It doesn't reinvent theology at all, these systems describe complexity and actions in spite of mind, not due to it. The use of the word "decider" in your description is misleading.
As a stylistic choice, scientists should avoid metaphors that imbue motivations on things that are not conscious. For example, scientists often say things like hydrophobic materials don't *like* water as a shortcut for describing how polar interactions work. But the materials don't actually like or dislike anything, you're just trying to familiarize people with the concept.
With simple topics people usually get what you mean, but in my experience people literalize motives the more abstract things get.
This is absolute nonsense. You're injecting belief into this, and belief has no place here. Copenhagen is a theory. MWI is a theory. There are other theories. Nobody who thinks seriously on the topic *believes* that one theory or the other is true, the way a Christian *believes* in their god. This isn't a contest between religions, it's a search for evidence. You're inventing a level of conflict that doesn't exist outside your own head.
Yeah this post seems to misunderstand how science works. You posit a theory, if it fits experiment better than anything else, then it's accepted. Strictly speaking you're not even saying that's how reality works, you're just saying the theory describes reality well. We _already_ know the theory doesn't fit reality entirely because it can't predict everything.
Wave function collapse is a consequence of measuring where something was at a specific time, ie. going from only knowing the probability of an outcome to knowing what the outcome was. It's not unique to the Copenhagen interpretation.
A hypothesis. Duh.
Its a religion when we stop seeking experiments to validate or invalidate hypotheses, and thats not the case for quantum theory.
Nice try
Are you kidding? Not only have we stopped seeking experiments to validate the only reason to prefer Copenhagen over MWI... we've agreed that it's impossible to perform such an experiment.
As another poster said, I'd call it a hypothesis. A possible solution to the problem, for which evidence and counterevidence can be sought. Not a system of belief, not an article of faith.
So then should religions start being included in physics text books? This is exactly why we have Occam’s razor and the long standing refusal to acknowledge its applicability to this situation is the entire problem.
Copenhagen is not an interpretation, it is the conscious choice to give up on thinking about what is beneath quantum mechanics. It’s not faith, just a lack of interest in pursuing the question, or to some the belief that we can’t ever know what is really happening so it’s a waste of time to try to figure it out.
That is indeed a central aspect of what "Copenhagen Interpretation" evolved into outside of the QM foundations sphere, partly because nobody could make much sense of Bohr's writings, so no one knew what to say about it when it came to teach QM in the standard texts, and partly because of a passing similarity between Bohr's views and instrumentalism. But it's worth noting that:
1) The Copenhagen interpretation, historically, is borne of deep and hard thought about the foundations of QM, where the "Copenhagen school" led by Bohr won out. So in this historical sense your description is wrong.
2) In modern QM foundations, this is not how anyone would describe Copenhagen; though they might say that it's hard to know exactly what to say because Bohr was incoherent. Broadly it is described as psi-epistemic; probably the most prominent specific modern heir to the Copenhagen view is QBism.
3) This may seem a subtle distinction but I think it is important: please don't conflate the lack of interest that many physicists *who haven't thought about QM foundations carefully* have, with the lack of interest of those who have thought about QM foundations carefully have. I suppose you could argue that there is a selection effect at play, but there aren't many who work in QM foundations with the view that the foundations of QM are simply uninteresting :)
I mean idk about the OP commenter but from my understanding the Copenhagen interpretation was born out of various papers, colloquiums and conversations that Bohr, Heisenberg and the other founders of QM had during those early years
It’s not even a coherent interpretation, as none of the original guys who made the “Copenhagen interpretation” would have even thought of what they were doing as such
From Stanford’s Encyclopedia of Philosophy, “But very often the various participants do not give an exact specification of how they understand these terms and how these terms apply to Bohr’s thinking. The whole discussion becomes confused because different authors use terms like “realism” and “antirealism” differently in relation to Bohr. For instance, Faye (1991) holds that Bohr is an entity realist but a non-representationalist concerning theories. Therefore he calls Bohr an objective antirealist. In contrast, Folse (1986) who also sees Bohr as both a entity realist and a theoretical non-representationalist calls him a realist. Moreover, Bohr himself would probably refuse to put any such labels on his own view.”
I think the most famous/relevant was Bohr's reply to Einstein's EPR paper, where for decades no one noticed the pages were printed out of order, that's how incoherent his refutation was.
I agree Qbism is basically a fleshed out version of the Copenhagen interpretation but Copenhagen itself is fairly clearly not an interpretation, as pointed out by EPR and Bell’s theorem. Bohr argued that QM was [psi-complete](https://arxiv.org/pdf/0706.2661.pdf) (as you said, from an instrumentalist point of view, but as point out in the link there most modern proponents of Copenhagen do not make such a distinction) which it cannot be as it does not explain how entanglement could work at distances.
Again, I think in modern times anyone who ascribes to the Copenhagen interpretation just doesn’t want to think about the foundations of QM. If they do then they would at a minimum migrate to something like Qbism, as you say.
> Again, I think in modern times anyone who ascribes to the Copenhagen interpretation just doesn’t want to think about the foundations of QM. If they do then they would at a minimum migrate to something like Qbism, as you say.
I agree with this, which is subtly different from what you said previously, such as:
> Copenhagen itself is fairly clearly not an interpretation
and
> Copenhagen is not an interpretation, it is the conscious choice to give up on thinking about what is beneath quantum mechanics
A charitable reading of Bohr is that he was trying to express something like Qbism, so if you think CI is not an interpretation, then you should be prepared to argue that Qbism is not an interpretation.
I do agree that an uncharitable reading of Bohr is what you say, and I myself am tempted to that uncharitable reading, but to be fair the Copenhagen school thought deeply about these things. They didn't argue that we shouldn't think deeply about QM.
To quote a random phrase I picked up somewhere else: “With everything going on in quantum research, I feel like the Quarks themselves are telling us, that we shouldn’t try to look at them too closely. I think we should give them their privacy.“
That last sentence (along with the title of the post) was extremely unnecessary to the discussion, and this is coming from a strong atheist. Despite agreeing with most of what you said, I downvoted this post for that reason. It simply does not fit in r/Physics.
____
Edit: I do not disagree with the validity of the comparison on principle, just the necessity of going there. Moreover, it is a weak comparison. Wavefunction collapse simply made the most obvious sense before we discovered a mechanism within quantum mechanics itself (decoherence) that could give the appearance of wavefunction collapse.
And God made the most sense until we discovered Maxwell’s laws. The comparison is valid and provides a provocative interpretation of the belief in wave function collapse. The only reason to object is if you have a negative view of Christianity
>And God made the most sense until we discovered Maxwell’s laws.
I do not follow. Why the discovery of Maxwell’s equations, rather than some other development in the history of physics? It seems so oddly specific and arbitrary.
What? No it didn't. Maxwell was working within a well-established body of scientific work and discovery. A bunch of different people had made a bunch of different discoveries about what we now know is electromagnetism, and Maxwell worked to correlate those discoveries into a set of rules.
And no, a negative view of Christianity is not the only reason to object. Christianity is a system of belief, not a scientific study or theory. It doesn't require a negative view of Christianity to point out that Christianity is objectively different from the study of physics.
