Many Worlds

[SelfSim]

.. they are saying this is the theory they like/prefer/think is best/ think is more likely to be correct or some such (any of the above, or another like them). That's what the word 'best' means in this context, to me. But for you that seemed not that way at all, so you thought I didn't address what she said there in the opening on the same scope, while I definitely addressed exactly that, on exactly that same subjective scope.

Rubbish. She gave her reason in the quote I quoted immediately prior to this one.
That reasons is: 'because its so simple'. Nothing to do with being 'correct' or 'more likely'.
She explains further that mathematically, MW is a simplification of quantum theory.

This has nothing to do with how I might interpret words differently from you.

Her words count because:
i) she explains and demonstrates her reasons .. and they have nothing to do with MW being 'correct' or 'more likely' and;
ii) Mithuna Yoganathan, has a PhD in quantum computing from the University of Cambridge.

You have not addressed anything on the same level as what she has throughout that video.

So, our word usage/meaning did not align there at all. That's quite a contrast in definitions/word usage between us.
So, you and I may be very often using words in very different ways.

That's bound to cause a lot of misunderstanding, because it would make it more likely that I'd sometimes think you are saying X when you meant Y, and more likely you'll sometimes think I'm saying R when I meant S (as here in this instance), etc.

A good thing to take caution about in discussion then. I wonder how many times we've misunderstood what the intended meanings we've written to each other. Half the time? More?

More diversionary rubbish.
From your nine lengthy posts thus far in this thread, all you have demonstrated is your complete and utter misunderstanding of the entire point of the video.
In your eagerness to tell us your mere beliefs and misguided opinions about MW, you haven't yet even come close to addressing the central point.

 

[FrumiousBandersnatch]

Talking about the variety of competing theories:

We have of course a large variety of phenomena where we see the appearance (seeming) of what might be wave function collapse -- the wide variety of phenomena alike in that way to the electrons in the double split experiment. Some have even speculated on whether the Copenhagen Interpretation could be all there is even for many or some aspects. (but that view itself is of course yet another speculative hypothesis) I want to repeat though that Many Worlds is just another runner in a race which has many competitors, and so one should reasonably look at the other competitors.

About liking Many Worlds for its simplification:
First, let me credit Bayesian inference as being definitely a good way to search for new theories. We know that over time in physics all the theories that prove out to be the most signficant and are real progress have been elegant, and fit together with existing theories generally. So, the Bayesian inference as a way to search for new theory is just reasonable, a good plan. It's like...starting a foot race heading in the correct road direction. And simplification is often a good thing to consider. But what about all the other runners (theories)?

The problem as I see it with favoring a theory that is not yet falsifiable, or possibly never testable, theories like Many Worlds (and for example, it could happen we might never be able to conclude, could never show that the wave function collapses or does not collapse in some conclusive way that would be more than the already large amount of results that seem as if a wavefunction collapse in a Copenhagen sense even) which we already have...)...is the variety of other theories that also have nice attributes.

So, when considering a theory, that one has a simplification isn't by itself all that impressive. (for instance, one could take an existing theory that does have plenty of unique supporting evidence and try to simplify it in some way we know would just make it less useful or even incorrect).

So, instead of seeing Many Worlds as in any way important, it seems then more like...wishful thinking to me to imagine it's likely correct. (if anyone does) At most, to me, Many Worlds would be more important (not more likely correct, but merely more prominently important) if there weren't competing theories. But there are, including intriguing other theories with interesting attributes of their own.

I don't think anyone who's familiar with the interpretations of QM would claim any of them are correct or more likely to be correct. They're all 'correct' to the extent that they all explain current observations and seem to have the same predictive power. Some might say they like to think that the interpretation they prefer is the 'correct' one, but it's not clear that this can mean more than that they think it is the best model.

