5 ms·

tldr: Basically a defense of the Copenhagen interpretation, i.e. "You shouldn't speculate what is happening to things you can't measure." (which is opposed to

by drcode 6y ago

tldr: Basically a defense of the Copenhagen interpretation, i.e. "You shouldn't speculate what is happening to things you can't measure." (which is opposed to the "many worlds" interpretation, which basically boils down to "Assume the simplest possibility when discussing things you can't measure.")

AnimalMuppet 6y ago
If you think that's what the many worlds interpretation is, then you have a very different idea of what "simplest possibility" means than I do.
- drcode 6y ago
  MWI just is what happens naturally if the schrodinger equation is obeyed. Every other interpretation assumes the schrodinger equation is obeyed BUT ALSO some other rules are obeyed.
  - lumost 6y ago
    The extra rules really only apply when for one reason or the other we've assumed that some exterior system which doesn't obey QM interacts with a QM system obeying the schrodinger equation. The exact border between when this is a valid assumption and we can apply extra rules to make up for it vs. an invalid assumption is ill-defined.
    - drcode 6y ago
      Rules on top of rules on top of rules
  - millstone 6y ago
    MWI makes the very strong claim that the Schrödinger equation is sufficient to explain observations that do not naturally fit into its framework, such as wavefunction collapse and the Born rule. You can simplify any theory by throwing out half its postulates. But now your theory has less explanatory power. The critiques of MWI are that it cannot explain observations. For example, consider the recent article on generating random bits through quantum fluctuations with a laser. MWI, like the Schrödinger equation, is fully deterministic; there is no randomness. The bits are not random in MWI. How to reconcile these?
    - jiggawatts 6y ago
      > MWI, like the Schrödinger equation, is fully deterministic; there is no randomness. The bits are not random in MWI. How to reconcile these? There is a key concept in MWI that people (even Nobel laureate level physicists) are just unable to wrap their heads around: You're also a quantum object, not just the experiment. In MWI, the fundamental concept is that quantum objects expand into multiple dimensions. Hence by the rule above, so do you. This is the source of "randomness". From your in-universe perspective, you can't know apriori which "path" into the multiverse you take. You take all of them, but after some time, any observation you make is from the perspective of one of your copies, and each copy thinks of themselves as the unique, singular copy. To summarise: You can talk meaningfully about the statistics that your future selves will experience, but you can't know ahead which one's perspective you'll have, because your current self will become all of them. So from "God's point of view", outside the multiverse, the whole thing looks deterministic. From inside the universe it seems inherently random. If you're a computer scientist by background, imagine this: You create a human-equivalent AI that you can converse with. Inside its memory you set up a 1-byte cell that it can observe. You then make 256 copies of the AI, one for each possible combination of bits set in the memory cell. If you ask one of the randomly selected copies what value it sees, it'll see whatever you've set, which will more than likely look some arbitrary -- random seeming -- combination of bits. If you repeat the procedure, each time with a randomly chosen AI, it'll report that the cell is changing "randomly". However, the overall system of all copies is entirely deterministic! The randomness is in your external selection. From the outside, you can remove the randomness by asking every AI the same question to reveal the deterministic pattern. From in-universe, this is not an option. The AIs can't ask the other AIs what they see!
      - goldenkey 6y ago
        Right, in the universal view, it's just a huge wavefunction following the Schrodinger eq at all times. God can peek at it, and not have to collapse anything. If he decides to sample it, he's choosing 1 universe from all possibilities. It's a huge space, but it's linear from his dimension in which collapse doesn't appear. [1] https://en.wikipedia.org/wiki/Universal_wavefunction https://en.wikipedia.org/wiki/Universal_wavefunction
  - zwkrt 6y ago
    While this is technically true I don’t think that that means that the many worlds theory is the simplest or the most straightforward. In other areas of science we don’t take our mathematical formalisms to be real. Scientist don’t fret about whether inches exist in the world or that energy is “real”, yet somehow we are led to believe that just trusting in the Schrodinger equation and assuming that it’s “real” leads us to the obvious conclusion that there are many worlds. Now there are other reasons that I like the many worlds interpretation. If you get over the conceptual hurdle of its implications, it’s nice because it doesn’t cause immediate theoretical breakdown based on questions that a precocious child would ask, like “what is an observer?”
deleted 6y ago
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by drcode 6y ago

