Here we have the German theoretical physicist, author, and science popularizer Sabine Hossenfelder giving an 11-minute talk called “You don’t have free will, but don’t worry”. (My own talk on the subject is the first five words she uses, and I think we should be concerned—though not in the sense she means.) The video and a written transcript are on her website Backreaction.
If you’ve read this site, you’ll know that my own views are pretty much the same as hers, at least about free will. We don’t have it, and the fundamental indeterminacy of quantum mechanics doesn’t give it to us either. Hossenfelder doesn’t pull any punches:
This means in a nutshell that the whole story of the universe in every single detail was determined already at the big bang. We are just watching it play out.
These deterministic laws of nature apply to you and your brain because you are made of particles, and what happens with you is a consequence of what happens with those particles. A lot of people seem to think this is a philosophical position. They call it “materialism” or “reductionism” and think that giving it a name that ends on –ism is an excuse to not believe it. Well, of course you can insist to just not believe reductionism is correct. But this is denying scientific evidence. We do not guess, we know that brains are made of particles. And we do not guess, we know, that we can derive from the laws for the constituents what the whole object does. If you make a claim to the contrary, you are contradicting well-established science. I can’t prevent you from denying scientific evidence, but I can tell you that this way you will never understand how the universe really works.
She adds this about quantum mechanics, which used to be a life preserver used to rescue the notion of “freedom”, but has largely been abandoned because with two seconds of thought you see that it doesn’t give us any freedom of the will:
What about quantum mechanics? In quantum mechanics some events are truly random and cannot be predicted. Does this mean that quantum mechanics is where you can find free will? Sorry, but no, this makes no sense. These random events in quantum mechanics are not influenced by you, regardless of exactly what you mean by “you”, because they are not influenced by anything. That’s the whole point of saying they are fundamentally random. Nothing determines their outcome. There is no “will” in this. Not yours and not anybody else’s.
Taken together we therefore have determinism with the occasional, random quantum jump, and no combination of these two types of laws allows for anything resembling this intuitive idea that we can somehow choose which possible future becomes real. The reason this idea of free will turns out to be incompatible with the laws of nature is that it never made sense in the first place. You see, that thing you call “free will” should in some sense allow you to choose what you want. But then it’s either determined by what you
Now note that she hasn’t actually defined free will so far, but later on she dismisses the concept that most people, including me, adhere to (my emphasis):
Taken together we therefore have determinism with the occasional, random quantum jump, and no combination of these two types of laws allows for anything resembling this intuitive idea that we can somehow choose which possible future becomes real. The reason this idea of free will turns out to be incompatible with the laws of nature is that it never made sense in the first place. You see, that thing you call “free will” should in some sense allow you to choose what you want. But then it’s either determined by what you want, in which case it’s not free, or it’s not determined, in which case it’s not a will.
Now, some have tried to define free will by the “ability to have done otherwise”. But that’s just empty words. If you did one thing, there is no evidence you could have done something else because, well, you didn’t. Really there is always only your fantasy of having done otherwise.
I don’t agree here, for the “could have done otherwise” definition of free will is the one that most people adhere to, and the “otherwise” comes not from physical randomness but from will. In fact, Hossenfelder doesn’t even agree with herself, for shortly thereafter she implicitly defines free will this way—after having disposed of a few varieties of compatibilism (again, my emphasis):
I also find it unenlightening to have an argument about the use of words. If you want to define free will in such a way that it is still consistent with the laws of nature, that is fine by me, though I will continue to complain that’s just verbal acrobatics. In any case, regardless of how you want to define the word, we still cannot select among several possible futures. This idea makes absolutely no sense if you know anything about physics.
Here she implicitly defines free will as whatever facility enables us to “[select] among several possible futures,” and that’s the notion she refutes. I’m not sure why this idea is any more “empty words” than is “the ability to have done otherwise”.
At any rate, she goes on to conclude that the absence of free will doesn’t mean that our moral behavior will erode. I agree, of course. I think it means our “moral responsibility” disappears, for to me “moral responsibility” comes with the notion of “having an ability to make the ‘right’ choice”, an ability that doesn’t exist. I think we are responsible for our acts in the sense that it is our brains that have produced them, and thus for many reasons we should either be punished or rewarded. If you want to say “we are responsible because we have either transgressed or supported the acts society considers ‘moral'”, I’m not going to beef.
Hossenfelder concludes by reiterating that free will is “nonsense” and that “the idea deserves going into the rubbish bin.” True, that. But that doesn’t mean that we can’t be happy, for we have the illusion of free will, and we can use that as a crutch to go through life. She even suggest a psychological trick for being happy:
If it causes you cognitive dissonance to acknowledge you believe in something that doesn’t exist, I suggest that you think of your life as a story which has not yet been told. You are equipped with a thinking apparatus that you use to collect information and act on what you have learned from this. The result of that thinking is determined, but you still have to do the thinking. That’s your task. That’s why you are here. I am curious to see what will come out of your thinking, and you should be curious about it too.
Why am I telling you this? Because I think that people who do not understand that free will is an illusion underestimate how much their decisions are influenced by the information they are exposed to. After watching this video, I hope, some of you will realize that to make the best of your thinking apparatus, you need to understand how it works, and pay more attention to cognitive biases and logical fallacies.
I’m not sure how it helps to realize that “you have to still do the thinking”, when in reality the thinking is doing itself! Just because we don’t know what will happen—that our predictability is not so hot—doesn’t make us any less a bunch of meat robots who are slaves to the laws of physics. I know this, and yet I’m tolerably happy (for a lugubrious Jew). We know our “choices” are illusions, and my realization that these illusory choices come from a brain embedded in the skull of one Jerry A. Coyne does not give me the consolation Hossenfelder promises. But I still beat on, a boat against the current.
One more point: I’m not sure why compatibilists don’t just admit what Hossenfelder does instead of trying to find a definition of free will that people do have. The physicist Sean Carroll and philosopher Dan Dennett have taken that route, which I call the Definitional Escape rather than Hossenfelder’s There’s No Escape but Isn’t it Cool to Not Know what Comes Next.
The one thing I think Hossenfelder neglects comes from her last paragraph. If we do understand that free will in the Hossenfeldian sense is illusory, that has enormous consequences for the judicial system and for how we think about people who are either more or less fortunate than we are. I won’t dilate on this as I’ve discussed it to death. But yes, realizing that our brains are particles and obey the laws of physics should cause us worry—worry about how we treat prisoners and those who are mentally ill, and worry about how some people hold others responsible for making the “wrong choices.”
That aside, I applaud Dr. Hossenfelder for realizing the truth, which, as she says, is the ineluctable outcome of science, and for saying it so straightforwardly. I’m a big fan of hers. And I applaud myself for agreeing with her.