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.