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Do physicists really believe in true randomness?

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Re: Do physicists really believe in true randomness?

#41

Post by matt-attack »

bkoa wrote: post #36
pvnick wrote: post #19

I love the idea of true randomness because it seems, to my uninformed mind, to allow us the possibility of free will. Without true randomness, while we may enjoy the illusion of free will, our decisions are ultimately left to deterministic hidden variables. That makes me sad. But given true randomness, we may in fact have some mechanism whereby we are truly autonomous. How that might work is way beyond me and probabl…

Just because CS people have a tendency to vastly overestimate their qualifications in other fields doesn't mean uniformed speculation about an incredibly well-discussed topic in philosophy is appropriate for HackerNews.

Well, maybe CS people realize most of the good questions in life simply cannot be answered by philosophers. They're just ill-equipped. It's really up to the physicists.

Re: Do physicists really believe in true randomness?

#42

Post by Totient »

I think this article is side-stepping an important philosophical point as to what randomness is.

Suppose we lived in a deterministic universe (e.g. one that actually ran on Newtonian mechanics and classic electromagnetism).

If you're of a mildly Bayesian persuasion, you 'believe' in randomness - even in a deterministic universe - because probability represents your knowledge. Sure, all the rules for the universe's evolution over time are deterministic, but you don't know the initial conditions, so you consider some probability distribution over initial conditions. Thus, the results of future events are 'random.'

The counterargument might go something along the lines of "that's not really random the way quantum mechanics is, because Bell's inequality demands violating either hidden-variables or locality and violating locality is worse. Without local variables, you can't meaningfully talk about having a 'underlying' deterministic universe."

Except you (sort of can). Bell's inequality implies that we can't have a theory with local laws of physics for single universe. But we can have a theory with local laws of physics for a multiverse which is the approach many-worlds takes.

Re: Do physicists really believe in true randomness?

#43

Post by rsp1984 »

Russell91 wrote: post #20

This article completely misses the point. You can never disprove hidden variable theories in a stochastic system, because hidden variable theories make the exact same predictions as 'true random' theories - the difference is only philosophical. What you can disprove are local hidden variable theories, which were somewhat popular (and favored by Einstein, for example) prior to Bell's thought experiment being empirical…

Thank you for this explanation, this makes so much more sense now.

Re: Do physicists really believe in true randomness?

#44

Post by Russell91 »

encoderer wrote: post #37
Russell91 wrote: post #20

This article completely misses the point. You can never disprove hidden variable theories in a stochastic system, because hidden variable theories make the exact same predictions as 'true random' theories - the difference is only philosophical. What you can disprove are local hidden variable theories, which were somewhat popular (and favored by Einstein, for example) prior to Bell's thought experiment being empirical…

"So in fact you do need instantaneous nonlocal interaction to explain the real world." Do you just mean quantum entanglement, or some other "spooky action"? (love that quote btw -- like many)

Haha, well the instances of Bell's experiment that I've seen so far all refer to entanglement. It's pretty easy to think about some unknown quantity having a probability distribution on its states. If you have an electron, and you don't know the spin yet, you say that it can be either up or down. What's special about entanglement between 2 particles is that it says the distributions on the two are not independent. In the classic example, one can only be spin up if the other is spin down - so they have a statistical dependence on each other. Bell's experiment tells us that the strength of this statistical dependence depends on how you measure the particles, which isn't determined until measurement time, when the particles are far away. But that being said, you could imaging all other sorts of spooky action at a distance - like 2 particles that have never been local to one another having some sort of statistical dependence. But that would be really hard to show until you found what type of nonlocal statistical dependence to look for, so usually when we're trying to figure out a good model we end up thinking about entanglement.

Re: Do physicists really believe in true randomness?

#45

Post by baddox »

colechristensen wrote: post #33
avalaunch wrote: post #22

Earlier quoted context omitted.

I'm not sure random will is equivalent to free will. Is a choice still a choice if it's made randomly? Couldn't you say that the photon in the experiment has free will then? What's the difference?

True randomness eliminates determinism. With determinism free will is ruled out. That doesn't mean everything that shows true randomness has free will.

> With determinism free will is ruled out.

Not according to compatabilism.

Re: Do physicists really believe in true randomness?

#47

Post by chrismonsanto »

bkoa wrote: post #36
pvnick wrote: post #19

I love the idea of true randomness because it seems, to my uninformed mind, to allow us the possibility of free will. Without true randomness, while we may enjoy the illusion of free will, our decisions are ultimately left to deterministic hidden variables. That makes me sad. But given true randomness, we may in fact have some mechanism whereby we are truly autonomous. How that might work is way beyond me and probabl…

Just because CS people have a tendency to vastly overestimate their qualifications in other fields doesn't mean uniformed speculation about an incredibly well-discussed topic in philosophy is appropriate for HackerNews.

That's very elitist. Academic philosophers do not 'own' philosophy. What is the harm of us ordinary folk discussing it? (Also, if anything is inappropriate for HN, it's snarky one-liners. Please don't do that.)

Re: Do physicists really believe in true randomness?

#48

Post by baddox »

davorak wrote: post #38
j2kun wrote: post #2

Isn't this just a question of whether they believe in quantum mechanics?

No, the many worlds interpretations of quantum mechanics, those that I am familiar with, do not contain any randomness.

I'm struggling to understand the distinction between randomness and unpredictability. The many worlds interpretation still implies unpredictability, doesn't it?

Re: Do physicists really believe in true randomness?

#49

Post by [deleted] »

jandrewrogers wrote: post #40

The difficulty with mathematical randomness (versus unpredictability) in physics is that you would not expect the Laws of Thermodynamics to exist in a universe governed by the former. Some literature on algorithmic information theory touches on this. Consequently, if local determinism is not plausible (Bell) and randomness is not plausible (Kolmogorov et al), that leaves non-local determinism as the most sensible ass…

[deleted]

Re: Do physicists really believe in true randomness?

#50

Post by coldtea »

bkoa wrote: post #36
pvnick wrote: post #19

I love the idea of true randomness because it seems, to my uninformed mind, to allow us the possibility of free will. Without true randomness, while we may enjoy the illusion of free will, our decisions are ultimately left to deterministic hidden variables. That makes me sad. But given true randomness, we may in fact have some mechanism whereby we are truly autonomous. How that might work is way beyond me and probabl…

Just because CS people have a tendency to vastly overestimate their qualifications in other fields doesn't mean uniformed speculation about an incredibly well-discussed topic in philosophy is appropriate for HackerNews.

You seem to have vastly overestimated your qualifications in philosophy.

Any rookie in philosophy 101 can tell you that tons of philosophers have been in favor of EVERYBODY participating in philosophical discussions, and that leaving philosophy to the "experts" is mostly an idea of academic philosophers (that is, people with very little contribution to the history of philosophy, and a whole lot of secondary and derived output of annotating the historically important --and usually "amateur"-- philosophers).

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