9 ms·

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 late

by 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.
- peterashford 2y ago
  Occam's razor?
  - ithkuil 2y ago
    Occam's razor cuts both ways :-) Some people when they hear that MWI implies that there are many worlds and that the wave function branches they think that implies that MWI is "adding" something so Occam's razor should work against it. OTOH what MWI postulates that the Schrodinger equation is all there is and the collapse of the wave function is observed because the observer is entangled with the system it measured. In order to make an intuitive sense of what's going on, MWI invokes the "worlds" and the "branching" but that's just a way for us to grasp how it would feel if ourselves are part of the entangled system. But as many analogies whose purpose is to tickle the intuition it doesn't work for everybody and may be confusing the discourse more than helping it. But the thing is: the everett interpretation is simpler and it requires less additional rules and mechanisms to explain what we observe. So Occam's razor should favor it.
    - hackinthebochs 2y ago
      Simplicity in terms of weighing theory cost isn't about rules, but about explanatory posits. MWI posits exponential growth in discernible state about which sufficient information must be carried by whatever grounds the wavefunction. But you don't get this multiplicity of state/information for free. This is a theory cost that is as profligate as one can imagine. It is magical thinking to imagine that the universe gets this for free.
      - medstrom 2y ago
        I don't know where the expression comes from, but "the only numbers that need no justification are zero and infinity". Think of it this way, if you found a coordinate system within the universe that goes from 0,0 to 100,100, you'd have to ask "but why exactly 100?" whereas it would be less surprising if the system had no apparent limit and just could go to infinity on any axis. The multiplicity of MWI is like that: just a maximally extended coordinate system.
        hackinthebochs 2y ago
        A coordinate system is an abstraction, whether anything has some large coordinate is irrelevant to the coordinate system itself. But my understanding of MWI is that there is discernible state being described by the Schrodinger that is taken as "real" or "concrete" by MWI. If we considered the non-actual branches as merely abstract coordinates, then there would be no problem with profligate state and its associated theory cost. But then it wouldn't be many worlds, but rather some kind of collapse theory.
        whimsicalism 2y ago
        Wavefunction state is just as “real” in the Copenhagen interpretation. There cannot be any hidden variables, it is not merely a mathematical abstraction. You then must posit this additional process of collapse Where the MWI takes additional theory burden is where it explains how the born rule translates to our lived experience - ie. why do we only experience one path of the wavefunction
  - adastra22 2y ago
    The sibling reply is correct, but I'll give a different answer connected to the analogy I gave that you are replying to. Occam's razor prefers simpler theories not smaller universes. The idea that the universe consists of seemingly uncountable numbers of stars, each of which is another Sun and perhaps has planets of its own, is vastly more detail than the old heliocentric model of one Sun, a fixed number of planets, and stars being pinpricks in the tapestry surrounding the solar system. Nonetheless Occam's razor suggests that we accept the view that the stars are suns and we are just one planet among many billions upon billions, because although that universe requires vastly more detail to describe, it is governed by a simpler set of rules. Unifying heaven and earth under a single, simple set of physical laws, discovered by Newton, makes for a simpler scientific model, even if it introduces the possibility of the universe being vastly larger than we originally thought. Similar situation with many-worlds. If MWI is right, then the "universe" if interpreted to include all reachable branches of the so-called multiverse, is vastly larger than we previously believed. But it is also simpler, in a strict Occam's razor sense, because it does away with the concept of collapse. Wave function collapse is an additional physical rule in the Copenhagen interpretation, whereas it's just an illusion and not an enumerated part of physical law in MWI.
