Quantum Interpretations history

Your favourite Quantum Interpretation?

  • Many worlds interpretation

    Votes: 13 27.7%
  • Copenhagen interpretation

    Votes: 8 17.0%
  • Hidden variables

    Votes: 6 12.8%
  • Transactional interpretation

    Votes: 2 4.3%
  • Another one

    Votes: 8 17.0%
  • Haven't made up my mind / I don't think quantum formalism is correct/final

    Votes: 10 21.3%

  • Total voters
    47
confusedashell
Messages
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With all the different quantum interpretations out there, which is your favourite or "most likely to be true" ?

I have a real hard time making up my mind about these things, it all reminds me of different religions trying to prove the unproveable.
EVERYONE is disagreeing, new evidence get thrown in the bin if it doesn't agree with the different phycisists pet theory.
Whate ver happened to simple science people agree'd on.
What I don't get is that quantum mechanics are dealing with the smallest things in the universe yet people seem to think it is arguing for other universes or that we are gods creating the world or that time goes back n foth.

Certaintly set your mind spinning, what is the future of quantum mechanics really?
They'll never agree, even if you disproved a interpretation and showed it was inconsistent with the quantum formalism people would still be on it like crazy.


Any thought or am I the only one bothered with the state of science these days?
 
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I think you miss the purpose of an interpretation. It is not about what is "true" but about what gives you the "best picture" to help you understand a formalism. At least, for me. It is a matter of "look at it this way, then you understand how it works".
Like interpreting the real numbers as "a point on a line in space", or to interpret historical times "on a time axis".
 
confusedashell said:
Certaintly set your mind spinning, what is the future of quantum mechanics really? They'll never agree, even if you disproved a interpretation and showed it was inconsistent with the quantum formalism people would still be on it like crazy.

Any thought or am I the only one bothered with the state of science these days?

I think the quest for unifying gravity with quantum mechanics, understanding the coupling between different complexity scales, and whatever comes out of it are quite likely to changed the preferred interpretation.

I am of the opinion that QG are likely to tweak the foundations of quantum mechanics, and the way we think of it. I don't think it's worth ripping off all your hair over how to make sense over the current state of normal QM. I've ripped off some and concluded that there is something wrong, but I think future development of physics should resolve that.

The main point IMO, is the ambigous usage of statistics and probability on "imagined" ensembles, that can not always be realized in a sensible way. These things become more significant conceptually in gravity, because statistics on particles is one thing, but if we are talking about statistics on spacetime geometries one really has to ask what this supposedly means in terms of observables, as opposed to in the world of crazy mathematics where you clearly can do anything you want :) IMO, one can not simply get away with applying the simplistic QM to such stuff, without thourough motivation.

/Fredrik
 
I see so its a religious/philosophical thing?
Its just ur personal belief based on nothing but wishful thinking?
I think I am starting to see why they say "interpretations is NON science".

Why even take a stand when you say "its not about what's true".

Would you keep ur belief in the interpretations even if they were inconsitant with the quantum formalism like MWI and CI is? cause then things start to be clearer to me:P
 
I personally think it's a simplification to decompose this into hard good science and philosophical crap. What is science anyway?

I think it's better to speak of subjective and objective views, and by common sense the objective view is formed by the collectively most commonly agreed upon subjective view, ie. when several subjective views agree - then that's a good sign. Typically science is supposedly objective, and whatever the scientific collective manages to agree upon is usually considered correct, or at least "the best guess", the measure of right in science is that other people can arrive at the same results. Sure everybody could be wrong, but it seems far more a priori plausible to think that the minority deviate results are more likely to be wrong and the majority right. But I think this is even part of the issue, and the scientific method, and there is a grey area where this measure is not so distingusihed.

This even connects to the idea of objective vs relative realism. And as to wether it makes sense for a admittedly strongly constrained obsever to "imagine" a background realism, that has a justification beyond his subjective view? He can certainly conclude wether his fellow neihgbours interacting with him seems to agree, and he may ahve not choice but to adjust his views to survive in that environment, but the basic question remains.

These types of somewhat philosophical questions can at least in my distored personal view not be disregarded as irrelevant when trying to understand QM and GR. Philosophy and science has as far as I know often evolved together.

I think that as long as one keeps a reasonably intellectual level on the philosophical thinking, it belongs to the scientific reasoning, since science isn't just about "book keeping of truths" it's IMO equally about asking new questions, and trying to find ways to answer them. The falsification, is probably the simplest part of all. But who comes up with the theories that is to be falsified? And who selects the theories to be tried first, we should try the most promising ones first right? How is this determined?

/Fredrik
 
Sorry for not seeing the other similar poll.

I aree Fra, but why would ANYONE chose MWI/CI , if MWI is true, your living in a solipsistic state, NOONE ever sees you(if they split constantly every atto second and visual input takes 0,1second, means you are NEVEr seen, you NEVER communicate with anyone(same reason) and suicide seems to be the only way to escape the upgrades hell the universe would be if MWI were true...
Same with CI, then no one exist unless u observe them(solipsism). Evolution neverh appened cause there was no conscious observers of it happening...
 
confusedashell said:
I aree Fra, but why would ANYONE chose MWI/CI , if MWI is true, your living in a solipsistic state, NOONE ever sees you(if they split constantly every atto second and visual input takes 0,1second, means you are NEVEr seen, you NEVER communicate with anyone(same reason) and suicide seems to be the only way to escape the upgrades hell the universe would be if MWI were true...
Same with CI, then no one exist unless u observe them(solipsism). Evolution neverh appened cause there was no conscious observers of it happening...

