91
What proof is there of the multiverse? (sh.itjust.works)
submitted 1 year ago by to c/askscience@lemmy.world
124 comments fedilink hide all child comments
 

I guess I've always been confused by the Many Worlds Interpretation of Quantum Physics and the fact that it's taken seriously. Like is there any proof at all that universes outside of our own exist?

I admit that I might be dumb, but, how does one look at atoms and say "My God! There must be many worlds than just our one?"

I just never understood how Many Worlds Interpretation was valid, with my, admittedly limited understanding, it just seemed to be a wild guess no more strange than a lot things we consider too outlandish to humor.

you are viewing a single comment's thread
view the rest of the comments
[–] 2 points 1 year ago* (6 children)

Incorrect. As I said, objective collapse theories can be non-deterministic without predicting many universes. The extra universes only appear if the wave function never collapses, and stochastic collapses are entirely possible.

Yea, the difference between a classical statistical theory with and without many worlds is whether or not you maintain a state that includes all possible outcomes as you continue your analysis, or restrict the state you are analyzing to one possible outcome from one of your statistical events. The same is true of quantum mechanics.

But you can't. Quantum physics cannot be explained by classical mechanics alone. If it could, we never would have formulated quantum physics to start with.

I’m arguing that quantum mechanics is a rethinking of statistics more so than a rethinking of physics. The world cannot be explained without it.

I think that even if I must consider a state that includes all possible outcomes while doing my analysis of the situation, that doesn’t mean those “alternate worlds” necessarily physically exist in any meaningful way.

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 6 child comments
    •
  • [–] 0 points 1 year ago (5 children)

    Yea, the difference between a classical statistical theory with and without many worlds is whether or not you maintain a state that includes all possible outcomes as you continue your analysis

    Yes, but, again, this is only because you have imperfect information about the underlying physical system. The array of possibilities presented by classical statistics are strictly epistemic; the actual real state of the system you're analyzing is always definitive and determinate.

    And very, very importantly, this is not that case in quantum physics. The indeterminacy of state in a super position is not just the result of imperfect information; it is a fundamental part of the underlying system. It is not the case that, in the double slit experiment, the electron only travels through one slit, and we just don't know which one. It really really does travel through both. This is fundamentally different from classical mechanics.

    I’m arguing that quantum mechanics is a rethinking of statistics more so than a rethinking of physics.

    Look, if you want to try and argue that quantum physics isn't physics, I won't stop you, but you'd better have an extraordinary argument, because this is an extraordinary claim. One that rejects the last century of scientific consensus. If you can demonstrate that quantum mechanics is just a different statistical model of classical physics, it would be a revolution in science.

    I think that even if I must consider a state that includes all possible outcomes while doing my analysis of the situation, that doesn’t mean those “alternate worlds” necessarily physically exist in any meaningful way.

    That's correct, and MWI doesn't argue otherwise. The important part isn't just that these states are possible, it's that they have real physical existence.

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 5 child comments
    •
  • [–] 3 points 1 year ago (2 children)

    Yes, but, again, this is only because you have imperfect information about the underlying physical system. The array of possibilities presented by classical statistics are strictly epistemic; the actual real state of the system you're analyzing is always definitive and determinate.

    You are glossing over my point. I’ll try to put it as concretely as I can think of:

    Assume for the sake of argument that there is a process in an otherwise classical physical system that is truly nondeterministic, meaning there is randomness that isn’t due to any hidden variable or otherwise incomplete knowledge of the state of the system.

    When describing such a system, you will run into the same dilemma of either needing a “wavefunction collapse” or “many worlds” interpretation of your statistics.

    And yet this model is not quantum. It is a classical nondeterministic model.

    My point being, it’s the existence of true nondeterminism that leads to the “many worlds” idea, not the other strange properties of quantum mechanics.

    If you can demonstrate that quantum mechanics is just a different statistical model of classical physics, it would be a revolution in science.

