Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Why Quantum Mechanics?

scottaaronson.blog

Post reply on HN
Print view View original

111–120 of 248 posts

Re: Why Quantum Mechanics?

#111

Post by BlueTemplar »

raindeer2 wrote: post #36
seiferteric wrote: post #25

Earlier quoted context omitted.

It's not satisfying that it would be considered free will if the outcome is based on the result of a probabilistic random number generator but perhaps that's what they mean... As for moral responsibility, essential no, it cannot exist again unless supernatural is involved for the same reasons outlined above, there is no "you" making a decision, just a process. As for whether you should feel guilty... well again I am…

"moral responsibility, essential no, it cannot exist again unless supernatural is involved for the same reasons outlined above, there is no "you" making a decision, just a process." This view is based on a misunderstanding of what moral responsibility is. Moral responsibility is essentially credit assignment [1]. It exists as a concept not because it matters whether or not you actually could have done differently bef…

Yeah, it's also related to how well we can simulate the behavior of others.

And here you eventually hit both the limitation that without abstractions you can only simulate a less complex system, and also how the information about the exact state of the system is fundamentally limited by the (quantum) uncertainty principle (which also allows the discretisation of information, via Planck's constant h) - entropy being a superfluous concept meaning just "lack of information" :

https://www.av8n.com/physics/thermo/entropy-more.html#sec-ph...

Re: Why Quantum Mechanics?

#112

Post by pontus »

guerrilla wrote: post #5

I've always liked these kinds of questions. Myself, I always wondered why specifically three dimensions. (Please don't start telling me about string theory.)

I know you explicitly asked for non-string theory answers, but I have to give one anyway -- sorry!

There's an argument in string theory called the brandenberger-vafa mechanism that I think is pretty clever:

Imagine that a bunch of particles and antiparticles travel along in one dimension. Because they can't spread out, they'll eventually collide and annihilate. However in 2d that's not the case: they're more likely to just miss each other all the time.

If you increase the dimension of the "particles" to strings, you can make a similar argument. In 2 (compactified) dimensions, strings will find each other but not in three.

Then if you start with some compactified space of 10d with a bunch of strings wrapped around various 2d subspaces, they will naturally constrain that space so that it can't expand. However, as strings move around randomly they'll tend to collide and unravel, allowing various 2d subspaces to cease being constrained and therefore expand.

If you analyze this carefully you can show that in fact three of the spatial dimensions will tend to expand while the six remaining ones will remain compactified.

Re: Why Quantum Mechanics?

#113

Post by rocqua »

_Nat_ wrote: post #92

> 4. To keep the discussion focused, in this post I’d like to exclude answers along the lines of “but what if QM is merely an approximation to something else?,” [...] imagine that, as fantastical as it sounds, QM were not only exactly true, [...] Seems like an absurd, conceptually-crippling stipulation, analogous to asking why [the fine-structure-constant is exactly 1/137]( https://en.wikipedia.org/wiki/Fine-structur…

This limitation is not because Scott things to know with certainty QM is true.

This limitation is because Scott is wondering "Is there a way to explain QM in a way that makes QM an obvious conclusion". That is an interesting question regardless of whether QM is true.

Re: Why Quantum Mechanics?

#114

Post by dskloet »

jiggawatts wrote: post #96
dskloet wrote: post #82

Earlier quoted context omitted.

You'll be convinced once you understand the EPR paradox and Bell's inequality. So look those up if you want to be convinced.

I did, and they make perfect sense if you look at them through the lens of MWI, which however seems weirdly unpopular in QM circles. I was taught the Copenhagen interpretation, which is just... madness.

Then I don't think I understood your question. I agree the Copenhagen interpretation doesn't make sense, mostly because I listen to Sean Carroll's podcast.

Re: Why Quantum Mechanics?

#116

Post by Paradigma11 »

seiferteric wrote: post #15
trixie_ wrote: post #11

Randomly found a link to this video on super determinism from his blog and found it super interesting. 100% agree, what is 'free will' anyways? A concept with no scientific definition. Why is it even used to explain anything in quantum mechanics? https://www.youtube.com/watch?v=ytyjgIyegDI

I think the question of free will is even simpler. It doesn't come down to determinism vs indeterminism because either way it's not "you" making a decision. At the lowest level (neuron or whatever) when a decision is "made" it is either deterministic (determinism) or probabilistic (indeterminism) based on physics but either way, where is the "you" in the process? Only way free will makes sense is if something superna…

Its also question about metaphysics. If you dont believe in metaphysics all this problems do not arise in the first place.

Re: Why Quantum Mechanics?

#117

Post by naasking »

trixie_ wrote: post #11

Randomly found a link to this video on super determinism from his blog and found it super interesting. 100% agree, what is 'free will' anyways? A concept with no scientific definition. Why is it even used to explain anything in quantum mechanics? https://www.youtube.com/watch?v=ytyjgIyegDI

> what is 'free will' anyways

I think it's important for everyone to keep in mind that "free will" is used differently in different contexts. In scientific contexts, it's more along the lines of experimental freedom, and free will and determinism are incompatible.

In ethics and law, it's more about moral responsibility and free will and determinism can be compatible (depending on who you ask).

Re: Why Quantum Mechanics?

#118

Post by naasking »

c01n wrote: post #57

I will give it a shot :) Q: Because consciousness is all there is. Q2: Because you need consciousness to observe the universe as classical. Q3: Way over my head.

> Q: Because consciousness is all there is.

But then the question becomes, why exactly is consciousness manifesting in exactly this way as quantum mechanics? There is no escaping addressing this question somehow.

Re: Why Quantum Mechanics?

#119

Post by r721 »

trixie_ wrote: post #11

Randomly found a link to this video on super determinism from his blog and found it super interesting. 100% agree, what is 'free will' anyways? A concept with no scientific definition. Why is it even used to explain anything in quantum mechanics? https://www.youtube.com/watch?v=ytyjgIyegDI

HN discussion: https://news.ycombinator.com/item?id=29610441

Re: Why Quantum Mechanics?

#120

Post by naasking »

guerrilla wrote: post #72
feanaro wrote: post #65

Earlier quoted context omitted.

The fact that your process knows about and is able to comprehend and reason about its own workings gives it the opportunity to change itself based on this knowledge. To hear about it and to then decide "this absolves me of any guilt, because I couldn't have done it any differently" is also a choice your process made. Counterfactually, it could've made the opposite choice (though it didn't do so). Now, me pointing thi…

Why do we absolve some people of guilt for being a product of their genes and environment and not others? Where do you draw the line? It would seem that "they couldn't help it" just as much as the people that you describe.

> Why do we absolve some people of guilt for being a product of their genes and environment and not others? Where do you draw the line?

These questions are decided in legal contexts all the time, so you can look up precedent. Generally there are considerations of coercion, mental fitness, and age/experience, because your responsibility is proportional in some sense to how much you know/have learned. If you literally have never learned right from wrong, say you were raised by wolves, then you are generally not held responsible until you do (or rather, you are held responsible, but the penalties are teaching you right from wrong rather than something more severe).

Post reply on HN