Quantum Mechanics: Paradoxical?

[ahrkron]

Originally posted by wuliheron
That assumes that the Many Worlds theory is false

No, it doesn't. The many worlds interpretation does assume an event at the time of measurement.

All of the possible states are present in the system to begin with and one is realized locally upon interacting with anything.

That is what I am talking about. The wavefunction is not "crazy". It just follows a set of rules different from the ones we used to train our everyday-intuition. It is good that you bring up QDecoherence, since it is an interpretation that makes things even more "normal": if true, then the reduction of the wavefunction happens because of the instability of coherent quantum states, instead of anything having to do with an "observer".

No, it is not merely everyday experience QM conflicts with, it conflicts with formal logic.

It does not. No matter how many times you repeat it, it won't become true.

 

[wuliheron]

Originally posted by ahrkron
No, it doesn't. The many worlds interpretation does assume an event at the time of measurement.

Yes, but these events do not collapse a wavefunction in the Many Worlds theory as other interpretations insist they do. The act of measurement/observation does not change the logic of the system from Quantum logic to classical, the logic remains classical throughout.

That is what I am talking about. The wavefunction is not "crazy". It just follows a set of rules different from the ones we used to train our everyday-intuition. It is good that you bring up QDecoherence, since it is an interpretation that makes things even more "normal": if true, then the reduction of the wavefunction happens because of the instability of coherent quantum states, instead of anything having to do with an "observer".

I'm sorry, but words such as "crazy", "supernatural", "paradox" etc. have meaning only because people give them meaning. Those meanings are based on human perception, not mathematical consistency or experimental results. Often QM is compared to Alice in Wonderland precisely because of its craziness. Mathematically the stories may be self-consistent just as the artwork of MC Echer is self-consistent and these mathematics may closely parallel those of QM, but they are crazy nonetheless by definition.

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No, it is not merely everyday experience QM conflicts with, it conflicts with formal logic.
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It does not. No matter how many times you repeat it, it won't become true.

Every explanation for QM incorporates nonlocal effects which defy the true or false, here or there, black or white and-never-the-two-shall-meet criteria of classical logic. No matter how many times you deny this, it remains a widely accepted fact within the physics community.

 

[Lifegazer]

Originally posted by ahrkron
QM is definitely not paradoxical in the predictions it makes. If it was able to produce mutually contradicting predictions, it would have no use as a physical theory.

I think you're missing the point here. Imagine, if you will, that all cats turned into frogs at midnight for several minutes. Now, the fact that we can accurately predict that my cat will start croaking at midnight does not mean that there isn't something 'mysterious' going on within that event itself.

 

[Mentat]

I think I'm going to agree with Ahrkron (sp?) on this issue. That's not to say that others haven't presented meritable arguments. It's just that people seem to keep sticking to "common sense" reasoning. Obviously this is not always a good idea. "Common sense" is for common circumstance, and the Quantum world doesn't meet that criteria.

 

[Lifegazer]

Originally posted by Mentat
I think I'm going to agree with Ahrkron (sp?) on this issue. That's not to say that others haven't presented meritable arguments. It's just that people seem to keep sticking to "common sense" reasoning. Obviously this is not always a good idea. "Common sense" is for common circumstance, and the Quantum world doesn't meet that criteria.

It's strange how you agree with Ahrkron, and then state that QM doesn't appeal to common-sense. Did I miss something?

 

[Mentat]

Originally posted by Lifegazer
It's strange how you agree with Ahrkron, and then state that QM doesn't appeal to common-sense. Did I miss something?

Possibly. You see, I said that it didn't appeal to common sense. Then I said that common sense is for common circumstance. Then I said that Quantum Mechanics doesn't deal with common circumstances. Conclusion: A different line of reasoning, then that which is "common", is required to understand the Quantum world. This new line of reasoning is still logical (or so it seems to be, after having read Arkhron's posts), it is just better suited for dealing with the "uncommon".

 

[Eyesee]

Originally posted by ahrkron
The "magic" and "craziness" of QM is not on the wavefunction, but in the effect that a measurement has over it and, mainly, in the unjustified expectation that quantum systems should agree with classical mental models.



