Why is no one ever asking how to falsify Copenhagen vs other interpretations? What did Copenhagen ever do to deserve this privilege?

So the question under discussion is whether many-worlds is, or should be, "generally accepted". It isn't. If it's not generally accepted and wants to be, then it has the burden of proof.

Claiming that many-worlds met its burden of proof (compared to Copenhagen) by something other than Copenhagen not being proven is completely missing the point. If you want people to believe many-worlds rather than Copenhagen, you have to disprove Copenhagen. If you don't, then people will continue to believe Copenhagen.

No, my question was: why did Copenhagen become generally accepted? You're saying: it just is, deal with it. That's unsatisfactory. Copenhagen proponents never seem to have to defend their stance, and you're telling me they don't have to because they're the majority.

Copenhagen doesn’t even seem to be well defined unlike Pilot Wave, Objective Collapse, GRW…

If I understand correctly, Copenhagen became generally accepted because it was around for several decades before many-worlds.

> You're saying: it just is, deal with it. That's unsatisfactory. Copenhagen proponents never seem to have to defend their stance, and you're telling me they don't have to because they're the majority.

I'm saying that Copenhagen is the de facto default, no matter what you think should be. If you want that to change, you have to change peoples' minds. These being scientists, you typically need some evidence to make them change their minds - they're not going to do it just because you think they should.

Without evidence (impossible in principle, if Copenhagen and many-worlds make the same predictions), you can argue that one shouldn't have a firm stance on this, since both interpretations give the same results, and there is no experimental way of discerning one from the other. (This looks a lot like "shut up and calculate".) Or you can argue that the philosophical position of many-worlds is more "parsimonious" or better in some other sense, but that's philosophy, and that doesn't persuade scientists all that well.

TL;DR: If you want people to move from where they are to where they aren't, give them a reason. If you don't, don't be surprised when they don't move.

> Copenhagen proponents never seem to have to defend their stance, and you're telling me they don't have to because they're the majority.

That is correct. Physics inherits that from culture, which runs on-top of reality, and that is how reality works.

Personally, I agree with you, but reality is consensus based. Deal with it (develop a better story, or meme - "Shut up and calculate" seems effective despite it being in no way whatsoever a proof of anything...try and come up with something catchy like that).

Pretty sure they are a plurality, not the majority.

Not a physicist but my guess is that Copenhagen was a "mental trick" (not in a bad sense) that got people off of worrying too much about questions we still don't have answers to e.g "what is a measurement", and got people to "shut up and calculate", which yielded results. Hence it's success

Copenhagen is somehow more persuasive.

Bohm's implicate and explicate order is an interesting relevant theory.

copenhagen is popular for historical reasons including our historical obsession with the mind-body duality. many physicists i talk to secretly admit to MWI/universal wavefunction making more sense but it is metaphysics and academia is a conservative institution, especially for metaphysics.

Popularity resolves to beliefs, and beliefs are formed via persuasiveness of stories. There may be some math contained within the stories, but ultimately physics is driven by persuasiveness of stories, as with all other endeavors involving humans.

Now that we're in the age of AI, perhaps things will change.

People do think about that. But it's rich of Carroll to claim that MWI is falsifiable, as if it is quantum theory.

Versus all others it’s more parsimonious (as has been noted elsewhere in this discussion) which is typically more desirable as a description of nature. So if it needs less and the others don’t have any more reason or evidence to be taken more seriously as a description of what is happening then shouldn’t it rank first as the best current interpretation of QM?

How is the answer “everything that can happen does happen, just in an alternate universe that is identical except for the outcome of one single measurement” a parsimonious answer to the measurement problem? To quote Sam Harris, many-worlds seems to be the least parsimonious concept ever produced by science.

> How is the answer “everything that can happen does happen, just in an alternate universe that is identical except for the outcome of one single measurement” a parsimonious answer to the measurement problem?

Because it drops straight out of the schroedinger equation, which is something you were already believing.

Do you consider believing in distant galaxies, rather than a novel type of astronomical object, to be more or less parsimonious? It means multiplying the size of the universe by millions; nevertheless most of us accept it.

And, I don't think that many-worlds even says that "everything that can happen does happen". It does say that a lot of branching goes on though :)

Might as well quote Sean Carroll again, he's an expert and I am not:

"The Schrödinger equation tells us that there's a wave function that evolves over time and then you can ask how I can divide that wave function into a set of decohered non-interacting worlds and those are the worlds that happen. It is nowhere close to saying everything happens. It is what is predicted by the Schrödinger equation That is what happens."

https://www.preposterousuniverse.com/podcast/2024/05/06/ama-...

Interestingly, people seem less bothered by the idea that the universe might be infinite in size even though that has a similar feature that a lot of things happen. So it just seems to me that the discomfort is people worrying about the idea that there are copies of themselves out there somewhere when they really shouldn't. At least no more than if in an infinite universe there would also be infinite repetition and infinite identical "yous". This is starting to sound like a Douglas Adams bit now :D

Infinite "yous" does not follow from an infinite universe unless one adds a constraint on the distribution of matter in that universe. E.g. one could have a finite observable universe that we see, then an infinite expanse of cheese. No extra "you", unless you're cheese. Infinite does not imply random.

But if I observe a Shroedinger's cat after opening the box every morning, I do get at least duplicated. Repeat this lots of times, and MWI says there are for sure 2^n copies of me as the lowest estimate.

Counting all daily QM-influenced events everybody experiences (a cosmic ray either passed through me or decayed before it reached me, a radon atom either decayed in the air right next to me or not when I went to my cellar etc.), I think it is fair to say there are nearly infinite copies of you in various multiverse branches (of course, some who collected lots of radioactive decay events are already dead from cancer by now).

If you observe the position of a system whose quantum wavefunction has non-zero probability over a non-empty interval, then according to MWI would you not create an uncountable infinity of duplicates of yourself?

Arguably this would be limited by the reporting accuracy of your equipment, but perhaps the thought experiment can be tweaked to get around that...

It's parsimonious because that was already the accepted answer as to the question of why you get an interference pattern in the two-slit experiment, even when you emit just one photon at a time.

Indeed, there are various pros and cons to all the leading interpretations. "Parsimonious" is often used to describe Everettian interpreations, although this is somewhat dubious as the leading advocates all have their own slightly different take on MWI (i.e. which quantities are "physical" and how to make experimental predictions - see [0] for more).

MWI has always suffered with issues around probability. Why should we assign probabilities to branches, and why do those probabilities coincide with the Born rule. My belief is that it won't be widely accepted until this is resolved. There are lots of (typically complex) attempts to derive the Born rule using decision theory or the like. There's no consensus that any of these attempts are compelling, or likely to succeed in the near future.

[0] https://arxiv.org/pdf/gr-qc/9703089