alt Hacker News"This rather fanciful interpretation of Quantum Physics has now become accepted by many theoretical physicists as being more satisfactory than the Copenhagen interpretation, despite the fact that the mechanism which causes the splitting of the Universe is not explained in any more detail than wavefunction collapse. As you can probably tell, I am in the minority of physicists who finds the Many Worlds interpretation dificult to accept, and not particularly illuminating."
I think these lectures are a good intro to QM. This statement feels very emotional though. Many-worlds just states there is no such thing as wave function collapse. The many worlds are a logical conclusion following. Copenhagen simply refuses to elaborate to when wave-function collapse happens, which to me is not a complete theory.
You could have some critique of many-worlds in relation to statistics, although I think many people have given quite satisfactory explanations.
Many worlds is just bare bones QM.. If any other theory is proposed, it should be falsifiable (like pilot wave theory for example). Doesn't mean it won't be difficult to measure.
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Many-worlds is an interpretation and not a theory. It makes no additional predictions beyond what QM does. Believing in any interpretation (or shutting up and calculating) is purely emotional; it has no scientific content.
The quantum world involves states that are a complex linear superposition of all possible states. It isn't just that the world bifurcates into one where the cat is |alive> or |dead>, but also all c1 |alive> + c2 |dead>, where c1^2+c2^2 = 1 and c1 and c2 are complex. The MWI has no explanation for how this other infinity of possible states disappears into just two states. You still wind up with the collapse of the wave function--involving a lot of hand-waving or appealing to some nebulous property of consciousness.
Given we haven’t bridged quantum with gravity yet, my bet is the function collapses right at the boundary when gravity starts to play a meaningful role.
That’s a more physically plausible interpretation than ever “tick” of the universe actually creates infinitely more universes because every fundamental particle is quantum and each one is constantly interacting under the wave function every plank second. And the infinite number of possible events that a single particle would experience is multiplied by the joint combination of all particles in the entire universe. It doesn’t seem plausible.
When the future has multiple instances of you, it becomes problematic to define what the Born rule means.
For example, "Many Worlds, the Born Rule, and Self-Locating Uncertainty" notices that the rule doesn't mean anything, but it is rational to behave like it does. It's not a very satisfying position, I'd say.
The Copenhagen interpretation doesn't even deserve to sit with the other interpretations because it's not well defined. It's protoscience, like alchemy.
"Many-worlds just states there is no such thing as wave function collapse" is the emotional statement. The contempt for many-worlds is both principled and rational.
Many worlds as real ontology are just as wild as saying their is a God. Physicists are thus making claims that just as wild as the theologians .. I find this fascinating.
Just like the AI nerds and the AGI singularity or Musk saying we are in simulation...
ie so many crazy ideas.. for the rationalist, its like being in an insane asylum and trusting one mental patient or another..
I suppose at some level its just not rational why we exist. We must accept some wild, fundamental metaphysical assumption
FWIW (and it's not worth a lot, since I'm a layperson), I think the interpretation that makes the most sense to me is Quantum Decoherence (https://en.wikipedia.org/wiki/Quantum_decoherence).
My interpretation of the interpretation is that the universe is a giant constraint resolution system. Particles are free to be anywhere randomly as long as they do not randomly interact with other particles. As soon as they interact they have fewer "degrees of freedom", since now they interacted. When they interact with anything macroscopic they have no freedom left. Makes sense to me anyway.