When choosing between interpretations of equal explanatory & predictive power, the traditional approach, and ISTM the most pragmatic approach, is to choose the one with the fewest assumptions or entities (Occam's razor). IOW, if one has the same explanatory & predictive power as others that have more assumptions or entities, it suggests that those additional assumptions and entities are unnecessary.

It may be that the universe is sometimes unnecessarily complicated, but, particularly when dealing with the fundamentals of nature, it seems sensible to use the simplest interpretation that will do the job until we discover otherwise. Why complicate matters with additional distractions that bring their own explanatory problems - until we discover that they're necessary?

Plus, I rather like the challenge to our understanding of 'reality' - as a vector in Hilbert space evolving according to the Schrödinger equation

 

[Halbhh]

I don't think anyone who's familiar with the interpretations of QM would claim any of them are correct or more likely to be correct. They're all 'correct' to the extent that they all explain current observations and seem to have the same predictive power. Some might say they like to think that the interpretation they prefer is the 'correct' one, but it's not clear that this can mean more than that they think it is the best model.

When choosing between interpretations of equal explanatory & predictive power, the traditional approach, and ISTM the most pragmatic approach, is to choose the one with the fewest assumptions or entities (Occam's razor). IOW, if one has the same explanatory & predictive power as others that have more assumptions or entities, it suggests that those additional assumptions and entities are unnecessary.

It may be that the universe is sometimes unnecessarily complicated, but, particularly when dealing with the fundamentals of nature, it seems sensible to use the simplest interpretation that will do the job until we discover otherwise. Why complicate matters with additional distractions that bring their own explanatory problems - until we discover that they're necessary?

Plus, I rather like the challenge to our understanding of 'reality' - as a vector in Hilbert space evolving according to the Schrödinger equation

While some were thought of as just interpretations, we have now some that make specific predictions, which makes them testable, and so it's best I think to label a testable formulation a 'theory'. While we can speculate about what might get unique supporting evidence some day, I usually refrain from suggesting a theory is 'likely correct' if it has no unique supporting evidence. And even for any that have predictions we cannot yet test, but might some day be able to test, I think the label 'theory' is helpful/more informative than just calling such an interpretation only.

You might recall how I posted about an experiment and observations from it that failed to show support a theory I liked? (while not definitive enough to simply kill the theory) To spark memory, this theory was the one I subjectively liked the most (even though if it turned out correct it would force me to revise some other views I have): De Broglie–Bohm theory - Wikipedia

It may be that the universe is sometimes unnecessarily complicated, but, particularly when dealing with the fundamentals of nature, it seems sensible to use the simplest interpretation that will do the job until we discover otherwise. Why complicate matters with additional distractions that bring their own explanatory problems - until we discover that they're necessary?

I don't see Many Worlds as really so much an elegant simplification, but more like just avoidance of the challenge that QM is for us. That said, if there ever arises any way to assess it more objectively that would be great.

 

[SelfSim]

When choosing between interpretations of equal explanatory & predictive power, the traditional approach, and ISTM the most pragmatic approach, is to choose the one with the fewest assumptions or entities (Occam's razor). IOW, if one has the same explanatory & predictive power as others that have more assumptions or entities, it suggests that those additional assumptions and entities are unnecessary.

It may be that the universe is sometimes unnecessarily complicated, but, particularly when dealing with the fundamentals of nature, it seems sensible to use the simplest interpretation that will do the job until we discover otherwise. Why complicate matters with additional distractions that bring their own explanatory problems - until we discover that they're necessary?

If you can see that its us choosing whether to prefer an either more complicated or a simpler interpretation, then why not also adopt the simpler explanation of what Occam's Razor is really about? (We've had conversations about this in the past).

Ie: since the goal is simply to understand, and the simplest theory that agrees with data is the best path to understanding, then that's clearly the best theory. That's it, that's the Razor .. nothing more.

The part where people somehow think that it leads to how the universe might actually work, is just as easy to delete as the OP vid presenter's deletion of the QM rule which says: '2) Measurement causes collapse'.