I'm not sure I follow or share the logic of your conclusions from mwi and ci, but to comment one thing:

That I don't know something, and that this something does not exists, sure isn't the same thing to me. Why would even think of the idea that I should, or rather COULD know everything? THAT makes no sense to me. It is counterintuitive too. I have never encountered the experience that I know everything. Not once. On the contrary, I constantly learn new things. So any strategy of mine that is building on the idea that things that I don't know doesn't exists, are highly likely to fail IMO.

The second question is, how the measure of existence is to be established in such a case? In my thinking, an analysis of these things shows that the questions posed may be poorly chosen which alone explains a great deal of the paradoxal conclusions.

I guess what I said is that one can talk about the interpretations either constructively as in trying to further develop the theory, or just think that the current theory is prefect, and just debate how to "interpret" it. I guess some people thing QM is prefect, and then the basis for the view is different.

I don't think QM is prefect, and thus my attention is not on trying to make sense out of something I think is flawed, but rather to try to understand how the missing bits can be fitted so that it does make sense.

Perhaps all these interpretational issues are on the table just due to this. When we understand QM better, I think the motivation for discussing interpretations will get a natural resolution.

But this is just my personal view :)

/Fredrik
 
How to confuse a shell

confusedashell said:
I see so its a religious/philosophical thing?
Its just ur personal belief based on nothing but wishful thinking?
I think I am starting to see why they say "interpretations is NON science".

Why even take a stand when you say "its not about what's true".

Would you keep ur belief in the interpretations even if they were inconsitant with the quantum formalism like MWI and CI is? cause then things start to be clearer to me:P

I can see this is bothering you, but don't worry, it doesn't mean anything in practical terms. The thing we call quantum theory is a mathematical model expressed in purely conceptual terms. It goes against our intuition and seems to have 'mysterious' elements which don't correspond to everyday reality. My own experience is not unusual. As soon as I understood the 'standard' QM ( Dirac, 'Principles of QM' ) I realized that superposed states were crazy, and no such such thing could actually exist ( I was young). So I took up the deBB 'causal' model. That requires a very strange non-local field that doesn't react in the classical way with the particles. Hmm. The point is that all the interpretations require the acceptance of at least one weird thing. Choosing an interpretation is a purely personal thing - and makes no difference whatever to practitioners ( well, hardly any ).

In a room full of particle physicists, some will espouse an interpretation, probably most don't care. When they talk to each other it's about Hamiltonians, scattering amplitudes and suchlike.

Interpretations can lead to lively discussions, but should probably be in the philosophy section.

Fra:
I guess what I said is that one can talk about the interpretations either constructively as in trying to further develop the theory, or just think that the current theory is perfect, and just debate how to "interpret" it. I guess some people thing QM is perfect, and then the basis for the view is different.

I don't think QM is perfect, and thus my attention is not on trying to make sense out of something I think is flawed, but rather to try to understand how the missing bits can be fitted so that it does make sense.

Perhaps all these interpretational issues are on the table just due to this. When we understand QM better, I think the motivation for discussing interpretations will get a natural resolution.
Yes, nicely put. Prefect, as you'd say.
 
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  • #10
confusedashell said:
Sorry for not seeing the other similar poll.

I aree Fra, but why would ANYONE chose MWI/CI , if MWI is true, your living in a solipsistic state, NOONE ever sees you(if they split constantly every atto second and visual input takes 0,1second, means you are NEVEr seen, you NEVER communicate with anyone(same reason) and suicide seems to be the only way to escape the upgrades hell the universe would be if MWI were true...
Same with CI, then no one exist unless u observe them(solipsism). Evolution neverh appened cause there was no conscious observers of it happening...

We had these discussions already, but for sure nor MWI nor CI would imply anything you say. But, as others point out to you, you seem to be missing the point of what an interpretation is all about. Nobody can claim that we already have the "final theory of everything", and - although this is more discussable - nobody can claim that this theory - in as much as it exists and will be found one day - is going to be a strict quantum theory as we know it today.

As such, an *interpretation* of quantum theory is a MENTAL GAME, in which you invent a TOY WORLD in your imagination in which quantum theory is STRICTLY TRUE. You start with "let us imagine a world in which blah blah blah...". As such, you can, if you like, PICTURE with your mind's eye, a bit better how things "behave according to quantum mechanics", that is, in a toy world where you assume the rules to be strictly true.

This is a bit like when you play a video game, where, in your imagination, you picture the "world" of that game in your mind, just to be able to understand better how the game works (and how to win).

Now, there is a caveat: although we cannot claim that the final theory - if it exists - is a strict quantum theory, it might also be the case that it is! In that case, our toy world is a possible description of the real world (if it exists). Of our video game, we're pretty sure that it is NOT existing in the real world (although...).

But for the moment, we are just having PARTIAL theories, each with their own paradigm. And quantum theory is one such paradigm. Interpreting it can hence do nothing else but just giving it a TOY world.

So is this useless ? As a "world view", yes. As a way of understanding, getting a feeling of, quantum theory, I'd say no !
 
