Hacker News Reader

Comment by awb | Hacker News Reader

> It's also the kind of thing that can open a backdoor for free will in a deterministic universe, your brain in this chaotic state might behave deterministically but the actual state would never be knowable with enough precision to predict the outcome of inputs for any amount of time (butterfly effect).

I think all it would mean is that the human brain is non-deterministic.

That’s different from free will though which is really an untestable, philosophical idea rather than a testable scientific hypothesis.

In any event, a random chaos state can be both non-deterministic and not intentional, or what many would call “free will”.

View on HN

> I think all it would mean is that the human brain is non-deterministic.

Chaotic systems are still deterministic. They're just extremely sensitive to their initial conditions/inputs.

I always find it interesting drawing the determinism line on chaotic systems.

For example, is a chaotic system that depends on initial conditions so precise that having adequate measurement to predict the outcome would violate the uncertainty principle still deterministic?

As far as I understand it, determinism is about being able to predict the next state if you have all knowledge about a system.

That we can't have all knowledge about most systems in the real world doesn't mean they're not deterministic.

And who knows what kind of magical science we'll find in the future that turns everything we know about measurement upside down?

> Chaotic systems are still deterministic.

Is there some definitive proof for this, or are we just taking it as a useful assumption?

it's the definition.

"chaotic systems" aren't just... unpredictable things that we find laying around and say "yeah we'll call that chaotic because it looks like my kid's bedroom". they've got to satisfy that description.

I'm asking if there's a proof for determinism itself. I was under the impression that we've only ever been inferring consistency is a property of reality.

If you can QED me to a conclusion that yes, in fact, the sun will rise in the morning, I would genuinely find that useful.

> I'm asking if there's a proof for determinism itself.

sounds like you tried to take a flying leap away from the mathematically sound, and pedestrian statement of darawk into philosophy. you should warn people about that, so that people know not to bother.

> If you can QED me to a conclusion that yes, in fact, the sun will rise in the morning, I would genuinely find that useful.

if "gravity" isn't enough of an answer for you, then nothing can ever be.

> darawk

Nice word. Does it have a definition?

Appears to be a username in this thread

If the underlying physics is deterministic, then a chaotic system (e.g. the Three Body Problem) is just a collection of deterministic parts interacting with each other, and is therefore itself deterministic. The overwhelming complexity and unpredictability we observe is just a commentary on our own ignorance and limitation as humans. There was never room for any non-deterministic thing to magic itself into the system at some point as the complexity and unpredictability of the system got bigger and bigger.

I appreciate the good faith engagement (cue side glare sigstoat), and I'm in agreement with everything but the use of "never" in the your closing sentence.

> There was never room for any non-deterministic thing to magic itself into the system

Depending what you mean by "into the system," existence itself is a glaring counterexample.

How did any of it get here in the first place? Was there an uncaused cause? Is entropy reversible?

Until we can explain-away these types of questions, it'd be prudent to remain noncommittal on the topic. The type of determinism that sigstoats expect might not even make sense in other regions or eras of reality. Things get profoundly hazy past Planck Era.

I wonder if it's possible to prove that you can't end up with a non-deterministic system if that system is constituted only by deterministic parts? I get the sense that such a proof is possible, but I am not sure. We can trivially prove it for deterministic systems that we can model mathematically, but what about a generic proof for those systems that are beyond our modelling capabilities?

Regarding existence itself, I agree that determinism is not an exhaustive set of possibilities (if it was, it would imply an infinite chain of causes, which presents its own problems). I just challenge the idea that one can possibly get a non-deterministic system if we assume that we're working with purely deterministic components/rules.

I've been thinking about it like we're located in some pocket of reality whose local conditions generate the nature we know and love, but outside of which might be unrecognizable.

Whatever the Big Bang event was, I'm assuming it was a result of some exterior nature.

What I worry about is whether or not its even possible to connect the dots between the two.

Gödel's second theorem may just straight up make this whole exercise pointless.

Just imagining that outcome gives me the urge to primal scream.

All I know for certain is I've got a lot of questions.

Deep philosophical discussions around free will can benefit from first defining what "free will" means.

Deep philosophical discussions around free will often consist entirely of defining what "free will" means.

If the human mind is deterministic there's no free will. If it isn't there might be. That makes free will half of a scientific question - science can only rule it out.

Oddly, nondeterministic systems tend to be statistically more predictable than certain classes of deterministic systems (to wit: a chaotic system is a type of deterministic system). So possibly the opposite is true, you need the human mind to be (mostly) deterministic for there to be free will.

I personally don't think that any macromolecular physical system can be entirely nondeterministic. We just don't understand how to make predictions for the system yet, but being beyond our understanding doesn't make it nondeterministic.

Reply on news.ycombinator.com