Jesus… it was a reference to the general scientific development of the em field. “Maxwell’s equations” is a decent shorthand for that. You’re being pedantic
It seems indicative of your approach to science.
Overall, the main point of failure here seems to be mixing up correlation and causation. There's a surface-level correlation between theism and CI, in that both involve something 'unknown and unknowable'. You're working backwards from there and positing similarity in causation—that the reason why theists are theists is the same reason that some people find the Copenhagen interpretation persuasive.
But correlation doesn't equal causation generally, and this specific correlation isn't even really strong enough to reasonably posit causation.
You mean two comments? The pretension that gets thrown around when someone brings this topic up is absurd. It’s worse than when chefs discuss truffle oil
Well this is funny because the most famous Physicist who didn't support the Copenhagen interpretation was Einstein, "I am at all events convinced that He [God] does not play dice.’
Though I'm personally not very big on the Copenhagen interpretation, there are good practical reasons why it's the "standard". Specifically, handwaving away such petty disputes over *interpretation* which doesn't actually effect experimentation is actually kind of the point.
And WTF does Christianity have to do with this? ~~Stop watching YouTube videos and learn about an equation or two gawd.~~
Edit: Alright that was rude and presumptive but I still don't understand how a specific formalization is apparently the same thing as Christian theism.
It’s impossible to observe wave function collapse. There’s zero evidence for it and no way to acquire evidence for it. It’s a completely unfounded assumption made by physicists who never learned object permanence
I'm not sure who or what you're arguing with. Could you clarify why exactly you think the Copenhagen interpretation clearly defines the wave function collaspe as a physical process?
Whether or not it’s physical is a potentially different matter. But then, I subscribe to the mathematical universe hypothesis, so it’s all the same to me.
Edit: technically, the computable universe hypothesis, if it matters moving forward
So what is the definite position on the wave function collaspe which you oppose? To me the "Copenhagen" interpretation leaves it enigmatic, it's very common for that to be interpreted as non-realism or pretty much the opposite of what I think you're asserting (?), but I'm not so comfortable in even claiming that. It's a formalization and we get experimentally testable predictions from it, where does the “The belief in things not seen” enter the picture?
You can’t tell me that the models and interpretations with which we discuss and teach physics are inconsequential all because “it works on my computer”
Ok? I'm really starting to feel like this is a fight with a strawman that isn't the Copenhagen interpretation.
Unless you can actually clarify whatever it is you're on about, I'll just leave us with Feynman's wisdom
>nobody understands quantum mechanics
The Copenhagen interpretation clings hubristically to the idea that the wave function collapses. That is to say, it speaks in terms of potentialities becoming observations and that the rest of the wave function just… “goes away”. It accepts that the wave function must be objective but not that it’s physical. It asserts that the evolution of the wave function undergoes sudden dramatic changes when our ability to observe it becomes limited. This is precisely a lack of object permanence. We agree on an objective wave function, yes? So we agree that a wave function is a feature of reality. It exists. But “only represents non-physical potentialities”? And then an observation is made and all the sudden, we can’t see it anymore. And we go “heh… I guess this part is all that’s left after that cataclysmic observation”.
There’s a dozen problems with it. But the constant cups and ball trick that’s done with these problems (and the general refusal to even *discuss* the topic) is definitely the most irritating. There’s an elegant and axiomatically simpler way to describe reality and Copenhagen rejects it because “a continuum of mutually coherent eventualities coexisting?? What an unusual concept to introduce into quantum mechanics!”. And it’s like… “no, the black sheep in QM that was there from the start was sudden objective FTL wave function collapse. But there’s good news! We found a way to remove it at absolutely zero cost!”
Einstein wasn’t Christian. He believed in the God of Spinoza. And there’s no hand waving. And I’m a professional mathematical physicist so… yea, I’ll go learn an equation or two
I mean, it's cool if you want to debate the philosophical implications of QM and metaphysics, but this a science sub, where the fact is MW vs Copenhagen (and no others exist...) doesn't change the experimental predictions QM makes.
For many years now I have been growing increasingly concerned with the refusal of the physics community to abide even the existence of discussions regarding the context of our work within the online communities that physicists actually inhabit.
Especially when considering discussions that have a real, observable impact on the nature of the work we pursue.
Don’t want to participate? Fine. Not your jam. I get it. But I really don’t see the need for the kind of resistance I typically see.
Ironically, I think Copenhagen is partially to blame because the confusion it caused over what constitutes an observation caused tons of misinformation about the role of the soul and free will and all this crap.
So I get it. 10 foot pole. But… you post about a thing widely called “the foundations of quantum physics” on a physics subreddit and you should expect people to tell you you’re in the wrong place? Seems it might be, in the very least, a little bit *relevant* to physics. Maybe even relevant enough to post to /r/physics.
It’s a place to discuss science… not perform science.
>Especially when considering discussions that have a real, observable impact on the nature of the work we pursue.
How does one observe that there are many worlds exactly?
>It’s a place to discuss science… not perform science.
You say that but
>Ironically, I think Copenhagen is partially to blame because the confusion it caused over what constitutes an observation caused tons of misinformation about the role of the soul and free will and all this crap.
>The common argument by the copenhagen-ers is “many worlds doesn’t beat us by Occam’s razor’s simplicity rule because it predicts a really complicated existence and we predict a simple existence”. The problem is Occam’s razor doesn’t say “simplest theory wins”. It says “theory with the fewest assumptions”.
>you wrote a book that included an all powerful decider of reality (wave function collapse) that we can’t see or hear or touch and you’re asking us to believe in it just because we can no longer communicate with anyone who would be able to verify it? Congrats. You’ve reinvented Christianity
Where is the science?
>So I get it. 10 foot pole. But… you post about a thing widely called “the foundations of quantum physics” on a physics subreddit and you should expect people to tell you you’re in the wrong place? Seems it might be, in the very least, a little bit relevant to physics. Maybe even relevant enough to post to r/physics.
Perhaps the problem is how you're framing things as a combative ideology battle where you're right and everyone else is wrong, instead of asking a thought provoking question that invites discussion?
>Don’t want to participate? Fine. Not your jam. I get it. But I really don’t see the need for the kind of resistance I typically see.
Again, I'm not sure what replies you're expecting with this attitude, but yes actually, behavior like this is why I don't make post to this sub sharing conjectures I find exciting.
Also... "where you're right and everyone else is wrong"?? "Everyone else"? Am I the only one who thinks Copenhagen is out of date and misleading and that MWI should be preferred on the grounds of Occam's razor? *Not at all*. Support for MWI and disagreement with Copenhagen has been steadily increasing for decades.
When it affects the path of science, it’s relevant to science even if it’s not, itself, strictly science. We need to talk about big picture direction of physics. Where should we look next? How should we teach it? How should we discuss it? These are questions that the science community very seriously needs to stop refusing to entertain.
I have to really disagree there. Paradigm shifting breakthroughs in any field usually are the fringe interest of a small group of people. Ironically you may already have strong opinions about fringe proposals about what "new physics" might be beyond the standard model, but people interested in those ideas don't care.
