Sabine Hossenfelder on Free-Will and Determinism

I’ve always kind of liked Sabine Hossenfelder and I’ve even agreed with many of the things she says. But I think that she’s wrong about free will and determinism.

Here’s why:

backreaction.blogspot.com/2020/ … worry.html

I sense some possible circularity there. “Laws of nature” are defined by mathematical physics in such a way that differential equations accurately express them. So triumphantly pulling out the conclusion that all laws of nature are equivalent to these differential equations would just seem to reveal a premise that the physicists themselves baked in at the beginning.

One might want to argue that using differential equations in this role is justified by success in using them to make predictions. But that sort of argument introduces the induction and underdetermination problems.

Circular if physics decides initially that it’s going to model physical reality with one-to-one mathematical functions. The question then would be whether the posited one-to-one correspondence between initial conditions and future states is a feature of reality itself or just a feature of the mathematics that physicists have chosen to model reality. The old map vs territory distinction. Just because maps are flat and printed on paper doesn’t mean that those things are going to be true of the territory. Yet maps do capture something of the territory and can indeed be informative. I’m inclined to think of physics’ relation to reality in much that way.

And it certainly seems to be.

We have to call it something. The tradition is to call doctrinal positions ‘-isms’. Whether or not we should believe them depends of whether they make sense, contradict experience or are justified convincingly.

Her invocations of “we do not guess, we know” doesn’t seem to derive from science at all. It sounds like lay epistemology. It also seems to me to ignore the many questions about emergence that ask to what extent we can know the nature of wholes merely from knowledge of their parts in isolation.

Chaos may be deterministic, but doesn’t it also say that even infinitesimal differences in initial conditions can lead to dramatically different evolutionary histories? If that’s correct, then the question would seem to hinge on the more metaphysical issue of whether reality is always precisely defined to any level of precision, or whether it’s kind of fuzzy and indistinct when we try to be too precise. If there is any fuzziness at all, any superimposed states, quantum probabilities or wave function collapses, then chaos might destroy the one-to-one correspondence between past and future states that Sabine is assuming.

Here is where we need a better definition of “free will”. When we say that we acted freely, we mean that we chose the action and that it wasn’t imposed on us by some outside force. Free will isn’t synonymous with behaving randomly. It isn’t the same thing as epileptic seizures. A free action is an action that’s produced by our own motivations, informed by our desires, our knowledge and all kinds of mental states like that.

Where did those mental states come from? From earlier mental states and from the environment. So any reasonable concept of free will will have to acknowledge temporally short-term determinism. I don’t think that most champions of free will would want to argue with that. Why did I behave as I did? Because I wanted to. Why did I want to? Because of my desires and my understanding of the situation. Why did I have those desires and that understanding? Because of my history.

Where champions of free will start to object is where people like Sabine argue that our mental states now as we will ourselves to take some action were all determined by the state of the universe long before any of us were born. Sabine said it herself up above: “This means in a nutshell that the whole story of the universe in every single detail was determined already at the big bang.” It’s a form of creationism, except with the idea of divine purpose removed.

My alternative would be that determinism is probably quite accurate if we are talking brain states in milliseconds. If we know the prior state we can accurately predict the later one. As I argued above, our concept of free will depends on this being so. (Since I determine my own actions when they are freely willed.) But knowing my brain states ten years ago wouldn’t be much help in predicting what I am going to do today. Knowing the state of the universe 15 billion years ago wouldn’t enable any prediction that the Earth or human beings would someday exist, let alone me personally, let alone this particular action.

If we combine the probabilistic nature of quantum mechanics with chaos, we seem to have a decent argument against temporally long-range determinism. The past wouldn’t seem to determine the future in any detail. There seems to be a fuzzy imprecision built into the evolution of future states from past states. Hence Sabine’s differential equations metaphysics may not be the best model of what’s happening.

As I just suggested, proponents of free will needn’t be pushed into embracing the caricature that she’s so busily attacking. They will be perfectly happy saying 'I did X because I wanted to. Why did I want to? Because I have particular desires and understood the situation in particular ways.

In other words, free will not only doesn’t deny temporally short-range determinism, it depends on it. What free will does deny is that the state of the universe long before any of us were born, even the initial state of the universe at its origin event, has determined everything to come and is pulling everyone’s strings as if we were merely puppets.

In my opinion that’s just bad metaphysics. I’m inclined to think that there’s a lot more contingency and unpredictability to how reality unfolds.

