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Comment by wongarsu | Hacker News Reader

Except for quantum mechanics. We can compute probabilities perfectly, but the actual outcome of any one event (e.g. the destination of any one photon) is unpredictable.

Any attempts to explain quantum mechanics as being deterministic require faster-than-light communication and are generally seen as unlikely [1] (unless we are in a simulation and there's a global random number generator, of course).

You can buy PCIe cards exploiting this for random number generation [2]

1: https://en.wikipedia.org/wiki/Hidden-variable_theory

2: https://www.idquantique.com/random-number-generation/product...

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The Many-Worlds Interpretation is a local (no FTL) and deterministic theory, though it works differently than what most people think of when they hear "deterministic theory of physics". Every possible outcome of a random quantum event occurs. (Technically the outcome space is continuous instead of discrete, but it's easier to talk about discrete outcomes.) If a human observes a random quantum event (which happens constantly), then there will be a separate version of the person for each outcome who observes that outcome.

However, even with a deterministic universe, there's still true randomness from the perspective of people in the universe. If you flip a quantum coin (that's appropriately set up to have a 50% chance either way and its output is dependent on some quantum random events), then it's impossible even in concept to predict which way it will land, because after the flip, there will be one version of you that sees it land heads and another version of you that sees it land tails.

What's your definition of unpredictable & random?

I'm interested because you write off quantum mechanics as unlikely to be deterministic. When everything being deterministic is more realistic and from scientific understanding of systems working in nature.

Contrary to determinism would be true magic. Having a force without any cause. That just feels like lack of understanding.

> Contrary to determinism would be true magic.

I used to think like this, that somehow underneath the apparent randomness of quantum mechanics there is a deterministic process that is either being sampled too slowly or too granular to see its fundamentally discrete nature.

Unfortunately that is not the case. No experiment has ever measured a significant deviance from truly random for a quantum-mechanical experiment. We have no better description for the outcome of quantum experiments than the probability distributions that come out of the Schroedinger equation.

Welcome to theory from 80 years ago, backed by every single experiment ever done in the intervening time.

The bottom of our universe is math manipulating probability equations, and we can't see beneath it.

Sorry. I was hopeful too.

> Unfortunately that is not the case.

The thing is we cannot say it's not the case. I used to think like you as well.

That's the disturbing problem I witness with people writing off quantum mechanics as not being deterministic. Magic as an adult is known to be trickery and only seems to be magic when lacking understanding of what forces is resulting in the trickery.

Super determinism is a situation where we could be actually witnessing determinism from quantum mechanics but similar to what we believe is true randomness and cannot be observed for the forces causing it.

The only thing I'm hopeful for is witnessing in my life a way to explain how something cannot be deterministic with real understanding. Besides people just thinking it must be random and if I spend hours all day thinking about this it seems like it cannot happen because it's an impossibility.

> Besides people just thinking it must be random and if I spend hours all day thinking about this it seems like it cannot happen because it's an impossibility.

It's not just people thinking it must be random or it isn't random. Literally every single experiment ever conducted has failed to turn up any evidence of a deterministic process underlying the apparent randomness of quantum mechanics. We can't keep this hope alive indefinitely just because our thinking is warped by everyday experience appearing classical and discrete. We have absolutely no reason to demand our universe be deterministic, and every reason to conclude it isn't. We need to reject the idea that our universe is intuitive to human minds.

For example, Bell's Theorem rules out local hidden variables. General Relativity says spacetime is warped in non-visualizable ways and that simultaneity is not even universal. That should be enough of a mindfuck for us to discard our puny human understanding of things, yet we don't.

Bell's theorem doesn't rule out super determinism. So it's kind of whatever you want to believe (kind of situation) when it comes to not being able to have proof one side or the other. I upvoted your post btw.

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