The universe isn't the thing which has to keep itself simple .. Its us who seek simplicity in our models of the universe, in order to efficiently explain phenomena to others. What I'm seeing across QM physicists, whenever they talk about the various interpretations, is their expression of what works best for them in doing that .. (and nothing more than that).

All Mithuna Yoganathan, (ie: the OP video presenter), is effectively saying then, is that the MWI works for her in pursuing that purpose .. (and nothing more than that).

 

[SelfSim]

You might recall how I posted about an experiment and observations from it that failed to show support a theory I liked? (while not definitive enough to simply kill the theory) To spark memory, this theory was the one I subjectively liked the most (even though if it turned out correct it would force me to revise some other views I have): De Broglie–Bohm theory - Wikipedia

...
I don't see Many Worlds as really so much an elegant simplification, but more like just avoidance of the challenge that QM is for us. That said, if there ever arises any way to assess it more objectively that would be great.

Bohmian mechanics also 'deletes' the measurement causes collapse QM rule.
Also, fom your Wiki reference:

The theory does not have a "measurement problem", due to the fact that the particles have a definite configuration at all times. The Born rule in de Broglie–Bohm theory is not a basic law. Rather, in this theory, the link between the probability density and the wave function has the status of a hypothesis, called the "quantum equilibrium hypothesis", which is additional to the basic principles governing the wave function.

 

[Neutral Observer]

Just throwing this out there, but I can't help but wonder that if you took MWI and added just one more parameter, specifically superdeterminism, then those many worlds might actually turn out not to be all that many, and then MWI might not be all that incompatible with some collapse theories.

Now I admit that I know nothing about this stuff, but it just seems to me that if you reduce the number of worlds in MWI then it might begin to look a lot like all the other theories.

 

[FrumiousBandersnatch]

While some were thought of as just interpretations, we have now some that make specific predictions, which makes them testable, and so it's best I think to label a testable formulation a 'theory'. While we can speculate about what might get unique supporting evidence some day, I usually refrain from suggesting a theory is 'likely correct' if it has no unique supporting evidence. And even for any that have predictions we cannot yet test, but might some day be able to test, I think the label 'theory' is helpful/more informative than just calling such an interpretation only.

Using scientific language, that would be a 'hypothesis'; a scientific theory is one that has been well-tested and is widely accepted.

You might recall how I posted about an experiment and observations from it that failed to show support a theory I liked? (while not definitive enough to simply kill the theory) To spark memory, this theory was the one I subjectively liked the most (even though if it turned out correct it would force me to revise some other views I have): De Broglie–Bohm theory - Wikipedia

Yes, the pilot wave idea was appealing - especially when a macro-scale 'equivalent' was demonstrated

I don't see Many Worlds as really so much an elegant simplification, but more like just avoidance of the challenge that QM is for us. That said, if there ever arises any way to assess it more objectively that would be great.

In what way is it 'an avoidance' of the QM challenge?

I don't really think of it as a simplification, because the other interpretations seem more like complications. It just says that the Schrödinger equation is all that matters, and (so far) it works... why add unnecessary complications? ¯\_(ツ)_/¯

 

[FrumiousBandersnatch]

Just throwing this out there, but I can't help but wonder that if you took MWI and added just one more parameter, specifically superdeterminism, then those many worlds might actually turn out not to be all that many, and then MWI might not be all that incompatible with some collapse theories.

Now I admit that I know nothing about this stuff, but it just seems to me that if you reduce the number of worlds in MWI then it might begin to look a lot like all the other theories.

I don't see how you could 'reduce the number of worlds' in MW, it is just the basic quantum formalism - on interaction with the environment, quantum superpositions spread out into the universe and decohere.

 

[Halbhh]

Using scientific language, that would be a 'hypothesis'; a scientific theory is one that has been well-tested and is widely accepted.

Heh. Well...String Theory.

