Bell experiment would somehow prove non-locality and information FTL?

[heusdens]

You've got it.

Yeah!

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...).

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. ]

 

[heusdens]

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%.

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.

 

[JesseM]

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.

(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.

 

[wm]

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

 

[heusdens]

(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 we 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 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.

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.

 

[heusdens]

http://www.chronon.org/Articles/localreal.html

(...)
Bell's inequality

Suppose we have a source of particles which sends out pairs of particles, with one in the opposite direction to the other. Suppose also that we are interested in some property of the particles which can be expressed in terms of an angle, such as spin or polarisation. We place a filter at a given angle and use a detector to see whether the particle goes through - this is done for both particles, and the two measuring apparatuses may be widely separated. Now such experiments have been done where it has been found that the source generates the particles in such a way that whether they go through the filter or not is random. However, when the two filters are at the same angle then the results at each detector always agree. OK, we say, the particles have some internal property, which is randomly set by the source, but which is the same for both particles. When the angles of the filter differ by 22½° the results disagree around 1/7 of the time. There's no problem explaining that in terms of the internal property of the particles. Now suppose the angles differ by 45°. Then you can think of what the result for each would be if they were both at the halfway angle, 22½° from their actual position. The each actual result would disagree with this hypothetical result 1/7 of the time, so a bit of thought says that the two actual results can only disagree with each other at most 2/7 of the time. That is a special case of Bell's inequality.

The only trouble is that when you do the experiment, the results at the two detectors differ from each other half of the time. The only way to explain this is if there is some secret communication between the two widely spaced measurements to fix the result. However, we can never use this communication to send actual information between the two locations.

(...)

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).

 

[JesseM]

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.

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:

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?

 

[DrChinese]

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.

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.

 

[vanesch]

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.

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.

That is even true for QM experiment outcomes, just by redefining "property" as I did, then also the inequality is not broken.

Yes. From the moment that you can set up a table, the Bell inequalities have logically to hold.

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.

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.

For conventional logic, this situation is not satisfyable and unrepairable.

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).

 

[gil7]

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.

 

[heusdens]

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.

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.

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.

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.

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.

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.

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 ?

See my previous remark.

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.

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.

Yes. From the moment that you can set up a table, the Bell inequalities have logically to hold.

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.

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).

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.

 

[heusdens]

Refutation of MWI:

Perhaps some advocates of MWI are fooled by the theory’s name (which is in fact a misnomer). If there were some sensible way of taking the many individual terms in the universal wave function to represent literally distinct universes, perhaps it could make sense to interpret a belief like the one considered in the last paragraph to be a “partial truth” (since the belief would then correspond to a fact that is realized in at least that one universe, and would hence indeed be true). And then perhaps an advocate of MWI could still consistently endorse Perceptual Realism. But, in fact, one cannot think about the terms this way (since, among other reasons, what distinct universes exist would then depend on our arbitrary choice of basis states).
No, to make sense of MWI, we must accept that there is just a single universe and that its complete physical description is provided by the massively entangled wave function we get from solving Schrödinger’s equation (and never applying the collapse postulate). And the price of that is unavoidably to give up the idea that our common sense (perceptually based) beliefs correspond to the actual state of the world. In other words, the price is the rejection of Perceptual Realism.
And this brings us back to our earlier claim that Perceptual Realism is a foundational principle for modern empirical science. To seriously entertain a scientific theory which requires us to reject Perceptual Realism is to engage in a vicious sort of large-scale circularity, as David Albert has pointed out. [23] To the extent that a theory poses as scientific, it asks to be considered as a possible best explanation of a certain class of empirical data. In the case of MWI, this includes primarily all of the data on which Schr¨odinger’s equation and its various relativistic extensions rest. But at the same time, the associated need to reject Perceptual Realism requires us to dismiss that same data as not actually reflecting the true state of the world. A theory like MWI would evidently have us dismiss as delusional the very evidence that is supposed to ground belief in the fundamental equations that define the theory – a very uncomfortable logical position, to be sure.
Let us formulate this important point in positive form. There is no possibility that one day in the future scientists will go into a laboratory, do some sophisticated experiments, and infer from the outcomes of those experiments that our eyes systematically delude us about the state of things in the world. Such a scenario is impossible because it involves a logical contradiction: the conclusion reached by the imaginary future scientists undercuts the imagined evidentiary basis for that conclusion.
The claim that the conclusion should be believed because of that evidence, is therefore self-refuting. Perceptual Realism is thus an axiom (in the Aristotelian sense of passing the test of reaffirmation-through-denial) for modern empirical science:
any allegedly empirical-scientific argument against Perceptual Realism would necessarily be self-refuting. Looked at this way, it is hard to understand what kind of evidence an MWI advocate might offer in favor of that theory. It is simply not very convincing to say that the theory offers the best possible explanation of a bunch of events in physics labs over the last 100 years – events which, according to the theory, didn’t actually happen.
There is one other important point to be made against MWI’s being taken seriously as a viable version of quantum theory. For MWI, the rejection of Perceptual Realism is general. It requires us to reject not just the data apparently showing violations of Bell’s inequalities, and not just the data underlying the specific equations (e.g., Schrödinger’s) that define the dynamics of that theory, but to reject, in principle, all the data coming from all experiments. And this includes, in particular, all of the experimental data that is normally taken to support relativity theory and the associated account of space-time structure – the saving of which was the only real motivation for taking MWI seriously in the first place! So not only is MWI apparently self-refuting in terms of its actual dynamical content; it is self-refuting also in regard to its basic motivation. As Maudlin explains this point, accepting MWI would mean accepting that