  • #11
vanesch said:
This is a bit like when you play a video game, where, in your imagination, you picture the "world" of that game in your mind, just to be able to understand better how the game works (and how to win).

This process is more explicit in the ancient text-only computer games such as the "Colossal Cave Adventure," which contain no images whatsoever, and it's up to the player to construct his/her own mental map of the cave and its inhabitants.
 
  • #12
Fra said:
I guess what I said is that one can talk about the interpretations either constructively as in trying to further develop the theory, or just think that the current theory is prefect, and just debate how to "interpret" it. I guess some people thing QM is prefect, and then the basis for the view is different.

Keep in mind that the current theory (in whatever interpretation) works very well for predicting the results of experiments. There have been many experiments that test fundamental aspects of QM, and they are still on-going (e.g. Aspect and Zeilinger). Any new theory that admits a more "plausible" interpretation has to agree with all those experiments. That doesn't mean that such a theory doesn't exist, of course, but searching for one is a highly speculative process at present. It would be easier if there were some experimental results that contradict QM, to point the way. That's why people do these experiments... anyone who actually discovers something like that is a shoo-in for a Nobel Prize!
 
  • #13
I voted "another one". I prefer "relational interpretation".
 
  • #14
jtbell said:
Keep in mind that the current theory (in whatever interpretation) works very well for predicting the results of experiments. There have been many experiments that test fundamental aspects of QM, and they are still on-going (e.g. Aspect and Zeilinger). Any new theory that admits a more "plausible" interpretation has to agree with all those experiments.

I agree. Certainly no serious suggestion would try to contradict the large body of phenomenology that we have massive evidence for - that in itself would of course be highly implausible :) That not anything near what I am after, neither am I looking to restore classical realism.

Even if some of the QM formalisms is replaced by something better, one certainly need to explain why the current formalism is so good effectively speaking, and there are some ideas how this can be so, how symmetries are emergent from a more dynamical formalism which greater unification, so that the standard QM formalism emerges as an effective description in certain special domains, but where the larger formalisms explaines how this emergent formalism is deformed into something completely different in other domains.

/Fredrik
 
  • #15
Interpretations are more than "just" interpretations: they have consequences for future research. I've read from proponents of both Bohm's interpretation as well as of MWI, that a future development of their theories will lead to additional predictions which will be verifiable.

This is also clear for computer games such as the "Colossal Cave Adventure", where a different mental map will easily make you look in different directions for different solutions.

Interpreting entanglement as 'non-local' may result in more research for, perhaps, other non-local features (such as perhaps tunneling), it may lead to questioning whether (also) relativity theory is incomplete, rather than (just) quantum theory.

Interpreting entanglement as 'local' a la MWI may lead to research for possibilities of storing large amounts of information in a single particle via entanglement.

Either, both or none of those may be fruitful, somewhat independently of the actual 'correctness' of the corresponding interpretation.

Also different ethical consequences may be possible. If one is convinced, that certain quantum events will create "more" worlds than others, one might find a moral obligation to create more worlds. If one has the idea that some quantum events might have the opposite effect, one might want to avoid them.

The always intensely debated topic of determinism has strong philosophical implications, and is often connected with different ethical, political and/or religious outlooks. One interpretation may look more deterministic than another one.

Furthermore, these interpretations may have implications for our understanding of consciousness, and future research in that direction.

In the absence of an obvious direction for future research in terms of basic theories, interpretations are perhaps the most important guideline in terms of looking for new basic "features" of the universe.
 
  • #16
colorSpace said:
Interpretations are more than "just" interpretations: they have consequences for future research. I've read from proponents of both Bohm's interpretation as well as of MWI, that a future development of their theories will lead to additional predictions which will be verifiable.

I'm somehow very wary of using interpretations to further research on fundamentals. No interpretation of Newtonian physics could suggest relativity, and no interpretation of it could suggest quantum theory. In other words, interpretations that have some meaning are deeply rooted in the fundamental principles of a theory. So any radical deviation from those fundamental principles will normally not be suggested by a good interpretation!

However, and that's probably where your examples are pertinent, different interpretations of a SAME theory might illustrate/suggest more conveniently certain areas of *application* of said theory.

This is where interpretations have btw IMO their main role: give you some *feeling* for the workings of a given theory, so that you can devellop some INTUITION for it, and hence some creativity. The suggestiveness and hints for creative work might indeed depend on the view you adhere. So it can even be interesting to switch interpretations sometimes, just to get a fresh view on things.

Interpreting entanglement as 'non-local' may result in more research for, perhaps, other non-local features (such as perhaps tunneling), it may lead to questioning whether (also) relativity theory is incomplete, rather than (just) quantum theory.

Personally, I think this is erroneous thinking, and one of the roads without issue in which certain interpretations can guide people! Hence the many (erroneous) proposals to make an FTL telephone using entanglement... although it can clearly be shown that this is, within QM, as impossible as making a perpetuum mobile is in thermodynamics.

Interpreting entanglement as 'local' a la MWI may lead to research for possibilities of storing large amounts of information in a single particle via entanglement.

Indeed, this is probably why people working on quantum computing often prefer MWI, because they can see it as "parallel working of classical machines".

Also different ethical consequences may be possible. If one is convinced, that certain quantum events will create "more" worlds than others, one might find a moral obligation to create more worlds. If one has the idea that some quantum events might have the opposite effect, one might want to avoid them.