I don't really think of it as a simplification, because the other interpretations seem more like complications. It just says that the Schrödinger equation is all that matters, and (so far) it works... why add unnecessary complications? ¯\_(ツ)_/¯

A reasonable view, but not mine. It's just another unsupported hypothesis to me, but with some problems also.

It's curious to me that another person in this thread got so emotional about it though that they descended into just writing insulting posts showing personal animus. Why even have any emotion about any of the current ideas, is my attitude, given an array of interesting hypotheses none of which have any supporting evidence?

While apparently that happens:

Arguments about the interpretation of quantum mechanics are noted for their passion, as disagreements that can’t be settled by objective evidence are wont to be. But when the MWI is in the picture, those passions can become so extreme that we must suspect a great deal more invested in the matter than simply the resolution of a scientific puzzle.
--https://www.quantamagazine.org/why-the-many-worlds-interpretation-has-many-problems-20181018/


btw, that article might be of interest to you.

Update: I just had a possible insight related to why this speculative theory might provoke such emotions, which I just posted in the next post below.

 

[Halbhh]

Hmmm... Looking over this article again I was just referencing (it had been a few years) -- Why the Many-Worlds Interpretation Has Many Problems | Quanta Magazine -- I wonder if the feeling that Many Worlds is important is like....sorta like a form of belief...which could be even religious like belief in a way. (and/or a basic fundamental world view belief)

If a person isn't already used to having a belief criticized many times, they might get upset to hear Many Worlds criticized.... Suppose for instance it is one of only a smallish number of times (say, less than a dozen times) they had a cherished belief criticized. That would be more likely to provoke an emotionally motivated response then. Maybe there's no help for that, but time and experience.

 

[Halbhh]

Bohmian mechanics also 'deletes' the measurement causes collapse QM rule.

Yep. That's the most basic observation about it -- it's one of the types of theories where there is a definite reality all along: the particle is in a definite place all the time, before being measured. There's a lot more that is interesting past that, imo. But, it's still in the no-man's-land of lacking any supporting evidence (including the suggestive oil pan droplet experiment that @FrumiousBandersnatch referred to also, as that was not confirmed in further tests ). Famous Experiment Dooms Alternative to Quantum Weirdness | Quanta Magazine (but this isn't really a definite end to it, but just a lack of supporting analogous observations on the macro level in the configurations tested, so it's not really ruled out)

 

[FrumiousBandersnatch]

Heh. Well...String Theory.

Yes, scientific usage seems to be dropping out of fashion - although String Theory is rather an edge case, being more of a mathematical theory...

A reasonable view, but not mine. It's just another unsupported hypothesis to me, but with some problems also.

It's curious to me that another person in this thread got so emotional about it though that they descended into just writing insulting posts showing personal animus. Why even have any emotion about any of the current ideas, is my attitude, given an array of interesting hypotheses none of which have any supporting evidence?

Well, I don't know about random individuals on internet forums, but emotion in the science world shows that scientists are human too! But IME most readily acknowledge that there are problems with MW, as with the other interpretations; they just prefer it. I can't claim to know their reasons, but I suspect simplicity is high on the list.

While apparently that happens:

Arguments about the interpretation of quantum mechanics are noted for their passion, as disagreements that can’t be settled by objective evidence are wont to be. But when the MWI is in the picture, those passions can become so extreme that we must suspect a great deal more invested in the matter than simply the resolution of a scientific puzzle.
--https://www.quantamagazine.org/why-the-many-worlds-interpretation-has-many-problems-20181018/


btw, that article might be of interest to you.

Thanks, I read that article when it came out, and remember thinking that his metaphysical problems were the kind of thing science messes with all the time - we shouldn't expect nature to endorse our cherished metaphysical notions, and experience tells us it doesn't.