“physical reality contains nothing like a relativistic space-time containing ocalized events and objects which even approximately correspond to the events and objects we think we see. In such a circumstance, it is hard to see why we would continue to hold the relativistic account of space-time structure seriously, since that account is based on observations which were taken to report objects and events in space-time. In short, it is hard to see why we would seriously believe that we had gotten the deep structure of space-time right if we had gotten questions about whether, for example, a needle on an instrument actually moved to the right or the left wrong.” [2, page 287]
​

The bottom line is the impossibility of any scientific basis for any (allegedly scientific) theory requiring the rejection of Perceptual Realism. MWI requires such a rejection, and hence cannot be taken seriously as a scientific theory. But, to return to the main development, this is only relevant by way of refuting the idea that the ‘realism’ in ‘local realism’ might justifiably denote Perceptual Realism. As we argued earlier, it doesn’t, so we will have to continue digging if we are to find some relevant sense of ‘realism’.

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
​

In other words:
Committing to MWI does not help us one bit, since it introduces new and even worse contradictions!

 

[DrChinese]

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.

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.

 

[vanesch]

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.

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.

It is not so in the simplistic way (and erroneous way) we are, 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.

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 !

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.

I have only seen you explain experiments that had nothing to do with the EPR situation...

Of course not. The table itself has nothing to do with the experiment, since it is just a logic construction.

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.

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.

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.

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.

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.

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.

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).

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?

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.

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.

No, it means that a statement about some physical observation has the same truth value as itself.

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.

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!

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.

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.

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.

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.

 

[DrChinese]

Excerpt taken from:

Against `Realism'
Authors: Travis Norsen
Comments: Revised version, forthcoming in Foundations of Physics
​

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.

 

[vanesch]

Refutation of MWI:
Excerpt taken from:

Against `Realism'
Authors: Travis Norsen
Comments: Revised version, forthcoming in Foundations of Physics
​

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.​

 

[heusdens]

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.

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.

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 !

And again, it is not about rejecting formal logic.

I have only seen you explain experiments that had nothing to do with the EPR situation...

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.

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.

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?

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.

Read the longer post which refutes MWI on logic grounds.

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).

See my post on MWI.

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.

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.

No, it means that a statement about some physical observation has the same truth value as itself.

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.

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.

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.

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!

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?

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.

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.

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.

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.

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.

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.

 

[DrChinese]

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.

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?

 

[heusdens]

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.

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.

 

[JesseM]

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?

 

[heusdens]

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?

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).