This would be one of the most stupid uses of an interpretation ! Interpretations of a formalism don't serve to deal with ethical questions !

The always intensely debated topic of determinism has strong philosophical implications, and is often connected with different ethical, political and/or religious outlooks. One interpretation may look more deterministic than another one.

I think that this would be completely silly ! Again, interpretations of quantum theory as we have it today shouldn't have any more implications for human society as Pascal's determinism. This is using concepts totally out of context. It is as if we were going to use Goedel's theorem in court, just to show that no logical system is complete, and hence that it could be that the case at hand is not determined by law :smile:
 
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  • #17
lightarrow said:
I voted "another one". I prefer "relational interpretation".

I've always seen the relational interpretation as a flavor of MWI, without explicitly saying that there are many worlds (because you stick to your own one)..., that is, without considering a "god's eye" objective viewpoint.
 
  • #18
Vanesch so your saying in MWI people don't split?
Cause if they do, think of it this way; the persons ur speaking to are reallly 1000000000 different ones every minute you speak.
So if you believe this is reality, wow, i thought the imaginated "hell" would be lame, but if MWI was true, wow everyone would comit suicide:P
 
  • #19
It seems to me whether something gets labeled as a "theory" or "interpretation" depends upon what those in charge decide to label it. Many-worlds "interpretation" is not really an interpretation because it makes predictions inconsistent with Copenhagen; we just don't yet know how to test them. But whether or not unobserved eigenstates continue to exist is very much a "real" question with a yes or no answer.

Personally I think desperately cleaving to Copenhagen is just an easy way of avoiding difficult questions. Just because you don't know the answer to the question doesn't mean it's not worth asking.
 
  • #20
peter0302 said:
It seems to me whether something gets labeled as a "theory" or "interpretation" depends upon what those in charge decide to label it. Many-worlds "interpretation" is not really an interpretation because it makes predictions inconsistent with Copenhagen; we just don't yet know how to test them. But whether or not unobserved eigenstates continue to exist is very much a "real" question with a yes or no answer.

I wonder what you are referring to. Normally, MWI makes the same observational predictions as CI... Both use the Born rule as the ultimate statistical prediction of repeated results when the measurements are irreversibly decohered (MWI) or when "transition to classical" is completed (CI).
 
  • #21
confusedashell said:
With all the different quantum interpretations out there, which is your favourite or "most likely to be true" ?

I have a real hard time making up my mind about these things, it all reminds me of different religions trying to prove the unproveable.
EVERYONE is disagreeing, new evidence get thrown in the bin if it doesn't agree with the different phycisists pet theory.
Whate ver happened to simple science people agree'd on.
What I don't get is that quantum mechanics are dealing with the smallest things in the universe yet people seem to think it is arguing for other universes or that we are gods creating the world or that time goes back n foth.

Certaintly set your mind spinning, what is the future of quantum mechanics really?
They'll never agree, even if you disproved a interpretation and showed it was inconsistent with the quantum formalism people would still be on it like crazy.


Any thought or am I the only one bothered with the state of science these days?


Really enjoy this question.

Everybody uses the term "quantum", but there is great confusion as to the meaning of the word. Try Googling some key words to see various definitions.

I prefer Professor Max Planck's original definition. He viewed the atom as an electronic oscillator (or an equivalent mechanical oscillator) that can oscillate in a anyone of a series of fixed states. The energy difference between adjacent states is constant at h*df. The energy states are defined by his "state equation". He described his theory in detail at Columbia University in 1908. See "Planck's Columbia Lectures".
 
  • #22
vanesch said:
I've always seen the relational interpretation as a flavor of MWI, without explicitly saying that there are many worlds (because you stick to your own one)..., that is, without considering a "god's eye" objective viewpoint.
That's not a small difference. Also, in MWI every possibility happens simultaneously; not in relational interpretation. For this reason I wouldn't see it as "a flavor of MWI".
 
  • #23
lightarrow said:
That's not a small difference. Also, in MWI every possibility happens simultaneously; not in relational interpretation. For this reason I wouldn't see it as "a flavor of MWI".

Ok, so in an EPR situation, Alice does a measurement on her side at 8:01 wednesday morning,, and bob on his side at 8:02 wednesday morning. Let us say that they live 10 lightminutes from one another (and don't move fast, so that a common time makes sense). From Alice's PoV, "bob doesn't have a result" at 8:05, because she, and her environment, cannot yet come to a mutual agreement on its outcome. But for bob ? Doesn't he have an outcome at 8:05, from his PoV ?

At 10:00 on saturday, they meet. They exchange results. For Alice, NOW Bob's measurement makes sense, and everybody agrees with it (in Alice's environment). So everybody agrees now that Bob DID have a result at 8:05 last wednesday. So, finally, did he, or didn't he have a result back then ?
 
  • #24
vanesch said:
I wonder what you are referring to. Normally, MWI makes the same observational predictions as CI... Both use the Born rule as the ultimate statistical prediction of repeated results when the measurements are irreversibly decohered (MWI) or when "transition to classical" is completed (CI).
For starters, MWI requires gravity be quantized, so if gravity were not quantized, it would be disproven.

Also, I believe there is speculation that intelligent computers could be used in the future to disprove certain aspects of naive CI in favor of MWI.

