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...I'm hoping there are some who will want to join in the debate and defend their position, over at PF.com

What is the real URL of this "PF.com" ?

Alex

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Only scientists have a right to talk about QM
Only philosophers have a right to tell scientist when they are talking nonsence.

Actually, anybody has a right to talk about QM. A non-scientist may not be able to engage in deep discussion of technical details, but a non-philosopher can for example point out that Many Worlds isn't actually a testable scientific theory.

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Pearlist: Check out the posts by user ttn. That is Travis Norsen, a professor of physics at Marlboro College, and an Objectivist. Also check out the documents on his site. In short - a sane interpretation has been around since the 20s (deBroglie), but was not taken seriously until much later with Bohm and JS Bell. They subscribe to something like the "causal interpretation" you mention - that particles follow wave trajectories. Your double-slit example assumes that all particles are following the same wave trajectory, but from what I've read of deBroglie-Bohm, each particle is seen as riding its own wave.

Edited by brian0918

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Pearlist: Check out the posts by user ttn. That is Travis Norsen, a professor of physics at Marlboro College, and an Objectivist. Also check out the documents on his site. In short - a sane interpretation has been around since the 20s (deBroglie), but was not taken seriously until much later with Bohm and JS Bell. They subscribe to something like the "causal interpretation" you mention - that particles follow wave trajectories. Your double-slit example assumes that all particles are following the same wave trajectory, but from what I've read of deBroglie-Bohm, each particle is seen as riding its own wave.

Thanks, yeah I read a lot on Bohm yesterday.

It just seems it got way too much problems and postulate too many things and would be dead after a meeting with barber Occam.

I just watched a few hours of material on MWI, video of the talks on [email protected] celebration/discussion meeting.

David Deutsch started off with: "I'll start off with stating a simple fact, in another Universe Everett is among us here in the crowd" and kept going from there, that guy is 100% certain there is other universes and claimed that neither ERP or quantum computation can't be solved without other Universes.

I hope someone can shed some light here.

I think in Bohm interprettion they believe theres only ONE wave to all of the universe, which is a little bit weird I think?

Is this TTN on here often?

PF.com = physicsforums.com btw

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Thanks, yeah I read a lot on Bohm yesterday.

It just seems it got way too much problems and postulate too many things and would be dead after a meeting with barber Occam.

I just watched a few hours of material on MWI, video of the talks on [email protected] celebration/discussion meeting.

David Deutsch started off with: "I'll start off with stating a simple fact, in another Universe Everett is among us here in the crowd" and kept going from there, that guy is 100% certain there is other universes and claimed that neither ERP or quantum computation can't be solved without other Universes.

I hope someone can shed some light here.

I think in Bohm interprettion they believe theres only ONE wave to all of the universe, which is a little bit weird I think?

Is this TTN on here often?

PF.com = physicsforums.com btw

Pearlist,

Could you be more specific about how you would apply Occam's razor to Bohm's interpretation of quantum mechanics? An interpretation must agree with the well-proven equations of motion for the wave function and avoid or explain the problem of wave-function collapse while retaining things like objectivity and primacy of existence.

I recently began revisiting my understanding of quantum mechanics (in my less philosophical days, I tacitly accepted the David Mermin's summary of the Copenhagen interpretation: "shut up and calculate"). Quantum Mechanics and Experience by David Z. Albert does a fair job of explaining the problem of wave function evolution and collapse, why the subjectivst formulations don't adequately address the problem and how the many worlds interpretation and the Bohm interpretation differ. He also tries to show how the Bohm interpretation allows free will while still deterministically describing particle motion. That particular argument didn't sink in well for me.

Travis Norsen's papers that I've read so far argue 1) that an interpretation of quantum mechanics is necessary and 2) that Bell's work (and subsequent experiment) does not disprove a hidden-variables interpretation (such as Bohm's) but only proves that the hidden variable must be nonlocal (i.e., contain faster-than-light causality, and hence violate special relativity). I haven't made it past his 2006 work yet (finishing up a Ph.D. takes time enough), but this is what I've gathered thus far.

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Pearlist,

Could you be more specific about how you would apply Occam's razor to Bohm's interpretation of quantum mechanics?

Occam razor is basically stating: "entities should not be multiplied unnecessarily"

Well, since it seems Bohmian mechanics postulate 3 'unecessary' (open for debate) entities:

1) pilot wave

2) quantum potential

3) needs to figure out how to make it relativistic because the interpretation requires infinite (or atleast 10thousand times the speed of light) superluminal effect.

While MWI doesn't postulate anything (atleast they claim), they say they just say the Schroedinger wavefunction is all there is and as a consequence you get infinite branches.

-

I agree, subjectivist interpretations are worth less than worthless, I don't even bother with them because the second you throw empericism out the window, you can't really speak upon consciousness either, it's a oxymoron.

