True randomness in QM

[ignoramus]

I believe there is no such thing as randomness.

If we are to analyse things to the nth degree, we would be able to accurately predict the behaviour of all things.
I don't believe nature has a built in RNG.

How granular do we want or can go?
Predict genetic mutations, angle and direction of blades of grass growing in a field?

On a smaller scale, smacking a rack of billiard balls? It's the butterfly effect everywhere.
One bees dick off and the ball at the end of the chain of collisions will just miss going into the hole by another bees dick!

Can someone tell me if we can predict the outcome of a complex RNG?
Surely we can? We programmed the bastard?

Disclaimer: no bees genitals were harmed in the making of this post!

[Fireball]

I believe there is no such thing as randomness.

If we are to analyse things to the nth degree, we would be able to accurately predict the behaviour of all things.
I don't believe nature has a built in RNG.

How granular do we want or can go?
Predict genetic mutations, angle and direction of blades of grass growing in a field?

On a smaller scale, smacking a rack of billiard balls? It's the butterfly effect everywhere.
One bees dick off and the ball at the end of the chain of collisions will just miss going into the hole by another bees dick!

Can someone tell me if we can predict the outcome of a complex RNG?
Surely we can? We programmed the bastard?

Disclaimer: no bees genitals were harmed in the making of this post!

Random number generators aren't random. Any time an algorithm is used, much of the randomness is removed. I think that there are newer methods which are better than what I used to program computers for Monte Carlo analysis of EM propagation errors on near field antenna ranges, back in y2k. I left that gig in y2k and haven't written a line of FORTRAN since.

[TheRealJoeFish]

If we are to analyse things to the nth degree, we would be able to accurately predict the behaviour of all things.

That's part of the issue, though: that statement makes perfect sense, and seems like it should be true, and has to be true, and in our every-day lives at the scales we work with it is true. But, universally, it *may not be true*. It's quite possible that an impossibility to predict, even with perfect knowledge, is a built in bugfeature in the universe

[Edwardo Piet]

I like how everyone just ignored the part about bee genitals as if it was completely normal and expected within quantum mechanics lol.

"Queerer than we can suppose"

There are many bees genitals within the mystery of the cosmos.

[Cato]

I think it's absolutely adorable when people gain a bit of knowledge regarding 'Quantum', but have no appreciation for a Planck length.

[Alex K]

I think it's absolutely adorable when people gain a bit of knowledge regarding 'Quantum', but have no appreciation for a Planck length.

It's just too small, you know...

[ErGingerbreadMandude]

True randomness as I understand is a variable in existence without any influence from other variables. If such a variable exists then we can say that true randomness is real, am I right?

Essentially that means creation because only creation can create a truly independent variable.
Since creation is impossible nothing we see are a product of randomness.

So true randomness is impossible.

[Alex K]

True randomness as I understand is a variable in existence without any influence from other variables. If such a variable exists then we can say that true randomness is real, am I right?

Essentially that means creation because only creation can create a truly independent variable.

Huh? What is "creation"...

Since creation is impossible nothing we see are a product of randomness.

...and why is it impossible?

[RozKek]

I think it goes too far to say that the consensus is that #2 true randomness is at the bottom of Quantum uncertainty. There is a consensus to use something like the Copenhagen interpretation (or should I say prescription) for all practical calculations in order to not get bogged down with metaphysical questions. That means that virtually everyone, for pragmatic reasons, uses a prescription to calculate results which does not contain rhe additional information (so called hidden variables) which would uniquely determine the result of a measurement involving quantum uncertainty. I believe people don't necessarily choose to do that because they believe in their hearts that there must be true randomness at the bottom of QM, but rather because it makes no difference for the result of any calculation if we included a (usually more complicated) deterministic description with hidden variables : we don't know the values of these hidden variables anyways, and they are constructed precisely such that ignorance of the hidden variable reproduces the same statistical distribution as true quantum randomness. Someone who "believes" in a deterministic interpretation of qm will generally still use the copenhagen or similar prescriptions to calculate concrete results because it is simple.

Doesn't Bell's theorem rule out hidden variables? And if we theoretically were to replay the universe many times would the outcomes be the exact same? If so, doesn't that imply that true randomness doesn't exist?

[Alex K]

I think it goes too far to say that the consensus is that #2 true randomness is at the bottom of Quantum uncertainty. There is a consensus to use something like the Copenhagen interpretation (or should I say prescription) for all practical calculations in order to not get bogged down with metaphysical questions. That means that virtually everyone, for pragmatic reasons, uses a prescription to calculate results which does not contain rhe additional information (so called hidden variables) which would uniquely determine the result of a measurement involving quantum uncertainty. I believe people don't necessarily choose to do that because they believe in their hearts that there must be true randomness at the bottom of QM, but rather because it makes no difference for the result of any calculation if we included a (usually more complicated) deterministic description with hidden variables : we don't know the values of these hidden variables anyways, and they are constructed precisely such that ignorance of the hidden variable reproduces the same statistical distribution as true quantum randomness. Someone who "believes" in a deterministic interpretation of qm will generally still use the copenhagen or similar prescriptions to calculate concrete results because it is simple.

Doesn't Bell's theorem rule out hidden variables?

No, it's only a statement about the properties of the hidden variables. The fact that the Bell inequalities are obviously violated in Nature only rules out local theories of hidden variables - This means that one cannot write down a quantum theory in which the hidden variables are a property of, say, individual particles only, without running afoul of observations. If you for example make an experiment where two quantum randomly polarized, but entangled photons are sent out in opposite directions and send them to two far apart polarization detectors, a hidden variable which deterministically determines the outcome of the polarization measurement on one side must depend on the setting of the polarimeter (or an equivalent value) on the other side. That's exactly the kind of game Bell plays in his papers.

And if we theoretically were to replay the universe many times would the outcomes be the exact same? If so, doesn't that imply that true randomness doesn't exist?

That question is kind of equivalent to the question whether true randomness exists - or in other words, whether the state of the universe at one point in time uniquely determines its future development. It is not known.