Finally, as others have pointed out the constant goal is to find an experiment where the "interpretations" predict different reuslts. That no one has succeeded to _everyone's_ satisfaction doesn't mean it's impossible.
 
  • #25
peter0302, what about afshar's experiment? doesn't it do exactly what your saying?
to quote John G Cramer:

"Does this mean that the Copenhagen and Many Worlds Interpretations, having been falsified by experiment, must be abandoned? Does it mean that the physics community must turn to an interpretation like the Transactional Interpretation that is consistent with the Afshar results? Perhaps. I predict that a new generation of "Quantum Lawyers" will begin to populate the physics literature with arguments challenging what "is" is and claming that the wounded interpretations never said that interference should be completely absent in a quantum which-way measurement. And most practicing physicists who learned the Copenhagen Interpretation at the knee of an old and beloved professor will not abandon that mode of thinking, even if it is found to be inconsistent with the formalism and with experiment.

But nevertheless, the rules of the game have changed. There is a way of distinguishing between interpretations of quantum mechanics. It will take some time for the dust to settle, but I am confident that when it does we will have interpretations of quantum mechanics that are on a sounder footing than the ones presently embraced by most of the physics community
."
 
  • #26
peter0302 said:
For starters, MWI requires gravity be quantized, so if gravity were not quantized, it would be disproven.

No, if gravity is not quantized, this disproves the universality of QUANTUM THEORY. That is, the superposition principle is then not applicable to, say, the position of the earth, and the Earth doesn't have quantum states.

CI as well as MWI limit themselves for the moment to an imaginary world in which there is no (active) gravity - as we know already that passive gravity DOES give rise to quantisation (example: neutron in gravitational field is in different quantum states).

So that's not a matter of interpretation, but of scope of validity of quantum theory. However, it is true that CI could ACCOMODATE easier to such a NEW THEORY than could MWI, because MWI is requiring strict quantum theory, and CI has a free parameter in it, which is the Heisenberg cut, which can be arbitrarily placed, on the level of molecules, on the level of humans, on the level of the solar system, or on the level of a galaxy or ...

Also, I believe there is speculation that intelligent computers could be used in the future to disprove certain aspects of naive CI in favor of MWI.

They could only prove that the Heisenberg cut is "higher up" than one might first think.

Finally, as others have pointed out the constant goal is to find an experiment where the "interpretations" predict different reuslts. That no one has succeeded to _everyone's_ satisfaction doesn't mean it's impossible.

But I don't understand how one can even IMAGINE thinking that one is going to find an experiment that distinguishes IDENTICAL SETS of numbers to which one has given different STORIES ?
 
  • #27
colorSpace said:
...
Also different ethical consequences may be possible. If one is convinced, that certain quantum events will create "more" worlds than others, one might find a moral obligation to create more worlds. If one has the idea that some quantum events might have the opposite effect, one might want to avoid them.
This worries me. How can your knowledge of a QM model possibly affect your ethics or behaviour ? Do you mean people should behave differently if MWI or CI is 'proven'? Sounds completely daft to me.

Should I say to a beggar, 'sorry, I can't let you have anything because the laws of physics ... blah.'

Morals and ethics have nothing to do with science per se. They are about how you deal with or treat other people. People who base their ethics on 'science' are nearly always nutters, who use it to justify some terrible atrocity.
 
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  • #28
It seems I pushed some buttons...
 
  • #29
Mentz114 said:
This worries me. How can your knowledge of a QM model possibly affect your ethics or behaviour ? Do you mean people should behave differently if MWI or CI is 'proven'? Sounds completely daft to me.

Should I say to a beggar, 'sorry, I can't let you have anything because the laws of physics ... blah.'

Morals and ethics have nothing to do with science per se. They are about how you deal with or treat other people. People who base their ethics on 'science' are nearly always nutters, who use it to justify some terrible atrocity.


Well if your to take MWI literal like david deutsch, why not kill people? you do in 30984723953285 other universes either way. why not **** ur mom, u do either way.
why not anything , you do eitehr way, and u never have a friend, its a clone of a friend.
so the best thing u can do in MWI is suicide and hope quantum suicide isn't a consequence of mwi.

As for CI: now this is solipsism, if observers create the world, we are god.
 
  • #30
confusedashell said:
Well if your to take MWI literal like david deutsch, why not kill people? you do in 30984723953285 other universes either way. why not **** ur mom, u do either way.

If you follow Deutsch to the end, you shouldn't kill your mom, because this will probably give rise to you having lousier experiences in YOUR future branch. Leave the bad experiences to your copies, not to yourself! Optimise good sensations for yourself, and leave the dirty work to your copies, which will then kill copies of the mom YOU will continue to experience. You don't care, do you, what happens to those you won't ever see anymore ? You care about those that WILL or CAN still have an influence on YOUR experiences, because you want to optimise YOURS (and not your copy's). This is what Deutsch argues in his "rational decider" paper...

In other words, by being perfectly egoist, you behave socially correct, in the same way as you would in a classical universe. The whole point is that you SHOULDN'T CARE about branches that are not going to be yours.
 
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  • #31
Thats solipissm, sorry, whoever believes this interpretation without evidence should seek a psychologist.
This is arguing you have free will, which MWI SUPERHARDDETERMINISM is all against, this is just retarded childish metaphyiscal philoshopical pseudoscience.

