum theory we run into troubles when we assume pre-existing values for non-commuting observables (not just the fact that we are ignorant of them, but their very existence is a problem - but this we knew already). The observations of spin under different angles are another example of such non-commuting observables. So it shouldn't surprise us somehow, from a quantum perspective, that this famous "table" doesn't exist (in the same way as phase space doesn't exist with well-defined positions and momenta). If the table doesn't exist, then the violations of the Bell inequalities (which follow from it) are no issue. However, we now have a problem in understanding the perfect anti-correlations. Without the properties pre-existing, how can we obtain perfect anti-correlations ?
The other approach is to start with the perfect anti-correlations, and take the (straightforward) explanation for them: the table exists. This would be the "empirical" approach, in ignorance of quantum theory. And THEN we run into troubles, because the existence itself of the table implies, from pure logic, that the Bell inequalities are to hold, which they (empirically) don't. So this simply points to the fact that whatever is responsible for the perfect anti-correlations, it cannot be the straightforward explanation of the existence of a table.
Yes. From the moment that you can set up a table, the Bell inequalities have logically to hold.
No, there is an almost "trivial" solution to the issue, which keeps logic, and locality intact. The thing you have to sacrifice this time is your common sense, that there is actually a unique outcome at Bob and at Alice. If you accept that they simply entangle with their objects, and hence that BOTH outcomes (up and down) are present as superpositions of the observers. It is the Many World Interpretation. As I've explained this already several times, here's one of those threads:
https://www.physicsforums.com/showthread.php?p=936155
Mind you, I'm not trying to force MWI through your throat. I only think that if you are puzzled by the EPR-Bell paradox, that you should be aware also of its "resolution" by the MWI view, in the same way as you should be aware by its "problem", and by its resolution, say, in Bohmian mechanics. You need to have different views on the issue in order to appreciate the problem thoroughly.
Not really. There are at least two "formal resolutions" to the issue which don't need any putting away of logic as we know it: Bohmian mechanics (which is explicitly non-local, and DOES change the "local variable"), and MWI (which is even totally local in its dynamics).
- #80
gil7
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What are the “laws”, the math, for the “information”? The mass=0, the speed >>c…
Bohm was talking in his book Wholeness and the Implicate Order about subquantic theories.
Bohm was talking in his book Wholeness and the Implicate Order about subquantic theories.
- #81
heusdens
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vanesch said:
Simply said, what I hold as "logic" for properties and property-values for objects, even my claim of what an "object" is, are simply logically bound interpretations of the world. Which do not have to coincide with the real world.
But "logic" does not dictate the real world how to behave, logic is just a tool for the mind, to make sense of what we observe.
There is no need for the world itself to obey logic, wether we like it or not.
It is not so in the simplistic way (and erroneous way) we are declaring out choices for the logical properties, objects and ourcomes which we try to force upon the real world, since for one, it was not exactly logical (as I have argumented before) to declear this setup as having two independent observations. That is already a sacrifice to logic.
The illogical results are just the effect of that.
For logic itself, it doesn't mind if we perform an actual measurement in the real world, or not.
It does not even adress the issue wether or not such a world exists or not.
We can invent invent logical objects, with logical properties and logical outcomes, and the result is that these invented objects in the invented experiment do obey logic, simply because we are only playing acc. to the rules of logic.
This is for us the way to look at things, but in no way is this a principle which can be forced upon nature. Nature plays by it's own rules.
See also my explenation of a different experiment and setup (in an earlier post in this thread), in which there is a logical explenation for the outcomes of the experiment.
I assume at least this explenation makes sense.
See my previous remark.
Of course not. The table itself has nothing to do with the experiment, since it is just a logic construction.
For explenations of physical results of physical experiment, we have to look at the physical states/entities which are involved.
It's not the table that enables you to do it, it is the choice of what you call "object" , "property" and "value". If they aren't logically well defined, then we can't have logical outcomes also.
