What are some physics-based arguments against hard determinism?

I don’t believe free will is real. I’m not a deep physics person (and relatively bad at math), but with my undergrad understanding of chemistry, classical mechanics, and electromagnetism, it seems most rational that we are creatures entirely controlled by our environments and what we ingest and inhale.

I’m not deeply familiar with chaos theory, but at a high level understand it to be that there’s just too many variables for us to model, with current technology, today. To me that screams “god of the gaps” fallacy and implies that eventually we WILL have sufficiently powerful systems to accurately model at that scale…and there goes chaos theory.

So I’m asking you guys, fellow Lemmings, what are some arguments to causality / hard determinism, that are rooted entirely in physics and mechanics, that would give any credit to the idea that free will is real?

Please leave philosophical and religious arguments at the door.

charonn0,
@charonn0@startrek.website avatar

I have a theoretical degree in nuclear physics, and it seems to me that sub-atomic scale events like quantum tunneling suggest that reality is neither fully determined nor fully chaotic, but something in between: probabilistic. Whether we can consciously affect the probabilities of our own actions remains an open question, but we can at least say that causality is not the whole picture.

bia,

Do you have a degree in theoretical physics, or do you theoretical have a degree. ;)

charonn0,
@charonn0@startrek.website avatar

I’m a theoretical theoretical physicist. That’s double the theory.

rbhfd,

I am Melllvar. Reader of the books! Knower of the theories!

Pelicanen,

Go back to work, Fantastic, you have a power plant to run.

moobythegoldensock,

We know cause and effect exist in the universe. We can use this to gain control of a lot of things in our world: for instance, when I push the letter “A” on my touchscreen, the letter “A” appears on my screen due to these cause/effect systems we have set up.

However, we know that the universe is not entirely describable via cause and effect. Heisenberg’s Uncertainty Principle precludes us from fully observing all aspects of a quantum system, Gödel’s Incompleteness Theorem shows that our knowledge of the universe will always be incomplete, and Schrödinger’s Cat shows us the absurdity of trying to make concrete claims about observed phenomena using probabilistic models.

If the universe was purely deterministic and we were theoretically able to gain all knowledge of it, there would not be free will. But this is not the universe we live in. The universe we live in is one where:

  • Probability exists, so we cannot fully predict the future state of events even with perfect knowledge (i.e. Schrödinger can never gain enough knowledge to predict whether the cat is alive or dead before opening the box, because the event is fully probabilistic.)
  • There are aspects of the universe we cannot fully observe, because by focusing on some aspects we must filter out others, so observation will never be fully reliable.
  • Regardless of how much we learn, there will always be knowledge we cannot fully categorize.

If events in the universe were fully deterministic, then free will would be an illusion, because everything could be traced to an earlier set of causes, and decisions would not actually exist. If events in the universe were random, free will would have no meaning, because decisions would be arbitrary.

But we live in a universe where things are not immutable, but things are not equally likely. I can roll a fair set of dice for randomness, or I can weight them to create an uneven probability, or I can select a number to eliminate probability altogether. And we all make decisions with limited observations using incomplete knowledge that will only have a partial effect to affect the probabilities of future events. And that means we shape events without controlling them, so all of our decisions have meaning. We can also tell objectively based on observations that some decisions are better than others, while at the same time conceding that no decision is 100% objectively right or wrong.

And that, my friend, is free will.

redballooon,

Slightly off topic, but the god-of-the-gaps has plenty of space in maths alone. The Incompleteness theorem by Goedel shows that in any mathematical system there will be unprovable truths.

I have no idea how to map that onto free will.

CodingAndCoffee,
@CodingAndCoffee@lemmy.world avatar

Yeah, I’ve thought about this a little bit but again my math isn’t so strong.

I guess approaching this more from computer science (something I’m more familiar with) you could compare with stuff like the NP Hard class of problems. And thus I offer that unproveable does not mean “wrong”. We generally “know” that P=NP is wrong but we cannot prove it only because we lack omniscience. Us lacking the information (in the physics sense of the word i.e. Hawking radiation) doesn’t mean the information isn’t there to be quantified.

