I had a bit of a hard time fully understanding this absorbing 20-minute video by physicist Sabine Hossenfelder, but I think I get most of it. The main problem I had was understanding the notion of “superdeterminism” in quantum mechanics (QM) and what it really means for things like the famous double-slit experiment. But, like reader Darrell, who sent it to me, I think you need to listen. She might convince you that quantum mechanics isn’t really indeterministic!
Hossenfelder is intrigued by the notion of libertarian free will (which she rejects) and maintains that a belief in this sort of dualism was held by many physicists working on QM. As you probably know, interpretations of quantum mechanics have differed historically, with some having maintained that QM is truly indeterministic. (Hossenfelder defines “determinism” as the system in which “everything that happens is a result of what happens before”.) Most advocates of QM think that it is not deterministic, but inherently indeterministic. Einstein never believed that, rejecting that idea with his famous assertion that God doesn’t play dice with the universe.
As far as I knew, “Bell’s theorem” and subsequent tests of it completely rejected any determinism of quantum mechanics and verified it as inherently indeterministic. But, as Hossenfelder argues in this video, this is not so. She argues that a sort of “superdeterminism” holds in quantum mechanics, so that, in the end, everything in the universe is deterministic according to the known laws of physics.
I’m not quite sure what “superdeterminism” means is on the level of particles, but it appears to be something like this: “What a quantum particle does depends on what measurement will take place.” And once the measurement system is specified, somehow a quantum particle is determined to behave in a certain way. That’s what I don’t get.
But my inability to understand it may be because the idea of superdeterminism is inherently mathematical (she gives a simply equation for “superdeterminism of quantum physics”). Like in QM itself, everyday interpretations of superdeterminism might not make sense. Any reader who understands the concept is invited to explain it below. (Briefly, if possible!)
But the part that especially interested me beyond superdeterminism is that many physicists rejected such deterministic interpretations of QM simply from their own emotional commitment to dualistic free will. For if determinism be true everywhere, say some physicists, then free will cannot be true. Indeed, Bell himself believed in libertarian, you-could-have-chosen-otherwise free will, while Einstein, a hardnosed determinist, didn’t. As I’ve reported before, physicist, atheist, and Nobbel Laureate Steve Weinberg also believed in libertarian free will. He sat next to me at the Moving Naturalism Forward meeting in Stockbridge, MA several years ago, and after I gave my spiel on the nonexistence of libertarian free will, Weinberg told me that he didn’t accept that his behaviors were determined by the laws of physics.
What I find fascinating is that physicists were conditioning their ideas and research directions on a philosophical belief that humans must have libertarian free will. Perhaps that impeded the ideas of “superdeterminism”.
I have no dog in the indeterminism vs. superdeterminism interpretation of QM; I don’t know enough. That’s my fault, and it’s probably my fault that I don’t fully understand Hossenfelder’s explanation of superdeterminism in the video. She is a great communicator of science, and except for that puzzling bit, I greatly enjoyed her clear explanation. (A transcript of her video is here.)
So I’m with Hossenfelder in our rejection of libertarian free will, which is the most common view of free will. I don’t give a hoot about compatibilism, which I see as a matter of semantics that is far less relevant than accepting the implications that pure naturalism—including any quantum indeterminism—has for society and for human behavior.
Weigh in below, but watch the video first. It’s excellent, especially in how it interweaves science with an a priori personal commitment to libertarian free will.
And if “superdeterminism” of QM is now widely accepted, let me know.