MWI is self-refuting, since the very reason you assume MWI to be an explenation, also refutes it's existence. Alice and Bob in the MWI intepretation would have different outcomes.
http://www.arxiv.org/abs/quant-ph/0607057
Bohmian mechanics means giving up relativity and the acknowledge - many times proven in observations - that the speed of light in vacuum is not surpassed by any physical process.
So both conclusions I refute. They are just "ugly" escape routes, and in fact deny the whole problem.
The real problem lies in our use of the tools of "logic" and especially because we confine them to be formal logic.
The real problem is that formal logic does not reflect the world as it is.
Take for instance the fundamental law of identity: A = A.
What does this law prescribe us? What does it state about the world?
If we take the law of identity literally and bring it to the physics world, it means an object (any physical entity) can at any given time only be equal to itself, and nothing else.
So, already at the very bottom of this "building of formal logic", there is the problem, that as logic sees it, no change whatsoever occurs anywhere and anytime. Logic would describe a static world, that is a world without change.
No if we know one thing sure about the real world, it is that it is change everywhere at any given moment. Any physical state without motion is clearly unthinkable.
We could mention here also the work of Kurt Gödel, which had a formal proof that any formal system is either inconsistent or incomplete. So this is even more reason to acknowledge the limits of formal logic.
Yet, our only way of trying to "fix" the situation, is set up new logic constructs to resolve the issue. Which are quite desperate attempts, because we know it can't work that way. The contradiction we see, we can not get rid of that so easily, and the only thing we do, is invent new constructions which introduce new and more serious contradictions.
The resolution to this problem then however is not to get rid of formal logic in total, but to commit to a new form of logic, which encompasses (ie. maintains) it's general outset, but at the same time overcomes it's limits, which has been done in the form of dialectics.
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- #82
heusdens
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Refutation of MWI:
Excerpt taken from:
In other words:
Committing to MWI does not help us one bit, since it introduces new and even worse contradictions!
Excerpt taken from:
Against `Realism'
Authors: Travis Norsen
Comments: Revised version, forthcoming in Foundations of Physics
We examine the prevalent use of the phrase ``local realism'' in the context of Bell's Theorem and associated experiments, with a focus on the question: what exactly is the `realism' in `local realism' supposed to mean? Carefully surveying several possible meanings, we argue that all of them are flawed in one way or another as attempts to point out a second premise (in addition to locality) on which the Bell inequalities rest, and (hence) which might be rejected in the face of empirical data violating the inequalities. We thus suggest that the phrase `local realism' should be banned from future discussions of these issues, and urge physicists to revisit the foundational questions behind Bell's Theorem.
http://www.arxiv.org/abs/quant-ph/0607057
Authors: Travis Norsen
Comments: Revised version, forthcoming in Foundations of Physics
We examine the prevalent use of the phrase ``local realism'' in the context of Bell's Theorem and associated experiments, with a focus on the question: what exactly is the `realism' in `local realism' supposed to mean? Carefully surveying several possible meanings, we argue that all of them are flawed in one way or another as attempts to point out a second premise (in addition to locality) on which the Bell inequalities rest, and (hence) which might be rejected in the face of empirical data violating the inequalities. We thus suggest that the phrase `local realism' should be banned from future discussions of these issues, and urge physicists to revisit the foundational questions behind Bell's Theorem.
http://www.arxiv.org/abs/quant-ph/0607057
In other words:
Committing to MWI does not help us one bit, since it introduces new and even worse contradictions!
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- #83
DrChinese
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heusdens said:
Vanesch said:
"However, we now have a problem in understanding the perfect anti-correlations. Without the properties pre-existing, how can we obtain perfect anti-correlations ?"
..and so you want to have it both ways. You dismiss the perfect (anti-)correlations, which point to well defined attributes. But then you talk about properties as ill-defined when it suits. Well, the fact remains that the "table" of values is what most folks call "reality". If you accept locality (as you do), you must reject a certain type of realism as well. And that is the Einsteinian realism of EPR.