From the talk David Z Albert gave at [email protected], it seems his biggest objection to MWI is probability, how do you arrive at the Born Rule etc.

If something got 99% probability of happening (lets take a quantum coin toss) and 1% probability of not happening, in MWI it would always be reduced to 50/50 as the universe would split into two.

So performing this experiment, we see outcome A 99times vs outcome B 1time. how is this?

However I guess they explain it away something like this:

Well if it had a 99% of happening, it means there is 99 different ways the outcome could be reached, hence the universe split into 100 universes, 99 where the outcome became A and 1 where the outcome become B?

I know little about MWI, and would love to hear some genuine criticism of it, however all I've found thus far is "its too weird" "it sounds scifi".

I haven't heard any arguments about things MWI goes in conflict over yet.

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I've been studying QM in school for awhile, and it seems that the more you know about QM the harder it makes a rational interpretation. The way I imagine the quantum mechanics of a particle is that everything is made up of a giant smooshy-cloud that pervades spacetime, observing the particle causes the cloud to recede within the limits of the observation, at which time the cloud begins to spread again. I don't have a problem asking whether electron exists, because the electron is the cloud with wave-particle properties. From a slightly deeper perspective, the electron may be thought of as a ripple in an electron-positron field which interacts with the electromagnetic field by way of ripples in that field. I find it hard to discuss which dogmatic coloringbook style story is right, because I don't follow any of them. I look at the mathematics and I try to figure out a causal rule for picturing it in my brain that corresponds with what happens, and that is how one interprets QM in my opinion.

Edited by Q.E.D.

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I've been studying QM in school for awhile, and it seems that the more you know about QM the harder it makes a rational interpretation. The way I imagine the quantum mechanics of a particle is that everything is made up of a giant smooshy-cloud that pervades spacetime, observing the particle causes the cloud to recede within the limits of the observation, at which time the cloud begins to spread again. I don't have a problem asking whether electron exists, because the electron is the cloud with wave-particle properties. From a slightly deeper perspective, the electron may be thought of as a ripple in an electron-positron field which interacts with the electromagnetic field by way of ripples in that field. I find it hard to discuss which dogmatic coloringbook style story is right, because I don't follow any of them. I look at the mathematics and I try to figure out a causal rule for picturing it in my brain that corresponds with what happens, and that is how one interprets QM in my opinion.

What does this amount to though?

The classical Schroedinger cat, do it live or die, both, or does it do both in 2 different universes?

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What does this amount to though?

The classical Schroedinger cat, do it live or die, both, or does it do both in 2 different universes?

The cat either lives or dies, because it is bound by the Law of Identity, which means that things cannot exist in contradictory states. Schroedinger wants you to think that there is some physical reality to the superposition of states that falls out of his equations, that things can exist suspended in multiple, mutually exlusive states, waiting for their wavefunction to collapse to force them into one state of existence. That is flat out nonsense. A thing exists as it is, not as a collection of maybe's.

Nor does X happen to the cat in "our universe", and Y happens to it in "another universe". The universe is everything that exists; there are no "other universes". If it exists, then it exists in our universe, because, by definition, that's the only one there is. You can talk about what happens in different regions of the universe, but that is not what Schroedinger and the other Copenhagen Interpretation peddlers are pushing.

If you want to get anywhere in QM, you'll need to understand why the physicality of the superposition of states is nonsense, and that the universe is everything that exists.

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The cat either lives or dies, because it is bound by the Law of Identity, which means that things cannot exist in contradictory states. Schroedinger wants you to think that there is some physical reality to the superposition of states that falls out of his equations, that things can exist suspended in multiple, mutually exlusive states, waiting for their wavefunction to collapse to force them into one state of existence. That is flat out nonsense. A thing exists as it is, not as a collection of maybe's.

Nor does X happen to the cat in "our universe", and Y happens to it in "another universe". The universe is everything that exists; there are no "other universes". If it exists, then it exists in our universe, because, by definition, that's the only one there is. You can talk about what happens in different regions of the universe, but that is not what Schroedinger and the other Copenhagen Interpretation peddlers are pushing.

If you want to get anywhere in QM, you'll need to understand why the physicality of the superposition of states is nonsense, and that the universe is everything that exists.

Uhm, ok.

I know the definiton of a universe, point is if MWI is true, there are infinite universes and we live in a multiverse, not a universe.

How can you say superposition is BS? soundwaves are in superposition?

Do you know QM ?

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Uhm, ok.

I know the definiton of a universe, point is if MWI is true, there are infinite universes and we live in a multiverse, not a universe.

How can you say superposition is BS? soundwaves are in superposition?

Do you know QM ?

