5 ms·

Is that counterintuitive? There's a finite number of electrons in a human brain (which fits in a space of size 1m^3), and information takes time to propagate ac

Is that counterintuitive? There's a finite number of electrons in a human brain (which fits in a space of size 1m^3), and information takes time to propagate across any distance, and humans die before 150 years; this all gestures at there being not only finitely many personality types and ways of thinking, but finitely many human mind states.

ainoobler 2y ago
I guess that means reincarnation is real.
- Smaug123 2y ago
  Assuming you're not trolling: nope, that would be an empirical question of how many brain states ever actually arise in the world during the time humans exist, and how much space and time it takes to maintain a given brain state. The universe is currently expected to stop being able to support human life at some point in the future, so the pigeonhole principle argument requires some physical parameters to be known before you can apply it; and even if the pigeonhole principle did apply, you still can't know by that argument whether any given brain-state is repeated (and if so, how many times). Things which you can deduce using only mathematics, and no physical data, are necessarily extremely weak statements about reality.
  - Y_Y 2y ago
    If you are a mental clone but uncausally linked then is that still reincarnation?
  - ainoobler 2y ago
    The universe is mathematical, all we can ever know about it is mathematical.
    - Smaug123 2y ago
      A very strong empirical statement about the nature of reality, and a strong statement about the nature of mathematics, neither of which everyone agrees with! (What will your reply be if we discover a halting oracle at the centre of the galaxy? Mathematics doesn't forbid that: the Church-Turing thesis is an empirical statement, and it's the empirical scientific law of induction which is what tells us that we're extremely unlikely to find a halting oracle.) But you've missed the point: even assuming that mathematics can perfectly model the universe, you cannot use weak physical hypotheses ("human brains are finite, there is an injection from human mind-states into human brains") and fully general mathematics (the pigeonhole principle) to derive such specific strong truths as "a particular human mind-state is repeated in a predictable way in the universe". You can at best derive general truths such as "at least one human mind-state is repeated at least once, somewhere", if the universe happens to have its physical parameters set in such a way that the pigeonhole principle holds.
  - throwaway43567 2y ago
    We do have https://en.m.wikipedia.org/wiki/Boltzmann_brain https://en.m.wikipedia.org/wiki/Boltzmann_brain That may appear every (10^10)^50 years according to https://en.m.wikipedia.org/wiki/Timeline_of_the_far_future https://en.m.wikipedia.org/wiki/Timeline_of_the_far_future
Y_Y 2y ago
But there may yet be more brain states than number of possible thoughts by the finite humans.
- Smaug123 2y ago
  Oh, 100%, it seems extremely unlikely that multiple brain states in this sense don't code for the same thought! If nothing else, you could only avoid that with an absurdly precise definition of "brain"; any practical definition of "brain" is very likely to include matter that is physically irrelevant to at least some thoughts. I hedged with "1m^3" because the argument goes through even if you take the entire body to be the brain.

ainoobler 2y ago

I guess that means reincarnation is real.

Smaug123 2y ago
Assuming you're not trolling: nope, that would be an empirical question of how many brain states ever actually arise in the world during the time humans exist, and how much space and time it takes to maintain a given brain state. The universe is currently expected to stop being able to support human life at some point in the future, so the pigeonhole principle argument requires some physical parameters to be known before you can apply it; and even if the pigeonhole principle did apply, you still can't know by that argument whether any given brain-state is repeated (and if so, how many times). Things which you can deduce using only mathematics, and no physical data, are necessarily extremely weak statements about reality.
- Y_Y 2y ago
  If you are a mental clone but uncausally linked then is that still reincarnation?
- ainoobler 2y ago
  The universe is mathematical, all we can ever know about it is mathematical.
  - Smaug123 2y ago
    A very strong empirical statement about the nature of reality, and a strong statement about the nature of mathematics, neither of which everyone agrees with! (What will your reply be if we discover a halting oracle at the centre of the galaxy? Mathematics doesn't forbid that: the Church-Turing thesis is an empirical statement, and it's the empirical scientific law of induction which is what tells us that we're extremely unlikely to find a halting oracle.) But you've missed the point: even assuming that mathematics can perfectly model the universe, you cannot use weak physical hypotheses ("human brains are finite, there is an injection from human mind-states into human brains") and fully general mathematics (the pigeonhole principle) to derive such specific strong truths as "a particular human mind-state is repeated in a predictable way in the universe". You can at best derive general truths such as "at least one human mind-state is repeated at least once, somewhere", if the universe happens to have its physical parameters set in such a way that the pigeonhole principle holds.
- throwaway43567 2y ago
  We do have https://en.m.wikipedia.org/wiki/Boltzmann_brain https://en.m.wikipedia.org/wiki/Boltzmann_brain That may appear every (10^10)^50 years according to https://en.m.wikipedia.org/wiki/Timeline_of_the_far_future https://en.m.wikipedia.org/wiki/Timeline_of_the_far_future

Y_Y 2y ago

But there may yet be more brain states than number of possible thoughts by the finite humans.

Smaug123 2y ago
Oh, 100%, it seems extremely unlikely that multiple brain states in this sense don't code for the same thought! If nothing else, you could only avoid that with an absurdly precise definition of "brain"; any practical definition of "brain" is very likely to include matter that is physically irrelevant to at least some thoughts. I hedged with "1m^3" because the argument goes through even if you take the entire body to be the brain.