- #84
vanesch
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heusdens said:
There has been no indication yet that we have to take on that stance. In fact, taking on that stance would immediately mean that we cannot reason about anything. So such a radical position is not needed.
There is absolutely nothing "logical" about requiring the observations to be independent ! This simply follows from two ASSUMPTIONS (which turn out not to hold, given the results). The two assumptions are the following:
1) There IS only one outcome at Bob's, for each of the measurements that he does (and same for Alice).
2) The principle of locality holds, meaning that everything that happens at one event is only determined by its immediate neighbourhood, and not by anything remote.
The first point can seem self-evident, but actually isn't: we know that quantum-mechanical descriptions are based upon the superposition principle, where two "classical" states are present at once.
The second point is only suggested by relativity.
It is only when we take on these two assumptions, that the EPR-Bell situation leads to difficulties. We are far from having to reject any logic !
I have only seen you explain experiments that had nothing to do with the EPR situation...
The table is a list of all POTENTIAL outcomes of the 3 measurements, of which only 1 can be actually done. Its very construction makes hence the assumption that the "potential outcome to a measurement that cannot be done" has a meaning - which it has, if there is a pre-determined value into each of the INDEPENDENT objects for each of the POTENTIAL outcomes. But that is an assumption, and one which is visibly erroneous when doing quantum mechanics. In the same way as you get erroneous results if you would set up a table for momentum + position of a particle, you also get erroneous results if you assume that the entries in the table exist. As such, it is not a logical construction, it is based upon a physical assumption, namely that there are pre-determined outcomes "present" in the object.
The *suggestion* that such pre-determined outcomes might exist within the object - despite the fact that this is quantum-mechanically forbidden - simply follows from the fact that this would be the evident explanation for the perfect anti-correlations.
The concept of "object" follows from the locality requirement, that requires you to treat spatially separate things as independent objects. Drop this hypothesis (as do the Bohmians) and the problem goes away (as relativity does go away). The "values" are simply assigned to the different objects, because they are the only trivial way to explain the perfect anti-correlations.
What do you mean ? I think this must be one of these misunderstandings of MWI again...The Alices and Bobs in the MWI scheme observe exactly the same outcomes as the single Alice and Bob would in standard QM.
Absolutely not. Both Bohmian mechanics and MWI treat the problem correctly, without introducing any mechanism beyond their basic postulates. MWI treats quantum mechanics entirely correctly, by applying the axioms of quantum theory as well to the "observations" as to the microphysics (that is, by allowing them to be in superposition) ; Bohmian mechanics treats the particles + wave dynamics in an entirely deterministic way.
My preference goes however, to MWI, for one single reason: Bohmian mechanics cannot be defined as a geometrical object on relativistic spacetime, while MWI can (or in other words, MWI can be written out in an entirely lorentz-invariant way, while Bohmian mechanics can't).
You have no idea of the disaster you obtain when you give up logic. The statement A = A means, that if you say something about the world, that you say something about the world. It means that if you have had the observation that the light went on, that you had the observation that the light went on.
No, it means that a statement about some physical observation has the same truth value as itself.
That is absolutely not what a logic statement is about. Logic doesn't say anything about any time evolution of the truth values of a statement or
whatever. In fact there's no such thing as the "change of the truth value of a statement", because a statement is a-temporal. The statement that 1+3 = 4 has no temporal dependence or whatever.
You seem to confuse a series of statements which can be parametrised with a single statement. If you have several statements, parametrised in time, say, then some of these statements can take on the truth value T and others, F. The logical tautology A = A doesn't mean, at all, that all these statements have to have the same truth value!
Goedel's theorem is often misquoted. It simply says that any formal system that contains the natural numbers, contains syntactically correct statements for which no proof is available, and for which no proof is available for the negation of the statement either.
