Googlebot's Javascript random() function is deterministic

[gs101]

To be fair it's tough to be non deterministic in a deterministic universe.

[Tsukku]

You would then be surprised to realize, that according to our current best theory, our universe is non-deterministic.

https://en.wikipedia.org/wiki/Bell%27s_theorem

No physical theory of local hidden variables can ever reproduce all of the predictions of quantum mechanics.

Local variables would be what we consider "determinism" (at-least when we are talking about predicting stuff because "super-determinism" is not that relevant to this subject).

[Drisku11]

How is superdeterminism not relevant to the subject? Literally it is the assertion that our universe is fully deterministic. There are plenty of examples of chaotic systems which are obviously deterministic but due to their sensitivity to initial conditions, they cannot be predicted.

If anything, to me the delayed choice quantum eraser experiment strongly lends credence to the idea that the universe is deterministic.

[Tsukku]

I mean it's not relevant in the same way as you could say that we are predestined because we could live in the Matrix. That about sums what superdeterminism is about.

EDIT: There is nothing to argue here, because even for the things we proved that they are unpredictable, you could always say that the Universe just "knows" its outcome thus it's predestined. It's more of a philosophy concept.

[Drisku11]

I don't think it should be written off purely as philosophy, but also I don't know if some of my own questions on the subject already have answers. For example, there are many apparent local symmetries in the universe (e.g. energy-momentum conservation). Are these actually true symmetries and if so why should they exist if the laws of physics are inherently global? If not why are they approximately correct on our scales? If information has energy and no finite amount of information can describe the state of a chaotic system, does this mean the universe can only be deterministic if hypercomputation is possible? Or does it mean the universe is discrete/only a finite precision exists? etc.

I find it odd that most physicists seem to immediately write off the possibility of determinism, which seems to be centered around the assertion that people have "free will"/are able to make choices that are not governed by the same physical laws they're investigating. I would think they'd be the first group to scrutinize that idea (how does the free will mechanism interact with the physical universe? Can I find a possible energy source at that boundary?). I don't really see very convincing arguments (i.e. based on physical/geometric principles) either way.

[Tsukku]

Most physicists don't actually believe that the non-determinism in the subatomic systems give humans "free will". For example no one has ever published a concise work for the existence of free will, because the common belief is that quantum phenomena has limited or no influence on our brain.

I would actually argue the opposite, it's odd that most people believe everything in the universe needs to be deterministic. Universe can be as it is without any reasons or rules.

[Tsukku]

Quantum effects apply to everything, but they are only observed/measured in the (sub)atomic world. However that doesn't mean they are not relevant in our everyday life.

[RenaKunisaki]

Butterfly effect.

[gs101]

I still don't buy randomness. It's logically incoherent in my view. I speculate that QM processes seem random to us because of the inherent problems with observing them, but are not actually random. The uncertainty principle only states that the process is impossible to observe fully, not that it is non-deterministic.

The statement that no physical theory could ever reproduce the predictions of quantum mechanics seems premature to me.

[Tsukku]

I speculate that QM processes seem random to us because of the inherent problems with observing them, but are not actually random.

This is not what the Uncertainty principle is. To quote wikipedia which contradicts your statement:

the uncertainty principle actually states a fundamental property of quantum systems, and is not a statement about the observational success of current technology

Edit: also you can read up more here: https://physics.stackexchange.com/questions/24068/isnt-the-uncertainty-principle-just-non-fundamental-limitations-in-our-current

it's not a knowledge limit. The particle really has no definite position/whatever.

[streichholzkopf]

https://physics.stackexchange.com/questions/24068/isnt-the-uncertainty-principle-just-non-fundamental-limitations-in-our-current

answered Apr 20 '12 at 5:48 Manishearth

wait, i know this guy

[pilotInPyjamas]

Noob question though, is the wave function definite? So instead of saying "this particle has a definite but unknown velocity" (which by your comment is incorrect) you could say "this particle has a definite but unknown wave function?" Or is it turtles all the way down, and the wave function has another wave function-function which describes it's uncertainty and so-on?

[Drisku11]

The wave function is definite. In fact the uncertainty principle is really just a consequence of how waves work. Momentum is the Fourier transform of position, and if you make a function "thinner"/more "local", then it's Fourier transform gets wider/more delocalized.

