Does quantum theory imply the universe is preordained?

https://www.nature.com/articles/d41586-023-04024-z

by pseudolus • 3 years ago

92 175 3 years ago

gavinray• 3 years ago

When I was a teenager I had an idea:

If you rolled marbles down a hill, assuming that identical starting conditions were applied each time, then the marbles' paths and final position would be the same each time.

This also implies that if you know the starting conditions, you could calculate the state of any point in time from there.

It made me curious whether you could apply this same logic to our universe -- though I get the feeling it's not quite as simple a system as marbles on a hill.

EA-31672• 3 years ago

The fundamental question here is whether or not you can get identical conditions in the first place. If for example spacetime is quantized, then it might be that the basic unit of our reality displays the sort of quantum behavior that makes it so hard to predict outcomes. It wouldn't just be a complex system, it would be an essentially random and ever-changing system. By the same token it could be the opposite, maybe it's just a really complex system as you were speculating about, and while nothing is random, it's essentially impossible to predict.

In essence, is this a universe where a version of Maxwell's Daemon could conceivably exist, or is it a universe that even a god-like being would find random?

https://en.wikipedia.org/wiki/Maxwell%27s_demon

sim7c00• 3 years ago

i think for physical systems this might hold true in some way, though, i am not a physics person at all. it just 'feels' that way to me. however, life is also there, and life doesnt nessesarily follow such rules, as actually most of (intelligent?) life is not physical. (emotions, thought etc.) but does have impact / effect on the physical. i dont think non physical things are so determenistic. (maybe they are, but it doesnt 'feel' that way to me)

sheepdestroyer2• 3 years ago

What makes you say that life is not physical?

There seems to be no reason to believe that it's not.

On the contrary it seems most plausible that everything, including emotions, thoughts, decisions, are just chemical and electrophysical reactions. Thus deterministic.

digging9• 3 years ago

For classical physics it's basically true[1]; see Laplace's demon. I recall also independently inventing determinism as a kid after I realized how easily I'd been swayed by external factors into buying one toy over another.

For non-physical things, such as emotions and thought... well, we have no actual proof they're anything but physical. We just don't have proof that they're entirely physical, either. But the simplest explanation is actually that they are completely physical processes and just as deterministic as everything else (which is to say, possibly not at all, depending on how QM is resolved).

[1] "Basically true" here means it's not strictly true (by that I mean it's not true in all possible cases) - but classical physics itself is not strictly true, thus relativity and QM... which are themselves not strictly true. We're still trying to find the theory that accurately describes all of physics.

aeonik2• 3 years ago

There's a good documentary called "The Secret Life of Chaos" that has a fairly cool overview of this concept.

Though it's just the beginning of a very deep rabbit hole, possibly unending.

Here is a link: https://www.dailymotion.com/video/xv1j0n

ewhanley• 3 years ago

There's also a decent (not documentary) limited series that explores the idea of determinism. It's pretty good and may be of interest. https://en.wikipedia.org/wiki/Devs_(TV_series)

gpderetta• 3 years ago

If the path of the marbles were to be determined by some sort of gate in the path that would open or close depending, via a Geiger detector, on whether some uranium atom had decayed, then, as far as we know, the path would be truly unpredictable.

taeric• 3 years ago

My mental model for this is to consider boiling water in a pot. You can make easy statements over how long it will take for all of the water to evaporate. It is, to my understanding, impossible to discuss any particular molecule or atom.

That is to say, the closer you get to the atomic behavior of atoms, the harder it is to make "deterministic" descriptions of what is going to happen.

We often describe this in terms of "coin flips" as you can make a decent discussion over what you will see on 1000 coin flips, but you cannot make such a statement over what you will see over 1.

pants2• 3 years ago

You can create a marble run and have marbles more or less follow the exact same path every time. However, on some scale there is an unpredictable nature to things like Brownian motion which affect the run in subtle ways. Perhaps you could get closer if you could account for the physical properties of every particle in the system beforehand, but a some scale these interactions are driven by quantum mechanical processes that aren't predictable even with perfect information (as far as we know).

To look at it another way, the entropy of a system is always increasing, so you don't have enough information when the marble is at the top of the hill to know the exact outcome when it's at the bottom (on a quantum scale, or over a long enough period of time).

mensetmanusman7• 3 years ago

They would be the same until some number of zeros, past which, Heisenberg uncertainty takes over and you cannot predict.

hkmaxpro• 3 years ago

The Nature article and your comment reminds me of [1]: What if the hill is a perfectly symmetric hemisphere, so that every path down the hill is equally valid?

In fact, this is precisely the shuttlecock analogy in the Nature article, even though that analogy is talking about the quantum Universe initial boundary state, as opposed to the hemisphere example in classical Newtonian mechanics.

I guess the shuttlecock analogy isn’t that useful after all, since it fails to set apart quantum Universe theory from Newtonian mechanics, in that the latter can also have no boundary.

[1] The Dome: A Simple Violation of Determinism in Newtonian Mechanics

https://sites.pitt.edu/~jdnorton/Goodies/Dome/

https://news.ycombinator.com/item?id=37012347

elromulous• 3 years ago

This does make me wonder: how do we know that random quantum processes are truly random?

This gets philosophical very quickly. But for our purposes: independent, uniform, etc. But how do we know there isn't another (earlier) way to observe the result in some fashion.

variadix• 3 years ago

I think Bell’s inequality implies the state can’t be deterministic but hidden. I’m not sure how you could evaluate the “quality” of the randomness, or if there are existing results analyzing this.

nyssos5• 3 years ago

We don't. What we know is that we can't have all of

    1. locality (no backwards causation / FTL information transfer)

    2. determinism

    3. counterfactual definiteness (unperformed measurements still have single definite results: we can talk meaningfully about what we would have seen had we done a different experiment)

    4. QM gives correct predictions.

Objective-collapse interpretations (like the version of Copenhagen described in introductory textbooks) reject 2: collapse is fundamentally indeterministic.

