I do not have a problem with it in principle; but it would imply that there are uncountably many.
The reason you can’t think of a superposition as just a sort of continuum without genuine parts, is that the part of reality we’re observing here is objectively differentiated from what it is not. Even if the specific branch you see around you is just part of a continuum, it must be a continuum made of parts that each have a distinct enough existence to, e.g., host an observer in a definite state. This means they can be counted (or have a cardinality), and so the only way to get a real-valued weighting is if there are continuum-many of them.
Something that I strongly suspect, but which I’m not 100% sure about, is that if branch A is supposed to be x times more likely than branch B, x not a rational number, then there must be uncountably many copies of A, and uncountably many copies of B, with the A-set being x times bigger than the B-set, according to some natural measure. The alternative would be to say that A exists once, B exists once; they’re both embedded in a continuum of branches, every member of which only exists once; but the measure is non-uniform for some reason. But I think this is another version of the “A exists more than B exists” fallacy. Formally we can write down a non-uniform measure, but what it actually means is that we are counting some branches for more than others, and the only way to justify that is to suppose that the branches in question are duplicated, in proportion to the extra factor.
Uncountably many distinct branches, each duplicated uncountably many times—at least it meets my criteria for a well-formed multiverse theory (the branches can be objectively individuated, and they have a cardinality), but it’s very extravagant metaphysically. I’m planning a post on forms of Many Worlds that I do think are well-defined, that will focus on approaches which I consider to be much better motivated than that one.
I do not have a problem with it in principle; but it would imply that there are uncountably many.
Yes, those two things seem roughly equivalent.
The reason you can’t think of a superposition as just a sort of continuum without genuine parts, is that the part of reality we’re observing here is objectively differentiated from what it is not.
I’m not entirely sure where you are going with this objective difference thing. The difference seems to just be that this is the part where the configurations that are us happen to be. Let’s see… say the universal wave function was represented with rock’s in an infinitely large desert. There are (assuming a non-obfuscated wave function representation) some rocks which, if moved, would change the part of the representation which is us. There are others which when moved wouldn’t change us at all—they’d change other stuff. The universe emulator could go paint those rocks a different color if he was so inclined. That’s the only ‘objective’ difference that I expect or require. Do you require more than that? (I sincerely do not understand what you mean by objective here and so wonder if that would satisfy you.)
Uncountably many distinct branches, each duplicated uncountably many times—at least it meets my criteria for a well-formed multiverse theory (the branches can be objectively individuated, and they have a cardinality), but it’s very extravagant metaphysically.
That seemed well formed. I’m not sure that it is extravagant metaphysically. It just seems like math that could be how the universe is. The extravagance all seems to be in the stories we try to tell ourselves about the math based on our intuitions. That is, it doesn’t seem like an especially complicated way for reality to be—it just seems weird to us because of the simplified models that we’ve been working with for convenience up till now.
I’m planning a post on forms of Many Worlds that I do think are well-defined, that will focus on approaches which I consider to be much better motivated than that one.
I’d be curious. No doubt there would be some folks complaining that lesswrongians are overstepping their bounds again into physics territory that is off limits to them but I’d enjoy reading anyhow.
I do not have a problem with it in principle; but it would imply that there are uncountably many.
The reason you can’t think of a superposition as just a sort of continuum without genuine parts, is that the part of reality we’re observing here is objectively differentiated from what it is not. Even if the specific branch you see around you is just part of a continuum, it must be a continuum made of parts that each have a distinct enough existence to, e.g., host an observer in a definite state. This means they can be counted (or have a cardinality), and so the only way to get a real-valued weighting is if there are continuum-many of them.
Something that I strongly suspect, but which I’m not 100% sure about, is that if branch A is supposed to be x times more likely than branch B, x not a rational number, then there must be uncountably many copies of A, and uncountably many copies of B, with the A-set being x times bigger than the B-set, according to some natural measure. The alternative would be to say that A exists once, B exists once; they’re both embedded in a continuum of branches, every member of which only exists once; but the measure is non-uniform for some reason. But I think this is another version of the “A exists more than B exists” fallacy. Formally we can write down a non-uniform measure, but what it actually means is that we are counting some branches for more than others, and the only way to justify that is to suppose that the branches in question are duplicated, in proportion to the extra factor.
Uncountably many distinct branches, each duplicated uncountably many times—at least it meets my criteria for a well-formed multiverse theory (the branches can be objectively individuated, and they have a cardinality), but it’s very extravagant metaphysically. I’m planning a post on forms of Many Worlds that I do think are well-defined, that will focus on approaches which I consider to be much better motivated than that one.
Yes, those two things seem roughly equivalent.
I’m not entirely sure where you are going with this objective difference thing. The difference seems to just be that this is the part where the configurations that are us happen to be. Let’s see… say the universal wave function was represented with rock’s in an infinitely large desert. There are (assuming a non-obfuscated wave function representation) some rocks which, if moved, would change the part of the representation which is us. There are others which when moved wouldn’t change us at all—they’d change other stuff. The universe emulator could go paint those rocks a different color if he was so inclined. That’s the only ‘objective’ difference that I expect or require. Do you require more than that? (I sincerely do not understand what you mean by objective here and so wonder if that would satisfy you.)
That seemed well formed. I’m not sure that it is extravagant metaphysically. It just seems like math that could be how the universe is. The extravagance all seems to be in the stories we try to tell ourselves about the math based on our intuitions. That is, it doesn’t seem like an especially complicated way for reality to be—it just seems weird to us because of the simplified models that we’ve been working with for convenience up till now.
I’d be curious. No doubt there would be some folks complaining that lesswrongians are overstepping their bounds again into physics territory that is off limits to them but I’d enjoy reading anyhow.