    - hackinthebochs 2y ago
      Occam's razor is not just about simple rules. The original formulation is: "plurality should not be posited without necessity". Necessity here is empirical adequacy. A theory that posits an unbounded, exponential growth in states fails the simplicity test against an empirically adequate theory that posits bounded state.
      - adastra22 2y ago
        The philosophy of science has advanced significantly since the 12th century, and scientists don’t generally use the original definition anymore. I have never, ever heard it expressed in this statistical mechanics sense, and it doesn’t line up with most advances in physics (my field) which have been accompanied by increased number of states but fewer rules.
- BatFastard 2y ago
  well, it would not be Billions of universes, it would basically be infinite number of universes popping up every second. Which while interesting, does not seem possible under any law of conservation of mass?
  - mr_mitm 2y ago
    They're not popping up, the wave function simply branches. In Copenhagen you cut off the branches, in MWI you do not. Total energy in MWI is the weighted sum of the energy of all branches (weighted according to borns rule). If one could dismiss MWI this easily, there wouldn't be any serious proponents of it and we wouldn't have to have this discussion.
- hackinthebochs 2y ago
  >Why? Do you have any reason for this, or is it just a gut feeling? MWI says these universes are actual, concrete physical state, for which the universe must somehow differentiate by discernible information. But you don't get this multiplicity of state/information for free. This is a theory cost that is as profligate as one can imagine. It is magical thinking to imagine that the universe gets this for free.
  - mitthrowaway2 2y ago
    Every quantum physics interpretation agrees that these universe-branches multiply for any isolated quantum system until a human makes a measurement of that system. They only disagree on what happens when and after a measurement is made. Even the Copenhagen interpretation agrees that if you do the two-slit experiment with a single photon, that one photon will traverse all trajectories to reach the target screen.
    - hackinthebochs 2y ago
      >until a human makes a measurement of that system. No one sane thinks human observation has anything to do with measurement in QM anymore.
      - mitthrowaway2 2y ago
        Then I'll take this opportunity to ask someone who presumably considers themself sane: How do you determine what kind of interaction counts as a measurement?
        hackinthebochs 2y ago
        Let me say that my previous comment was unfair. It's unfair to say that no one sane would consider quantum measurement related to consciousness. Rather its an extremely fringe position at this point. It's certainly a deep mystery of nature and I don't claim to have an answer. Quantum erasure experiments strongly suggest to me that measurement has to do with information about the system that entails constraints on the evolution of the system. Nature seems to abhor inconsistency. If the state of the system is such that one can in principle derive constraints on its evolution up to this point, then nature ensures its evolution up to this point is consistent with that information. A measurement then is just any interaction with the property of imparting a constraint on the evolution of the system up to now.
whimsicalism 2y ago
it’s not “billions of universes springing up”, it’s just simple wavefunction evolution according to the laws we already know. “collapse” seems much more arbitrary, especially as we are able to construct larger and larger objects that are best described by wavefunction mechanics. it seems obvious we just become entangled with the experiment through decoherence. idk, it probably is non-falsifiable
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by prerok 2y ago