Everett (the badly misnamed "many-worlds" interpretation) rejects 3: "measurement" is just what unitary evolution looks like from the inside, and from that perspective always has multiple outcomes.

Superdeterminism rejects 4: QM is wrong, but the initial conditions of the universe were for some reason set up in such a way as to prevent us from carrying out any experiments that would demonstrate that.

cb321• 3 years ago

Bricmont does a good job of discussing entropy, arrow-of-time, and irreversibility, information and probability in a purely classical statistical mechanics setting in https://arxiv.org/abs/chao-dyn/9603009 .

Bricmont has continued to write/expound upon these ideas ever since and more recently "come out" as a non-local hidden variables proponent of the de Broglie/Bohm variety which rejects your (1. locality) for which you left out an example. :-)

Sometimes people refer to giving up "locality" in this context with the mouthful "a preferred fundamental foliation of spacetime". { "fundamental" here does the work to block the Cosmic Microwave Background / "average rest frame" which people have no trouble treating as a preferred inertial reference frame that is "merely contingent" not "fundamental", although Ernst Mach might have begged to differ, but that is further afield. :-) }

throwawaymaths3• 3 years ago

Correct me if I'm wrong, but I don't think we even know what "collapse" is. Maybe a better way to say it is that arguments about what is collapse are at the root of distinguishing interpretations

karmakaze2• 3 years ago

My bet is on 1. backwards causation. Light takes the shortest path, by (virtually) taking all of them.

Similarly all paths to the future are taken and the present must agree with boundary conditions in the future.

lmm2• 3 years ago

how do we know that random quantum processes are truly random?

If it looks like randomness and quacks like randomness, it's randomness, right? We've experimentally verified these things to dozens of decimal places. Asking whether it's "truly" randomness is meaningless without a measurable way to distinguish what's "truly" random or not.

how do we know there isn't another (earlier) way to observe the result in some fashion.

Bell's inequalities.

DebtDeflation2• 3 years ago

I think, ultimately, there are only 3 possible explanations for the paradoxes of the quantum world. 1) superdeterminism (everything including our choices in quantum experiments today were fully determined at the instant of the Big Bang), 2) something "outside" our observable reality acting as a global hidden variable (whether something like the bulk in brane cosmology or whatever is running the simulation in simulation theory) or 3) emergent spacetime (if space and time are emergent phenomena then locality and causation are not fundamental).

digging9• 3 years ago

Actually, how are 1 and 2 different? If 2 simply refers to another layer of reality, don't we still have to figure out if it's deterministic or not? I suppose if it has its own completely different (or slightly different[1]) physics, we'd be starting over, but we'd still work our way back to the question of top-level determinism eventually).

[1] Referring to cosmological natural selection as a theory of the "fine-tuned" universe: https://en.wikipedia.org/wiki/Cosmological_natural_selection (a fun favorite of mine but not looking likely)

hermannj314• 3 years ago

It's simulations all the way down.

DebtDeflation2• 3 years ago

Fair point. I'm assuming that additional layer of reality is deterministic.

hnthrowaway0328• 3 years ago

I have been thinking about this. Definitely not a Physicist or even a Scientist, but how do we figure out the world that the simulation occurs?

I think one lead we can have is that simulations are called simulations because they try to emulate the real world (the one simulations are running). By observing from inside the simulation what kind of input and reaction the "God" people has when we output something, we might be able to understand the "real" world better. It's like the "people" in the Sims game -- given they are of their own mind, they can figure out some rules of our world.

But then how can we jump out of simulation to really really figure it out?

Filligree• 3 years ago

Many-Worlds? Or does that fall under #2 for you?

coderenegade• 3 years ago

Many worlds is really just another form of determinism. If everything that can happen does, no one in any of the individual universes has free will.

TheOtherHobbes2• 3 years ago

Superdeterminism on its own doesn't explain why quantum phenomena are statistical, not deterministic.

It seems strange that a superdeterministic universe constrains certain kinds of phenomena to statistical distributions for no obvious reason.

Free choice is a completely different issue, and I'm not even sure it requires quantum theory. Clearly we have the illusion of free choice, but just as obviously our choices are very heavily constrained. In fact the constraints pretty much determine personality. And there's plenty of evidence from psychology that if you you have an accurate model of personality you can manipulate someone's choices without them being aware of it.

So I'm not seeing what quantum theory adds to this. It seems to assume consciousness is quantum and works back from there. Which is a weak argument (IMO).

__turbobrew__• 3 years ago

I have yet to see a subscriber of superdeterminism not look both ways before crossing the road.

digging9• 3 years ago

A good quip, lol. But of course they would, because they must, because the feeling of control (that is: the unconscious belief in control) is just as intrinsic as the actual absence of control.

voxl• 3 years ago

which in other words makes superdeterminism unfalsifiable, because any attempt to do so can be met with "it must have been that way"

karmakaze2• 3 years ago

Or rather they must, because it was determined that they do.

And I'm sure sometimes, some of them don't look both ways for the same reason.

qarl• 3 years ago

That's because superdeterminism doesn't imply you shouldn't.

Superdeterminism implies that you don't really have a choice as to whether you look both ways.

jeswin• 3 years ago

The subscriber has no free will. The question would be - why exist?

sheepdestroyer2• 3 years ago

If true, superdeterminism would not permit them to make that choice to look around or not anyway.

PheonixPharts3• 3 years ago

Does believing that gravity exists mean a person will not roll down a hill?

