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The many-worlds interpretation is a good way to reason about quantum mechanics (certainly better than giving some special status to the experimenter), but it's
by Diggsey 7y ago
The many-worlds interpretation is a good way to reason about quantum mechanics (certainly better than giving some special status to the experimenter), but it's meaningless to ask whether those other worlds really exist or not, not just because it's un-falsifiable, but also because if one defines "existence" to include alternate worlds, then every possible state of the world exists. If everything exists, then it's no longer a useful property to talk about.
One can replace many-worlds with an idea similar to relativity: you can only make statements about the universe from the perspective of a particle within that universe. Things entangled with that particle are "real", and one can make statements about them, things not entangled with that particle are not real.
When dealing with composite observers like ourselves, it's possible for a particle to be entangled with only part of the observer. Since entanglement propagates quickly, this is only a temporary inconvenience, but there are certainly some metaphysical questions to answer about that interim state.
- deleted 7y ago[deleted]
- tim333 7y ago>it's meaningless to ask whether those other worlds really exist or not Dunno - if you think of something like the two slit experiment whether the worlds where the particle goes through slit one or where it goes through slit two exist or not seems to have experimental results as they produce an interference pattern. You can also ask about more complicated situations and whether the other worlds exist may not be meaningless if they have an effect on event probabilities in ours, if only a small one.
- Diggsey 7y agoIn the many worlds interpretation, as soon as a world has "split"/"the wave of differentiation has hit"/"particles have been entangled"/"whatever terminology you want to use" from the observer, it has zero impact on any future results, not just a small impact. Until that split happens, we're just talking about our own world. It's never possible to observe any evidence for more than one world, that follows from the way we define what a "world" is. Many-worlds does not try to explain why particles have a wave function, it only tries to explain the source of the apparent randomness in the way that wave function collapses, whilst removing the need for experimenters to be in some way "special" and immune from quantum effects.
- n4r9 7y agoIs that really true? In principle, if many worlds is the case then you could have a super machine enact a powerful unitary transformation which transforms the state of the observer such that there is interference between the two copies of the observer.
- kgwgk 7y ago> if you think of something like the two slit experiment whether the worlds where the particle goes through slit one or where it goes through slit two exist or not seems to have experimental results as they produce an interference pattern Intereference is not due to the interaction between "worlds". You don't have "one world" where the particle goes through one slit and "another world" where it goes through another. (If you think that's the case, how does "our world" where the interefence can be observed fit in that description?) You can perfectly explain interference with a single world where the particle doesn't go through any particular slit. It doesn't have to, because we're not trying to determine which slit it goes through (and if we do, the interference disappears).
- EGreg 7y agoWhy is it better than Pilot Wave Theory? It doesn’t even rule out non locality.
- Diggsey 7y agoI didn't comment on its superiority to any other interpretation, in fact I only pointed out a problem with it? Pilot wave theory seems good in that it contains more falsifiable components than many other interpretations. I have no idea whether it's true or not though. It feels like trying to "avoid" the weirdness in quantum mechanics is a human bias though.
- perl4ever 7y agoIf "many-worlds" is unfalsifiable, doesn't that mean "not-many-worlds" is unfalsifiable?
- Diggsey 7y ago"not-<anything>" is un-falsifiable. You can't prove that something is true with an experiment (which is what your double negative is suggesting).
- perl4ever 7y agoI think you're still saying that X and not-X aren't symmetric. But it seems to me that you can always define not-X as Y, and X as not-Y.