From what I understand, the Many Worlds interpretation of quantum physics is deterministic—everything possible does happen. It only seems probabilistic from inside one of the worlds. You can’t predict the outcome of a quantum event, since different instances of you will observe all possible outcomes. Take with a grain of salt, since Many Words is unproven (possibly unprovable?) and my understanding is surface level at best.
On the macro level, a coin toss of a fair coin becomes predictable if you have perfect knowledge and enough computational power. The point of probabilities and statistics is that they give us the rules for mapmaking with imperfect knowledge and limited computational power.
In short, a deterministic universe doesn’t lead to certainty in our maps—hence “probability may be a “subjective state of belief”, but the laws of probability are harder than steel.”
A common reaction to QM is that it doesn’t matter since quantum randomness will
never manifest itself at the macroscopic level—that is, in the world of sticks and
stones we can see with the naked eye. An appeal is usually made to the “law of large numbers”,
according to which random fluctuations at the atomic (or lower level) will cancel
each other out in a macroscopic object, so that what is seen is an averaged-out behaviour
that is fairly predictable.
Something like this must be happening in some cases, assuming QM is a correct
description of the micro-world, or there would not even be an appearance of
a deterministic macro-world. Since deterministic classical physics is partially correct, there
must be a mechanism that makes the QM micro-world at least approximate to the
classical description.
However, it it were the case that all macroscopic objects behaved in a 100% deterministic fashion,
there would be no evidence for QM in the first place—since all scientific apparatus is in the macro-world !
A geiger-counter is able to amplify the impact of a single particle into an audible click. Richard Feynman suggested
that if that wasn’t macroscopic enough, you could always amplify the signal further and use it to set off a stick of dynamite!
It could be objected that these are artificial situations. However, because there is a well-known
natural mechanism that could do the same job: critical dependence on initial conditions, or classical chaos.
Oops! Beautiful. Your comment described my implicit assumptions probably better than I could, before showing me the error in my thinking. I will have to try and accept the consequences of QM on a deeper level. “It all adds up to normality” is a weak consolation, if you happen to be far from the median after all. It’s also becoming blindingly obvious I should finally just sit down and read Feynman.
Huh. The universe is non-deterministic after all. Like, for real. I knew May was going way too peacefully.
From what I understand, the Many Worlds interpretation of quantum physics is deterministic—everything possible does happen. It only seems probabilistic from inside one of the worlds. You can’t predict the outcome of a quantum event, since different instances of you will observe all possible outcomes. Take with a grain of salt, since Many Words is unproven (possibly unprovable?) and my understanding is surface level at best.
On the macro level, a coin toss of a fair coin becomes predictable if you have perfect knowledge and enough computational power. The point of probabilities and statistics is that they give us the rules for mapmaking with imperfect knowledge and limited computational power.
In short, a deterministic universe doesn’t lead to certainty in our maps—hence “probability may be a “subjective state of belief”, but the laws of probability are harder than steel.”
A common reaction to QM is that it doesn’t matter since quantum randomness will never manifest itself at the macroscopic level—that is, in the world of sticks and stones we can see with the naked eye. An appeal is usually made to the “law of large numbers”, according to which random fluctuations at the atomic (or lower level) will cancel each other out in a macroscopic object, so that what is seen is an averaged-out behaviour that is fairly predictable.
Something like this must be happening in some cases, assuming QM is a correct description of the micro-world, or there would not even be an appearance of a deterministic macro-world. Since deterministic classical physics is partially correct, there must be a mechanism that makes the QM micro-world at least approximate to the classical description.
However, it it were the case that all macroscopic objects behaved in a 100% deterministic fashion, there would be no evidence for QM in the first place—since all scientific apparatus is in the macro-world ! A geiger-counter is able to amplify the impact of a single particle into an audible click. Richard Feynman suggested that if that wasn’t macroscopic enough, you could always amplify the signal further and use it to set off a stick of dynamite! It could be objected that these are artificial situations. However, because there is a well-known natural mechanism that could do the same job: critical dependence on initial conditions, or classical chaos.
Oops! Beautiful. Your comment described my implicit assumptions probably better than I could, before showing me the error in my thinking. I will have to try and accept the consequences of QM on a deeper level. “It all adds up to normality” is a weak consolation, if you happen to be far from the median after all. It’s also becoming blindingly obvious I should finally just sit down and read Feynman.
Huh. The universe is non-deterministic after all. Like, for real. I knew May was going way too peacefully.
Edit: Forgot to say: Thank you for that!