CanadaPlus, (edited )

Free will is tricky, but there’s interpretations of quantum mechanics that aren’t deterministic. (Although multiple worlds QM is deterministic!)

That’s it. Everything else in physics supports determinism. The fundamental physics so far even conserves information/can be traced (CP-inverted) backwards.

Chrobin,

CP symmetry has been experimentally measured to be violated. What we still believe is that our world is invariant under CPT symmetry.

CanadaPlus, (edited )

Yes. As I understand it, to preserve CPT during a T violation, you have to invert (break) CP, but it can be done.

So, you could theoretically make a kaon plasma with weird unidirectional (and so T-violating) non-thermodynamic behavior if you had a strong enough box, but in the process it would inevitably accumulate handedness and electric charge in a way that preserves information.

CodingAndCoffee,
@CodingAndCoffee@lemmy.world avatar

Yeah, when writing this I sort of had the notion that any argument against hard determinism using quantum mechanics would instead 1) actually prove multiverse theory, and 2) therefore still prove in favor of determinism.

apt_install_coffee,

Quantum Mechanics’ hard indeterminism doesn’t prove the multiverse interpretation, it’s just one of several potential explanations for the randomness we see.

doublejay,

The very concept of the Self, presumably the director of free will, in context, is under threat. Eastern philosophies has held this position for centuries - now science seems like the idea :

https://bigthink.com/the-well/eastern-philosophy-neuroscience-no-self/

I don’t suppose any of you meditate by any chance ?

ComradeKhoumrag,
@ComradeKhoumrag@infosec.pub avatar

While quantum mechanics certainly gives random jumps, by no means is anything in control of those random processes (otherwise, they wouldn’t be random)

So, even though the universe may not be fundamentally deterministic, that doesn’t mean free will exists

burningquestion, (edited )

Quantum mechanics presents the most meaningful challenge to determinism because unlike chaos theory it asserts that reality really is indeterminate. Physicists have been wrestling with this problem since quantum mechanics was formulated. Even Einstein tried to prove quantum indeterminacy was false, but he shrank from the implications of his own solutions.

en.wikipedia.org/wiki/Hidden-variable_theory

Spoiler: there’s no strong evidence for most hidden variable theories. There has been a revival of interest in some deterministic re-interpretations of quantum mechanics over the last few years (recommend Lee Smolin, he has a book and some talks on Youtube re this discussion), but right now, the prevailing theory is that reality really is just fundamentally indeterminate. Hey, I hate it, makes my skin crawl, but that’s most likely the way it is based on the science.

EDIT – I’m not a strong advocate for free will in the abstract, but I do think the basic worldview underpinning certain forms of hard determinism has been superseded by a non-deterministic view in physics.

EDIT – for greater precision/clarity

CanadaPlus,

You don’t need a hidden variable for determinism though. Multiple worlds theory has no hidden variables but also no non-deterministic processes.

TokenBoomer,

This is the best thing I’ve seen on Lemmy so far. Physics based philosophy, hell yes.

lemmyseizethemeans,

Sensitive dependence on initial conditions. Time is kind of an iterative equasion so we can predict something to an extent but because we don’t no the initial conditions to an infinite degree there will always be chaos. That’s where the freedom is. As in, it’s both. There is deterministic (you didn’t choose where you were born, your economic status) but with those initial conditions you can make choices etc.

DaaftRaaft,

Also not very educated on this, but just throwing out what i thought was the outline here:

  1. Tiny differences in position or speed can lead to drastically different outcomes en.m.wikipedia.org/wiki/Chaos_theory
  2. We can only know position or speed en.m.wikipedia.org/wiki/Uncertainty_principleThus, predicting the future cannot reach 100% accuracy.

If this means that we might have free will i cant say, but if the world is wholly deterministic, the above at least underlines our lack of ability to predict it.

