“Now I’m not clear exactly how often quantum events lead to a slightly different world”
The answer is Very Very often. If you have a piece of glass and shine a photon at it, such that it has an equal chance of bouncing and going through, the two possibilities become separate worlds. Shine a million photons at it and you split into 21000000worlds, one for each combination of photons going through and bouncing. Note that in most of the worlds, the pattern of bounces looks random, so this is a good source of random numbers. Photons bouncing of glass are just an easy example, almost any physical process splits the universe very fast.
The answer is: it all depends on what you mean by “world”.
There is an approach to MWI based on coherent superpositions, and a version based on decoherence. Following Yudkowsky, you are assuming the coherence based approach.
The issue is not whether superpositions exist, but whether they qualify as worlds.. it’s a conceptual issue.
Superposed states lack a number of features that one would typically assiciate with a world: objectivity, size, causal isolation, and permanence.
I’m not sure what you mean by objectivity or why superimposed states don’t have it.
If a pair of superimposed state differ by a couple of atom positions, they can interact and merge. If they differ by “cat alive” to “cat dead” then there is practically no interaction. The world stays superimposed forever. So that gives causal isolation and permanence.
I mean maybe some of the connotations of “worlds” aren’t quite accurate. Its a reasonably good word to use.
No objectivity means that superpositions can be made to disappear by a suitable choice of basis
If there is no inteerction, they are decoherent states. If you could show that decoherence smoothly follows from coherent superposition, without any additional postulates, you would be on to something .
“Now I’m not clear exactly how often quantum events lead to a slightly different world”
The answer is Very Very often. If you have a piece of glass and shine a photon at it, such that it has an equal chance of bouncing and going through, the two possibilities become separate worlds. Shine a million photons at it and you split into 21000000worlds, one for each combination of photons going through and bouncing. Note that in most of the worlds, the pattern of bounces looks random, so this is a good source of random numbers. Photons bouncing of glass are just an easy example, almost any physical process splits the universe very fast.
The answer is: it all depends on what you mean by “world”.
There is an approach to MWI based on coherent superpositions, and a version based on decoherence. Following Yudkowsky, you are assuming the coherence based approach.
The issue is not whether superpositions exist, but whether they qualify as worlds.. it’s a conceptual issue.
Superposed states lack a number of features that one would typically assiciate with a world: objectivity, size, causal isolation, and permanence.
I’m not sure what you mean by objectivity or why superimposed states don’t have it.
If a pair of superimposed state differ by a couple of atom positions, they can interact and merge. If they differ by “cat alive” to “cat dead” then there is practically no interaction. The world stays superimposed forever. So that gives causal isolation and permanence.
I mean maybe some of the connotations of “worlds” aren’t quite accurate. Its a reasonably good word to use.
No objectivity means that superpositions can be made to disappear by a suitable choice of basis
If there is no inteerction, they are decoherent states. If you could show that decoherence smoothly follows from coherent superposition, without any additional postulates, you would be on to something .