I think he makes a common error with the quantum suicide issue - just because we rationally think some scientific view of the world is probably the best or most useful one we currently have, doesn't mean that you're prepared to die for it - a scientist, in particular, ought to know that it may just be a better model and, until it's tested, it's just an idea.

It wouldn't surprise me if someone became convinced it was true and turned up dead - did they survive in another branch of the wavefunction? Possibly or probably? we'll never know. It's a bit like the Star Trek Transporter - one might rationally think that an identical copy is you, so the original can be destroyed, but many (myself included) are uncomfortable about one of us being destroyed... Also, we should consider, in quantum suicide, that most of us are socially connected, and even if a version of us is a billionaire in one branch, there would be a lot of grieving relatives & friends in another.

Ball's problem with consciousness & self seems poorly thought out. Given the scientific view that consciousness is a product of brain activity, all branch versions of you will (quantum suicide apart!) have the same brain activity immediately after the branch point and slowly drift apart as their experiences differ. Likewise, the sense of self isn't a problem - all versions at a given branching initially have an identical sense of self, but will then develop it in different ways over time. Once the branch occurs, each is an independent individual with their own consciousness & sense of self, no matter how many there may be.

As for the probability issue, it's is a tricky one, but the Born rule has been derived for observers in MW, and the inclination of particular observers to give equal probability to each possible outcome during 'self-locating uncertainty' (i.e. before they know which branch they're on) is a mistake; rather, a 'strong epistemic separability principle’ (strong ESP!) is more productive. This is one of those explanations that seem to make sense as I read them, but my understanding evaporates shortly afterwards, so I'll just give a link: Self-locating Uncertainty and the Origin of Probability in Everettian Quantum Mechanics. Self-locating uncertainty is a quite a MW topic in its own right, as you'll see if you Google it - for example, Self-locating Uncertainty in the Cosmological Multiverse Workshop(!)

Update: I just had a possible insight related to why this speculative theory might provoke such emotions, which I just posted in the next post below.

As I said, scientists are human too, and perhaps if you've spent years of your time on one version or interpretation of the world, you can get very emotionally attached to it. I hope good scientists generally avoid this, not least because it softens the potential blow of being wrong! Living with uncertainty is the scientist's way.

 

[SelfSim]

It's curious to me that another person in this thread got so emotional about it though that they descended into just writing insulting posts showing personal animus. Why even have any emotion about any of the current ideas, is my attitude, given an array of interesting hypotheses none of which have any supporting evidence?

You continue to completely misunderstand the issue (and now proceed in making false accusations about the articulated reasoning contained within this "other person's" posts).

One more time: You were misrepresenting the contents and scope presented in the video, in your posts.
This has nothing to do with QM interpretations.

If you demonstrate an inability to accurately describe what we can all observe in the video presentation, why should anyone accept your opinions about the pros and cons of the various QM interpretations?
The presenter, in the video, demonstrated her reasoning basis, that being deeply rooted in theoretical principles and experimental test observations. Your posts addressed none of those elements.

While apparently that happens:

Arguments about the interpretation of quantum mechanics are noted for their passion, as disagreements that can’t be settled by objective evidence are wont to be. But when the MWI is in the picture, those passions can become so extreme that we must suspect a great deal more invested in the matter than simply the resolution of a scientific puzzle.
--https://www.quantamagazine.org/why-the-many-worlds-interpretation-has-many-problems-20181018/


btw, that article might be of interest to you.

Update: I just had a possible insight related to why this speculative theory might provoke such emotions, which I just posted in the next post below.

As clarified numerous times over now, this is a completely unrelated issue from your inability to accurately represent the contents and scope presented in the video.

Its a deceptive shift of the goalposts, which you now demonstrate.

 

[Halbhh]

we shouldn't expect nature to endorse our cherished metaphysical notions, and experience tells us it doesn't.

Amen!

String Theory is rather an edge case, being more of a mathematical theory...