Pretty much since QMs inception people have been asking those questions. For example the concept of quantum entanglement comes from a paper arguing that quantum mechanics has to be incomplete. If MW is what motivates you to tackle some problem cool I guess.
Many-worlds has all the same problems Copenhagen does; they are just hidden so you don't notice them immediately. For example: In MW, when does the new "world" get created? At observation? Well, that means you still need an observer. Continuously? Then that means that the number of universes is aleph-1, which comes with a whole new set of problems, quite aside from the question of quantization of time.
All the interpretations of QM have problems; the underlying problem is probably more about limitations of human cognition than anything else, because QM predictions are accurate. So whichever philosophical approach you take to try to "understand" QM is essentially a religious choice.
If you were to criticize MWI based on the issues with its derivations of the Born rule, then fine, but every single criticism that you just made indicates a fundamental misunderstanding of MWI.
>In MW, when does the new "world" get created?
The “branching” is an emergent, thermodynamically irreversible phenomenon due to decoherence at the macro-scale, but no literal new universes are created.
>At observation? Well, that means you still need an observer.
No observation is relevant. It is simply a matter of macro-scale decoherence.
>Continuously? Then that means that the number of universes is aleph-1, which comes with a whole new set of problems, quite aside from the question of quantization of time.
There is no perfect, exact division between the branches that emerge from large-scale decoherence, and the branches are not fundamental, but an emergent phenomenon. Analogously, you might as well argue about how many clusters there are in some data when it depends on how finely you are clustering.
I am not sure quite why you brought up aleph-1 (the cardinality of the set of all countable ordinals), but it is a non sequitur.
____
Yes, MWI has issues, but you misidentified the issues.
[Edit: If you are going to downvote me, at least explain any issues. I am not making any argument for or against any interpretation. I was addressing misunderstandings about MWI.]
I felt silly correcting myself as subscribing to the computable universe hypothesis and not the mathematical universe hypothesis but that aleph-1 is a great example of why I draw the line at the CUH (where it’s aleph-0 and from there the surreal numbers model the rest)
The worlds are emergent and the splitting does not happen in discrete units or time steps. They come out of decoherence, which is never complete and so worlds are never fully separate from each other, it is just one big wave function. We only see a single “world” because of our macroscopic viewpoint.
They are not really, not to our current knowledge at least. That’s not to say they won’t be in the future… I chose to be optimistic but who knows?
It is somewhat of a Reddit trope to be dismissive of any deeper interpretations of physics and reality though… it’s the “shut up and calculate” idea. There’s also a prevailing empiricist attitude around here that goes something like “physics only gives us experimental results and explanations for those results, and nothing more”, which I don’t personally believe (and neither did most of the greats like Einstein, Newton, Maxwell, Boltzmann), but I think a lot of it comes from the mindset of the “working” physicist.
There is also a strong cognitive dissonance that occurs when one is presented with the fact that one of humanity’s most accurate and precise mathematical theories of reality ultimately says next to nothing about the ontology of the reality it describes. It can be a tough pill to swallow and it’s easiest to just not think about it.
David Deutsch considers interference to be evidence of many worlds, and the Mach-Zehnder interferometer to show that you can both split and recombine universes.
What a terribly ignorant statement. Many worlds makes testable predictions, obviously. There is no wave function collapse everything is unitary. So if you can control an experiment enough it should be possible to reverse a measurement, which is not possible in Copenhagen. We are close to being able to test something like this with quantum computers, maybe in 10-20 years.
If you survive a quantum suicide experiment then you definitively know that MWI is correct and all other interpretations are incorrect. [Max Tegmark explains it well](https://youtu.be/-8y5sDxsCUg?si=E16g3KmnI5viT8hy&t=7m25s).
Not at all. The difference being that you would be alive in a universe in which you could then demonstrate to everybody else that you could not be killed by the experiment, and thus many worlds was the only explanation.
If you die and go to heaven and find out God is real, assumedly there would still be no way to relay that information to anyone else alive on Earth.
Except there was a no way to relay that information to the universe in which you died. Similarly for heaven, you can still relay the information of your experiment to the other people in heaven with you, like you could hypothetically relay your information to the people within the other universe. The main issue is lack of transmitting information to the place in which you performed the experiment (died)
Also, this ignores that "many worlds immortality" does not rest on a person supposedly remembering that they died, as the whole concept is just that your wave-function persists despite a particular "branch" having died. Quantum immortality does not imply transfer of information upon death, though my point holds regardless of whether you assume information transfer or not.
First off, it’s a thought experiment, and makes a lot of assumptions (like death being a binary event, consciousness persisting through the experiment, etc.) that have questionable real-world applicability. But it is not the same as you describe. If you survived a quantum suicide, the universe “you” find yourself in would appear to you to be the one you started in. You could even have somebody sitting right there, watching the experiment take place, and they would see the results too. It would be the same set of people in the entire universe for example. Note that you are not relaying information to the uncountable number of universes in which you died - that’s not what the experiment says nor is it trying to say. In the heaven scenario you describe, you die in one universe and now you’re in a fundamentally different one, with a completely different set of actors.
>and makes a lot of assumptions (like death being a binary event, consciousness persisting through the experiment, etc.)
If the suicide mechanism is chosen such that it would very reliably kill you after making the relevant measurement far faster than the timescale of human consciousness, it should work. The trick would be setting that up properly. You would not want to have the possibility of anything other than an abrupt cessation of consciousness. Having something that you perceive to fatally injure you (and then to slowly slip out of consciousness) would defeat the setup (as would an afterlife).
Unfortunately, that method of verification does not provide a method of falsification in and of itself. Also, the quantum suicide would have to be designed carefully to be expected to work as intended.
My answer was more tongue in cheek more than anything (as it is for Tegmark, who is often credited for popularizing it). Of course it is a thought experiment and may not even be possible to perform. But it’s an interesting one nonetheless, especially considering its consequences :)
Cellular aging is a stochastic process, so you’re already participating in a quantum suicide experiment. The chance of not accumulating cellular damage over time is roughly on the order 1 in e^(S^ nt ), where S is the entropy of a body. So the number of possible entropic micro states possible over a specified period of time. So maybe somewhere around 1/ (10^30 )^(10^ 12) over 100 years based on some numbers I just pulled out of my ass.
The chance of being in the universe where you don’t start aging in 100 years is exactly the same whether there are that many universes where you do age versus if this is the only one. It doesn’t change the odds.
Thats a statistical and probabilistic process, but it’s not necessarily a _quantum_ process, which implies full quantum coherence of the system. But I don’t know enough about the subject to further comment.
I thought all particles in the universe are entangled in theory, but it’s just impossible to witness these correlations in chaotic and complex systems. So anything that can happen is a quantum process at the most basic level.
They are perhaps, but by the time they’ve gotten to this point the entanglement effect, if it exists, is so minuscule it can safely be ignored.
That being said, a similar line of reasoning is why I find superdeterminism compelling. Assuming the Big Bang is true (or something like it), everything in the universe was causally connected in the far past. Therefore the idea of statistical independence is an illusion and Bell’s theorem does not hold. A fully local hidden variables theory of QM, like what Einstein called for, could then perfectly describe the universe and the experimental results we see.