This is an over-reaction to a much more down-to-earth problem. The EPR-Bell paradox is based upon assumptions. Now, when we derive a contradiction from a set of assumptions, the usual reaction is not to doubt the workings of logic, but to doubt the validity of the assumptions.
This is in no way different.
We made two assumptions, which can both be wrong. The first one is that there are unique outcomes. Quantum theory itself already tells us that this is not true: if you apply the axioms of quantum theory to the observers themselves, (Alice and Bob), then you find that quantum theory tells you that they are not in a unique state of observation, but rather that the two observations occur in the overall state description (that's MWI btw, but it simply follows from the coherent application of the axioms of quantum theory).
The theory which gives us the predictions (quantum theory) also contains the solution: superposition of outcomes.
The second one is locality. Although relativity is highly suggestive of locality, it needn't be so. Maybe the "past lightcone business" is not correct. This is suggested by any "collapse" model, and by Bohmian mechanics.
So we are far, far away from having to say that logic is not valid.
- #85
DrChinese
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heusdens said:
Travis adamently opposes the idea that realism is a factor in Bell's Theorem. He argues that only locality is an element of BT. His is not considered an orthodox position. (He and I have debated this in circles here previously.) He is one of those who considers Einstein's version of realism to be "naive realism". Regardless, that form of realism is clearly present in BT, and that is something you should acknowledge easily if you are aguing that it is Logic itself which is at issue.
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vanesch
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heusdens said:
I know Travis, he sometimes visits us here under the nickname ttn. He's an avid Bohmian, but he never understood MWI. I know this objection of his, but it is flawed. He focusses on the idea that MWI tells you that all you see is delusion, and his argument is simply: if all we see is delusion, then the Schroedinger equation and all that are also delusion, and there's no reason to assume that it contains anything serious. But the Schroedinger equation was the basis for the claim of our delusion, hence exit. A bit like the Liar's Paradox.
But what goes evidently wrong with this claim is the following: it is a carricature of what MWI says. The point is NOT that "we are deluded", as if this somehow would mean that everything we know is WRONG. MWI doesn't say that everything we know and see is wrong, it only tells us that what we know and see is only part of a bigger reality. But the part that we know and see is there all right ! This is the flaw in Norson's critique ! If you rewrite his text where you replace "deluded" with "is not the FULL description of the ENTIRE world, but is only part of it", then his argument loses all its power, because the PART of reality that is available to our observations is 1) a correct part of reality and 2) contains enough suggestions to set up the equations for the overall world view, even though we don't observe all elements of it. It is like being able to only see a surface of an object. If we've seen enough surfaces of objects, we might start guessing at what is its 3-dim form, even though we only have access to part of the information. It is not because we are "deluded" in seeing only surfaces, that the concept of a massive object of which only the surface is visible is self-rejecting !
The only thing MWI does, is to derive the rules which "ought to apply to the whole world" from the rules which apply to smaller scale experiments. In small scale experiments we observe that things appear in superpositions, and that the Schroedinger equation works. We now also apply that to the bigger scale. From that viewpoint, it then follows that we are only aware of "part" of the solution, and that there are "other parts of the solution" which rarely ever show up in what we can observe. (they show up in EPR-Bell kind of situations!). We also know why: the linearity of the Schroedinger equation makes that "just our solution" or "the solution plus another solution" comes out the same (as long as the other solution stays orthogonal to ours, which is no problem with decoherent entanglement). So we now also understand why we rarely if ever hear of that "complement of reality out there". We "understand our delusion" to use Travis' words, that we only see *part of reality* most of the time. But that doesn't mean that, within our observable part of reality, things are totally different from "all of reality". We can derive the rules (such as Schroedinger's equation), and this is a genuine part of reality. Contrary to being deluded, we can do experiments and observe things. But we get the suggestion that there is maybe a much bigger reality out there, of which we only perceive a small part, but which obeys exactly the same rules as the part we can observe.