I'm sorry, but the "confusedashell" you spoke to over this forum for the first time a few weeks ago in that branch, is still the same branch, same me, you are the same you, same branch, forever "trapped in this branch" no splitting has occurred can or will ever occur.

Even David Deutsch said that in the future he believes quantum theory will be changed a lo and that maybe parallel universes DOESNT exist.

You HONESTLY believe there is 39529530958329 copies of you in other universe raping your mom as we speak? cmon truly honestly, answer this.
 
  • #32
confusedashell said:
Even David Deutsch said that in the future he believes quantum theory will be changed a lo and that maybe parallel universes DOESNT exist.

Eh, so do I.

That's why MWI is an interpretation of quantum theory. It is not a theory of the world.
 
  • #33
So, tell me honestly, do you believe that MWI is jst a way of looking at the QUANTUM world, or the "REAL WORLD" ?
Do you believe ou constnatly split and speak to different "copies" of other people all the time?
 
  • #34
confusedashell said:
So, tell me honestly, do you believe that MWI is jst a way of looking at the QUANTUM world, or the "REAL WORLD" ?
Do you believe ou constnatly split and speak to different "copies" of other people all the time?

It is a way of looking at the quantum formalism. As is any other interpretation of that formalism. In the same way as picturing the world as a 4-d "blob" of static spacetime is a way of looking at the formalism of relativity...

However, however, that doesn't exclude that the "real world" might, eventually, really be that way. But there's no way of telling, and I think we are still FAR FAR away from making any such claims, which will always remain speculative.
 
  • #35
Yeah I agree, but I don't agree there exist other universes.
It's too science fiction brink of losing my sanity to me.
Thats not a good "scientific arguement" but there is other interpretations of the formalism, could you (since your a PhD) lead me to a more rational single universe independant of observer interpretation?
You accept MWI(beyond my capabilities), to me accepting MWI would be accept life is utterly meaningless and life is impossible to live (for me).
Luckily, MWI might not be true at all, so as long as it's not proven at all, I will cling to proven science and the one observeable universe and hope it'll be confirmed even at the quantum world.
 
  • #36
confusedashell said:
Yeah I agree, but I don't agree there exist other universes.
It's too science fiction brink of losing my sanity to me.
Thats not a good "scientific arguement" but there is other interpretations of the formalism, could you (since your a PhD) lead me to a more rational single universe independant of observer interpretation?

There's only one I know of, and that's Bohmian mechanics. However, in order to accept that, you have to give up the principles of relativity... and you won't be able to do a lot with it if you want to understand quantum field theory (which is understandable, QFT is strongly mixed with special relativity).

You accept MWI(beyond my capabilities), to me accepting MWI would be accept life is utterly meaningless and life is impossible to live (for me).
Luckily, MWI might not be true at all, so as long as it's not proven at all, I will cling to proven science and the one observeable universe and hope it'll be confirmed even at the quantum world.

My only motivation to stick to MWI is that it is in fact a non-interpretation. It says that the mathematical entities you manipulate in the quantum formalism are "really out there", and that ALL happenings are quantum interactions, the way they are described in the quantum formalism. In other words, MWI is nothing else but applying strictly the axioms of quantum theory to the whole world, and give a status of reality to the mathematical objects that these axioms claim, give the state of the system.
So it is in fact nothing else but "picturing for real" the mathematical entities of the quantum formalism (hence you will have a hard time finding an experiment that "violates MWI" but is "in agreement with QM": this is why I'm so sure about this!).

The "many worlds" are then just a natural consequence of the axioms of quantum theory. Indeed, a fundamental axiom (the superposition principle) of quantum theory tells you that

"if a system can be in state A and can be in state B, then it can be in any state x |A> + y |B> with x and y complex numbers, and in as much as these states aren't multiples of one another, they represent physically distinct states".

It is this statement which is crazy ! But it is a fundamental axiom of the quantum formalism.

So, apply this to a guy in his lab: "the guy seeing a green light flashing" as a possible state, right ? "the guy seeing a red light flashing" is another possible state, right ?

Well, apply bluntly the axiom of the superposition principle, and you will find that the guy can be in states which correspond to superpositions of "seeing a green light flashing" and "seeing a red light flashing".

And it turns out that - under the assumption of strict applicability of quantum theory - that if the lights flashing are a result of a quantum experiment on a small system, that these superpositions are unavoidable, and moreover, give the correct OBSERVATIONS if we re-interpret the complex numbers by squaring them, and giving them the probability of observation.

So, you say AAAH, easy. These "superpositions" are just probabilities, right ?
Well, wrong. Because if you do that on the *microscopic* scale, the complex coefficients don't behave as probabilities.

Let's apply the superposition principle to our photon. The axiom of the superposition tells us that |slit1> + |slit2> is a different physical state, distinguishable from slit 1 or from slit 2. And indeed, in a 2-slit experiment, the |slit1> + |slit 2> state gives rise (using the formalism of quantum theory) to an interference pattern. This is NOT compatible with saying that |slit1> + |slit 2> represents 50% chance of |slit1> and 50% chance of slit 2, because that would give you two bumps, each with a weight of 0.5. That's what I mean with "the complex coefficients don't behave as probabilities".

Now, the CI tells us that somehow, on a "classical scale", we have to see these coefficients as probabilities, but not on a microscopic scale.
MWI tells us that the "state" continues to have these complex coefficients, but that they represent "probabilities to be experienced".