Not necessarily, but even if that was the case, scientific models may be surprising and (again) very different from your everyday-life ideas, but why do you think models are proposed (and later on accepted)? It is precisely because, once all details are investigated thoroughly, they do make sense of known experimental results. That is precisely what science is all about.

Again, the fact that QM is seems to conflict daily life experiences comes from the fact that if you assume daily-life rules to work on atoms, then calculate what you should see, and then make an experiment, the result of the experiment does not match your calculation.

Once you make many more experiments and find a model for how the atom behaves, you end up:
1. understanding that there were many hidden assumptions on the original calculation,
2. realizing that those were unwarranted assumtions, that do not hold at quantum level,
3. finding that using the right assumptions for the behavior of quanta, not only the original experiment makes sense, but also many other macroscopic behaviors are explained.

It is differerent from what "common-sense" expects, but it does make sense.

Don't forget that "common-sense" or "normal-logic" is basically a set of assumptions based on a very limited set of conditions (small velocities, small energies, "meduim" sizes, low temperatures, low pressures, small gravitational fields) and filtered through a very useful, but also very limited, set of perceptual mechanisms. The fact that many of those assumptions are wrong should not be a big surprise, neither be food for assuming that the conflict comes from "essential paradoxes". The conflict is a rather natural result of the limited range of what constitutes the human perceptions.

How can a particle know how to interact with any other particle if it isn't even sure of who it is? We may be UNCERTAIN about the particle's state functions but I think it knows very well who it is at every moment in time. I've got three words for you: Einstein's hidden variables.

 

[Mentat]

Originally posted by Eyesee
How can a particle know how to interact with any other particle if it isn't even sure of who it is? We may be UNCERTAIN about the particle's state functions but I think it knows very well who it is at every moment in time. I've got three words for you: Einstein's hidden variables.

You think the particle knows something? I have a question for you, why does it take our complex assortement of particles (our brains) to create a consciousness that we exist, while other animals (who also have - slightly less complex - assortments of particles) do not have this level of consciousness?

 

[ahrkron]

Originally posted by Eyesee I've got three words for you: Einstein's hidden variables.

The problem with those three words are two other words: Bell's theorem.

 

[Eyesee]

Originally posted by Mentat
You think the particle knows something? I have a question for you, why does it take our complex assortement of particles (our brains) to create a consciousness that we exist, while other animals (who also have - slightly less complex - assortments of particles) do not have this level of consciousness?

I find your rebuttal question inadequate. My question was directed at the fundamental properties of the particles themselves whereas yours address the different arrangements of particles resulting in different properties- the former is about apples, the latter, of orangutangs. And even then, I think you answered your own question in your question: our assortment of particles is different than other animals- it would only be amazing if we were the same and not different. Would you expect your car keys to open the front door of your house?

So, again, how can a particle know how to behave if it wasn't sure of itself? If you were an electron and you weren't sure you were going east or west, how can you respond to some proton that approaches you? As a matter of fact, according to the schizophrenic interpretation of the universe given by QM, the proton itself wouldn't be sure if it was approaching the electron from the east or west either, so how can momentum between this simple system of particles be conserved 100% of the time?

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The universe exists for Helen Keller the same way as it does for every one else.

 

[ahrkron]

Originally posted by Eyesee
So, again, how can a particle know how to behave if it wasn't sure of itself? If you were an electron and you weren't sure you were going east or west, how can you respond to some proton that approaches you? As a matter of fact, according to the schizophrenic interpretation of the universe given by QM, the proton itself wouldn't be sure if it was approaching the electron from the east or west either, so how can momentum between this simple system of particles be conserved 100% of the time?

Wavefunctions and quantum fields are well defined (notice I am not talking about what we call "particles"). They do have many symmetries, some of which imply that a subset of our interactions with them (those we call "experiments") conserve momentum and other quantities.

The confusion arises when we try to use categories ("electron", "wave", "trajectory") that are not well suited for their description.