"seeing only a part, but a sufficiently significant one as to be able to derive the rules for the whole" is different from "being totally deluded". Which invalidates entirely Norsen's argument against MWI being some kind of self-contradictory statement.
- #87
heusdens
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vanesch said:
That is not what has been said. It's not about the invality if logic but much more the limitations recognized of formal logic to deal with the real world.
Dialectics, as has been said, maintains formal logic but also overcomes its limitations.
And again, it is not about rejecting formal logic.
Except one.
Yes, that is true, but that was only to explain some things. I recall that I never mentioned this to be real artefacts of experimens in which quantum behaviour shows up.
Yes, but the point that you miss then that any detectable object is spatially spread, this would then mean also that it contains "independent objects" - by your same reasoning! - rather as one object! So, if on that account the world is treated, independent objects wouldn't exist!
So when can we know wether an object - any object at all! - can be treated as one object, or as a constellation of independent objects?
The Alices and Bobs in the MWI scheme observe exactly the same outcomes as the single Alice and Bob would in standard QM.
Read the longer post which refutes MWI on logic grounds.
See my post on MWI.
Such "disaster" does not arise, since we ain't given up formal logic!
Dialectics is not a replacement of formal logic, but instead a logic tool that builds on formal logic, but recognizes and overcomes it's limitations.
What you state there is that formal logic deals about logical statements, and not about the real world. Even if "things" in reality, might be referenced, this reference is strictly within the formal world of logic.
There is nothing there in logic, which contemplates real world objects, etc.
In logic that is correct, since we don't deal with real objects, but only with abstract figures.
However in the world itself, this logic can not always be applied.
1 cloud + 1 cloud might equal 1 cloud, that is the clouds themselves may merge, and what we previously saw as two separate cloud, becomes one new cloud.
Still in numbers/abstract form, 1+1=2 still applies, only the underlying reality we speak about, does not hold on to this formality.
This is of course because what for logic is a requirement, that we can speak of independend and seperable "objects", is not a requirement for the world itself.
And likewise, as it is for the mathematician a requirement for dealing with infinities to start out from the finite, yet this is not a requirement for the world itself.
The "true" problem then is of course if such logically valid statements exist, that exactly reflect what goes on in the real world. That is of course the domain physics deals with.
For example you could make a logical valid statement about an object and from the dynamics of the situation you could describe it's motion, which would incorporate making statements about where in the world the object would need to be found at any given time.
So this formaly would then state that an object at some given time would either be at location x, or not be a location x, but not both or something else.
So, there you already see the limitations of such formalism.
The question then is: is there a complete and consistent description of the world possible at all, in which what we recognize on abstract/formal and mathematical grounds as true, also is true in the real world?
The result can be more generalized to formalized systems.
But I'm not exactly sure about what constraints the formalized or formalizable system must have.
No, this is completely wrong, in the sense that the limitations of formal logic were discovered long time before quantum mechanics showed us these paradoxes.
Dialectics is not a reaction to any such physical discoveries, yet is applicable to these and other fields of knowledge.
The notions of dialectics for instance about motion would recognize that an object in motion must at the same time be at some place, and not be at some place, for otherwise in the formal/abstract logic, as for example was laid about by Zeno, paradoxes occur which make motion impossible.
This recognition however was made independent of and long before quantum mechanics ran into this, but it can be said that the way quantum mechanics treats this issue, for sure gives rise to recognizing the valid perspective of dialectics on such matters.
For logic, motion is problematic, since it can not deal with a fact of reality that an object is in some place and not in that place at the same time.
Logically seen an object that moves would be at any instance at an exact place. Quantum mechanics shows us that this does not reflect the real situation. So, in all these cases it can be show that dialectics deals with these matters more delicately.