Why would belief that we are just agents responding predictably to stimuli imply that one would not respond predictably to stimuli?

The fact that ones behavior does not change when one acknowledges that all behavior is deterministic and predetermined seems evidence in favor not against that hypothesis.

nyssos5• 3 years ago

Why would belief that we are just agents responding predictably to stimuli imply that one would not respond predictably to stimuli?

This is determinism, not superdeterminism.

Superdeterminism claims that the state of any system you measure is always already correlated with the measurements you perform on it: photons emitted a billion years ago encode information about where someone is going to choose to point a telescope tomorrow. Not because of any interaction between the two, but because the initial conditions of the early universe just happened to be set up that way.

PheonixPharts3• 3 years ago

"Random" is a property of your mind, not of the world.

If I shuffle a deck of cards in a way that you don't know about, then the next card I pull is "random" to you even though, obviously, if one were to turn the cards face up nothing would have changed about the order of the cards, but now the next card would be fully deterministic.

I could likewise sort the deck with an algorithm completely unknown to you. I could perfectly predict the next card pulled because I know the algorithm, and yet the next card would still be random for you.

Heisenberg uncertainty principle is more a statement about the limits of knowledge than about "God throwing dice". Randomness often has a supernatural property in the popular mind, but is really just a statement about how much information we have about an event.

The famous Bayesian philosopher ET Jaynes refereed to this tendency to confuse the randomness as a property of the world rather than our mind as the "Mind Projection Fallacy" [0]

0. https://en.wikipedia.org/wiki/Mind_projection_fallacy

danbruc2• 3 years ago

"Random" is a property of your mind, not of the world.

Limited information about the initial state is one source of randomness but not necessarily the only one. Whether there is true randomness in the universe is at very least an open question.

PheonixPharts3• 3 years ago

Can you clarify what "true randomness" means out side of the context of human agency and perception?

Can you also give an example where "true randomness" would differ from the randomness I describe on the actions a human would take? That is to say, if a my internal model of the world tells me a coin landing on heads is 50/50 how does "true randomness" or not of the resulting coin toss impact how I should gamble on coin tosses?

imho the idea of "randomness" separate from our own internal state of belief is a nonsensical concept, but would appreciate examples to the contrary.

losvedir• 3 years ago

I'm not an expert, but I think the "orthodox" understanding is that quantum mechanics is fundamentally rooted in probabilities at the lowest level. The position you're taking, that quantum uncertainty isn't inherent in the system, but just related to us not knowing enough about it, is considered a "hidden variables" hypothesis.

And I think those have been ruled out by Bell's Theorem, or at least implies other very counterintuitive things have to be true instead.

phkahler• 3 years ago

> And I think those have been ruled out by Bell's Theorem, or at least implies other very counterintuitive things have to be true instead.

Non locality seems less weird to me than any of the other interpretations of quantum mechanics. But I feel like I'm in a small minority with this. Besides, what we think about it isn't really relevant.

digging9• 3 years ago

Not sure I agree fully in the case of Uncertainty. To the best of our knowledge, an undetermined quantum property is actually undefined. Whether we go with the simple Many Worlds or the Copenhagen wave function collapse or even Pilot Wave theory, when the value becomes defined it is randomly selected (or our World is a random selection of all of them) according to the wave function.

I believe what you're saying is that there is indeed a superdeterministic hidden variable that would allow us to know before the value is defined what it will be. For simplicity let's assume the Many Worlds interpretation... this variable would tell us which world we're in.

The issue with this explanation is that we're not in that World yet, because our current World is only the result of past quantum events. When this next undefined value becomes defined, our single world splits into Many more Worlds, each of which has ours as a parent, so how could one of those be more or less intrinsically ours? Each is equally our World, and if we back up a single "step", our World contains all of the supposed hidden variables that say which child World is which. So I find that Many Worlds seems to invalidate superdeterministic hidden variables.

With other, single-World interpretations, the hidden variables make more sense. What you say would be true. But single-World interpretations are already more complicated than Many Worlds, with or without hidden variables and superdeterminism.

simiones4• 3 years ago

I don't think you're right about the many worlds interpretation here.

In the most popular "simple" many worlds interpretation, the whole universe is a QM system described by the universal wavefunction. The "worlds" are just "branches" of the wavefunction that are not entangled with one another.

The Schrodinger equation (and the more advanced QFT versions) are fully deterministic differential equations: the state of the universe at time T is fully determined by the state of the universe at time T-x, for any x. This remains true even if x is negative: there is no "arrow of time" in QM, there is no distinction between the past and the future in any QM equations.

The only "non-determinism" in Many Worlds is thus of the knowledge kind: you don't know which "world" you happen to be in, so you don't know which result you'll notice. But this is like being spun around a coin: you don't know which face you'll end up looking at, but you know both faces actually exist. All the possible outcomes of any QM event are realized in "some world", there is 0 uncertainty.

Jensson• 3 years ago

Heisenberg uncertainty principle is more a statement about the limits of knowledge than about "God throwing dice".

This isn't what physicists believe though, Heisenberg uncertainty principle is about a wave not having both a well defined position and velocity. They either drift apart (undefined velocity) or they are spread apart (undefined position). Then the wave collapse keeps the wave together over time by randomly removing parts of it, we have no theory where that isn't random even "many world" means you randomly select one of the branches to follow.

We do know for sure that particles are waves that spread out and exist in all of those parts, it isn't just that it represent a point particle with unknown location. And we know for sure that those waves under certain circumstances withdraw from parts and just keep other parts, ie wave collapses. Both of those are easily observed in experiments and not up for debate.

GoblinSlayer13• 3 years ago

In many worlds selection isn't random, but bayesian - really deterministic that can be subjectively interpreted as random.

simiones4• 3 years ago

If QM is correct and there is no "deeper" hidden variable theory that explains the movement of all particles, then you're wrong.