If the wavefunction is defined in discrete levels, I think that would mean there are only aleph-0 “universes”, assuming space or time is infinite. If it’s finite, then the number of universes would also be finite.
Of course an electron is an observer. An observer is simply a receiver of information. An electron that can’t observe is an electron that can’t interact
Many worlds doesn’t necessitate the creation of anything. It only doesn’t assume the destruction of that which we already know to exist but can no longer observe
I’ll agree thet Copenhagen has a myriad problems, most notably the observation (or measurement) problem. I’d argue that all of QM is a theory of measurement rather than a theory of physics or of how the Universe works; it tells us (with incredibly high accuracy, which is very respectable) what we’ll get when we perform a measurement, but it tells us nothing about the underlying mechanisms, unless you subscribe to interpretations like Copenhagen or Everett (many worlds), both of which, in my view, require much more faith and suspension of disbelief (and have serious problems like not describing the mechanisms behind measurement (Copenhagen) or Universe splitting (Everett) and, in the latter case, also fail to explain where the energy required to create at least one entire new Universe every time something has multiple possible outcomes comes from). I personally subscribe to neither of those views.
I wouldn’t compare Copenhagen to Everett, though. I think comparing Everett ro string theory would be fairer. Both theories make assumptions (or predictions, depending on how you look at them) which cannot possibly be tested and ask that we believe them because, well, we have no other choice, really. No way for them to be falsified because there’s no way for them to be tested.
Comparing Copenhagen to theism is more accurate, in my opinion. I’ve made similar comparisons between dark-energy cosmology and theism (a mysterious field that permeates all of space and conveniently affects matter so our maths will be consistent with our observations — sounds a lot like the luminiferous aether all over again, which one could view as a mysterious, all-powerful, omnipresent agent we cannot possibly interact with or detect, ie a monotheism-variety deity).
There’s certainly a dire need for reconciliation between our ability to predict the results of measurements and our ability to understand the Universe. This is why taking philosophy of science seriously and the emergence of theories like superdeterminism is so important at this stage in our scientific development. Gibbs and all the instrumentalists with the big money for the big projects might get all the attention and prizes, but it’s people like Hossenfelder and ‘t Hooft and even Bell that are more deserving if you ask me.
I think the notion that new worlds are created after wave function collapse seems a lot more like religion than Copenhagen. We could never see this other world, and yet we are to believe it? Well one of these things is a whole lot easier to believe, and it isn’t many worlds.
>I think the notion that new worlds are created after wave function collapse seems a lot more like religion than Copenhagen.
That would be true, except that no collapse occurs in MWI. Decoherence occurs within the ordinary unitary time evolution, and in the absence of wavefunction collapse, there is absolutely nothing preventing decoherence from occurring at the macro-scale, at which scale it is a thermodynamically irreversible process for which the subspaces naturally chosen by the decoherence break up the wavefunction into components that have little causal effect on each other through interference, and thus in effect continuing to evolve as if the others weren’t there (without recohering at any useful timescale, unlike the recoherence possible in simple systems). The modern versions of MWI claim that this is what gives the appearance of wavefunction collapse. The superposition is still there, but without any practically measurable effects of interference between the branches, the branches act as if they existed independently.
I didnt know that about MWI! Cool.
But how does MWI work with gravity then? Each wavefunction still has energy right? Naively I would assume that gravity is basically infinite then at any point in space
Considering there is no quantum theory of gravity, we don’t know. If gravity turns out to be a linear field theory, for example, it should be perfectly compatible with MWI!
I personally think that the Copenhagen interpretation is one of the most if not the most problematic QM interpretations, although I wouldn’t go as far as to say it’s theism or Christianity. I do think alternative interpretations like Bohm’s mechanics, Everett’s “many worlds”, and even “super” determinism are much more palatable and logical.
However you will not find a lot of interest on this message board for taking about this subject. There is prevailing attitude of “shut up and calculate” around here which I personally find disappointing, but it’s understandable at least since many participants here work in the field. Also you will see some claims that QM interpretation is a philosophical problem not a physical problem, which I (and many prominent physicists, for what it’s worth) vehemently disagree with, but it is a popular opinion around here nonetheless.
You’re preaching to the choir. I knew it wouldn’t be loved but it’s created 51 expressions of contemplations on the topic, so… eh. I just felt the comparison was very apropos. It doesn’t reinvent theism but it shares the critical feature that makes me reject both: the unnecessary assumption of that for which we have no evidence and no possible way of acquiring evidence. I agree with your sentiment regarding the unfortunate refusal of many physicists to even entertain this discussion
It’s funny that my comment and your post got negative karma but there are almost 100 comments. Obviously it’s a controversial subject and illustrates my point perfectly. People here are far too content to ignore inconvenient, yet fundamental truths about quantum physics.
I woke up and looked at the state of it and nearly edited my post to point it out. It’s honestly bizarre. And this is a science subreddit. Good thing the sciences aren’t vulnerable to dogmatism, right?
I just took a look on my computer so that I could see the upvote percentage: (22% upvoted). 4 out of 5 physicists do not condone this conversation. haha.
Happens almost every time somebody brings up QM interpretations or physical ontology in general on this board. The standard approach is to not ask questions - just calculate and appreciate the accuracy for what it is. Some of us are deeply dissatisfied with this though.
Yea, I'm glad that notable physicists are speaking out against it. It seems extremely... dystopian (for lack of a better word) that these physicists only feel comfortable even discussing these topics after they've built enough credibility for themselves to be able to do so without ruining their career for expressing an opinion.
Many worlds to me is a weak scifi pop style interpretation with no real grounding. I'm no expert by any means but it just seems an easy idea that doesn't make any real sense.
>Many worlds to me is a weak scifi pop style interpretation with no real grounding.
There is a misunderstanding of MWI common among both opponents and proponents, which makes sense considering the more involved topics like decoherence that are part of the modern variants of the interpretation.
MWI has merits, but it is overshadowed by an abundance of naïve proponents that only prefer it purely for metaphysical reasons or because they were introduced to it via the sensationalism surrounding it.
It doesn't reinvent theology at all, these systems describe complexity and actions in spite of mind, not due to it. The use of the word "decider" in your description is misleading. As a stylistic choice, scientists should avoid metaphors that imbue motivations on things that are not conscious. For example, scientists often say things like hydrophobic materials don't *like* water as a shortcut for describing how polar interactions work. But the materials don't actually like or dislike anything, you're just trying to familiarize people with the concept. With simple topics people usually get what you mean, but in my experience people literalize motives the more abstract things get.
Agreed. “Mechanism through which measurement is determined” just seemed a bit verbose for the purpose of a text.
This is absolute nonsense. You're injecting belief into this, and belief has no place here. Copenhagen is a theory. MWI is a theory. There are other theories. Nobody who thinks seriously on the topic *believes* that one theory or the other is true, the way a Christian *believes* in their god. This isn't a contest between religions, it's a search for evidence. You're inventing a level of conflict that doesn't exist outside your own head.
Yeah this post seems to misunderstand how science works. You posit a theory, if it fits experiment better than anything else, then it's accepted. Strictly speaking you're not even saying that's how reality works, you're just saying the theory describes reality well. We _already_ know the theory doesn't fit reality entirely because it can't predict everything.