Logic in it's own domain is of course still valid, and I have said nothing that would contradict that point of view. Dialectics incorporates formal logic (which is in other words, not the same as rejecting it, but the opposite of it), but also surpasses it.
In your above paragraph you already recognize the very limitations of formal logic and formal statements that can be made about the world.
Instead of inventing more and more complex formal constructions to overcome these limitations, dialectics deals with that in a more delicate way, by overcoming the limitations of logic itself.
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- #88
DrChinese
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heusdens said:
I don't get it, heusdens. Your position - as expressed above - is as similar to the non-realistic position as I have seen. The HUP, if taken as representing accurately underlying mechanics, is non-realistic. So where is there a point of disagreement?
- #89
heusdens
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DrChinese said:
Make that last statement read: limitations of formal logic, since we ain't going to reject formal logic itself, but rather try to overcome it's limitations, at least that's the way dialectics treats it.
- #90
JesseM
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heusdens, aside from the philosophical issues, do you agree with my previous post (#77) about the impossibility of producing the pattern of +'s and -'s seen on Alice and Bob's screens using any sort of classical setup?
- #91
heusdens
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DrChinese said:
That above weren't my words, it was a quote in my post (but I had not paired the quote - unquote well, but I re-editted it, see the actual post now).
- #92
heusdens
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Nobody wants to make any comments on my post some time ago?
https://www.physicsforums.com/showpost.php?p=1214117&postcount=76
https://www.physicsforums.com/showpost.php?p=1214117&postcount=76
- #93
JesseM
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heusdens, did you see the question I posted right before you responded to DrChinese above? In your older post #76 which you just linked to, when you say "I don't see why this would not be a good explenation of the above mentioned experiment" are you claiming that you have a classical-style explanation for the experiment?
- #94
heusdens
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JesseM said:
Wether you ascribe the explenation to be "classical" or not is somewhat irrelevant to me, but I just claimed that it appeared to be there is a simple explenation for the results of that specific experiment.
For which I can not claim is the whole truth, since as I already explained in that post, therefore one has to actually perform the experiment again and experiment with different width polarization filters.
Yet, the question is, from what the experiment appears to be, is this explenation I gave approximate correct or not? Or where can the explenation be shown to be wrong (for instance the assumption that the gap width of the polarization filter can have something to do with it, which could be demonstrated false if changing the gap width makes no difference to the outcomes).
So, I don't make rigorous claims, esp. since I never studied quantum mechanics much, and never made any experiments.
And yet another remark, as is my main issue here, which is the inapproproriateness of formal concepts and thoughts to speak about the world, is that when defining in the formal sense objects, properties and values, we always or most of the time, run into problems.
For instance the outcome of a distinghuishable observable, can show us the behaviour of total randomness, and yet it can also show us strong correlation. Formal logic has some problems with such features, since it breaks the law of excluded middle. Either a property of an object is A, or it is not A, but never both. Dialectics has no problems with that, however.
For dialectics, there is the distinction of appearance and essence. What appears to be random and what is random, are two separate notions, that need not coincide and can often be shown to contradict. So, dialectics does not dictate that appearence and esence must coincide.
I will post a short primary to dialectics shortly, it might explain some of the aspects of dialectics and how it differs from formal logic, and how it might serve to get a broader picture of reality then formal logic can give us.
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- #95
JesseM
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But the problem is that your "explanation" does not refer to anything specifically quantum, so it must be incomplete if you agree that no classical setup could replicate the results (and by 'classical' I basically just mean a system which is in a definite measurable state at every moment)--how do you account for the fact that your experiment cannot be replicated using some classical source of randomness like dice?heusdens said:
You seem to be discussing philosophical ideas rather than the sort of clearly-defined concepts used in physics, so maybe you should post your discussion on dialectics in the philosophy forum and just post a link here.heusdens said:
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- #96
heusdens
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JesseM said:
We are talking here about quantum mechanics in terms applicable for understanding. I have not yet read a clear and self-consistent strictly physical explenation of the outcomes of such experiments, that is just the reason we discuss it on here. If it were 'clear', why would we discuss it so extensively?