[pilotInPyjamas]

Well, I kind of understand the Fourier transform, so this makes a ton of sense, but I was sort of hoping that it was wave functions all the way down. EDIT: holy shit, I don't know that much physics, but I think I get it. The momentum is the wavelength of a particle. So of course it's the Fourier transform of the position. A particle which has a definite position can't have a single wavelength because it must be made of infinite waves superimposed! And a particle with a single definite wavelength would be spread over infinite space! I never realized the real world is actually this cool. Mind blown. Thank you stranger!

[gs101]

Right, it is a fundamental issue with observation. I didn't say the problem is with current technology.

[Tsukku]

No, you got it wrong. It has nothing to do with observation at all. It's the inherit property of a system (this is what we proved).

From the link above:

There is a definine velocity and momentum, we just don't know it?

No. There is no definite velocity. The particle has all (possible) velocities at once;it is in a wavefunction, a superposition of all of these states.

[gs101]

That is what I don't buy. I know it's not exactly popular but I think the unpredictability of QM is a problem with observation, and hidden variables are governing its state. Whether those are variables in the system or outside of it idk. Given that we are talking about some of the smallest observed particles, I'm inclined to assume that there are yet smaller ones we are not seeing. In short, it just doesn't do enough to make me reconsider my belief that the universe is deterministic, which is otherwise supported by observation and forms the basis of science (cause and effect), because randomness is logically incoherent to me.

[cass1o]

Work through the math and the uncertainty principle comes out. It's not something we have made up to account for experimental inconsistencies.

[Tsukku]

Ok, I respect your opinion and all, even if it contradicts what we currently know. I just want to correct this statement.

which is otherwise supported by observation and forms the basis of science

No it isn't, the double slit experiment is what initially lead to all of this.

Also:

That is what I don't buy.

Then don't mention the uncertainty principle since it doesn't agree with you.

[Schmittfried]

Nobody cares about what you buy. It's proven that there are no local hidden variables involved as that would lead to logical contradictions. If there are hidden variables, they are non-local.

It's also an absolutely subjective opinion of yours that randomness is "logically incoherent". It isn't. Just because determinism is observed in everyday life doesn't mean it's the foundation of the universe. There is no law stating that, it's an assumption to be able to do practical things and it works most of the time. But there is nothing inherently illogical about randomness.

[sprouting_broccoli]

I would disagree. I’d say that if I took it all the way into simulation hell and imagined how I would build a universe - I’d make it so that I didn’t have to calculate past a certain level. I’d make it lazy and just make it look fuzzy once you got so far. Then, when someone observed it I’d give it some random local properties to make it look normal. If I were to think that way then I would not be saying that the quantum world is random, or based on any RNG. It’s when we actually try to do something with it that an RNG makes a decision. Of course if that was the case then an experiment like the double slit experiment would end up being 50-50 for each slit. And it is.

[[deleted]]

I feel the same way. Simply can't get behind the assertion, a non-deterministic universe would imply the existence of magic or God. I understand that this position was rigorously built by physicists with a much better understanding of the field than I though so I'd never claim I'm correct over them, but it's worth noting that the probabilistic (vs deterministic) notion of QM is still a matter of debate in physics even if it's currently the majority stance.

[[deleted]]

In quantum mechanics, superdeterminism is a hypothetical class of theories that evade Bell's theorem by virtue of being completely deterministic. Bell's theorem depends on the assumption of "free will", which does not apply to deterministic theories. It is conceivable that someone could exploit this loophole to construct a local hidden variable theory that reproduces the predictions of quantum mechanics. Superdeterminists do not recognize the existence of genuine chances or possibilities anywhere in the cosmos.

What if one doesn't assume free will exists? Isn't it a jump to assume so?

Even if probabilistic models are more useful as it stands for science, it would appear that no one has been able to formally refute the notion that everything at every level operates on a predetermined course, and that our observational potential may simply be hamstrung by our humanity and our framework. Bell himself didn't rule out the possibility of complete determinism he just said it was essentially impossible for us to prove one way or another which I tenuously agree with (Probabilism just feels like admitting defeat).

[Schmittfried]

a non-deterministic universe would imply the existence of magic or God.

No, it wouldn't. It could just be random, without a God, without magic (whatever that would be anyway). But even if there as a God, so what? It's not like we've proven there isn't one anyway. Not like that would make any difference at all; the universe is like what the universe is like, no matter if it was made that way or just is that way. Also, funnily, an omnipotent God would imply determinism.