Last year, Sabine Hossenfelder and Tim Palmer published “Rethinking Superdeterminism” (Frontiers in Physics, 8, 139), a startling defence of determinism in quantum physics. Hossenfelder, who is a physicist with the Frankfurt Institute of Advanced Studies, is well known as a critic of the current direction of physics research. (You can go to her blog, YouTube channel or very readable recent book “Lost in Math” for more, but the book title gives you the general idea.) Palmer is a physics professor at Oxford, a Fellow of the Royal Society and a Dirac Medal winner for climate modelling. If you’re looking for a critique of the conventional wisdom in physics—one that isn’t based on crankery or amateur incomprehension—there aren’t many better people to get it from.
Their target is the apparent randomness of Quantum Mechanics.1 Notoriously, for example, QM refuses to predict for certain where particles will go. All it will give you are odds, statistical predictions about where they are likely to be found next. To find out where a particle actually goes, you have to wait for it to go there and take a look.2
This randomness famously offended Einstein, who insisted that “God does not play dice with the Universe”.3 But the great theoretician was defeated by experiment. Starting in 1969, physicists have observed violations of a formula known as Bell’s inequality, which can only happen if events are random (unless something even weirder than that is going on). Since then the consensus of physicists has been that, at the fundamental level, shit just happens.
So how do H&P deal with Bell’s inequality? By saying one of the even weirder things is going on.
The Bell’s inequality experiments depend on some assumptions about the experimental setup. Those assumptions are very plausible, but they are still assumptions. Over the years, physicists have tried to confirm them formally, and so close the remaining loopholes for determinism. But some theoretical outs remain.
The assumption that H&P target is, basically, that fundamental particles don’t care about physicists, and, in particular, that they aren’t coordinating their behaviour to make it look to physicists like they are acting randomly when they aren’t.
Imagine that whenever physicists set up devices to measure particles, they encountered particles with properties that were just right to screw up those experiments and make it look like the results were random. If the physicists had measured different features of those particles, they would have seen ordinary deterministic behaviour. But if they’d set up their experiments to measure those other properties, different particles would have found their way into the instruments, ones with properties that would make those experiments seem random.
That seems… pretty bizarre. Obviously microphysical particles don’t literally care what observations physicists make. Electrons have no interest in defending an orthodox interpretation of QM, or indeed any interests at all. And, conversely, the physicists don’t know what the particles’ properties are until after they’ve run the experiment, so they can’t be making their set-up decisions based on the particles’ properties. Which suggests that… something… would have to be making physicists’ decisions for them, in order to ensure they measure the right properties to get apparently random results. Even worse (!) experiments have shown that whatever that something is, it must have done its work billions of years in the past.
With that setup, you might be surprised to read that I think Hossenfelder and Palmer have done an excellent job. Indeed, they’ve convinced me. Not that superdeterminism is true—the actual physics of superdeterminism is still in its early stages, and might still prove fruitless. But that it’s a perfectly reasonable approach, and, in fact, less implausible than the alternatives. Moreover, it seems to me that their approach might shed light on some long-standing philosophical puzzles.
So: astrology on steroids and why I’m now a one-boxer. [To be continued…]
[1] There are deterministic approaches to fundamental physics besides superdeterminism, but these are weird in other ways. One is the “many worlds” interpretation of QM, where all the possible outcomes occur, but in different universes; which seems like an expensive way to save determinism. A less fantastical approach is called pilot-wave mechanics; but like the conventional view this is non-local”, which means that events in one place can have effects in distant places instantaneously, breaking the light-speed limit imposed by Relativity. Superdeterminism tries to rescue both determinism and locality.
[2] Of course in everyday life the number of particles involved in events is so huge that the averages rule; ordinary objects behave in predictable ways.
[3] For the benefit of any Einstein-theism-truthers, his actual words were ‘The theory [QM] produces a good deal but hardly brings us closer to the secret of the Old One. I am at all events convinced that He does not play dice.’ https://aeon.co/ideas/what-einstein-meant-by-god-does-not-play-dice