An argument against Bohmian mechanics?

[Demystifier]

I am not a poor spactator. I have the thermal interpretation.

Fair enough. And is there an analog of thermal interpretation for the rabbit-from-the-hat phenomenon?

 

[Spinnor]

The question for everybody: What do you do when you see a magician trick?

Accept and enjoy that the magician did a great trick and then try and figure out how he did it.

 

[vanhees71]

Where is a abbit-from-the-hat phenomenon in QM that is not already there in classical physics? In a way it's indeed a miracle that we can describe nature quite well with mathematical tools. Someone (Einstein?) said the most incomprehensible about nature is its comprehensibility.

 

[A. Neumaier]

Fair enough. And is there an analog of thermal interpretation for the rabbit-from-the-hat phenomenon?

Yes:

6) Study physics and extrapolate from what the physicists really do when they compare experiments with theory.

This is how I discovered the thermal interpretation.

 

[Demystifier]

Accept and enjoy that the magician did a great trick and then try and figure out how he did it.

Does your attempted explanation involve some hidden variables, like those in 5) above?

 

[Demystifier]

Yes:

6) Study physics and extrapolate from what the physicists really do when they compare experiments with theory.

This is how I discovered the thermal interpretation.

I still don't understand how that helps to explain the rabbit-from-the-hat phenomenon.

 

[Mentz114]

Accept and enjoy that the magician did a great trick and then try and figure out how he did it.

Does the rabbit have a definite position before it is pulled out of the hat ? Or is that interpretation dependent ?

 

[A. Neumaier]

I still don't understand how that helps to explain the rabbit-from-the-hat phenomenon.

Without physics, how can you explain the appearance of the rabbit? Physics tells you that mass is conserved (and much more). So you know that the rabbit must have been there before.

 

[Demystifier]

Without physics, how can you explain the appearance of the rabbit? Physics tells you that mass is conserved. So you know that the rabbit must have been there before.

That still doesn't explain the trick.

 

[A. Neumaier]

That still doesn't explain the trick.

It also tells you that brains are not very reliable detectors and may fail when their attention is somewhere else.

 

[vanhees71]

I still don't know, what you consider as a "trick" in QT. It's a mathematical description of objective empirical facts of nature, no more no less, and it's I am principle not different from classical mechanics, it's just more comprehensible (while still not complete as long as there is not a consistent quantum theory of the gravitational interaction).

 

[Demystifier]

Where is a abbit-from-the-hat phenomenon in QM that is not already there in classical physics? In a way it's indeed a miracle that we can describe nature quite well with mathematical tools. Someone (Einstein?) said the most incomprehensible about nature is its comprehensibility.

The rabbit-from-the-hat can be explained even without mathematics. To a great extent, Bohmian interpretation also can be understood without mathematics, just by visualizing localized wave packets and particle trajectories within them.

 

[Demystifier]

It also tells you that brains are not very reliable detectors and may fail when their attention is somewhere else.

Which still doesn't explain the trick.

 

[vanhees71]

I don't need particle trajectories. The wave packets are enough. If there's a position observable (for all massive particles there is) and if I've prepared a particle with a pretty well determined position, then it is described by a position probality distribution which is quite narrow. That's it. No rabbit in sight ;-).

 

[Demystifier]

I still don't know, what you consider as a "trick" in QT. It's a mathematical description of objective empirical facts of nature, no more no less, and it's I am principle not different from classical mechanics, it's just more comprehensible (while still not complete as long as there is not a consistent quantum theory of the gravitational interaction).

Sure, there is no trick in quantum theory. But it looks as if there is a trick in quantum phenomena. I want to know how Nature (the magician) does it, not how a poor spectator describes what he sees.

 

[Demystifier]

No rabbit in sight

Except that the appearance of a rabbit is what the whole trick is about.