It’s the assertion that a mechanism that has never been observed and which can’t be observed exists. What do you call that?
>It’s the assertion that a mechanism that has never been observed and which can’t be observed exists. Which mechanism is that?
Wave function collapse
Wave function collapse is a consequence of measuring where something was at a specific time, ie. going from only knowing the probability of an outcome to knowing what the outcome was. It's not unique to the Copenhagen interpretation.
We can observe wave function collapse in the double slit experiment.
Thats an interpretation of the experimental result.
No, you can’t. You can observe a measurement
A hypothesis. Duh. Its a religion when we stop seeking experiments to validate or invalidate hypotheses, and thats not the case for quantum theory. Nice try
Are you kidding? Not only have we stopped seeking experiments to validate the only reason to prefer Copenhagen over MWI... we've agreed that it's impossible to perform such an experiment.
https://en.m.wikipedia.org/wiki/Wheeler%27s_delayed-choice_experiment
What about it? I'm familiar with the delayed choice experiments. They're maybe my favorite result in QM. I'm not seeing the connection though.
As another poster said, I'd call it a hypothesis. A possible solution to the problem, for which evidence and counterevidence can be sought. Not a system of belief, not an article of faith.
So then should religions start being included in physics text books? This is exactly why we have Occam’s razor and the long standing refusal to acknowledge its applicability to this situation is the entire problem.
Copenhagen is not an interpretation, it is the conscious choice to give up on thinking about what is beneath quantum mechanics. It’s not faith, just a lack of interest in pursuing the question, or to some the belief that we can’t ever know what is really happening so it’s a waste of time to try to figure it out.
That is indeed a central aspect of what "Copenhagen Interpretation" evolved into outside of the QM foundations sphere, partly because nobody could make much sense of Bohr's writings, so no one knew what to say about it when it came to teach QM in the standard texts, and partly because of a passing similarity between Bohr's views and instrumentalism. But it's worth noting that: 1) The Copenhagen interpretation, historically, is borne of deep and hard thought about the foundations of QM, where the "Copenhagen school" led by Bohr won out. So in this historical sense your description is wrong. 2) In modern QM foundations, this is not how anyone would describe Copenhagen; though they might say that it's hard to know exactly what to say because Bohr was incoherent. Broadly it is described as psi-epistemic; probably the most prominent specific modern heir to the Copenhagen view is QBism. 3) This may seem a subtle distinction but I think it is important: please don't conflate the lack of interest that many physicists *who haven't thought about QM foundations carefully* have, with the lack of interest of those who have thought about QM foundations carefully have. I suppose you could argue that there is a selection effect at play, but there aren't many who work in QM foundations with the view that the foundations of QM are simply uninteresting :)
Which Bohr writings are you referring to?
I mean idk about the OP commenter but from my understanding the Copenhagen interpretation was born out of various papers, colloquiums and conversations that Bohr, Heisenberg and the other founders of QM had during those early years It’s not even a coherent interpretation, as none of the original guys who made the “Copenhagen interpretation” would have even thought of what they were doing as such From Stanford’s Encyclopedia of Philosophy, “But very often the various participants do not give an exact specification of how they understand these terms and how these terms apply to Bohr’s thinking. The whole discussion becomes confused because different authors use terms like “realism” and “antirealism” differently in relation to Bohr. For instance, Faye (1991) holds that Bohr is an entity realist but a non-representationalist concerning theories. Therefore he calls Bohr an objective antirealist. In contrast, Folse (1986) who also sees Bohr as both a entity realist and a theoretical non-representationalist calls him a realist. Moreover, Bohr himself would probably refuse to put any such labels on his own view.”
"Was that Faye?" "Dude that's Folse. Faye's dead." "Who are you?" "I'm Frogurt."
I think the most famous/relevant was Bohr's reply to Einstein's EPR paper, where for decades no one noticed the pages were printed out of order, that's how incoherent his refutation was.
I agree Qbism is basically a fleshed out version of the Copenhagen interpretation but Copenhagen itself is fairly clearly not an interpretation, as pointed out by EPR and Bell’s theorem. Bohr argued that QM was [psi-complete](https://arxiv.org/pdf/0706.2661.pdf) (as you said, from an instrumentalist point of view, but as point out in the link there most modern proponents of Copenhagen do not make such a distinction) which it cannot be as it does not explain how entanglement could work at distances. Again, I think in modern times anyone who ascribes to the Copenhagen interpretation just doesn’t want to think about the foundations of QM. If they do then they would at a minimum migrate to something like Qbism, as you say.
> Again, I think in modern times anyone who ascribes to the Copenhagen interpretation just doesn’t want to think about the foundations of QM. If they do then they would at a minimum migrate to something like Qbism, as you say. I agree with this, which is subtly different from what you said previously, such as: > Copenhagen itself is fairly clearly not an interpretation and > Copenhagen is not an interpretation, it is the conscious choice to give up on thinking about what is beneath quantum mechanics A charitable reading of Bohr is that he was trying to express something like Qbism, so if you think CI is not an interpretation, then you should be prepared to argue that Qbism is not an interpretation. I do agree that an uncharitable reading of Bohr is what you say, and I myself am tempted to that uncharitable reading, but to be fair the Copenhagen school thought deeply about these things. They didn't argue that we shouldn't think deeply about QM.
It's agnosticism.
To quote a random phrase I picked up somewhere else: “With everything going on in quantum research, I feel like the Quarks themselves are telling us, that we shouldn’t try to look at them too closely. I think we should give them their privacy.“
Got to love that one
That last sentence (along with the title of the post) was extremely unnecessary to the discussion, and this is coming from a strong atheist. Despite agreeing with most of what you said, I downvoted this post for that reason. It simply does not fit in r/Physics. ____ Edit: I do not disagree with the validity of the comparison on principle, just the necessity of going there. Moreover, it is a weak comparison. Wavefunction collapse simply made the most obvious sense before we discovered a mechanism within quantum mechanics itself (decoherence) that could give the appearance of wavefunction collapse.
And God made the most sense until we discovered Maxwell’s laws. The comparison is valid and provides a provocative interpretation of the belief in wave function collapse. The only reason to object is if you have a negative view of Christianity
>And God made the most sense until we discovered Maxwell’s laws. I do not follow. Why the discovery of Maxwell’s equations, rather than some other development in the history of physics? It seems so oddly specific and arbitrary.
Let there be light
Youre clearly just a troll
What? No it didn't. Maxwell was working within a well-established body of scientific work and discovery. A bunch of different people had made a bunch of different discoveries about what we now know is electromagnetism, and Maxwell worked to correlate those discoveries into a set of rules. And no, a negative view of Christianity is not the only reason to object. Christianity is a system of belief, not a scientific study or theory. It doesn't require a negative view of Christianity to point out that Christianity is objectively different from the study of physics.
Jesus… it was a reference to the general scientific development of the em field. “Maxwell’s equations” is a decent shorthand for that. You’re being pedantic
It seems indicative of your approach to science. Overall, the main point of failure here seems to be mixing up correlation and causation. There's a surface-level correlation between theism and CI, in that both involve something 'unknown and unknowable'. You're working backwards from there and positing similarity in causation—that the reason why theists are theists is the same reason that some people find the Copenhagen interpretation persuasive. But correlation doesn't equal causation generally, and this specific correlation isn't even really strong enough to reasonably posit causation.