Regarding god of the gaps, annoyingly, the claim here is actually that we ”know” that we cant know:

”Thus, the uncertainty principle actually states a fundamental property of quantum systems and is not a statement about the observational success of current technology.”

Of course, only until falsified - field is always changing: scientificamerican.com/…/common-interpretation-of…

needthosepylons,
@needthosepylons@lemmy.world avatar

carefully leaves his philosophical hard determinism at the door.

Well, I’d better learn a thing or two

intensely_human,

One of the highest-level, most abstracted arguments against the idea of humans as deterministic goes like this:

When you treat people as if they’re automatons, they really don’t like it. And societies that don’t model people as having free will tend not to do so well.

needthosepylons,
@needthosepylons@lemmy.world avatar

That’s a good argument. It reminds me of the idea of free will as a necessary illusion. Something that us fundamentally not true, but without which societies can’t operate.

intensely_human,

A functional truth, demonstrated by the success of its adopters, rather than by its intact logical proof.

needthosepylons,
@needthosepylons@lemmy.world avatar

I’m trying to patch together my conception of free will and determinism to sum it up here in answer, but it’s full of holes. Basically it goes like this. Determinism is the rule of nature and, of course, mankind. Free will doesn’t exist. Some measure of freedom and emancipation, on the other hand, do exist. It’s hard to sum it up. Basically, very close to a spinozist stance, just with more holes and gaps. But I’ll stop here since the OP specifically asked to leave philosophical perspectives at the door.

intensely_human,

Free will can be defined as:

A state of existence in which one’s decisions are a predictor of one’s actions.

I don’t see where that conflicts with determinism, honestly. It’s two different levels of analysis.

If you define free will as, by definition, something that breaks the laws of physics, then free will, by definition, does not exist.

Kinda like when someone defines “magic” the same way. If “magic” is by definition something impossible, then by definition it doesn’t exist.

The questions get a lot more interesting when you define these things in a way that doesn’t make them, by definition, non-existent.

Maybe this type of reasoning should be called Trivial Dismissal.

Another example. If you define God as a man in the sky who controls everything, you’re not really an intellectual tour de force if you conclude he doesn’t exist. It’s the more interesting definitions of God that lead to more interesting discussion of whether God exists.

lolcatnip,

That seems to me like an entirely inadequate description of free will, because the interesting question isn’t how decisions lead to actions, but where the decisions themselves come from, i.e. whether the decisions are made freely. Unfortunately I’ve yet to see any definition of free will that doesn’t rely on hand-waving the definition of words like “free” or “could”. We have intuition about what those words mean, but they don’t appear to have any rigorous definition that applies in the context of defining free will.

A_A,
@A_A@lemmy.world avatar

The double-rod pendulum is one of the simplest dynamical systems with chaotic solutions. …from Wikipedia

This system is very simple yet even with initial conditions varying by (less than) Planck’s time or Planck’s length, theoretical resulting behavior changes after a few cycle.
Physical determinism says that there cannot be creation of (new) information yet this system does exactly that.

grabyourmotherskeys,

Here’s the thing. At what point does the causal chain get interrupted, free will kick in, and then the old causal chain fires back up? Because that’s what arguments like yours are implying.

The response is always that I don’t understand the theory you have put forward. I’ll grant that.

If the proof free will is tied to a seemingly stochastic system how is that “free will”. If I replaced your decision making with a random number generator would that be free will?

I sincerely hope you will engage with me here.

To be perfectly clear, my view is that we do not have free will but our limited set of information makes it seem like we do and so it is rational to continue on despite this. Put another way, I know the latest Mission Impossible movie was made months before I saw it, and that the outcome was predetermined, but wow, what a ride.

A_A, (edited )
@A_A@lemmy.world avatar

At what point does the causal chain get interrupted ( … ?)