Hence, the "many" worlds are just the other terms in the wavefunction. In CI, we "put them to 0", in MWI we tell you that we "don't experience them although they are still there".

The formal advantage of MWI over CI is that it can be mathematically shown that "putting the coefficients to 0" cannot happen within the strict quantum formalism, and moreover, that if ever there were such a mechanism, that it would be strictly non-local (and would violate the principles of relativity). So MWI simply doesn't put them to 0.

MWI sounds crazy ? Sure ! But it only ILLUSTRATES the crazyness of the axioms of quantum theory. Nevertheless, these axioms do give rise to a highly successful formalism, as I guess you know. So in order to get a "feel" for this crazy formalism, it can be good to have a faithful (crazy) PICTURE of it.
 
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  • #37
Thanks, obviously your way into this than me.
To me, I go wit William Occam and cut the other universes out of existence, they are not needed.
You agree that it's a way to "picture" quantum world.

People like Weinberg and Hawking agree with the mathemathical formalism, yet they do not believe other universes really exist, only as "abstractions".
Like the number 10 is a abstraction, but not real like "10 onions".
Which interpretation would this be? still MWI math, but a different variant which saves single universe?

I've favoure the Bohmian mechanics for a while, as it's the most rational philosophically and fits our EXPERIENCE of the world, what we have to go by.
So your saying bohmian mechanics CANNOT be right?
 
  • #38
confusedashell said:
Thanks, obviously your way into this than me.
To me, I go wit William Occam and cut the other universes out of existence, they are not needed.
You agree that it's a way to "picture" quantum world.

The problem with using Occam that way is that in order to do away with the worlds, you have to INTRODUCE a new, unknown mechanism (which might, btw, very well given by gravity! That's Penrose's idea, and I like it a lot,... only, as far as I know, it just remains a vague idea and has never been worked out).

People like Weinberg and Hawking agree with the mathemathical formalism, yet they do not believe oter universes really eist, only as "abstractions".

Well, I'm slightly more careful about this. I'm *agnostic* about whether this is "real" or not. I'm even agnostic about whether the world I perceive is really real, the way I intuitively perceive it ! And that's where we enter philosophy...

Like the number 10 is a abstraction, but nto real like "10 onions".
Which interpretation would this be? still MWI, but a different variant which saves single universe?

I think personally, that these considerations are premature. As long as we haven't any clue as to the quantum nature of gravity we haven't any scientific argument one way or another, and it might take a long time (maybe forever!) to find out experimentally. However, given that Hawking himself has used SUPERPOSITIONS of black hole states over times of billions of years, and found agreement with some thermodynamic predictions, we shouldn't go so lightly over the superposition principle on macroscopic (REALLY macroscopic) scales. And if the superposition principle is true on macroscopic scales, I really don't see how you can escape any MWI-like flavor.

I've favoure the Bohmian mechanics for a while, as it's the most rational philosophically and fits our EXPERIENCE of the world, what we have to go by.
So your saying bohmian mechanics CANNOT be right?

No, no, not at all. But Bohmian mechanics has fundamental difficulties integrating the PRINCIPLES of relativity (for very obvious reasons). In fact, the path to Bohmian mechanics is:

Newtonian mechanics ---> ether theory (equivalent to relativity, but without its principles, and a lot of ad hoc concepts) --> quantum potential.

In other words, Bohmian mechanics is obtained by sticking to Newtonian mechanics, and introducing all the necessary machinery each time to save Newtonian mechanics in the light of relativity and quantum theory. But the problem with that approach IMO is that these concepts were each time "introduced after the fact". That is, in relativity, the whole theory is built up on a few principles (speed of light constant, ... ), from these principles you derive a lot of results, and then you IMPLEMENT these results as "god given" directly in the Newtonian frame "length changes", "clocks slow down"... while denying the principles that were at its basis. Of course, you can build an observationally identical theory that way. But you would never have "found it" without having used the principles which you deny after the fact.

In the same way, the quantum-mechanical wavefunction is used to calculate "quantum forces" on the particles such that they deviate exactly as to arrive where they have to to be in agreement with the statistical predictions of QM. But the principles of QM (superposition principle, unitary evolution...) are then relegated to the background once they have given the "quantum potential" (which you would, again, never have found without genuine quantum mechanics).

So although this can be made working, it looks nevertheless a lot like "using a principle, taking the results, and then denying the principle".

And although one can say that Bohmian mechanics does have some elegance in non-relativistic quantum theory, it becomes a genuine mess when trying to do QFT. It is not impossible, but the constructions that have to be invented to "keep agreement with QFT" become rather big and ugly. And you would never have invented it without first looking at QFT.

For non-relativistic QM, Bohmian mechanics is again experimentally identical to quantum theory, so it can be seen as an "interpretation". I'm not so sure about the QFT case, whether it is "mostly in agreement" or "perfectly in agreement". I'm simply not knowledgeable about it.
 
  • #39
Thanks again, you got a big intellect vanesch... Thank you for your input and help in solving some questions I've had...

You seriously doubt perception?
Ofcourse the world infront of us is the way the world is, doubting that is leading to solipsism and if that's a position you could take in anycase, your mentality is not very healthy.
NO OFFENSE:P
 
  • #40
vanesch said:
And if the superposition principle is true on macroscopic scales, I really don't see how you can escape any MWI-like flavor.

