8 ms·

Sean Carroll claims many-worlds is “super duper falsifiable” “ Right, so speaking of which, look, many-worlds says there is a wave function or a state vector,

by jahnu 2y ago

Sean Carroll claims many-worlds is “super duper falsifiable” “ Right, so speaking of which, look, many-worlds says there is a wave function or a state vector, it evolves all the time under the Schrödinger equation. So all you need to do to falsify the many worlds-interpretation is to do an experiment where the wave function is not under the Schrödinger equation. These experiments are ongoing. Roger Penrose makes predictions that we should see them. There’s other theories of objective collapses that says we should see them. So that’s just one way. Also, you could find evidence for dynamical variables other than the wave function, ’cause those don’t exist in many-worlds. So there’s plenty of ways in which you could experimentally do these things. They’re hard experiments to do, and they may never converge on anything, but they’re there in principle. If you care about the philosophy of it rather than the practice of it, there’s zero question that many-worlds is completely 100% super-duper falsifiable.” https://www.preposterousuniverse.com/podcast/2021/04/14/ama-april-2021/ https://www.preposterousuniverse.com/podcast/2021/04/14/ama-...

n4r9 2y ago
That's not very convincing! He's only talking about falsifying it vs extensions of quantum theory. The interesting question is whether it can be falsified vs other interpretations of quantum theory.
- deleted 2y ago
  [deleted]
- mr_mitm 2y ago
  Why is no one ever asking how to falsify Copenhagen vs other interpretations? What did Copenhagen ever do to deserve this privilege?
  - mistermann 2y ago
    Copenhagen is somehow more persuasive. Bohm's implicate and explicate order is an interesting relevant theory.
    - whimsicalism 2y ago
      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.
      - mistermann 2y ago
        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.
  - n4r9 2y ago
    People do think about that. But it's rich of Carroll to claim that MWI is falsifiable, as if it is quantum theory.
  - AnimalMuppet 2y ago
    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.
    - throwawaymaths 2y ago
      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
    - mr_mitm 2y ago
      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.
      - mistermann 2y ago
        > 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).
      - sebzim4500 2y ago
        Pretty sure they are a plurality, not the majority.
      - 2y ago
- jahnu 2y ago
  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?
  - cfgauss2718 2y ago
    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.
    - lmm 2y ago
      > 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.
      - jahnu 2y ago
        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-may-2024/ 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
pdonis 2y ago
> all you need to do to falsify the many worlds-interpretation is to do an experiment where the wave function is not under the Schrödinger equation. Which, Carroll conveniently fails to note, happens every time we make a measurement on a system that is not in an eigenstate of the observable being measured. For example, every time an H polarization measurement is made on a V+ polarized qubit, which happens all the time in quantum computing, the result is either H+ or H-, with 50% probability of each; but before the measurement the qubit was in state V+. The time evolution from V+ to H+ or H- is not time evolution under the Schrodinger equation. MWI proponents explain this away by saying there is another branch of the wave function where the result is the other one (for example, H- if we observed the result H+), so that the whole time evolution is still under the Schrodinger equation. (Note that "the whole time evolution" here has to include the entire universe, not just the qubit being measured.) But MWI proponents also have to say that this other branch of the wave function is in principle unobservable. In other words, the MWI itself says it is not falsifiable.
- prerok 2y ago
  In a general, philosophical sense it probably is non-falsifiable. But... where does it end? What if we took the measurement 5ns, 500ms, 5 seconds, 5 hours later, because of, you know, things. Billions of universes springing up every second does not seem plausible to me and it does sound like an escape hatch: we don't know why it happened that way, so let's just say there is another unobservable universe where it happened the other way round. Which is nice, I don't have to think about it anymore. But... it kind of reminds me of the flying arrow or a turtle you can never reach. If you are thinking in the same problem space you will never reach the correct conclusion. So, what we really need is the different mode of thought (I wish I would know to suggest something ;) ), not an escape hatch.
  - adastra22 2y ago
    > Billions of universes springing up every second does not seem plausible to me Why? Do you have any reason for this, or is it just a gut feeling? If it’s just a gut feeling, I’ll note that this was exactly the reaction most of the intelligencia had to Capurnicus and Galileo. Turns out the universe is a caster place than we previously knew.

by jahnu 2y ago

n4r9 2y ago

That's not very convincing! He's only talking about falsifying it vs extensions of quantum theory. The interesting question is whether it can be falsified vs other interpretations of quantum theory.

deleted 2y ago
[deleted]
mr_mitm 2y ago
Why is no one ever asking how to falsify Copenhagen vs other interpretations? What did Copenhagen ever do to deserve this privilege?
- mistermann 2y ago
  Copenhagen is somehow more persuasive. Bohm's implicate and explicate order is an interesting relevant theory.
  - whimsicalism 2y ago
    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.
    - mistermann 2y ago
      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.
- n4r9 2y ago
  People do think about that. But it's rich of Carroll to claim that MWI is falsifiable, as if it is quantum theory.
- AnimalMuppet 2y ago
  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.
  - throwawaymaths 2y ago
    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
  - mr_mitm 2y ago
    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.
    - mistermann 2y ago
      > 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).
    - sebzim4500 2y ago
      Pretty sure they are a plurality, not the majority.
    - 2y ago
jahnu 2y ago
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?
- cfgauss2718 2y ago
  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.
  - lmm 2y ago
    > 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.
    - jahnu 2y ago
      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-may-2024/ 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

pdonis 2y ago

> all you need to do to falsify the many worlds-interpretation is to do an experiment where the wave function is not under the Schrödinger equation. Which, Carroll conveniently fails to note, happens every time we make a measurement on a system that is not in an eigenstate of the observable being measured. For example, every time an H polarization measurement is made on a V+ polarized qubit, which happens all the time in quantum computing, the result is either H+ or H-, with 50% probability of each; but before the measurement the qubit was in state V+. The time evolution from V+ to H+ or H- is not time evolution under the Schrodinger equation. MWI proponents explain this away by saying there is another branch of the wave function where the result is the other one (for example, H- if we observed the result H+), so that the whole time evolution is still under the Schrodinger equation. (Note that "the whole time evolution" here has to include the entire universe, not just the qubit being measured.) But MWI proponents also have to say that this other branch of the wave function is in principle unobservable. In other words, the MWI itself says it is not falsifiable.

prerok 2y ago
In a general, philosophical sense it probably is non-falsifiable. But... where does it end? What if we took the measurement 5ns, 500ms, 5 seconds, 5 hours later, because of, you know, things. Billions of universes springing up every second does not seem plausible to me and it does sound like an escape hatch: we don't know why it happened that way, so let's just say there is another unobservable universe where it happened the other way round. Which is nice, I don't have to think about it anymore. But... it kind of reminds me of the flying arrow or a turtle you can never reach. If you are thinking in the same problem space you will never reach the correct conclusion. So, what we really need is the different mode of thought (I wish I would know to suggest something ;) ), not an escape hatch.
- adastra22 2y ago
  > Billions of universes springing up every second does not seem plausible to me Why? Do you have any reason for this, or is it just a gut feeling? If it’s just a gut feeling, I’ll note that this was exactly the reaction most of the intelligencia had to Capurnicus and Galileo. Turns out the universe is a caster place than we previously knew.