 

[vanhees71]

Where is a trick in phenomena (no matter whether quantum or not)? It's what we observe nature does, and there's nothing else we can do. What do you want when you asking for knowledge how Nature does it? You'll never get an answer from the natural sciences, and philosophy leaves you most probably unsatisfied since it's not explaining anything either.

 

[Demystifier]

Where is a trick in phenomena (no matter whether quantum or not)? It's what we observe nature does, and there's nothing else we can do. What do you want when you asking for knowledge how Nature does it? You'll never get an answer from the natural sciences, and philosophy leaves you most probably unsatisfied since it's not explaining anything either.

So how would you qualify my attempted explanation of rabbit-from-the-hat in the entry 5)? Is it philosophy? Don't you do something similar when you see a performance by a magician?

 

[A. Neumaier]

without mathematics, just by visualizing localized wave packets and particle trajectories within them.

How do you do that without mathematics?

 

[rubi]

Which does not mean that one does not need to criticize the specific gaps in order to criticize the final conclusion of the argument.

Arnold already criticised some points in his post #16 and you didn't respond to it.

5) Try to devise a rational mechanism which could explain it.

That's what physicists try to do, but I don't think that anything about Bohmian mechanics can be considered rational. It's so irrational that most physicists even consider something as stupid as "shut up and calculate" to be more rational than BM. Arnold's list in post #84 can be continued almost indefinitely. In additional to what is absurd about BM, I also consider it highly irrational to expect naive 17th century ideas about physics to be the final word.

 

[Demystifier]

How do you do that without mathematics?

I meant without equations. I can visualize a wave packet and a trajectory without having an equation in my mind.

 

[Demystifier]

That's what physicists try to do, but I don't think that anything about Bohmian mechanics can be considered rational. It's so irrational that most physicists even consider something as stupid as "shut up and calculate" to be more rational than BM.

What is the most rational interpretation of QM in your opinion?

 

[Spinnor]

Does your attempted explanation involve some hidden variables, like those in 5) above?

I can not, right?

 

[Spinnor]

Does the rabbit have a definite position before it is pulled out of the hat ? Or is that interpretation dependent ?

That is classical physics, so it must.

 

[Demystifier]

I can not, right?

Why not? I think you can.

 

[vanhees71]

So how would you qualify my attempted explanation of rabbit-from-the-hat in the entry 5)? Is it philosophy? Don't you do something similar when you see a performance by a magician?

I'd say that's the most rational "explanation" of the phenomenon, and I'd consider it the most convincing one too. I, however, don't see in which this sense is an analogue to Bohmian mechanics. In your rabbit example you can check your assumptions and figure it out (provided the magician allows you to investigate his setup), while Bohmian mechanics claims unobservable trajectories and doesn't offer anything more than standard QT. I don't see, why I should evaluate the trajectories, if I can't check the result against experiment (except for the fun in the sense of a mathematical puzzle I solve for my pleasure).

 

[Demystifier]

I'd say that's the most rational "explanation" of the phenomenon, and I'd consider it the most convincing one too. I, however, don't see in which this sense is an analogue to Bohmian mechanics. In your rabbit example you can check your assumptions and figure it out (provided the magician allows you to investigate his setup), while Bohmian mechanics claims unobservable trajectories and doesn't offer anything more than standard QT. I don't see, why I should evaluate the trajectories, if I can't check the result against experiment (except for the fun in the sense of a mathematical puzzle I solve for my pleasure).

You have a point, but what if, for some reason, magician never allows you to investigate his setup? Would that change anything?

 

[vanhees71]

Well, then natural science must capitulate, i.e., its methods cannot be applied to the magician's trick, because he doesn't allow to apply them. Nature seems not to be that malicious since obviously she allows us to observe her.

 

[Spinnor]

Why not? I think you can.

I though Bell's theorem ruled out Hidden Variables?

 

[Demystifier]

I though Bell's theorem ruled out Hidden Variables?

No. It ruled out local hidden variables. Non-local hidden variables, such as those in Bohmian interpretation, are not ruled out.