The system is diverging at every point in time :

In chaotic systems, the uncertainty in a forecast increases exponentially with elapsed time. (… same article from Wikipedia)

I believe one has to see this before being able to apply it to free will explanations.

grabyourmotherskeys,

So, at what point is your personal decision making controlling the divergence so that it reflects your will? That is what I am asking.

A_A,
@A_A@lemmy.world avatar

at what point ( … ? )

Before answering this I need to know if you get the basics : what do you understand so far ? About chaotic systems ? About their variable rate of exponential divergence ? About their “liberty” ? About the fact we have such systems in us, only far more complex ?

And beyond any explanations, if you came to know we have free will, how could we stand the shame and guilt of not doing enough ?

grabyourmotherskeys,

You can’t answer the question.

A_A,
@A_A@lemmy.world avatar

It’s something I think about constantly, whether I want to or not! ;)

When I was young I was in that situation, with those same questions. But I was lucky : I had the right science and the right IQ and I found the answers. You are now thirsty and I gave you some salt ; if you are too blind to see it or too arrogant, bad for you, so i will not come back to this.

Goodbye.

grabyourmotherskeys, (edited )

You still haven’t answered the question and have made at least a couple of inferences about me that aren’t really accurate.

Anyway, people say it you can’t explain it you don’t understand it

Edit: sorry, wrong thread. I would still say you are making lot of assumptions.

How old do you think I am? Let’s start with that. :)

CodingAndCoffee,
@CodingAndCoffee@lemmy.world avatar

I’m glad you’re enjoying this topic as much as I am

grabyourmotherskeys,

It’s something I think about constantly, whether I want to or not! ;)

intensely_human,

Also it should be pointed out that this doesn’t require indeterminacy to happen. A perfectly deterministic Newtonian model of the double pendulum will exhibit the chaotic behavior.

It’s almost like if you put a black box around that pendulum, on which a light blinked each time the two pendula were parallel (ie when their joint was straight), the blinking of that light would seem “probabilistic”.

And it would be unpredictable too. Despite a perfect, zero-fuzziness Newtonian model determining the pendulum’s behavior, it would be impossible to predict the blinking of the light.

I’ve only had the briefest introductions to chaos theory but it’s fascinating.

A_A,
@A_A@lemmy.world avatar

Hi @intensely_human
You are the only one here who gets it easily even though I didn’t say much. Also in this tread I’m now up to 8 levels’ comments with @grabyourmotherskeys but we are getting nowhere & I am quite feedup. So if you could do something here I would appreciate.

Thanks

NoneOfUrBusiness,

And it would be unpredictable too. Despite a perfect, zero-fuzziness Newtonian model determining the pendulum’s behavior, it would be impossible to predict the blinking of the light.

Wait really? How?

intensely_human,

Basically a chaotic system is such that it tends to expand differences in path instead of shrink them.

An example of a non-chaotic system is a cannonball fired at X1 speed and X2 angle in a gravitational field, where you measure the distance Y being how far it flies.

You fire the cannon, the ball lands a little short of the target, so you know you can increase the firing velocity a bit and probably hit that target.

If you overshoot, you shoot slower next time. If you undershoot, you shoot faster. (I’m not playing with the angle here because the angle is slightly weirder, too low and angle and you undershoot, but too high an angle and you also undershoot).

So the relationship between the position of the muzzle speed knob, and the final position of the cannonball, follows a “linear” relation. If turning the knob 100 mph results in the cannonball landing 100 m away, and turning the knob 300 mph cresults in the cannonball being 500 m away, then because it’s a linear system you can reason that turning the knob 200 mph results in the cannonball being somewhere between 100 m and 500 m away.

In short, given a function mapping points in one space onto points in another space, a linear function ensures that two points close on the input space will be close to two points in the output space.

A chaotic function doesn’t preserve this. It scrambles the relationships between input and output. The lines between input points and output points cross each other; if they were hair they’d no longer be combed.

Say you replace your empty sky with a giant 3D pinball machine, and then you fire cannonballs into that.