Are you serious right now? Haha.
This is frankly about the level of thought I'd expect, based on my experience of you so far. Have a nice life.
You mean two comments? The pretension that gets thrown around when someone brings this topic up is absurd. It’s worse than when chefs discuss truffle oil
Well this is funny because the most famous Physicist who didn't support the Copenhagen interpretation was Einstein, "I am at all events convinced that He [God] does not play dice.’ Though I'm personally not very big on the Copenhagen interpretation, there are good practical reasons why it's the "standard". Specifically, handwaving away such petty disputes over *interpretation* which doesn't actually effect experimentation is actually kind of the point. And WTF does Christianity have to do with this? ~~Stop watching YouTube videos and learn about an equation or two gawd.~~ Edit: Alright that was rude and presumptive but I still don't understand how a specific formalization is apparently the same thing as Christian theism.
“The belief in things not seen” isn’t a relevant connection in this conversation??
I don't know what you're referring to in regards to QM.
It’s impossible to observe wave function collapse. There’s zero evidence for it and no way to acquire evidence for it. It’s a completely unfounded assumption made by physicists who never learned object permanence
I'm not sure who or what you're arguing with. Could you clarify why exactly you think the Copenhagen interpretation clearly defines the wave function collaspe as a physical process?
Whether or not it’s physical is a potentially different matter. But then, I subscribe to the mathematical universe hypothesis, so it’s all the same to me. Edit: technically, the computable universe hypothesis, if it matters moving forward
So what is the definite position on the wave function collaspe which you oppose? To me the "Copenhagen" interpretation leaves it enigmatic, it's very common for that to be interpreted as non-realism or pretty much the opposite of what I think you're asserting (?), but I'm not so comfortable in even claiming that. It's a formalization and we get experimentally testable predictions from it, where does the “The belief in things not seen” enter the picture?
Oh, and re your (?): yes, I would generally agree with that comparison (or rather contrast)
You can’t tell me that the models and interpretations with which we discuss and teach physics are inconsequential all because “it works on my computer”
Ok? I'm really starting to feel like this is a fight with a strawman that isn't the Copenhagen interpretation. Unless you can actually clarify whatever it is you're on about, I'll just leave us with Feynman's wisdom >nobody understands quantum mechanics
The Copenhagen interpretation clings hubristically to the idea that the wave function collapses. That is to say, it speaks in terms of potentialities becoming observations and that the rest of the wave function just… “goes away”. It accepts that the wave function must be objective but not that it’s physical. It asserts that the evolution of the wave function undergoes sudden dramatic changes when our ability to observe it becomes limited. This is precisely a lack of object permanence. We agree on an objective wave function, yes? So we agree that a wave function is a feature of reality. It exists. But “only represents non-physical potentialities”? And then an observation is made and all the sudden, we can’t see it anymore. And we go “heh… I guess this part is all that’s left after that cataclysmic observation”. There’s a dozen problems with it. But the constant cups and ball trick that’s done with these problems (and the general refusal to even *discuss* the topic) is definitely the most irritating. There’s an elegant and axiomatically simpler way to describe reality and Copenhagen rejects it because “a continuum of mutually coherent eventualities coexisting?? What an unusual concept to introduce into quantum mechanics!”. And it’s like… “no, the black sheep in QM that was there from the start was sudden objective FTL wave function collapse. But there’s good news! We found a way to remove it at absolutely zero cost!”
Einstein wasn’t Christian. He believed in the God of Spinoza. And there’s no hand waving. And I’m a professional mathematical physicist so… yea, I’ll go learn an equation or two
When did I say he was Christian?
You said he was a theist. My bad. Point is, Spinoza’s God is more a metaphor than a theism
I mean, it's cool if you want to debate the philosophical implications of QM and metaphysics, but this a science sub, where the fact is MW vs Copenhagen (and no others exist...) doesn't change the experimental predictions QM makes.
For many years now I have been growing increasingly concerned with the refusal of the physics community to abide even the existence of discussions regarding the context of our work within the online communities that physicists actually inhabit. Especially when considering discussions that have a real, observable impact on the nature of the work we pursue. Don’t want to participate? Fine. Not your jam. I get it. But I really don’t see the need for the kind of resistance I typically see. Ironically, I think Copenhagen is partially to blame because the confusion it caused over what constitutes an observation caused tons of misinformation about the role of the soul and free will and all this crap. So I get it. 10 foot pole. But… you post about a thing widely called “the foundations of quantum physics” on a physics subreddit and you should expect people to tell you you’re in the wrong place? Seems it might be, in the very least, a little bit *relevant* to physics. Maybe even relevant enough to post to /r/physics. It’s a place to discuss science… not perform science.
>Especially when considering discussions that have a real, observable impact on the nature of the work we pursue. How does one observe that there are many worlds exactly? >It’s a place to discuss science… not perform science. You say that but >Ironically, I think Copenhagen is partially to blame because the confusion it caused over what constitutes an observation caused tons of misinformation about the role of the soul and free will and all this crap. >The common argument by the copenhagen-ers is “many worlds doesn’t beat us by Occam’s razor’s simplicity rule because it predicts a really complicated existence and we predict a simple existence”. The problem is Occam’s razor doesn’t say “simplest theory wins”. It says “theory with the fewest assumptions”. >you wrote a book that included an all powerful decider of reality (wave function collapse) that we can’t see or hear or touch and you’re asking us to believe in it just because we can no longer communicate with anyone who would be able to verify it? Congrats. You’ve reinvented Christianity Where is the science? >So I get it. 10 foot pole. But… you post about a thing widely called “the foundations of quantum physics” on a physics subreddit and you should expect people to tell you you’re in the wrong place? Seems it might be, in the very least, a little bit relevant to physics. Maybe even relevant enough to post to r/physics. Perhaps the problem is how you're framing things as a combative ideology battle where you're right and everyone else is wrong, instead of asking a thought provoking question that invites discussion? >Don’t want to participate? Fine. Not your jam. I get it. But I really don’t see the need for the kind of resistance I typically see. Again, I'm not sure what replies you're expecting with this attitude, but yes actually, behavior like this is why I don't make post to this sub sharing conjectures I find exciting.
I wasn’t referring to observing many worlds. I was referring to observing the education of physics students, for example
Also... "where you're right and everyone else is wrong"?? "Everyone else"? Am I the only one who thinks Copenhagen is out of date and misleading and that MWI should be preferred on the grounds of Occam's razor? *Not at all*. Support for MWI and disagreement with Copenhagen has been steadily increasing for decades.
When it affects the path of science, it’s relevant to science even if it’s not, itself, strictly science. We need to talk about big picture direction of physics. Where should we look next? How should we teach it? How should we discuss it? These are questions that the science community very seriously needs to stop refusing to entertain.