Heisenberg uncertainty as it exists in QM today is not a statement about your knowledge, it is a statement about the possible interactions between particles. It tells you that if a particle collides with another at a specific point in space, then their trajectories after that collision can't depend on the momentum of either particle, for example, because that would violate the inequality.

This indeed does not necessarily imply randomness per se. But it is much more than a statement about precision of measurements at a human scale: it is a statement about the possible interactions at even the lowest scales.

Lichtso• 3 years ago

The uncertainty principle is just a really misunderstood concept because it was first discovered in the context of quantum physics (Heisenberg 1927) and only later (Gabor 1946) the underlying mathematical principle that causes it was discovered.

It has nothing to do with measurement, knowledge, randomness or even our physical reality at all. It is a much more fundamental mathematical phenomenon [0] that always occurs when you switch representation between time and frequency domains and it tells you how you can arrange information in such mixed representations.

[0] https://en.wikipedia.org/wiki/Uncertainty_principle#Signal_p...

munch117• 3 years ago

Appealing to quantum theory to defend free will does not make sense.

If the quantum randomness is fundamental, and reality is stochastic at heart, that makes it non-deterministic, but it doesn't make it any less mechanical. It's in the name, after all: Quantum mechanics. If there is any guiding light to the randomness, any pattern to how the random choices come out, then it's not really random, is it?

So, if you think that a deterministic reality is devoid of free will, then you must equally think that a Copenhagen-interpretation fundamentally stochastic reality is devoid of free will.

nwiswell5• 3 years ago

If there is any guiding light to the randomness, any pattern to how the random choices come out, then it's not really random, is it?

Well, yeah, that's the point. By definition, a deterministic model of reality means there is no room for a free agent to make decisions: things couldn't have worked out another way.

But a mechanism that appears random provides at least the potential for a free agent, since randomness is exactly what it looks like when you cannot predict system outputs purely from system inputs.

It's really a semantic issue. It's not that it's a source of randomness that we're after in order for free will to be possible, but rather non-causality, and quantum mechanics does provide some potential in that regard.

dotsam6• 3 years ago

I find the idea of computational irreducibility useful for rescuing a type of free will in a fully determined world. Computationally irreducible programs are perfectly deterministic, yet you can't predict the output before you run them, and nor are there any shortcuts to get there before running them for the first time. The program running in our brains for 'free will' can be computationally irreducible in this way. No-one can say with perfect accuracy what we will choose to do in advance, not even us.

For me, this kind of free will is enough, though it is rather deflationary when compared to some kind of godlike non-causal free will. I think that if we search for non-causal free will, we lose any hope of explanation or understanding: presumably if it's non-causal, then anything can happen, for no reason.

akomtu3• 3 years ago

The universe can be deterministic without infringing on free will. The game of chess is deterministic, but free will is expressed in picking the moves.

nwiswell5• 3 years ago

The issue is that if the universe is deterministic, so is the brain.

mewpmewp27• 3 years ago

The move you pick is also deterministic, which is coming from the state of your neurons and how they have got to that place from studying so far and then getting the current input of the board to go through several cases to reach the output.

tromp2• 3 years ago

All the observed complexities can be regarded as partial descriptions of a simple fundamental reality: the Universe’s wavefunction. As an analogy, a perfect sphere can be cut into many chunks with complicated shapes, yet they can be put back together to form a simple sphere.

As another analogy, the 100-bit lambda calculus term

(λ 1 1) (λ (λ λ λ 1 (2 (λ λ λ 3 1 (2 (λ 2)))) (3 (λ 4 (λ 4 (2 1))))) (1 1)) (λ 1)

is a binary tree containing all (infinitely many) closed lambda terms at its leaves. Thus including representations of all possible data and all programs.

dd1988• 3 years ago

Fascinating - familiar with basic lambda calculus, but trying to wrap my head around this. Can you link to anything that explains more about how this works?

tromp2• 3 years ago

A more readable form of the program is given at [1]. The tree contains all combinators built up from the single point basis A = λxλyλz. x z (y (λ_.z)), which is encoded as bit 0 (left branch), while bit 1 (right branch) encodes prefix application.

[1] https://github.com/tromp/AIT/blob/master/ait/allA.lam

ericfrazier2• 3 years ago

Proving the world operates without free will is trivial.

mensetmanusman7• 3 years ago

Just die and see?

ericfrazier2• 3 years ago

If you want. I've proven it without dying.

MrGinkgo• 3 years ago

Not sure if this is just a moot point, but I'll say it because I'm genuinely curious to hear what people have to say. Anytime I hear theories like this, I feel wary of accepting it as an air-tight reliable outlook because of human limitations. Like, our understanding of quantum physics and all natural laws come from what we can percieve and measure, but there's bound to be phenomena which we can't percieve or measure (either yet, or ever) which limit our understanding of the universe. I understand that science is a constant process, and that we shouldn't jump to conclusions of any theories being "truth" because of this process, but anytime anything like this comes up, I'm always wary of the consequences that occur from all the people who DO dogmatically assert that it's undeniable, especially with how easily theories of predeterminism tend to enable unproductive, nihilistic outlooks. I don't necessarily see science as trivial pursuit because of our human limitations, but I feel like not enough people have learned their lesson about the consequences of eagerly accepting a "work in progress" as "ultimate truth".

moritzwarhier• 3 years ago

Very well put!

I don't necessarily see science as trivial pursuit because of our human limitations

Me neither, quite the opposite, but the problem you are describing has always been a problem when discussing metaphysics, as it is commonly called.

Science is aware of its limitations, that's what makes it science.