You set the dial to 100 mph: cannonball lands 100 m away.
You set the dial to 300 mph: cannonball lands 500 m away. you set the dial to 200 mph: where will it now?

Because you’ve introduced the pinball machine to the sky, you can no longer predict that the cannonball is going to land between 100 and 500 meters away.

Maybe the 100 mph cannonball went under a bumper, the 300 mph cannonball went over it, but the 200 mph cannonball hits it, and bounces back over your head and it lands behind you.

Now you’ve got this table of inputs to outputs:

| muzzle speed | landing position | | 100 mph | 100 m | | 200 mph | -750 m | | 300 mph | 500 m |

(The choice to mix imperial and SI units is deliberate, by the way, because in real life these variables might have totally unrelated units. Like “value of a gram of gold in yen” “number of red blood cells passing into the brain per hour”. Nonlinearity isn’t a property specifically of space so I didn’t want it to look like it was an equation about space or distance)

Anyway, I’m probably wrong about 20% of that but it’s my understanding of chaos.

Now to your question:

How [would it be unpredictable]?

It relies on my assumption that there is an infinite amount of information in the positions and velocities of the particles.

(This is probably false but I’m carrying the argument through anyway to see where it goes)

In other words, that if you wrote the position or velocity of the particle it would take an infinite number of written digits to capture the position, or velocity, precisely.

The chaos comes from this: when there’s no longer a relationship forcing points “between” each other to be “between” each other in the output, it happens at every level. (for math people: linear isn’t literally a line, but any complex polynomial with real number coefficients. I think? Maybe it’s no compound terms that makes it linear? Something like that.It’s been 20 years and I lost my old diff eq book). But it can be a very squiggly line and still be mathematically a “linear function”.

Meaning that each input number is unpredictably related to the number next to it: 1’s relationship to 2 isn’t known. Whether 2 falls between 1 and 3 isn’t known.

But surely 1.5 is between 1 and 2 right? Nope it happens in the first decimal place too.

You might be able to predict the probability, because maybe the input can’t travel too far from the output. But after the system cycles, the positions are at least a little shuffled. And as time goes on, just the random shuffling will tend to move input lines further from each other.

The end result is that tiny deviations in input become huge deviations in output, and 1.11342 might map to 100 while 1.11343 maps to 975, and 1.11344 maps to 42, and 1.113421 maps to 4,350.

It’s like zooming into a fractal. Each tiny detail gets larger and larger and can move the entire thing.

And it can even happen with finite input (though it does become literally predictable by simulation, but is still computationally irreducible).

Shit I’m really bad at keeping things short.

It’s like pointing a camera at a live feed of itself. If you haven’t seen it, try it or look it up on youtube.

TL;DR: Tiny differences in input become huge differences in output in a chaotic system, meaning in a continuous universe imperfections too small to measure doom the prediction

CAPSLOCKFTW,
@CAPSLOCKFTW@lemmy.ml avatar

TL;DR: Tiny differences in input become huge differences in output in a chaotic system

You’re missing a “can” there. Tiny differences in input can become huge differences in output in a chaotic system. (Infinitely) many chaotic systems are structurally stable. For example consider systems that have the Anosov property.

intensely_human,

I don’t know what that is

School_Lunch,

I’m far from knowledgeable about this, but the only thing I’m aware of that might disrupt determinism is quantum mechanics. Something about particles at that level not having set values until they are observed, making them truly random. I have no clue how that could lead to free will. We still have no control over it. It’s more like they are the base that everything else is determined off of.

omnislayer88,

It controls us, so the randomness has free will, and since the randomness is a part of us, we have free will

Jamie,

One argument that might be made is that inconsistencies at the quantum level create an element of randomness that, while miniscule, could create massive cascading butterfly effects over the course of a large enough timespan. Whether those inconsistencies are enough to make more than a minimal difference in a single given lifespan is debatable at best, and the entire idea could be debunked if quantum physics was proven to be deterministic.

However, as it stands, we don’t have accurate methods of predicting quantum behavior.

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