I don't hold on to the idea that the quantum mechanical part of nature is totally separate from the classical part, although it is correct to say that the attributes we use in the macroscopic world can not be applied in the quantum world.
Who says the experiment can not be reproduced using -what is called- "classical" concepts? Although the question is of course, what do we mean with 'reproduce', since likely our experiment will involve totally different set up, objects, properties and range of values as also methods of detection.
If you can formalize that into something that is also applicable to the macroscopic world, then maybe we can proceed.
- #97
heusdens
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Here is an example of a superposition of two macroscopic states:
http://www.anti-thesis.net/child.html
http://www.anti-thesis.net/child.html
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- #98
JesseM
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What kind of "physical explanation" are you looking for, though? A verbal one? Physicists usually try to focus on finding mathematical models in which the verbal terms they used can be translated into elements of the model, rather than just relying on words alone.heusdens said:
I didn't say it was. My point about the impossibility of finding a "classical" explanation is just that we can come up with a model of what a classical universe would be like--one ruled by classical laws which obey locality such as Maxwell's laws of electromagnetism, for example--and show that in this imaginary universe, you could never reproduce the same results we see in EPR-type experiments. You could even perform a simulation of a classical universe on a computer if you wished. And remember the comment I made in parentheses in my last post--"by 'classical' I basically just mean a system which is in a definite measurable state at every moment". We don't have to assume the classical laws are the laws known to 19th century physicists, we could even invent some new "classical" laws which didn't resemble our universe at all, I'd still call them classical as long as the universe had a single well-defined state at each moment and the results of measurements followed from this state.heusdens said:
- #99
NateTG
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JesseM said:
Bell's theorem isn't quite that strong. Bell's theorem does not apply to models where the coincidence of non-commutable measurement results is undefined. This is probably possible using non-standard notions of probability, and certainly possible with strong determinism.
- #100
heusdens
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JesseM said:
Right so, because that is how physics reflects on the world, using the language of mathematics. This has it's merits, but also brings forward it's own dismerits.
I for sure could not bring forward a universe to which the classical laws of physics apply, so I hope you forgive me that I can not do that.
The whole point here again, is what do you define as a "well defined state"?
A signal that by all means is random can not, by mere logic, be also non-random, yet it can be easily shown to be the case.
I just have to create a clear signal, and split that into two signals that are correlated, and add to both signals a random noise (the same random noise, that is, so that after subtraction, it can be eliminated).
Each of the signals now is random. Yet I can manage to recreate the clear signal from both random signals.
So, how is this possible even in the classical case, if I am to assume the signal was really random, and could not contain any information at all?
How does random + random become a clear signal? It does not make sense when using only formal descriptions (a random signal is something that can bey definition carry no information), yet it is the case.
This being the case, doesn't make it a QM event, neither have I stated that it beats the Bell Inequality.
However, if you give me a clear formal description of an experiment and set up which can in principle be made using only the "classical" aspects of physics, I am about sure one can show a deviation from the Bell Inequality in the non-QM case too.
Btw. I think I almost described a rather classical anology already. If we use the previously mentioned signal, and use some device to spread the signals around some frequency peak, and have both observers take the data and give them the ability to "tune in" on different frequences and add different random noise for different frequencys, we are able to show that:
- when both observers use the same frequence, they can extract a perfect signal.
- when their frequency somewhat deviates, they get a less perfect signal
- when their frequency deviates above a certain range, all they can get is random noise.
(but if we really design this thing, using electronics, this would raise the objection then that electronic devices are based on QM phenomena, not classical phenomena, and neither can I use a computer for the same reason, but a setup using dices to create a stream of data works however the same in my example, although the elaboration of it in a real experiment would be rather dreadfull...)
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