 

[heusdens]

Nobody wants to make any comments on my post some time ago?

https://www.physicsforums.com/showpost.php?p=1214117&postcount=76

 

[JesseM]

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?

 

[heusdens]

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?

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.

 

[JesseM]

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.

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?

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.

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]

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--how do you account for the fact that your experiment cannot be replicated using some classical source of randomness like dice? 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.

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.

 

[heusdens]

Here is an example of a superposition of two macroscopic states:

http://www.anti-thesis.net/child.html

 

[JesseM]

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?

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.

I don't hold on to the idea that the quantum mechanical part of nature is totally separate from the classical part

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.

 

[NateTG]

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.

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.

 

[heusdens]

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.

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 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.

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...)

 

[JesseM]

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.

What do you mean by "undefined"? What would happen when you measured the non-commuting observables? Can you give an example of the sort of model you're talking about?

This is probably possible using non-standard notions of probability, and certainly possible with strong determinism.

Could you have a non-standard notion of probability that applies to a deterministic computer simulation, for example? If so, what aspects of the program's output would fail to obey the standard laws of probability?

 

[wm]

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.

Dear heusdens

I sent you a personal email on this point: ''I have not yet read a clear and self-consistent strictly physical explenation of the outcomes of such experiments.'' Did you receive it?

It describes a classical class-room demonstration that refutes Bell's inequality. If it is not clear, just let me know off-thread.

In summary: It is ''Bellian realism'' that is false, not Einstein locality.

NB: It is no insult to Einstein to reject such naive realism from both Bell and EPR: EPR was written by Podolsky; Einstein did not see the submitted version and was not happy with it. (Who could be!? Since ''measurement'' perturbation of the pristine (''measured'') system was known from classical mechanics, and certainly in QM from its beginnings.)

Regards, wm

 

[DrChinese]

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).

The above represents an improper understanding of polarization and how it is measured. The "gap" has nothing WHATSOEVER to do with the cos^2 relationship. In fact, such filters are sometimes used in Bell tests but often they are not. Instead, polarizing beam splitters (bifringent prisms) are used and these have no gap.

You seem to keep missing the idea that the setup is tuned initially so that "perfect" correlations are seen (0 degrees of difference). There is very little noise to speak of when the angles are the same. So this is not an issue in any sense. All reputable experiments have a small amount of noise and this is considered when the margin of error is calculated. This is on the order of magnitude of 50+ standard deviations in modern Bell tests.

If you like, I can provide several references for Bell tests to assist in seeing that it is not an experimental issue.

Bell test results agree with the basic predictions of ordinary QM, without the need for adding a non-local component. My conclusion is that the HUP is fundamental, and there is no observation independent layer of reality for quantum observables. (But that is merely one possible interpretation. MWI and BM are others.)

 

[DrChinese]

NB: It is no insult to Einstein to reject such naive realism from both Bell and EPR: EPR was written by Podolsky; Einstein did not see the submitted version and was not happy with it.

Einstein's view of realism was repeated by him long after EPR. He may not have liked the paper, but not because he thought it was erroneous. He was not happy with the focus on certain specifics of QM.

Einstein never disavowed "naive" realism: "I think that 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." Personally, I don't think this is a naive statement. But that does not make it correct, either.

 

[heusdens]

Dear heusdens

I sent you a personal email on this point: ''I have not yet read a clear and self-consistent strictly physical explenation of the outcomes of such experiments.'' Did you receive it?

No, or I accidently deleted it when removing all the spam that keeps filling my mail box. Sorry of that happens.

It describes a classical class-room demonstration that refutes Bell's inequality. If it is not clear, just let me know off-thread.

Why don't you post it here so it can be discussed?

In summary: It is ''Bellian realism'' that is false, not Einstein locality.

NB: It is no insult to Einstein to reject such naive realism from both Bell and EPR: EPR was written by Podolsky; Einstein did not see the submitted version and was not happy with it. (Who could be!? Since ''measurement'' perturbation of the pristine (''measured'') system was known from classical mechanics, and certainly in QM from its beginnings.)

Regards, wm

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