But sometimes, people tend to conflate a materialistic world view (maybe even strong determinism) with believing in the scientific method.

The "belief" I mean here is strongly tied to assigning the appropriate role in ones thinking to scientific facts.

Proving an all-encompassing scientific world view is a logical paradox.

broscillator7• 3 years ago

But sometimes, people tend to conflate a materialistic world view (maybe even strong determinism) with believing in the scientific method.

I would say more than sometimes. It seems that if you're not like that, you're immediately labeled religious.

dotsam6• 3 years ago

Scientific knowledge, like all knowledge, is fallible. All we can hope to do is correct errors and generate better explanations.

There is no "ultimate truth" or airtight reliable outlook at which we can stop and say we know everything there is to know -- that would be a dogmatic assertion, and it is false.

broscillator7• 3 years ago

I think you're just describing human nature. We can look back and see how incomplete theories about the world led to horrible acts, or to averting our eyes from those acts because we thought it was justified, or because we thought there was no better way, or out of fear.

Yet there's the prevalent sense of "this time we're getting it right".

pmontra3• 3 years ago

People did horrible acts because they did want to do those acts to those other people. They picked a theory to justify them.

lmm2• 3 years ago

I don't think "this belief has negative consequences" is a good argument; we can only reach the truth by sincerely looking for it.

To my mind the very concept of free will is nonsense; as soon as you make a sincere effort to pin it down it breaks down. Yes, there is no absolute proof that it's impossible, but like the second law of thermodynamics, I would be much more surprised to see it violated than, IDK, finding a real magnetic monopole.

GoblinSlayer13• 3 years ago

especially with how easily theories of predeterminism tend to enable unproductive, nihilistic outlooks

That's an essential claim, not doubt. First, you're wrong that determinism is a synonym for predeterminism, science doesn't support it, because predeterminism contradicts the second law of thermodynamics. Next you're wrong that nihilism is bad. Is it a dogma? What if you're wrong? Especially since you know yourself your knowledge about nihilism is fragmentary and you spent only microscopic amount of effort to understand it and can't make grand conclusions about it. Then you also imply that delusion is somehow more constructive than truth. That's counterintuitive and needs proofs.

at_a_remove• 3 years ago

I've never seen some consensus as to the definition of free will to the extent that it was testable. As in, "What experiment can we perform to show this thing has free will?" or "Define free will in such a fashion that a universe with free will is notably and different from a universe without free will, in a manner we can detect."

If we cannot do that, I am not even sure what the point is of discussing the concept. It is like some box we are told lies sealed in a distant continent, and we argue about what is in the box. Why? We'll never know, and the answer doesn't seem to change anything.

karaterobot• 3 years ago

I have not heard a convincing explanation of how the universe could produce the Monorail episode of The Simpsons merely by a certain configuration of energies in the first moment of the big bang, and the consequences of thereof. The most obvious argument is that the Monorail episode of The Simpsons is not only possible in at least one of the infinitude of quantum, deterministic universes, but inevitable, and that the seeming absurdity is merely my inability to acknowledge my anthropic bias. Nonetheless, I laugh every time I think about the motion of particles leading unavoidably to the invention of everything required for someone to type "I call the big one Bitey!", and for me to appreciate it, or believe—as I must—that I appreciate it. The mind reels!

twiceaday• 3 years ago

The three body problem is impossible to solve analytically. The state space is clearly all connected but in a way that cannot be short-cut. You have to walk it deterministically one state at a time. Once you reach some interesting state, you know that you will always reach it from your initial state. It is inevitable but in general impossible to predict. There is no simple story to tell as to why you'd end up there, you just do as a culmination of the state-path up to that state. We've reached a state where that Simpsons episode was created. It's very interesting and was impossible to predict from all the way back during the bing bang. Maybe it was inevitable?

mewpmewp27• 3 years ago

It was inevitable, there is nothing else it could have been. How could it have been something else? What would have had to make it something else and if there was randomness why would it matter?

aap_• 3 years ago

The cosmic ballet goes on.

dist-epoch• 3 years ago

I have a similar problem as you, I just can't understand how determinism makes the lion's atoms move exactly in the direction of the gazelle's atoms.

At the same time, I also can't ignore the large number of very famous and accomplished physicists which take determinism very seriously.

GoblinSlayer13• 3 years ago

Computers already have arbitrarily complex behavior, is it absurd too?

Xcelerate• 3 years ago

I feel like “deterministic” and “predictable” are often conflated. Suppose I give you the output of encoding a secret message with a one-time pad. Can you predict the message contents without the one-time pad? No. Does that mean the output was generated non-deterministically? No.

More generally, there are strings with Kolmogorov complexity of at least the length of the string but for which the conditional Kolmogorov complexity is very small given some other string.

In this sense, it’s quite possible that quantum mechanics is fully deterministic and there is a hard limit on our ability to predict the future (so for all intents and purposes, quantum mechanics is at some level indistinguishable from true randomness to us despite there being no randomness whatsoever in the laws of physics). In fact, I think the former actually implies the latter:

Consider a completely classical, deterministic universe (or at least imagine a high fidelity molecular dynamics simulation of our lightcone of the universe). Then all of the actions that humans take in an attempt to predict future observations are fully pre-ordained. Why should it be the case that these actions just so happen to lead to output that describes another subsystem’s behavior to arbitrary precision? That would be a strange coincidence to have for whatever set of laws describes the time evolution of this hypothetical universe. Mathematically, how many universes like that are even possible? What sort of bizarre initial conditions would there have to be for this to be the case?

My take is pretty simple: 1) the universe is fully deterministic and 2) quantum mechanics appears inherently random to us because we are inescapably part of the system we are trying to study and predict.

