This post isn’t about my theories. It should not take an abnormal conceptual effort to reject the proposition that “there are many worlds, but no particular number of them”. It is, on the face of it, illogical, like a round square. It doesn’t express a coherent idea. Should we spend time thinking about the possibility that true things are also false, or that reality is an elephant, or that time is actually running backwards? Maybe it’s a good cognitive workout to think about such things, and just maybe, on a very rare occasion, nonsense will turn out to be sense. But hopefully you can see my point—that this dispute is on a different level from a dispute over whether it’s reasonable to believe that there are other worlds, ten dimensions, disembodied souls, and other such hypotheses. Those hypotheses may be strange, but they are unquestionably logically well-formed. They have a meaning.
The same can not be said for “no definite number of worlds”. If something exists, it can be counted (or given a cardinality, if it is infinite). The defense of vagueness about branches rests on analogies like the ink blot, but it’s a false analogy, because the ink blot is “created” by perception, by definition, or by a rule. This is why I engaged in my speculative psychoanalysis about the imperial ego of the abstract theorist, who creates a map of reality which remains unfolded before their mind’s eye, and who never gets around to considering whether the correctness of the map is consistent with the fact of their own existence.
The existence of the world (the existence of “a” world, the existence of “this world”) is not a matter of definition, it is an elemental fact, and you can’t treat its existence as resulting from the mere mental projection of a boundary onto an underlying continuum. If your underlying-continuum theory of reality doesn’t contain objectively distinct structures, one of which corresponds to observed reality, then that is a problem for your theory, it’s not a revelation about reality.
you have never in all your posts and comments addressed the fact that all the issues with probability and personal identity in Many Worlds can apply to classical systems too
In fact I have, but perhaps not recently. This very same reasoning also invalidates various attempts to be vague about the number of selves, or to have fractionally existing selves; but that is another unpopular conclusion (unpopular on LW), and one which perhaps experiences even more resistance than the argument against vagueness about worlds.
This is an interesting discussion, but this claim struck me as odd:
If something exists, it can be counted (or given a cardinality, if it is infinite).
This seems like an open philosophical question. Clearly you are a finitist of some sort, but as far as I know it hasn’t been empirically verified that real numbers don’t exist. Certainly continuous functions are widely employed in physics, but whether all of physics can be cast into a finitist framework is an open question last I checked.
So your assertion above doesn’t seem firmly justified, as uncountable entities could exist. I have no informed opinion as to whether worlds must be countable or can be uncountable. It certainly seems like they ought to be countable, since the total number of particle configurations in the universe at any given moment in time seems finite, but that’s just an uneducated guess.
I am not a finitist. There are cardinals for uncountable sets. I was objecting to people who say things like (page 16) “how many worlds there are” is a “non-question”.
This post isn’t about my theories. It should not take an abnormal conceptual effort to reject the proposition that “there are many worlds, but no particular number of them”. It is, on the face of it, illogical, like a round square. It doesn’t express a coherent idea. Should we spend time thinking about the possibility that true things are also false, or that reality is an elephant, or that time is actually running backwards? Maybe it’s a good cognitive workout to think about such things, and just maybe, on a very rare occasion, nonsense will turn out to be sense. But hopefully you can see my point—that this dispute is on a different level from a dispute over whether it’s reasonable to believe that there are other worlds, ten dimensions, disembodied souls, and other such hypotheses. Those hypotheses may be strange, but they are unquestionably logically well-formed. They have a meaning.
The same can not be said for “no definite number of worlds”. If something exists, it can be counted (or given a cardinality, if it is infinite). The defense of vagueness about branches rests on analogies like the ink blot, but it’s a false analogy, because the ink blot is “created” by perception, by definition, or by a rule. This is why I engaged in my speculative psychoanalysis about the imperial ego of the abstract theorist, who creates a map of reality which remains unfolded before their mind’s eye, and who never gets around to considering whether the correctness of the map is consistent with the fact of their own existence.
The existence of the world (the existence of “a” world, the existence of “this world”) is not a matter of definition, it is an elemental fact, and you can’t treat its existence as resulting from the mere mental projection of a boundary onto an underlying continuum. If your underlying-continuum theory of reality doesn’t contain objectively distinct structures, one of which corresponds to observed reality, then that is a problem for your theory, it’s not a revelation about reality.
In fact I have, but perhaps not recently. This very same reasoning also invalidates various attempts to be vague about the number of selves, or to have fractionally existing selves; but that is another unpopular conclusion (unpopular on LW), and one which perhaps experiences even more resistance than the argument against vagueness about worlds.
This is an interesting discussion, but this claim struck me as odd:
This seems like an open philosophical question. Clearly you are a finitist of some sort, but as far as I know it hasn’t been empirically verified that real numbers don’t exist. Certainly continuous functions are widely employed in physics, but whether all of physics can be cast into a finitist framework is an open question last I checked.
So your assertion above doesn’t seem firmly justified, as uncountable entities could exist. I have no informed opinion as to whether worlds must be countable or can be uncountable. It certainly seems like they ought to be countable, since the total number of particle configurations in the universe at any given moment in time seems finite, but that’s just an uneducated guess.
I am not a finitist. There are cardinals for uncountable sets. I was objecting to people who say things like (page 16) “how many worlds there are” is a “non-question”.