It's seeming more that way now, yes, after the failure to detect the predicted particles of one variety of string theory, supersymmetry. So, yes, it's seeming less to be physics, and more just math.

did they survive in another branch of the wavefunction? Possibly or probably? we'll never know.

heh heh...that's a nice example of a subjective (but meaningful) reason to me, personally, to think many worlds just feels unlikely. Of course, I know this is only my subjective opinion, but I like this example for that. Is the cat dead or alive: one view (mine) is it is definitely only one or the other (no superposition), because it's macro. (or more strictly without assuming too much, " It is impossible for a large system such as a cat to remain completely isolated from its surroundings" Coherent Schrödinger's cat still confounds – Physics World)

Ok, gotta run for now, but I'll try to read more of your post later.

 

[FrumiousBandersnatch]

Amen!

It's seeming more that way now, yes, after the failure to detect the predicted particles of one variety of string theory, supersymmetry. So, yes, it's seeming less to be physics, and more just math.

SUSY isn't dead just yet (on life support). But String Theory has provided physics with some very useful mathematical tools and ideas.

Is the cat dead or alive: one view (mine) is it is definitely only one or the other (no superposition), because it's macro. (or more strictly without assuming too much, " It is impossible for a large system such as a cat to remain completely isolated from its surroundings" Coherent Schrödinger's cat still confounds – Physics World)

Yes, the same applies to the radiation detector. Our ignorance prior to opening the box is epistemic, not quantum, as Schrödinger was pointing out.

 

[Halbhh]

You continue to completely misunderstand the issue (and now proceed in making false accusations about the articulated reasoning contained within this "other person's" posts).

One more time: You were misrepresenting the contents and scope presented in the video, in your posts.
This has nothing to do with QM interpretations.

If you demonstrate an inability to accurately describe what we can all observe in the video presentation, why should anyone accept your opinions about the pros and cons of the various QM interpretations?
The presenter, in the video, demonstrated her reasoning basis, that being deeply rooted in theoretical principles and experimental test observations. Your posts addressed none of those elements.

As clarified numerous times over now, this is a completely unrelated issue from your inability to accurately represent the contents and scope presented in the video.

Its a deceptive shift of the goalposts, which you now demonstrate.

Re the guesses at my thinking you keep doing, such as for example in this last post your characterization of my wording as 'deceptive', etc. When people try to guess at the thoughts of near-strangers over the internet, given the reality that we cannot read minds of near strangers at all, it follows that everyone guessing at the thoughts of others has fill in various unknowns (like what someone intends, etc.) in their guessing at those thoughts of the stranger from their own intuition/feelings/stuff inside their own mind. Inevitably.

So, the following process below in the link is what happens consistently when anyone tries to guess at someone else's thoughts/motives/etc. and feels confident or pretty sure they know what is really going on in that stranger's mind:

Psychological projection - Wikipedia

en.wikipedia.org

It happens every time you try to characterize my thoughts/motives/etc. You end up telling me what is in your own mind -- in those guesses, projections -- things which I wouldn't have expected, usually. And I can't easily help you with those feelings.

Everyone does projection (of their own stuff onto other people) until they learn better. The best possible way to deal with one's own projections is to get the great benefits of having someone to help you work through old feelings you have, in a skilled professional setting (often covered under normal health insurance by the way).

 

[Neutral Observer]

I don't see how you could 'reduce the number of worlds' in MW, it is just the basic quantum formalism - on interaction with the environment, quantum superpositions spread out into the universe and decohere.

Well, in the Schrodinger's Cat thought experiment for example, what if we simply take away the assumption that the decay of the radioactive particle is random, what happens to our many worlds then?

 

[SelfSim]

Well, in the Schrodinger's Cat thought experiment for example, what if we simply take away the assumption that the decay of the radioactive particle is random, what happens to our many worlds then?

That's hardly optional in QM. Ie: its not an assumption.

 

[Neutral Observer]

its not an assumption.

How so?

 

[SelfSim]

How so?

It works (out).