So now the interesting question: is there is an experiment that can distinguish between the case of a fully deterministic universe and one with non-deterministic processes, given that the two would seem to appear the same as far as human observation is concerned?

GoblinSlayer13• 3 years ago

If an experiment has a consistent deterministic model, it indicates determinism, because it should be impossible to model indeterministic experiment deterministically.

Animats2• 3 years ago

No new info. From the article: "So how deterministic is the Universe? The answer will depend on the final theory that bridges the divide between quantum physics and relativity — and that remains a far-off prospect."

Unless physics is totally noise-free, with zero randomness, there is indeterminism. There are so many chaotic processes that amplify randomness that any randomness at all will cause wide divergence in outcomes.

Whether or not noise and free will are the same thing is a question for theologians. Rudy Rucker addressed that question in passing in one of his SF novels.

lern_too_spel2• 3 years ago

If you can't control the noise, there is no free will. If you could control the noise, that would be measurable. You need both to be able to control the noise and to not have that be a direct consequence of another physical process in order to demonstrate free will.

jakeogh• 3 years ago

Determinisim is impossible because randomness is baked in; knowing position and momentum isnt a thing, and as far as we can tell the only closed systems are light cones.

Odd that the article didnt mention Heisenberg.

https://news.ycombinator.com/item?id=21253267

GoblinSlayer13• 3 years ago

Noise doesn't necessarily participate in reasoning, it can be just a factor to ignore or smooth out. You can calculate 1+1 at a random moment of time, but the result will be 2 - deterministic in spite of present randomness.

Animats2• 3 years ago

The reverse, however, is not true. If you have no source of randomness at all, you get the same answer every time.

"Anyone who considers arithmetical methods of producing random digits is, of course, in a state of sin." - Von Neumann

FredPret3• 3 years ago

I always see references to free will when certain people start talking about quantum mechanics. Why do people care if free will exists or not?

It doesn't seem to affect anything I can think of.

- It feels like it exists; it feels like I'm making my decisions. Even if my whole life is a series of decisions calculated by me in some inevitable way, the calculations still had to happen in my head, and the experience of deciding was part of that. Therefore I own my decisions either way.

- For that reason, a criminal is just as guilty of their crime, whether they spiritually willed themselves to rob the bank, or whether they are predetermined to. The decision to rob the bank happened in their head.

- Punishment for a crime makes just as much sense either way and for the same reason. Seeing criminals get punished will affect the calculations happening in nearby brains, possibly lowering the chances they will in turn decide to rob the bank. Removing errant decision-making matrices from society should reduce the amount of badness.

- All of the opposite things are also true for rewarding good behavior.

What would you do with a CPU that can do nothing but churn out malware due to a design flaw? What if it's a CPU that only does amazing things? Or if it's some mix of both? It seems very similar to how we'd treat people who behave differently.

jddj2• 3 years ago

For that reason, a criminal is just as guilty of their crime, whether they spiritually willed themselves to rob the bank, or whether they are predetermined to. The decision to rob the bank happened in their head.
Punishment for a crime makes just as much sense either way and for the same reason. Seeing criminals get punished will affect the calculations happening in nearby brains,

This could be a local maxima. I'm not sure there is a reason (other than us having arrived at it, which does count for something) why blaming, and particularly hating/attributing evilness to people for performing a certain act while operating under an imagined agency is more effective than some alternative.

It's possible that there could be a means of dissuading others from the behaviour without that illusion/emotional baggage.

It could arrive at the same conclusion (incarceration, for example) but more compassionately. Does that matter? For the bigger picture arguably not, but for the human experience maybe.

FredPret3• 3 years ago

It could be more or less compassionate - if we say "this unit is faulty, put it in a firewalled environment with the others" it might encourage us to be nicer to the criminal, especially for minor misbehaviors. But we might also conclude "this unit only churns out malware" and that might encourage us to end all further processing, or to banish it forever to some lonely, inescapable cell.

Edit: now that I think about it, this way of thinking might actually predispose us to try debugging first.

mewpmewp27• 3 years ago

We are all using mechanisms that developed throughout evolution to peform as well as we could in order to spread our genes. That is it. Free will doesn't matter, you are right. As a society we try to align incentives so that everyone would do as good as possible for the group, because throughout evolution the groups who did that were more likely to survive. And, yes it is all pre determined.

The reason to praise or condemn is because these are the pre determined things we are bound to do because it increases our odds of survival.

radiojosh2• 3 years ago

I came to a very different conclusion on criminality in the absence of free will: compassion and understanding.

How often do children do shitty things, and then say "I don't know" when asked why they did it? I have personally had problems lashing out in anger and not even understanding why. Our brains put a lot of effort into keeping us away from painful thoughts and memories. All of that is to say that you don't have to invoke determinism or quantum mechanics to demonstrate that people aren't always consciously in control of their actions.

Some people are far more capable of compassion and forgiveness in the face of tragedy when they can see that a genuine accident occurred, or when they understand the generational trauma that laid the ground work for unthinkable choices. Why not take it one step further and recognize that we're all stuck on this involuntary ride and we all deserve a little grace because none of us could have chosen any differently?

Does this mean we expect the aggrieved to forgive the perpetrator? No. Does that mean we cease handing out jail sentences for dangerous crimes? No again. But if there is no free will in the choices we make, what's the point of punishing people? I get that people who hurt other people should feel remorse, and people who are dangerous should be isolated, but how can you say anyone deserves punishment when their actions are predetermined?

kybernetikos• 3 years ago

I am not a huge fan of justice-as-punishment, but the argument for punishment is straight-forward:

The deterrent effect of punishment does not require free will to work.

mewpmewp27• 3 years ago

But if there is no free will in the choices we make, what's the point of punishing people

What's the point of hitting a ball to score a goal if the ball had no free will and it was moving deterministically?