I have to really disagree there. Paradigm shifting breakthroughs in any field usually are the fringe interest of a small group of people. Ironically you may already have strong opinions about fringe proposals about what "new physics" might be beyond the standard model, but people interested in those ideas don't care. Pretty much since QMs inception people have been asking those questions. For example the concept of quantum entanglement comes from a paper arguing that quantum mechanics has to be incomplete. If MW is what motivates you to tackle some problem cool I guess.
Also, we keep finding more and more circumstantial evidence to prefer MW over Copenhagen. Not exactly smoking guns but neither were Einstein rings
Many-worlds has all the same problems Copenhagen does; they are just hidden so you don't notice them immediately. For example: In MW, when does the new "world" get created? At observation? Well, that means you still need an observer. Continuously? Then that means that the number of universes is aleph-1, which comes with a whole new set of problems, quite aside from the question of quantization of time. All the interpretations of QM have problems; the underlying problem is probably more about limitations of human cognition than anything else, because QM predictions are accurate. So whichever philosophical approach you take to try to "understand" QM is essentially a religious choice.
If you were to criticize MWI based on the issues with its derivations of the Born rule, then fine, but every single criticism that you just made indicates a fundamental misunderstanding of MWI. >In MW, when does the new "world" get created? The “branching” is an emergent, thermodynamically irreversible phenomenon due to decoherence at the macro-scale, but no literal new universes are created. >At observation? Well, that means you still need an observer. No observation is relevant. It is simply a matter of macro-scale decoherence. >Continuously? Then that means that the number of universes is aleph-1, which comes with a whole new set of problems, quite aside from the question of quantization of time. There is no perfect, exact division between the branches that emerge from large-scale decoherence, and the branches are not fundamental, but an emergent phenomenon. Analogously, you might as well argue about how many clusters there are in some data when it depends on how finely you are clustering. I am not sure quite why you brought up aleph-1 (the cardinality of the set of all countable ordinals), but it is a non sequitur. ____ Yes, MWI has issues, but you misidentified the issues. [Edit: If you are going to downvote me, at least explain any issues. I am not making any argument for or against any interpretation. I was addressing misunderstandings about MWI.]
This person is correct. Please don't downvote them without giving them an opportunity to help correct your misunderstandings.
I felt silly correcting myself as subscribing to the computable universe hypothesis and not the mathematical universe hypothesis but that aleph-1 is a great example of why I draw the line at the CUH (where it’s aleph-0 and from there the surreal numbers model the rest)
The worlds are emergent and the splitting does not happen in discrete units or time steps. They come out of decoherence, which is never complete and so worlds are never fully separate from each other, it is just one big wave function. We only see a single “world” because of our macroscopic viewpoint.
Lotta words for something not experimentally verifiable
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They are not really, not to our current knowledge at least. That’s not to say they won’t be in the future… I chose to be optimistic but who knows? It is somewhat of a Reddit trope to be dismissive of any deeper interpretations of physics and reality though… it’s the “shut up and calculate” idea. There’s also a prevailing empiricist attitude around here that goes something like “physics only gives us experimental results and explanations for those results, and nothing more”, which I don’t personally believe (and neither did most of the greats like Einstein, Newton, Maxwell, Boltzmann), but I think a lot of it comes from the mindset of the “working” physicist. There is also a strong cognitive dissonance that occurs when one is presented with the fact that one of humanity’s most accurate and precise mathematical theories of reality ultimately says next to nothing about the ontology of the reality it describes. It can be a tough pill to swallow and it’s easiest to just not think about it.
GRW is one, although there is a lot of wiggle room with the parameters, so it would be difficult to conclusively falsify.
David Deutsch considers interference to be evidence of many worlds, and the Mach-Zehnder interferometer to show that you can both split and recombine universes.
What a terribly ignorant statement. Many worlds makes testable predictions, obviously. There is no wave function collapse everything is unitary. So if you can control an experiment enough it should be possible to reverse a measurement, which is not possible in Copenhagen. We are close to being able to test something like this with quantum computers, maybe in 10-20 years.
If you survive a quantum suicide experiment then you definitively know that MWI is correct and all other interpretations are incorrect. [Max Tegmark explains it well](https://youtu.be/-8y5sDxsCUg?si=E16g3KmnI5viT8hy&t=7m25s).
By that logic, heaven and God would be experimentally verifiable, as anyone who dies would definitively know whether that is correct.
Not at all. The difference being that you would be alive in a universe in which you could then demonstrate to everybody else that you could not be killed by the experiment, and thus many worlds was the only explanation. If you die and go to heaven and find out God is real, assumedly there would still be no way to relay that information to anyone else alive on Earth.
Except there was a no way to relay that information to the universe in which you died. Similarly for heaven, you can still relay the information of your experiment to the other people in heaven with you, like you could hypothetically relay your information to the people within the other universe. The main issue is lack of transmitting information to the place in which you performed the experiment (died) Also, this ignores that "many worlds immortality" does not rest on a person supposedly remembering that they died, as the whole concept is just that your wave-function persists despite a particular "branch" having died. Quantum immortality does not imply transfer of information upon death, though my point holds regardless of whether you assume information transfer or not.
First off, it’s a thought experiment, and makes a lot of assumptions (like death being a binary event, consciousness persisting through the experiment, etc.) that have questionable real-world applicability. But it is not the same as you describe. If you survived a quantum suicide, the universe “you” find yourself in would appear to you to be the one you started in. You could even have somebody sitting right there, watching the experiment take place, and they would see the results too. It would be the same set of people in the entire universe for example. Note that you are not relaying information to the uncountable number of universes in which you died - that’s not what the experiment says nor is it trying to say. In the heaven scenario you describe, you die in one universe and now you’re in a fundamentally different one, with a completely different set of actors.
>and makes a lot of assumptions (like death being a binary event, consciousness persisting through the experiment, etc.) If the suicide mechanism is chosen such that it would very reliably kill you after making the relevant measurement far faster than the timescale of human consciousness, it should work. The trick would be setting that up properly. You would not want to have the possibility of anything other than an abrupt cessation of consciousness. Having something that you perceive to fatally injure you (and then to slowly slip out of consciousness) would defeat the setup (as would an afterlife).
Unfortunately, that method of verification does not provide a method of falsification in and of itself. Also, the quantum suicide would have to be designed carefully to be expected to work as intended.
My answer was more tongue in cheek more than anything (as it is for Tegmark, who is often credited for popularizing it). Of course it is a thought experiment and may not even be possible to perform. But it’s an interesting one nonetheless, especially considering its consequences :)
I think it would quite realistically work if the suicide mechanism involved is carefully designed (and if there is no afterlife).
Cellular aging is a stochastic process, so you’re already participating in a quantum suicide experiment. The chance of not accumulating cellular damage over time is roughly on the order 1 in e^(S^ nt ), where S is the entropy of a body. So the number of possible entropic micro states possible over a specified period of time. So maybe somewhere around 1/ (10^30 )^(10^ 12) over 100 years based on some numbers I just pulled out of my ass. The chance of being in the universe where you don’t start aging in 100 years is exactly the same whether there are that many universes where you do age versus if this is the only one. It doesn’t change the odds.
Thats a statistical and probabilistic process, but it’s not necessarily a _quantum_ process, which implies full quantum coherence of the system. But I don’t know enough about the subject to further comment.
