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Comment by amelius | Hacker News Reader

> My personal belief is that the deepest things we’ve learned about quantum gravity—including about the Planck scale, and the Bekenstein bound from black-hole thermodynamics, and AdS/CFT—all militate toward the view that the answer is “yes,” that in some sense (which needs to be spelled out carefully!) the physical universe really is a giant Turing machine.

Doesn't the non-determinism of QM in fact say that there's fundamentally an issue with computability?

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Schmidhuber says that there's no evidence for non-determinism (randomness):

https://people.idsia.ch/%7Ejuergen/randomness.html

https://old.reddit.com/r/MachineLearning/comments/2xcyrl/i_a...

> Doesn't the non-determinism of QM in fact say that there's fundamentally an issue with computability?

One take on this that Sabine mentioned in one of her videos is that we simply do not yet understand the full picture of what gives rise to QM. If we did, perhaps it turns out to be deterministic again.

> Doesn't the non-determinism of QM in fact say that there's fundamentally an issue with computability?

I don't see why it should mean that in the theoretical sense. In the sense that it could signal that we are in a simulation that has a precision limitation ie it shows the limit of the computability of the simulation, then that seems quite plausible.

In fact I've argued before that a universe that has a consistent set of (relatively) straightforward rules, with a lot of symmetries, and a precision limit, would probably be hallmarks of a simulated universe. Because it would save on compute assuming that the simulator has vast but finite resources to run the simulation.

I'm a postdoc in theoretical quantum physics and most of my colleagues believe in MWI which is deterministic

Is MWI falsifiable in any way?

I'm not sure. Most likely not with current technology. In my experience the reason most people like it is because a lot of great quantum physics has come out of studying MWI (that is also compatible with all other interpretations), such as a lot of progress in decoherence and things like Quantum Darwinism. I try and keep a distance from these things so I don't know that much about it. I don't work on it directly so my policy is that I won't believe in any particular interpretation unless there is good evidence for it. That said, from what I know about them, MWI is one of the better ones, I certainly prefer it to Bohmian mechanics.

>It’s trivial to falsify EQM — just do an experiment that violates the Schrödinger equation or the principle of superposition, which are the only things the theory assumes. Witness a dynamical collapse, or find a hidden variable.

https://www.preposterousuniverse.com/blog/2014/06/30/why-the...

Non-deterministic Turing machines are computationally equivalent to deterministic ones. Quantum mechanics only causes issues with the practical feasibility of the computation, not its theoretical possibility given unbounded time and storage.

Not a physicist, but I vaguely recall an argument that it might be only non-deterministic from where we stand. Like trying to predict a CSPRNG.

And isn't the fact that the universe seems to be a result of computation in fact just because we are abstracting it with mathematics?

What else would it be but computation? Coming up with something that isn't computation in some form or other is exceedingly hard. I'm not even sure it's meaningfully possible.

Computation call still have non-determinism. For example, the computation gives e.g. 2 possible options at every step (both physically valid). Then a "consciousness" decides which of the 2 options it prefers, and that's the part we'll see and the other part of the tree is simply not observed.

So you can compute it to some extent, just not fully.

That doesn't address what I said at all. If you assert dualism, like what you did here as an attempt to inject "non-computation" all you do is give rise to infinite regress. E.g. how do you propose this "consciousness" would decide in a way that is not itself computation?

"non-determinism of QM".

Think this is still in doubt.

There is the whole branch of physics called 'super determinism' , trying to find the underlying causes of events that look 'undetermined'.

Yes. Do hidden variables and processes exist? The universe could be perfectly deterministic from outside but appear very random here.

It's an open question. No one knows the answer.

That's why I think it's an interesting question.

Personally I find the references to god or theology offensive and distracting. These are perfectly valid questions to ask. They don't imply any kind of biblical god. They don't even imply a creator.

We only fall back to creators because we can't imagine that something, or some set of rules, or some arbitrary process, or whatever might Just Exist.

It's quite possible this is a simulation - in the sense that it's a secondary not a primary reality - that appeared spontaneously, and no one/nothing created it deliberately.

> We only fall back to creators because we can't imagine that something, or some set of rules, or some arbitrary process, or whatever might Just Exist.

Is this to say that we simulate creators? From where I sit, people on both sides seem[1] absolutely sincere that their version of "reality" is the correct one.

[1] To check, try disagreeing with a few from either side, ask what proof they read before adopting the belief, etc.

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