Well, in the double-slit experiment, where you definitely have superposition and interference, you still eventually measure each photon at a specific location on the screen. So finally, at the point of measurement, you still have the phenomenon of either a collapse, or a "split", or something else, that has to explain why the photon eventually shows up in a specific place. (Or why it appears to do so.)
 
  • #41
vanesch said:
They could only prove that the Heisenberg cut is "higher up" than one might first think.
I dunno, to me it would prove there is no "Heisenberg cut" at all, because if the "cut" happens at a higher level than the elementary particles then where it happens is just chosen at the whim of the experimenter depending on the goal of the experiment, which means the cut has no meaning except on paper. Unless you adhere to the view that the human observer somehow is responsible for the very existence of the particle, which I'm not even going to begin to get into...

But I don't understand how one can even IMAGINE thinking that one is going to find an experiment that distinguishes IDENTICAL SETS of numbers to which one has given different STORIES ?
That's just my point. Just labeling it a "story" is nothing but a way to marginalize it. It becomes more than a "story" the moment someone divines an experiment that would produce different results. And we already agree that MWI could be decisively disproven if spacetime and gravity were not quantized, so I don't know what more you want of it before you would accept it as a theory.
 
  • #42
confusedashell said:
peter0302, what about afshar's experiment? doesn't it do exactly what your saying?
The jury's still out on Afshar. Some say there's really no way of knowing that the photon that exited a particular slit wound up at a particular detector because the lens may have served to re-randomize the EM field.

I for one think this is a stretch but a lot of people much smarter than me believe it so I am not really in a position to argue with them. :)
 
  • #43
peter0302 said:
The jury's still out on Afshar. Some say there's really no way of knowing that the photon that exited a particular slit wound up at a particular detector because the lens may have served to re-randomize the EM field.

I for one think this is a stretch but a lot of people much smarter than me believe it so I am not really in a position to argue with them. :)

Or the "wires" placed in the interference positions (causing a similar effect as the slits).
 
  • #44
Or the "wires" placed in the interference positions (causing a similar effect as the slits
Isn't that even more of a stretch? The wires don't block any photons (the slits do!). That's what the experiment shows. As I often say, a photon is not a magic bullet.
 
  • #45
peter0302 said:
Isn't that even more of a stretch? The wires don't block any photons (the slits do!). That's what the experiment shows. As I often say, a photon is not a magic bullet.

I'm not talking about blocking. Just like slits, they may cause more uncertainty in the momentum. The slits also alter the path of those photons that go through, otherwise you would only see two narrow stripes on the screen [Edit: in the case of the double slit experiment]. The photons have the option of "bending" around them.
 
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  • #46
The slits also alter the path of those photons that go through, otherwise you would only see two narrow stripes on the screen
Yes, the presence of the slits determines the state vector of the photons that go through them, but the slits only allow a small % of the photons to actually pass through - the rest are blocked. By contrast, the number of photons going through the Afshar grid is virtually unchanged. That's the whole point.

So the difference is, with the slits, most are being blocked, and the ones that aren't come out in a superpositioned state. Whether the slits merely isolated those photons in that state, or caused them to be in that state, is a matter of interpretation. But either way, with the Afshar grid - NONE of the photons are blocked. Yet you still want to say hat their state vectors are changed by the presence of a device which otherwise doesn't seem to interact with the photons at all? Again, I think this is a stretch.
 
  • #47
peter0302 said:
Yes, the presence of the slits determines the state vector of the photons that go through them, but the slits only allow a small % of the photons to actually pass through - the rest are blocked. By contrast, the number of photons going through the Afshar grid is virtually unchanged. That's the whole point.

So the difference is, with the slits, most are being blocked, and the ones that aren't come out in a superpositioned state. Whether the slits merely isolated those photons in that state, or caused them to be in that state, is a matter of interpretation. But either way, with the Afshar grid - NONE of the photons are blocked. Yet you still want to say hat their state vectors are changed by the presence of a device which otherwise doesn't seem to interact with the photons at all? Again, I think this is a stretch.

Yes of course I want to say that. Diffraction applies to photons which pass the slits, or the wires, in any case, not to those which would be blocked (if any). And when you have diffraction, then you can't tell anymore which way the photon came. The which-way-information is lost for the path prior to the grid. Too simple to be true?

http://en.wikipedia.org/wiki/Diffraction
 
  • #48
But the slits don't cause diffraction like a lens or prism does. The slits merely pick out photons in such a way as to make it ambiguous which slit they went through. But I still say they only went through one slit or another, as evidenced by the fact that if you put detectors immediately beyond the slits before any interference pattern can show up, you only see one detector or the other go off.
 
  • #49
peter0302 said:
But the slits don't cause diffraction like a lens or prism does. The slits merely pick out photons in such a way as to make it ambiguous which slit they went through. But I still say they only went through one slit or another, as evidenced by the fact that if you put detectors immediately beyond the slits before any interference pattern can show up, you only see one detector or the other go off.

Did Vanesh tell you that?
 
  • #50
BTW, there will always just one detector be hit. Photons just don't spread out like butter, even when they interfere. Even in a tunneling situation, you won't be able to quickly insert a bigger separator and then find the photon in both places. Which reminds me that I wanted to find out more about Bose-Einstein Condensates.
 
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