You punish people in order to provide incentives for people that would align with society's goals.

Human being, having the input and knowledge that they would get punished, would make them avoid doing certain things.

"Deserves" is just a way to provide some idea of a framework on what is the behaviour expected from people for society to perform at its best, together.

sonicanatidae• 3 years ago

This is a grand idea and I wish the world was capable of it, but it isn't.

With humans specifically, there is ALWAYS an asshole. Always.

There is always someone that will see a community, think those people are idiots, marks, suckers, etc. and will do whatever they can to take things from them, like their property, or their lives, because they look different, worship a different god, talk differently, etc. In other cases, it's a power thing. They will lie about whatever they need to, so assume control, then shit on everyone around them, for their own "betterment".

Humans will always be the absolute worst enemy of humans.

Again, I wish we lived in a world where your idea could work. It would be a much, much better place.

rexpop• 3 years ago

[If] they are predetermined to, the decision to rob the bank happened in their head.

That's nonsense. If they're predetermined, then the decision happened _outside_ their head. You might otherwise describe a river as its own source and tributary.

FredPret3• 3 years ago

If I build an AI that is biased toward creating malware, is it the AI's fault?

I say "maybe" because the calculations are performed by the AI, you say "maybe not" because of the creators' influence, but it still makes sense to me that we should debug/firewall/shut down that AI.

ithkuil• 3 years ago

Our natural languages are just too confusing to talk about this topic.

I think GP meant that when we say that a decision happens "inside the head" it means that the brain performs a computation where it combines all the "training* the brain got during its life so far and the perceptions of the current events and produces stimuli for muscles that will act on the world.

In order to produce the right kind of stimuli for the muscles the brain performs a modeling of what the future will look like after the muscles have been moved.

Imagine a scenario where you're walking with a child on the side of a road with some car traffic. You hold the child's hand.

The brain constantly asses the sensorial input of pressure in your hand and gauge what will happen if the child hand slips from yours. The brain computes the possible outcomes of that particular child veering off in the traffic and weighs in the horror of an accident that might happen into the decision making of whether to move the muscle of your hand just a little bit more so that the child's hand doesn't slip away.

This computation, the imagining of the accident happening and your reaction may or may not reach your awareness (i.e. feel conscious). It involves an enormous amount of assumptions about how the world works and about the things you value in life, your past experience, your expectations of torment in the case something bad happened while the child was under your watch.

This "computation" is determined by millions of factors that we colloquially smuggle under a single deceivingly simple word: "you"

All those parameters, what it means to be "you", is constantly changing based on what happens every single second to you. Everything that makes you you is based on this constant flux of input your brain processes, since the day you were born. The structure of your body as built by your genes also affects this since it produces the very machinery that processes these inputs and reacts to them causing new inputs to be fed, since the day you were born.

This incredibly complex mechanism, that involves constant imagining and predicting the future, weighting different predicted outcomes and reaping the rewards of correct ones and suffering the consequences of bad ones happens continuously in your head without any "agency" on your part. This very mechanism is your agency.

Whether each little step in this cascade of events that implements your "agency" is "deterministic" it doesn't change the fact that the computation that defines that agency must happen for the agency to have effects on the real world.

A deterministic evolution of a system still requires the system to exist. When you predict the exact movement of a billiard ball hitting other balls and the walls of the table you don't say "ah since I know exactly where the ball will go this means that the other balls and the table are useless, I'll just place the ball I care about in the final position and call it a day, since it's all predetermined anyway*. You don't say that because the positions of the other balls after the action will matter for the next actions.

Similarly, even if the underlying laws of physics are deterministic and can be in principle used to predict the behaviour of a complex system like brain, the act of predicting it must perform at the very least the same computation that the brain is doing (and much more, since that one brain constantly reacts to other things including many other brains making their own action/reaction loops?)

Even if we all lived in a simulation it would make sense to say that your brain makes the decisions. Because that's a useful way of talking about what this organ does.

It's a useful way to coarse grain reality in systems and environment. It's compatible with another way of looking at the overall simulated system from the POV of the simulator. Those two points of view can coexist and are equally real.

In practice our real world is so complex that even if in principle the laws of physics are deterministic, you need a pretty special being, (a laplacian deamon) with enormous compute power to carry out the predictions of the whole system. This being would have to be external to the system it is predicting and better have to effect on it otherwise it would have to simulate itself too.

Whether a laplacian daemon exists, or whether the underlying laws are indeed deterministic, doesn't change the fact that it's useful to describe individual agents in the system and talk about them in terms of what these agents so based on their local inputs and outputs.

Both views are "compatible" with each other. In the same way as the view of a gas being made of molecules that move and bump to each other each with their own position and momentum is compatible with the way of talking that the gas has a temperature and a pressure.

thebricklayr• 3 years ago

I like to ask people _how_ non-deterministic laws of nature would give rise to free will, and listen as they stumble toward the realization that determinism is orthogonal to the subject.

h0l0cube• 3 years ago

I think you would like ‘Determined’ by Robert Sapolsky (mentioned in the article), an endocrine neurobiologist and ethologist. He talks about predeterminism from a biological point of view, as well as implications on responsibility and justice systems in the absence of free will.

mo_42• 3 years ago

I always see references to free will when certain people start talking about > quantum mechanics. Why do people care if free will exists or not?
It doesn't seem to affect anything I can think of.

Most of the time, we don't care actually. Only in philosophical discussions similar to this one, we talk about free will.

To me, it seems that it's really an unnecessary assumption. In my everyday life I just don't care whether someone has free will or not. It's more about a meaningful interaction or to get something accomplished together.