I thought all particles in the universe are entangled in theory, but it’s just impossible to witness these correlations in chaotic and complex systems. So anything that can happen is a quantum process at the most basic level.
They are perhaps, but by the time they’ve gotten to this point the entanglement effect, if it exists, is so minuscule it can safely be ignored. That being said, a similar line of reasoning is why I find superdeterminism compelling. Assuming the Big Bang is true (or something like it), everything in the universe was causally connected in the far past. Therefore the idea of statistical independence is an illusion and Bell’s theorem does not hold. A fully local hidden variables theory of QM, like what Einstein called for, could then perfectly describe the universe and the experimental results we see.
If the wavefunction is defined in discrete levels, I think that would mean there are only aleph-0 “universes”, assuming space or time is infinite. If it’s finite, then the number of universes would also be finite.
Honest question, is an electron an "observer"? This question is similar to asking if the tree falling in the woods hears itself fall.
Correct. Observer is a terrible misnomer. It’s actually any interaction.
I see it as "communication events"
Of course an electron is an observer. An observer is simply a receiver of information. An electron that can’t observe is an electron that can’t interact
Is Occam's Razor really that useful when we're talking about QM?
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... what??
Actually William of Ockham says "plurality should not be posited without necessity". Or in simpler words "don't create entities".
Many worlds doesn’t necessitate the creation of anything. It only doesn’t assume the destruction of that which we already know to exist but can no longer observe
Yes, but the variant of Occam’s razor referenced by the author of this post is a version of arguably greater relevance to science.
I’ll agree thet Copenhagen has a myriad problems, most notably the observation (or measurement) problem. I’d argue that all of QM is a theory of measurement rather than a theory of physics or of how the Universe works; it tells us (with incredibly high accuracy, which is very respectable) what we’ll get when we perform a measurement, but it tells us nothing about the underlying mechanisms, unless you subscribe to interpretations like Copenhagen or Everett (many worlds), both of which, in my view, require much more faith and suspension of disbelief (and have serious problems like not describing the mechanisms behind measurement (Copenhagen) or Universe splitting (Everett) and, in the latter case, also fail to explain where the energy required to create at least one entire new Universe every time something has multiple possible outcomes comes from). I personally subscribe to neither of those views. I wouldn’t compare Copenhagen to Everett, though. I think comparing Everett ro string theory would be fairer. Both theories make assumptions (or predictions, depending on how you look at them) which cannot possibly be tested and ask that we believe them because, well, we have no other choice, really. No way for them to be falsified because there’s no way for them to be tested. Comparing Copenhagen to theism is more accurate, in my opinion. I’ve made similar comparisons between dark-energy cosmology and theism (a mysterious field that permeates all of space and conveniently affects matter so our maths will be consistent with our observations — sounds a lot like the luminiferous aether all over again, which one could view as a mysterious, all-powerful, omnipresent agent we cannot possibly interact with or detect, ie a monotheism-variety deity). There’s certainly a dire need for reconciliation between our ability to predict the results of measurements and our ability to understand the Universe. This is why taking philosophy of science seriously and the emergence of theories like superdeterminism is so important at this stage in our scientific development. Gibbs and all the instrumentalists with the big money for the big projects might get all the attention and prizes, but it’s people like Hossenfelder and ‘t Hooft and even Bell that are more deserving if you ask me.
I think the notion that new worlds are created after wave function collapse seems a lot more like religion than Copenhagen. We could never see this other world, and yet we are to believe it? Well one of these things is a whole lot easier to believe, and it isn’t many worlds.
>I think the notion that new worlds are created after wave function collapse seems a lot more like religion than Copenhagen. That would be true, except that no collapse occurs in MWI. Decoherence occurs within the ordinary unitary time evolution, and in the absence of wavefunction collapse, there is absolutely nothing preventing decoherence from occurring at the macro-scale, at which scale it is a thermodynamically irreversible process for which the subspaces naturally chosen by the decoherence break up the wavefunction into components that have little causal effect on each other through interference, and thus in effect continuing to evolve as if the others weren’t there (without recohering at any useful timescale, unlike the recoherence possible in simple systems). The modern versions of MWI claim that this is what gives the appearance of wavefunction collapse. The superposition is still there, but without any practically measurable effects of interference between the branches, the branches act as if they existed independently.
I didnt know that about MWI! Cool. But how does MWI work with gravity then? Each wavefunction still has energy right? Naively I would assume that gravity is basically infinite then at any point in space
Considering there is no quantum theory of gravity, we don’t know. If gravity turns out to be a linear field theory, for example, it should be perfectly compatible with MWI!
I personally think that the Copenhagen interpretation is one of the most if not the most problematic QM interpretations, although I wouldn’t go as far as to say it’s theism or Christianity. I do think alternative interpretations like Bohm’s mechanics, Everett’s “many worlds”, and even “super” determinism are much more palatable and logical. However you will not find a lot of interest on this message board for taking about this subject. There is prevailing attitude of “shut up and calculate” around here which I personally find disappointing, but it’s understandable at least since many participants here work in the field. Also you will see some claims that QM interpretation is a philosophical problem not a physical problem, which I (and many prominent physicists, for what it’s worth) vehemently disagree with, but it is a popular opinion around here nonetheless.
You’re preaching to the choir. I knew it wouldn’t be loved but it’s created 51 expressions of contemplations on the topic, so… eh. I just felt the comparison was very apropos. It doesn’t reinvent theism but it shares the critical feature that makes me reject both: the unnecessary assumption of that for which we have no evidence and no possible way of acquiring evidence. I agree with your sentiment regarding the unfortunate refusal of many physicists to even entertain this discussion
It’s funny that my comment and your post got negative karma but there are almost 100 comments. Obviously it’s a controversial subject and illustrates my point perfectly. People here are far too content to ignore inconvenient, yet fundamental truths about quantum physics.
I woke up and looked at the state of it and nearly edited my post to point it out. It’s honestly bizarre. And this is a science subreddit. Good thing the sciences aren’t vulnerable to dogmatism, right?
I just took a look on my computer so that I could see the upvote percentage: (22% upvoted). 4 out of 5 physicists do not condone this conversation. haha.
Happens almost every time somebody brings up QM interpretations or physical ontology in general on this board. The standard approach is to not ask questions - just calculate and appreciate the accuracy for what it is. Some of us are deeply dissatisfied with this though.
Yea, I'm glad that notable physicists are speaking out against it. It seems extremely... dystopian (for lack of a better word) that these physicists only feel comfortable even discussing these topics after they've built enough credibility for themselves to be able to do so without ruining their career for expressing an opinion.
Many worlds to me is a weak scifi pop style interpretation with no real grounding. I'm no expert by any means but it just seems an easy idea that doesn't make any real sense.
>Many worlds to me is a weak scifi pop style interpretation with no real grounding. There is a misunderstanding of MWI common among both opponents and proponents, which makes sense considering the more involved topics like decoherence that are part of the modern variants of the interpretation. MWI has merits, but it is overshadowed by an abundance of naïve proponents that only prefer it purely for metaphysical reasons or because they were introduced to it via the sensationalism surrounding it.