Here is where we need a better definition of “free will”. When we say that we acted freely, we mean that we chose the action and that it wasn’t imposed on us by some outside force. Free will isn’t synonymous with behaving randomly. It isn’t the same thing as epileptic seizures. A free action is an action that’s produced by our own motivations, informed by our desires, our knowledge and all kinds of mental states like that.

Sounds like you’ve got a compatiblist definition of free will here.

What free will does deny is that the state of the universe long before any of us were born, even the initial state of the universe at its origin event, has determined everything to come

But here it doesn’t.

The only way to avoid the “determined everything to come” world is if you introduce some randomness. So does your concept of free will hinge on randomness, or not?

In another thread I posted the rebuttal by a PhD physicist student of Sabine’s free will stance, here.

Unfortunately it’s a bit long-winded with lots of run-on sentences and no paragraph breaks, but I find myself agreeing with it.

From the article:

This seems to accord with my own view that the laws of physics are not laws at all, but merely descriptions of regularities or occurrences, Some of the regularities occur without exception (behavior of gravity, speed of light, etc.) but others, like human actions, have great varieties. On this view the laws of physics never prescribe, only describe, and take their truth values from the way that the world actually is, rather than the world being the way that it is because of the laws,

Existence has to exist in order for us to exist.

This condition is necessary. It’s a condition.

Suddenly, Will is not “free”. It’s conditional.

So then the question is about complete determinism.

In an existence of complete determinism, it’s impossible to conceive of a will. Because it doesn’t exist.

Thus, compatiblism is the correct answer through proof of nothingness on either side.

Free will is for smug people that think they earned their good luck.

And for people who don’t want to think of themselves as helpless, trapped, powerless, without control, without options.

I’m curious if you have a compatibilist view of free will, or incompatiblist view

I’m a compatibilist.

Ah okay, fair enough, no further questions lol

Maybe, but probably not. I certainly think that free will is consistent with causality. But I’m less convinced that it’s consistent with determinism in the strong cosmic determinism sense in which everything that subsequently happens in the universe was already determined by the laws of physics and the initial conditions at the big-bang. I basically question the premise that this sort of strong cosmic determinism is a true description of reality. I’m not arguing for the proposition that it’s somehow compatible with free will.

Free will seems to me to be inconsistent with that sort of strong cosmic determinism. If the decisions that I make today were already determined by the state of the universe long before I make the decision, then free-will would seem to be false.

Yes. That’s why I wrote this –

Chaos is a funny concept.

It means that if the initial conditions are all different, the results would always be the same.

Also.

If the initial conditions are always the same, the results would be different.

I agree with this.

The way that I understand it, Chaos is nonlinear dynamics.

Imagine the graph of a straight line, with its x and y axes.

In calculus, linearity is defined by the idea that the smaller the change in the x axis, the smaller the change in the y axis.

But some functions aren’t linear. We see cases where as we make points on the x axis closer and closer together, points on the y axis don’t get closer to each other at all. They are scattered all over the place. So instead of getting a ‘line’ on a graph, like in the first example, we get what mathematicians call a ‘dust’.

It’s still deterministic, since each x value is determining a particular y value. But those y values aren’t gathering closer and closer to each other as we choose x values closer to each other. Even infinitesimal differences in x can result in big differences in y.

en.wikipedia.org/wiki/Nonlinear_system

Then introduce the idea from quantum mechanics that some physical variables and some physical states aren’t defined with absolute precision. Make those states a bit probabilitistic.

The whole determinism idea seems to revolve around the idea that reality is defined by one-to-one mathematical functions. (Which might be an artifact of how physicists decide to conceptualize things as opposed to an innate feature of reality, but never mind that.) Plug in an x and out pops a y. Determinism.

But what if the x is fuzzy and what if the function is nonlinear? Even if the value of x is imprecise by the smallest amount, we might get a whole assortment of very different y’s popping out. If that uncertainty is a feature of how reality really ontologically is, then determinism would seem to me to be false.

We could know an earlier state of the universe A with all the precision physically possible even in theory, but still be unable to predict even in theory how temporally distant state of the universe B turns out.

Humans are uncertain, reality is not.

Quantum mechanics shows a pretty uncertain reality.

What would it even mean for reality to be in an uncertain state?

Quantum mechanics.

Quantum mechanics is a theory about reality. It is not reality.

All of science consists of theories about reality. In that case, how could we know anything about reality, the noumena, the thing in itself? You can’t. And therefore you have no grounds to say reality is certain, uncertain, or anything at all. We just have access to our phenomenological sense impressions of the external world. In point of fact, we can’t even say that an external world exists at all, still less that it is “certain.”

Certainty applies to human knowledge.

I don’t think it makes sense to try to apply the word to reality.