I guess we need to separate simulations about the real world happening in our brains from the actual reality. Actual reality is based on quantum mechanics. Of course our brains developed as an organ that supports survival of the organism. So there's not really a reason to reflect an accurate picture of physical reality.

ajuc• 3 years ago

Free will is a very useful heuristic that lets you quickly determine when to stop looking for the root cause of events that interest you.

When a stone hits you - you want to attack the person that threw it at you and not the stone or that person's ancestors. So you divide the world into agents with free will and objects without. And stop asking "why" when you encounter the first agent in the root-cause chain.

It's a very effective heuristic, so people are strongly persuaded it's real.

GoblinSlayer13• 3 years ago

If you don't believe in free will, you become fatalist, and that's harmful for decision making. Hard determinists also often think in absurdist way, and losing ability into logic is very dangerous. The popular take how to use free will to punish everyone in most cruel way or how to evade such punishment by pretending to be a piece of inert matter is very dumb if not outright malicious and ignores the whole point that free will is primarily needed for the agent himself for survival and isn't needed for most cruel punishments at all. If you really want to cruel, just be cruel for no reason.

apatil• 3 years ago

Penalizing a crime might make sense for the purpose of deterrence even if there is no conscious free will. The size of the deterrent effect is a scientific question, and how to weigh the benefits of deterrence to society vs. the harm the punishment inflicts on the criminal is a moral question (where by moral I mean "should we do this").

However, penalizing a crime for the purpose of retribution makes no sense if there is no conscious free will. The criminal's consciousness experiences the harm of the punishment, but didn't cause the actions that constituted the crime. This is patently unfair.

I don't think conscious free will exists. One of the reasons I care is that, if most people shared that belief, we would talk and think about crime so differently that our approach to crime would change in the direction of becoming more humane.

For example, given the news of SBF's conviction for fraud, no one would be happy about the fact that he will likely experience many years in prison. We might be happy that the harm his actions caused has been stopped, and we may feel a kind of dutiful satisfaction in the knowledge that the system is working to deter and prevent this kind of harm. However, these emotions would be tempered by regret that a young man is going to lose part of his life, and we would be questioning whether there's any way to achieve the same level of harm prevention without inflicting such serious harm on one person.

bobsh• 3 years ago

It is massively distributed, the universe, with each local structure having its own determinations. It’s not pre-ordained so much as it is jit-ordained, where each thing (and sub-thing) is doing its own jitting, with each and every change of local state.

RagnarD• 3 years ago

Short answer: absolutely not.

The whole idea actually originated in wholly mistaken idea that Newtonian mechanics implied that the universe was a big clockwork, unfathomably complex but still predetermined. This rests on the false philosophic view that Newtonian mechanics are the only form of causality (or more broadly, that the laws of physics are the only form causality.)

Free will is a type of causality emerging from a particular kind of entity. It in no way violates any other type of causality, and vice-versa. Free will can't violate physics; you can't say "I have free will, therefore I can throw this ball to 50% of light speed." It pertains to an entity with free will making a choice among certain finite possible choices at any given time.

AndrewKemendo2• 3 years ago

Describing the precise positions and momenta of all the particles involved requires so much information that any statement of the initial condition is too complex to be a law.
Hartle suggested that quantum mechanics can solve this complexity problem. Because a quantum object’s wavefunction is spread out across many ‘classical’ states (cat alive or cat dead, for instance), you could propose a simple initial condition that includes all the complexities as emergent structures in the quantum superposition of these states.

So the one theory I have that I have absolutely no backing for and I recognize is not really falsifiable is that the purpose of humanity is to build general intelligence…

general intelligence is then supposed to build Laplace’s demon

Laplaces demon actually counting all the things would look like a giant condensation aka slowing down and “freezing” because there is no more entropy left and everything is pulled together which is the event that kicks off the next iteration of the universe, a.k.a. “the big bang” which then redistributes everything back out again (not sure why)

Again: I do not endorse this as what actually happened it’s just a crazy idea that feels right to me.

DontchaKnowit• 3 years ago

Pretty sick sci fi novel plot in there at the least

AndrewKemendo2• 3 years ago

Hey, if it worked for L. Ron Hubbard right…?

kromem• 3 years ago

If anything, it seems like QM existing makes a pretty good case free will also exists looking at more recent tech developments.

We have virtual worlds that could be described deterministically, such as with procedural generation and a seed function.

Often, these functions are theoretically continuous.

But also often, there's a mechanism by which the continuous function converts into discrete units.

Why?

In order to track state changes to what would otherwise be deterministic by free agents (i.e. players changing stuff).

That reality goes from continuous behavior to discrete upon interactions with free agents, and then goes back to continuous if the persistent information about those interactions is erased, looks a lot like what we might expect from a universe that needed to keep track of changes by free agents in an optimized manner (such that information erasure resets behavior back to functionally defined continuous behavior and not tracking discrete units).

Interestingly, this was predicted by the earliest philosophers thinking about quantized matter being solely governed by natural laws. They reasoned that if the laws of motion governing quanta were singular outcomes, that free will could not exist, thus given their belief in free will they hypothesized that quanta had variable outcomes which they likened to a 'Swerve' moving in a different direction suddenly from the other option. Over 2,000 years before we had experimental evidence that not only was matter made up of quantized parts, but that those parts were best described as moving probabilistically with variable outcomes.

That the behaviors of these quantized parts is time reversible seems less indicative of determinism and more like they serve the function of state tracking for interactions.

amai• 3 years ago

As the flow of a river on the big scale the flow of the universe might be entirely predictable. But we are living on the smallest scales of the universe. So we might simply not experience this determinism of the universe, as a molecule in the river might not notice that the river is flowing into the sea.

Does quantum theory imply the universe is preordained?

Related Stories