    I really, genuinely, think this is not a controversial take. The idea that quantum mechanics is more of a rethinking of statistics than physics comes from my own personal experience studying quantum physics. Most of the time, you take the classical Newtonian mechanics equations (sometimes including “corrections” for relativity), and treat them with the “quantum mechanics” version of statistics, and out pops all the important things you’d like to model, like how electrons arrange into orbitals in an atom. The results of slit/entanglement/bell experiments depend on having an object that obeys quantum statistics, but it can be a wide variety of objects with vastly different physical properties and behaviors (e.g. slit experiments have been done with both photons and electrons).

    The important part isn't just that these states are possible, it's that they have real physical existence.

    I don’t think there is any reason to believe the “other worlds” needed to analyze quantum systems “physically exist” to any meaningful extent. It’s the same as considering all possible outcomes of a classical truly random event (if you assume there exists true nondeterminism, not simply a lack of complete information).

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 2 child comments
    •
  • [–] 0 points 1 year ago* (last edited 1 year ago) (1 child)

    You are glossing over my point.

    I promise I'm not doing it deliberately.

    When describing such a system, you will run into the same dilemma of either needing a “wavefunction collapse” or “many worlds” interpretation of your statistics.

    Yes, I would agree with that if we're using "wave function collapse" to refer to any truly probabilistic mechanism in a general sense (as, strictly speaking you could have a non-deterministic mechanics without wave functions at all).

    But I note the important fact that you don't need both.

    My point being, it’s the existence of true nondeterminism that leads to the “many worlds” idea

    Well no, it's the existence of true non-determinism without any form of wave function collapse.

    I really, genuinely, think this is not a controversial take. The idea that quantum mechanics is more of a rethinking of statistics than physics comes from my own personal experience studying quantum physics.

    Well if that's the case, with all due respect, I think you need to study quantum physics more. Because trying to overturn a century of scientific consensus is definitely controversial, at best.

    The results of slit/entanglement/bell experiments depend on having an object that obeys quantum statistics, but it can be a wide variety of objects with vastly different physical properties and behaviors (e.g. slit experiments have been done with both photons and electrons).

    How, specifically, are you modeling the double slit experiment using only Newtonian Mechanics? How about quantum tunneling?

    I don’t think there is any reason to believe the “other worlds” needed to analyze quantum systems “physically exist” to any meaningful extent.

    Are claiming that super positions don't actually exist at all? Because, again, you'd better have a solid argument for such a radical claim.

    It’s the same as considering all possible outcomes of a classical truly random event

    Is it? Hard to say when we're talking about something that doesn't actually exist.

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 1 child comment
    •
  • [–] 2 points 1 year ago

    Because trying to overturn a century of scientific consensus is definitely controversial, at best.

    I don’t think what I’m suggesting is “trying to overturn a century of scientific consensus”. It’s a mildly different interpretation of the same math, that doesn’t require many physical worlds. It’s also not that uncommon. The “many worlds” idea is not scientific consensus. Go read about interpretations of quantum mechanics from sources other than Sean Carroll.

    How, specifically, are you modeling the double slit experiment using only Newtonian Mechanics? How about quantum tunneling?

    Both the double slit experiments and quantum tunneling emerge when you apply quantum statistics to any point particle following Newtonian mechanics.

    Are claiming that super positions don't actually exist at all? Because, again, you'd better have a solid argument for such a radical claim.

    Superpositions are a mathematical tool for describing the statistics of potential measurements.

  • permalink
  • fedilink
  • source
  • parent
  • [–] 1 point 1 year ago (1 child)

    Here’s an interesting example:

    The Bell test about entanglement is one of the best-known proofs that quantum mechanics can’t be explained using classical statistics.

    The Bell test is an analysis of the correlation between two entangled particles.

    However, that correlation is only notable because we are analyzing the evolution of both particles.

    If we analyze one particle, alone, we wouldn’t be able to determine if it is entangled with any other particles (and we wouldn’t be able to model it without the need for quantum mechanics).

    In other words, you only need the “other worlds” when you are analyzing a system and trying to predict its behavior. You can completely ignore all information or “other worlds” external to the system you are studying.

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 1 child comment
    •