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.

peterashford 2y ago
Occam's razor?
- ithkuil 2y ago
  Occam's razor cuts both ways :-) Some people when they hear that MWI implies that there are many worlds and that the wave function branches they think that implies that MWI is "adding" something so Occam's razor should work against it. OTOH what MWI postulates that the Schrodinger equation is all there is and the collapse of the wave function is observed because the observer is entangled with the system it measured. In order to make an intuitive sense of what's going on, MWI invokes the "worlds" and the "branching" but that's just a way for us to grasp how it would feel if ourselves are part of the entangled system. But as many analogies whose purpose is to tickle the intuition it doesn't work for everybody and may be confusing the discourse more than helping it. But the thing is: the everett interpretation is simpler and it requires less additional rules and mechanisms to explain what we observe. So Occam's razor should favor it.
  - hackinthebochs 2y ago
    Simplicity in terms of weighing theory cost isn't about rules, but about explanatory posits. MWI posits exponential growth in discernible state about which sufficient information must be carried by whatever grounds the wavefunction. But you don't get this multiplicity of state/information for free. This is a theory cost that is as profligate as one can imagine. It is magical thinking to imagine that the universe gets this for free.
    - medstrom 2y ago
      I don't know where the expression comes from, but "the only numbers that need no justification are zero and infinity". Think of it this way, if you found a coordinate system within the universe that goes from 0,0 to 100,100, you'd have to ask "but why exactly 100?" whereas it would be less surprising if the system had no apparent limit and just could go to infinity on any axis. The multiplicity of MWI is like that: just a maximally extended coordinate system.
      - hackinthebochs 2y ago
        A coordinate system is an abstraction, whether anything has some large coordinate is irrelevant to the coordinate system itself. But my understanding of MWI is that there is discernible state being described by the Schrodinger that is taken as "real" or "concrete" by MWI. If we considered the non-actual branches as merely abstract coordinates, then there would be no problem with profligate state and its associated theory cost. But then it wouldn't be many worlds, but rather some kind of collapse theory.
        whimsicalism 2y ago
        Wavefunction state is just as “real” in the Copenhagen interpretation. There cannot be any hidden variables, it is not merely a mathematical abstraction. You then must posit this additional process of collapse Where the MWI takes additional theory burden is where it explains how the born rule translates to our lived experience - ie. why do we only experience one path of the wavefunction
- adastra22 2y ago
  The sibling reply is correct, but I'll give a different answer connected to the analogy I gave that you are replying to. Occam's razor prefers simpler theories not smaller universes. The idea that the universe consists of seemingly uncountable numbers of stars, each of which is another Sun and perhaps has planets of its own, is vastly more detail than the old heliocentric model of one Sun, a fixed number of planets, and stars being pinpricks in the tapestry surrounding the solar system. Nonetheless Occam's razor suggests that we accept the view that the stars are suns and we are just one planet among many billions upon billions, because although that universe requires vastly more detail to describe, it is governed by a simpler set of rules. Unifying heaven and earth under a single, simple set of physical laws, discovered by Newton, makes for a simpler scientific model, even if it introduces the possibility of the universe being vastly larger than we originally thought. Similar situation with many-worlds. If MWI is right, then the "universe" if interpreted to include all reachable branches of the so-called multiverse, is vastly larger than we previously believed. But it is also simpler, in a strict Occam's razor sense, because it does away with the concept of collapse. Wave function collapse is an additional physical rule in the Copenhagen interpretation, whereas it's just an illusion and not an enumerated part of physical law in MWI.
  - hackinthebochs 2y ago
    Occam's razor is not just about simple rules. The original formulation is: "plurality should not be posited without necessity". Necessity here is empirical adequacy. A theory that posits an unbounded, exponential growth in states fails the simplicity test against an empirically adequate theory that posits bounded state.
    - adastra22 2y ago
      The philosophy of science has advanced significantly since the 12th century, and scientists don’t generally use the original definition anymore. I have never, ever heard it expressed in this statistical mechanics sense, and it doesn’t line up with most advances in physics (my field) which have been accompanied by increased number of states but fewer rules.
BatFastard 2y ago
well, it would not be Billions of universes, it would basically be infinite number of universes popping up every second. Which while interesting, does not seem possible under any law of conservation of mass?
- mr_mitm 2y ago
  They're not popping up, the wave function simply branches. In Copenhagen you cut off the branches, in MWI you do not. Total energy in MWI is the weighted sum of the energy of all branches (weighted according to borns rule). If one could dismiss MWI this easily, there wouldn't be any serious proponents of it and we wouldn't have to have this discussion.
hackinthebochs 2y ago
>Why? Do you have any reason for this, or is it just a gut feeling? MWI says these universes are actual, concrete physical state, for which the universe must somehow differentiate by discernible information. But you don't get this multiplicity of state/information for free. This is a theory cost that is as profligate as one can imagine. It is magical thinking to imagine that the universe gets this for free.
- mitthrowaway2 2y ago
  Every quantum physics interpretation agrees that these universe-branches multiply for any isolated quantum system until a human makes a measurement of that system. They only disagree on what happens when and after a measurement is made. Even the Copenhagen interpretation agrees that if you do the two-slit experiment with a single photon, that one photon will traverse all trajectories to reach the target screen.
  - hackinthebochs 2y ago
    >until a human makes a measurement of that system. No one sane thinks human observation has anything to do with measurement in QM anymore.
    - mitthrowaway2 2y ago
      Then I'll take this opportunity to ask someone who presumably considers themself sane: How do you determine what kind of interaction counts as a measurement?
      - hackinthebochs 2y ago
        Let me say that my previous comment was unfair. It's unfair to say that no one sane would consider quantum measurement related to consciousness. Rather its an extremely fringe position at this point. It's certainly a deep mystery of nature and I don't claim to have an answer. Quantum erasure experiments strongly suggest to me that measurement has to do with information about the system that entails constraints on the evolution of the system. Nature seems to abhor inconsistency. If the state of the system is such that one can in principle derive constraints on its evolution up to this point, then nature ensures its evolution up to this point is consistent with that information. A measurement then is just any interaction with the property of imparting a constraint on the evolution of the system up to now.

whimsicalism 2y ago

it’s not “billions of universes springing up”, it’s just simple wavefunction evolution according to the laws we already know. “collapse” seems much more arbitrary, especially as we are able to construct larger and larger objects that are best described by wavefunction mechanics. it seems obvious we just become entangled with the experiment through decoherence. idk, it probably is non-falsifiable

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