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I've always wondered if this (kinda widespread?) theory stems from most people thinking that "infitnity" includes every possible option, which is not true. (I'

by rmi_ 1y ago

I've always wondered if this (kinda widespread?) theory stems from most people thinking that "infitnity" includes every possible option, which is not true. (I'm a layman, too)

druskacik 1y ago
Doesn't infinity include every possible option (possible meaning that it can happen within rules of physics)? If the model of the universe is one where events are happening with some probability, then if the probability is nonzero and the number of universes is infinite, then the event should happen in some of the universes. (Still a layman, though.)
dzdt 1y ago
Mathematician here, so educated layman on the physics but expert on infinity if you like. Mathematically, "infinity" doesn't imply every possible option. But in terms of quantum physics, yes it kind of does include every possible option. There is a kind of joke classroom exercise in quantum physics class to calculate the probability that a piano would instantaneously rematerialize a meter away from its previously observed location. Its 10^-[ ridiculous number] but still thats not zero. The size of physical reconfiguration of a person's brain to cause them to break out singing is a much smaller deviation so comparatively likely. So 10^-[somewhat less ridiculous nunber]
- XorNot 1y ago
  The bigger issue with all those non-zero probabilities is they're meaningless while you still experience actual time as a human...but become pretty damn significant when you experience no time after you die. So tiny probabilities become essentially guarantees unless the heat death of the universe is so thorough as to erase the slight probability that the whole thing pops back into existence.
  - cuttothechase 1y ago
    Isn't it cold death of the universe?
mhl47 1y ago
This is related to the question whether a system/the universe is ergodic (among other properties changing energy, space).
- pmarreck 1y ago
  What are examples of things that are NOT ergodic?
  - mhl47 1y ago
    I think an example would be the two body problem. It stays on an eccentricity. So it does not explore different eccentricities although they can have the same total energy. (But I just looked that up too because this concept is mostly used/assumes in statistical physics)

by rmi_ 1y ago

I've always wondered if this (kinda widespread?) theory stems from most people thinking that "infitnity" includes every possible option, which is not true. (I'm a layman, too)

druskacik 1y ago

Doesn't infinity include every possible option (possible meaning that it can happen within rules of physics)? If the model of the universe is one where events are happening with some probability, then if the probability is nonzero and the number of universes is infinite, then the event should happen in some of the universes. (Still a layman, though.)

dzdt 1y ago

Mathematician here, so educated layman on the physics but expert on infinity if you like. Mathematically, "infinity" doesn't imply every possible option. But in terms of quantum physics, yes it kind of does include every possible option. There is a kind of joke classroom exercise in quantum physics class to calculate the probability that a piano would instantaneously rematerialize a meter away from its previously observed location. Its 10^-[ ridiculous number] but still thats not zero. The size of physical reconfiguration of a person's brain to cause them to break out singing is a much smaller deviation so comparatively likely. So 10^-[somewhat less ridiculous nunber]

XorNot 1y ago
The bigger issue with all those non-zero probabilities is they're meaningless while you still experience actual time as a human...but become pretty damn significant when you experience no time after you die. So tiny probabilities become essentially guarantees unless the heat death of the universe is so thorough as to erase the slight probability that the whole thing pops back into existence.
- cuttothechase 1y ago
  Isn't it cold death of the universe?

mhl47 1y ago

This is related to the question whether a system/the universe is ergodic (among other properties changing energy, space).

pmarreck 1y ago
What are examples of things that are NOT ergodic?
- mhl47 1y ago
  I think an example would be the two body problem. It stays on an eccentricity. So it does not explore different eccentricities although they can have the same total energy. (But I just looked that up too because this concept is mostly used/assumes in statistical physics)