 

[Eyesee]

Originally posted by ahrkron
Wavefunctions and quantum fields are well defined (notice I am not talking about what we call "particles"). They do have many symmetries, some of which imply that a subset of our interactions with them (those we call "experiments") conserve momentum and other quantities.

The confusion arises when we try to use categories ("electron", "wave", "trajectory") that are not well suited for their description.

Ok, this reply makes much sense.

 

[drag]

Greetings !

Originally posted by Mentat
Possibly. You see, I said that it didn't
appeal to common sense. Then I said that common
sense is for common circumstance. Then I said
that Quantum Mechanics doesn't deal with
common circumstances. Conclusion: A different
line of reasoning, then that which is "common",
is required to understand the Quantum world.
This new line of reasoning is still logical
(or so it seems to be, after having read
Arkhron's posts), it is just better suited
for dealing with the "uncommon".

What does "logical" mean to you ?
I proposed a nearly similar solution. However,
my solution is that of a totally different
reasoning system (different common sense).

The difference is that in that case my definition
of "logical" is just that the new r.s. does
not result in internal paradoxes - it is consistent.

Ahrkron's definition, with which you claim to agree,
is that "logical" means more than that - there
are some general criteria which define what
is "logical" and this new r.s. is the same in this
respect as that what you call "common sense".

However, is there anything you can be certain of
in the Universe to create such criteria ?
Hasn't reality shown us repeatedly that what
we consider absolute and certain is not really so.
(I should point out that my current ignorance
about what ahrkron called "structural rules" for
"logical" systems may in fact mean that they're
the same as my self consistency consideration above
and nothing more, and I simply didn't know that.
But, all those rules and stuff he mentioned sounds
like too many limmitations to me.
What can I say ? I'm foolish and I'll have to study
this stuff before I can express a really educated
opinion on this.)

Originally posted by Eyesee
How can a particle know how to interact with
any other particle if it isn't even sure
of who it is? We may be UNCERTAIN about the
particle's state functions but I think it
knows very well who it is at every moment
in time. I've got three words for you:
Einstein's hidden variables.

QM crushes the classical physics trait
of individuality. It is not possible to
distinguish between similar particles
more than it is possible to distinguish
between individual water drops in the ocean.

"Simplicity is the ultimate sophistication."
Leonardo Da Vinci

Live long and prosper.

 

[Mentat]

Originally posted by Eyesee
I find your rebuttal question inadequate. My question was directed at the fundamental properties of the particles themselves whereas yours address the different arrangements of particles resulting in different properties- the former is about apples, the latter, of orangutangs. And even then, I think you answered your own question in your question: our assortment of particles is different than other animals- it would only be amazing if we were the same and not different. Would you expect your car keys to open the front door of your house?

So, again, how can a particle know how to behave if it wasn't sure of itself? If you were an electron and you weren't sure you were going east or west, how can you respond to some proton that approaches you? As a matter of fact, according to the schizophrenic interpretation of the universe given by QM, the proton itself wouldn't be sure if it was approaching the electron from the east or west either, so how can momentum between this simple system of particles be conserved 100% of the time?

------------------------------------------------------------
The universe exists for Helen Keller the same way as it does for every one else.

You may have missed the point of my rhetorical question (afore-quoted), so I will try to be more clear: Why do you think that a particle knows something? You keep speaking of particles as individual, conscious, entities - when they are, in fact, neither individual or conscious.

 

[Mentat]

Originally posted by drag
Greetings !

What does "logical" mean to you ?
I proposed a nearly similar solution. However,
my solution is that of a totally different
reasoning system (different common sense).

"Logic" is the use of reasoning systems (to be absolutely basic). So, it doesn't matter what reasoning system you use, or what premise it's based on, you still have something "logical".

Ahrkron's definition, with which you claim to agree,
is that "logical" means more than that - there
are some general criteria which define what
is "logical" and this new r.s. is the same in this
respect as that what you call "common sense".

Yes, it's in the same respect as "common sense" because it's the same reasoning system, merely without the premise: "an individual object can exist in only one state, at any given time".