I'm not an expert in QM, but I've studied it at the university level and understand it fairly well. I say that physical superposition is nonsense because it claims that objects exist in multiple physical states simultaneously, according to their wavefunction, and that "observation" causes objects to go from a state of superposition (multiple possibilities of identity) to an eigenstate (one state of identity). That is complete garbage. Things are something, not possibilites of something just waiting for an observation to give them a single identity. Superposition is BS because not only does it contradict everything man has ever observed, and has no evidence to support it, but it contradicts existence itself.

Soundwaves are not in superposition -- whatever gave you that idea?!? They are defined oscillations in pressure through a medium, such as a gas or liquid. Soundwaves don't exist as a potential of multiple physical states -- what superposition implies -- but they are real, localized phenomena. Perhaps you're unclear on just what "superposition" means (see above).

If you know that the universe is everything that exists, then it doesn't make sense to talk about multiple universes. What are multiple everythings? How would "universe A" be everything that existed if there were something else that existed in "universe B"? If it exists, it exists in the universe, not a universe.

If you really want to understand modern physics, and from the safety of a layman's perspective, I would heartily recommend the Feynman Lectures in Physics.

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^^Even though I did not study QM in college, I have done my fair share of reading on the subject and I reached the same conclusions you did. Just wanted to state my agreement. It seems like there is some terrible epistemological misunderstanding in modern physics. I've actually heard of "scientific" theories to the effect that our observations create the universe. No kidding.

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The cat either lives or dies, because it is bound by the Law of Identity, which means that things cannot exist in contradictory states. Schroedinger wants you to think that there is some physical reality to the superposition of states that falls out of his equations, that things can exist suspended in multiple, mutually exlusive states, waiting for their wavefunction to collapse to force them into one state of existence. That is flat out nonsense. A thing exists as it is, not as a collection of maybe's.

Actually Schroedinger just got the math right, he was objecting to it's implication just as much as Einstein and deBroglie, but noone came up with a solution that solved the paradox.

So take superposition, what is it then? you think every PhD in the world who says superposition is real, is wrong?

Nor does X happen to the cat in "our universe", and Y happens to it in "another universe". The universe is everything that exists; there are no "other universes". If it exists, then it exists in our universe, because, by definition, that's the only one there is. You can talk about what happens in different regions of the universe, but that is not what Schroedinger and the other Copenhagen Interpretation peddlers are pushing.

If you want to get anywhere in QM, you'll need to understand why the physicality of the superposition of states is nonsense, and that the universe is everything that exists.

Ok, forget the word Universe, EVERYTHING in the universe replicas then, same deal, godddamn wtf is the point of getting hung up on details.

And yes, that the world splits into branches of different outcomes is Many Worlds Interpretation.

I don't care about Copenhagen interpretation as I stated in my first post.

Tell me how you explain the double slit experiment and erp

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The cat either lives or dies, because it is bound by the Law of Identity, which means that things cannot exist in contradictory states. Schroedinger wants you to think that there is some physical reality to the superposition of states that falls out of his equations, that things can exist suspended in multiple, mutually exlusive states, waiting for their wavefunction to collapse to force them into one state of existence. That is flat out nonsense. A thing exists as it is, not as a collection of maybe's.

Nor does X happen to the cat in "our universe", and Y happens to it in "another universe". The universe is everything that exists; there are no "other universes". If it exists, then it exists in our universe, because, by definition, that's the only one there is. You can talk about what happens in different regions of the universe, but that is not what Schroedinger and the other Copenhagen Interpretation peddlers are pushing.

If you want to get anywhere in QM, you'll need to understand why the physicality of the superposition of states is nonsense, and that the universe is everything that exists.

I personally have a much wider understanding of the law of identity (against what rand said). I wouldn't consider the coppenhagen interpretation against it. I simply state, that it is in the nature of the electron to act random with all it's implications. It is it's identity to be a fusion of a wave and a particle. Saying it is both, is obviously wrong because of the definition of wave and particle.

I don't see how you can reject some QH-Interpretation with the law of identity, because I think it really doesn't tell much at all about reality. It merely says that everything has a certain nature. But what nature that is and how they act is a different story. Saying: "Coppenhagen must be wrong because it violates the law of identity" IMO begs the question.

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The cat either lives or dies, because it is bound by the Law of Identity, which means that things cannot exist in contradictory states. Schroedinger wants you to think that there is some physical reality to the superposition of states that falls out of his equations, that things can exist suspended in multiple, mutually exlusive states, waiting for their wavefunction to collapse to force them into one state of existence. That is flat out nonsense. A thing exists as it is, not as a collection of maybe's.

Nor does X happen to the cat in "our universe", and Y happens to it in "another universe". The universe is everything that exists; there are no "other universes". If it exists, then it exists in our universe, because, by definition, that's the only one there is. You can talk about what happens in different regions of the universe, but that is not what Schroedinger and the other Copenhagen Interpretation peddlers are pushing.

