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.
The definition of "free" and "will" are to shady to be scientific.
So there is no scientific arguing about it, just philosophical.
I like this take, but it also makes me feel like I could do a better job describing the intent of my question in more scientific terms. I hope to do so, here.
If one were to have sufficiently advanced technology akin to future MRI machines that could image the state of the human brain at Planck time resolution, my argument is that the very process of "a decision" (act, choice, idea, etc.) could be quantified. And if that is the case, then there must be chemical triggers and causal events that could have predicted that state of the matter and energy. And if that's the case, then we must really be products of our environment in an (currently) incomprehensibly large chemistry equation.
If any one decision could be quantized, reverse engineered, and then predicted through such means, then it stands to reason every decision can be. And if that's the case, free will cannot exist.
I agree with the other poster that you need to define what you even mean when you say free will. IMO, strict determinism is not incompatible with free will. It only provides the mechanism. I posted this in another thread where this came up:
The implications of quantum mechanics just reframes what it means to not have free will.
In classical physics, given the exact same setup you make the exact same choice every time.
In Quantum mechanics, given the same exact setup, you make the same choice some percentage of the time.
One is you being an automaton while the other is you being a flipped coin. Neither of those really feel like free will.
Except.
We are looking at this through an implied assumption that the brain is some mechanism, separate from "us", which we are forced to think "through". That the mechanisms of the brain are somehow distorting or restricting what the underlying self can do.
But there is no deeper "self". We are the brain. We are the chemical cascade bouncing around through the neurons. We are the kinetic billiard balls of classical physics and the probability curves of quantum mechanics. It doesn't matter if the universe is deterministic and we would always have the same response to the same input or if it's statistical and we just have a baked "likelihood" of that response.
The way we respond or the biases that inform that likelihood is still us making a choice, because we are that underlying mechanism. Whether it's deterministic or not it's just an implementation detail of free will, not a counterargument.
That was poetic and beautifully described.
Fascinating. đź––
Well-put
Now here’s an interesting take.
In principle, one might be able to predict behavior based on this model.
But I would asset that it is not possible to achieve these conditions no matter what godlike technology one has.
Let’s go simpler. We don’t want to predict a human we want to predict the path of one electron.
Starting from initial conditions we should be able to predict the path of that electron right Wrong!
It’s wrong because it is impossible, in a way that cannot be overcome in this or any universe, to know those initial conditions.
And that may seem like a technicality, but that’s exactly where the chink in the armor is: no matter how precise your model, it’s impossible to determine the state of a closed system, because it’s closed, and it’s impossible to predict the behavior of an open system, because its evolution is determined by its interactions with its surroundings, and you can’t get all that information.
So the idea of using physics to predict things precisely is a Platonic ideal, not a thing which can manifest in reality.
But unpredictability is not the same as free will. Doesn't free will imply a conscious decision being made?
But does it really matter if it's possible for us to make such predictions? If a hypothetical omniscient observer (i.e. Laplace's demon) could predict all your decisions, then that already shows that they're deterministic. Us not being able to actually do the determination wouldn't change the fact that there is a definitive state of the universe for any point in time.
I think this is my favorite answer so far.
Thanks, it’s mine as well.
The problem with your simplification is that it loses all predictability.
We can't predict an electron on a miniscule scale. But we certainly can predict the rock it is a part of falling.
We can't predict an electron. But we can determine and estimate with some probabilities. And on a higher scale the summation of individual behavior becomes quite predictable.
If we were to take only your electron argument, it implies we can not predict any material movement.
But the macroscopic universe responds to the subatomic universe because of the existence of chaotic systems which can amplify the tiniest difference. The prediction of the rock breaks down over time because it’s interacting with macroscopic inputs from chaotic systems around it.
The brain as far as we know works like nowadays "ai" it makes assumptions and tries to get the best and most fitting outcome for itself, this decision is influenced by a astronomical amount of data (thats the difference to nowadays ai) and (for the lack of better scientific measurements) emotions, meaning that theoretically it is possible to perfectly predict your choices, however, if you know about said prediction it will influence the system again.
Saying you have to pick between a Red and a Green Gummy Bear with the exact same taste, you will probably pick the red one because the subconscious associates red usually with food (red and yellow, that's btw why many fast food chains use those colors) however, if you are aware of this, this will likely end up in picking the green one as rebellious act against nature, wich again is predictable because humans are self aware and don't want "to be slave to their own instincts" now if you know about the prediction, the only way to "be unpredictable" would be to not chose a Gummy Bear thus "breaking" the test... Wich is predictable. This is of course a very simplistic experiment but gets the point across, you can't be unpredictable unless you break the laws of physics. This does however not prove or disprove the "free will" inside the system you are in, you could chose things freely, you just don't because its unnecessary and time consuming.
TLDR: we don't know.
Thank you for a fun answer.
I'll have to find some gummy bears.
I believe your scenario conflicts with Heisenberg's uncertainty principle. As far as I know it's one of the most ironclad laws of physics. As a quote I found in Wikipedia puts it,
Maybe? My layman understanding of that topic is that the act of observation collapses alternative waveforms down to a single observed state. And if that's the case, why couldn't you "observe" the whole brain?
I don't know enough to give details but I've watched PBS Space Time enough to know the answer is no.
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.
Do you have a degree in theoretical physics, or do you theoretical have a degree. ;)
I'm a theoretical theoretical physicist. That's double the theory.
Go back to work, Fantastic, you have a power plant to run.
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.
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
Free will can be defined as:
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.
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.
This is the best thing I’ve seen on Lemmy so far. Physics based philosophy, hell yes.
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.
CP symmetry has been experimentally measured to be violated. What we still believe is that our world is invariant under CPT symmetry.
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.
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.
Quantum Mechanics' hard indeterminism doesn't prove the multiverse interpretation, it's just one of several potential explanations for the randomness we see.
Also not very educated on this, but just throwing out what i thought was the outline here:
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: https://www.scientificamerican.com/article/common-interpretation-of-heisenbergs-uncertainty-principle-is-proven-false/
All I know is that this post makes me want to watch Devs again. OP, if you haven't seen it, check it out - one season miniseries about exactly this
Ohh thank you! Is missed this one - looking forward to it
Thanks for this recommendation. I'm going to have to watch it.
I'll have to check it out
carefully leaves his philosophical hard determinism at the door.
Well, I'd better learn a thing or two
One of the highest-level, most abstracted arguments against the idea of humans as deterministic goes like this:
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.
A functional truth, demonstrated by the success of its adopters, rather than by its intact logical proof.
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.
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.
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.
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.
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.
Wait really? How?
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:
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
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.
I don’t know what that is
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.
I'm glad you're enjoying this topic as much as I am
It's something I think about constantly, whether I want to or not! ;)
The system is diverging at every point in time :
I believe one has to see this before being able to apply it to free will explanations.
So, at what point is your personal decision making controlling the divergence so that it reflects your will? That is what I am asking.
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 ?
You can't answer the question.
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.
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.
It controls us, so the randomness has free will, and since the randomness is a part of us, we have free will
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:
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.
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 ?