AnimalMuppet 6y ago

If you think that's what the many worlds interpretation is, then you have a very different idea of what "simplest possibility" means than I do.

drcode 6y ago
MWI just is what happens naturally if the schrodinger equation is obeyed. Every other interpretation assumes the schrodinger equation is obeyed BUT ALSO some other rules are obeyed.
- lumost 6y ago
  The extra rules really only apply when for one reason or the other we've assumed that some exterior system which doesn't obey QM interacts with a QM system obeying the schrodinger equation. The exact border between when this is a valid assumption and we can apply extra rules to make up for it vs. an invalid assumption is ill-defined.
  - drcode 6y ago
    Rules on top of rules on top of rules
- millstone 6y ago
  MWI makes the very strong claim that the Schrödinger equation is sufficient to explain observations that do not naturally fit into its framework, such as wavefunction collapse and the Born rule. You can simplify any theory by throwing out half its postulates. But now your theory has less explanatory power. The critiques of MWI are that it cannot explain observations. For example, consider the recent article on generating random bits through quantum fluctuations with a laser. MWI, like the Schrödinger equation, is fully deterministic; there is no randomness. The bits are not random in MWI. How to reconcile these?
  - jiggawatts 6y ago
    > MWI, like the Schrödinger equation, is fully deterministic; there is no randomness. The bits are not random in MWI. How to reconcile these? There is a key concept in MWI that people (even Nobel laureate level physicists) are just unable to wrap their heads around: You're also a quantum object, not just the experiment. In MWI, the fundamental concept is that quantum objects expand into multiple dimensions. Hence by the rule above, so do you. This is the source of "randomness". From your in-universe perspective, you can't know apriori which "path" into the multiverse you take. You take all of them, but after some time, any observation you make is from the perspective of one of your copies, and each copy thinks of themselves as the unique, singular copy. To summarise: You can talk meaningfully about the statistics that your future selves will experience, but you can't know ahead which one's perspective you'll have, because your current self will become all of them. So from "God's point of view", outside the multiverse, the whole thing looks deterministic. From inside the universe it seems inherently random. If you're a computer scientist by background, imagine this: You create a human-equivalent AI that you can converse with. Inside its memory you set up a 1-byte cell that it can observe. You then make 256 copies of the AI, one for each possible combination of bits set in the memory cell. If you ask one of the randomly selected copies what value it sees, it'll see whatever you've set, which will more than likely look some arbitrary -- random seeming -- combination of bits. If you repeat the procedure, each time with a randomly chosen AI, it'll report that the cell is changing "randomly". However, the overall system of all copies is entirely deterministic! The randomness is in your external selection. From the outside, you can remove the randomness by asking every AI the same question to reveal the deterministic pattern. From in-universe, this is not an option. The AIs can't ask the other AIs what they see!
    - goldenkey 6y ago
      Right, in the universal view, it's just a huge wavefunction following the Schrodinger eq at all times. God can peek at it, and not have to collapse anything. If he decides to sample it, he's choosing 1 universe from all possibilities. It's a huge space, but it's linear from his dimension in which collapse doesn't appear. [1] https://en.wikipedia.org/wiki/Universal_wavefunction https://en.wikipedia.org/wiki/Universal_wavefunction
- zwkrt 6y ago
  While this is technically true I don’t think that that means that the many worlds theory is the simplest or the most straightforward. In other areas of science we don’t take our mathematical formalisms to be real. Scientist don’t fret about whether inches exist in the world or that energy is “real”, yet somehow we are led to believe that just trusting in the Schrodinger equation and assuming that it’s “real” leads us to the obvious conclusion that there are many worlds. Now there are other reasons that I like the many worlds interpretation. If you get over the conceptual hurdle of its implications, it’s nice because it doesn’t cause immediate theoretical breakdown based on questions that a precocious child would ask, like “what is an observer?”

deleted 6y ago

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