If you want to get anywhere in QM, you'll need to understand why the physicality of the superposition of states is nonsense, and that the universe is everything that exists.

I personally have a much wider understanding of the law of identity (against what rand said). I wouldn't consider the coppenhagen interpretation against it. I simply state, that it is in the nature of the electron to act random with all it's implications. It is it's identity to be a fusion of a wave and a particle. Saying it is both, is obviously wrong because of the definition of wave and particle.

I don't see how you can reject some QH-Interpretation with the law of identity, because I think it really doesn't tell much at all about reality. It merely says that everything has a certain nature. But what nature that is and how they act is a different story. Saying: "Coppenhagen must be wrong because it violates the law of identity" IMO begs the question.

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The cat either lives or dies, because it is bound by the Law of Identity, which means that things cannot exist in contradictory states. Schroedinger wants you to think that there is some physical reality to the superposition of states that falls out of his equations, that things can exist suspended in multiple, mutually exlusive states, waiting for their wavefunction to collapse to force them into one state of existence. That is flat out nonsense. A thing exists as it is, not as a collection of maybe's.

Nor does X happen to the cat in "our universe", and Y happens to it in "another universe". The universe is everything that exists; there are no "other universes". If it exists, then it exists in our universe, because, by definition, that's the only one there is. You can talk about what happens in different regions of the universe, but that is not what Schroedinger and the other Copenhagen Interpretation peddlers are pushing.

If you want to get anywhere in QM, you'll need to understand why the physicality of the superposition of states is nonsense, and that the universe is everything that exists.

I personally have a much wider understanding of the law of identity (against what rand said). I wouldn't consider the coppenhagen interpretation against it. I simply state, that it is in the nature of the electron to act random with all it's implications. It is it's identity to be a fusion of a wave and a particle. Saying it is both, is obviously wrong because of the definition of wave and particle.

I don't see how you can reject some QH-Interpretation with the law of identity, because I think it really doesn't tell much at all about reality. It merely says that everything has a certain nature. But what nature that is and how they act is a different story. Saying: "Coppenhagen must be wrong because it violates the law of identity" IMO begs the question.

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I'm not an expert in QM, but I've studied it at the university level and understand it fairly well. I say that physical superposition is nonsense because it claims that objects exist in multiple physical states simultaneously, according to their wavefunction, and that "observation" causes objects to go from a state of superposition (multiple possibilities of identity) to an eigenstate (one state of identity). That is complete garbage. Things are something, not possibilites of something just waiting for an observation to give them a single identity. Superposition is BS because not only does it contradict everything man has ever observed, and has no evidence to support it, but it contradicts existence itself.

What if the wavefunction of the electron IS the physical thing, and the electron is just an aspect of it? Then you could say that the wavefunction occupies space, and that would be no different than the fact that a soccerball occupies several inches of space, for example.

Also, since we don't observe individual electrons, but rather whole things which are composed of electrons and similar such things, there is not a contradiction. It would only be a contradiction to say that something macroscopic (IE on the scale of perception) acted this way.

Soundwaves are not in superposition -- whatever gave you that idea?!? They are defined oscillations in pressure through a medium, such as a gas or liquid. Soundwaves don't exist as a potential of multiple physical states -- what superposition implies -- but they are real, localized phenomena. Perhaps you're unclear on just what "superposition" means (see above).

If you know that the universe is everything that exists, then it doesn't make sense to talk about multiple universes. What are multiple everythings? How would "universe A" be everything that existed if there were something else that existed in "universe B"? If it exists, it exists in the universe, not a universe.

If you really want to understand modern physics, and from the safety of a layman's perspective, I would heartily recommend the Feynman Lectures in Physics.

Well again, there cannot be two universes, but hypothetically, if "Many Worlds Scenario" was true, the splitting would just be an expansion of the universe, and we would have to have a different fractions of the universe.

An appeal to perception alone is not a warrant to refuse to recognize the conceptual faculties we have in addition to perception. Our conceptions of things must follow the world, not the other way around.

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The cat either lives or dies, because it is bound by the Law of Identity, which means that things cannot exist in contradictory states. Schroedinger wants you to think that there is some physical reality to the superposition of states that falls out of his equations, that things can exist suspended in multiple, mutually exlusive states, waiting for their wavefunction to collapse to force them into one state of existence. That is flat out nonsense. A thing exists as it is, not as a collection of maybe's.

This ignores the experimental evidence- Van Harlingen's group at the University of Illinois managed to super-impose clockwise and counter-clockwise macroscopic currents in a squid junction. I think this is a clincher for macroscopic superpositions, experimentally.

Things cannot be true simply because we WANT them to be true. We have a duty to check with objective reality whenever possible.

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