Why SuperDeterminism Might be Real | Sabine Hossenfelder

Some interpretations of quantum mechanics assert that the apparent randomness in the universe is due to lack of information. But if we had full knowledge of all the information available, we could predict the future as well as know the past.

One such deterministic model is Bohmian mechanics, or pilot wave theory. But another model is Superdeterminism. What is Superdeterminsim? What are its benefits and drawbacks? Is it real or a fantasy? I give you my opinion and Sabine Hossenfelder rebuts.

Determinism is the idea that all events are predictable, because they are triggered by events immediately preceding them. So if we knew all the states of all the components of the universe at any moment to infinite accuracy, we could predict everything that will ever happen for all of eternity. And this applies to the past.

But Quantum mechanics doesn't seem to work this way, as identical sets of initial conditions can result in different outcomes.

This is because the outcomes of measurements cannot be predicted in advance. We can only predict their probabilities.

But Quantum mechanics is not deterministic, nor non-deterministic. It’s the interpretation of quantum mechanics where the non-determinism comes from. The Copenhagen interpretation is a non-deterministic interpretation.

But alternative interpretations of quantum mechanics are deterministic. For example the pilot wave theory, also known as Bohmian mechanics. In it, a particle’s position is predictable in advance, if we had access to hidden variable information.

In addition to being deterministic, a superdeterministic model postulates that the measurement setting, as well as the person doing the measuring, are correlated with the system being measured. In other words, the object being measured is not independent of the measurement set up.

This still violates Bell’s inequality and makes all the predictions of quantum mechanics. In a superdeterministic theory this statistical or measurement independence is not there. This allows superdeterminism to exploit a loophole in Bell’s theorem. So a superdeterministic theory can have local hidden variables, while still violating Bell’s inequality, and reproduce all the predictions of quantum mechanics.

Like Bohmian mechanics, Superdeterminism postulates real particles with real properties. But unlike Bohmian mechanics, the hidden variables can be local. Superdeterminsm says that there are hidden variables in the particles, and the detector, and even the person making the measurements, that caused the particle to have the results that we found when we measured it. So there is a correlation between the particle’s measured properties and the measurement settings, and the surroundings.

So what are some of the problems with Superdeterminism? Many physicists object to it because they say it rules out free will. But I don't think so because we don’t control quantum interactions by our decisions.

Superdeterminism requires hidden variables to exist, but no one knows what those hidden variables are, nor where they can be found.

So we don’t know what to look for, where to look for it, nor how it works. Furthermore, there is no testable prediction that Superdeterminism makes , that we could use to verify it, since it is not a theory, but a property of a potential theory.

Some toy models have been proposed, but they are not falsifiable. So even if we could conduct the tests, we could not be certain whether the results conclusively support superdeterminism or not.

Finaly, to me superdeterminism cannot even in principle be tested, because the correlations, if true, have always existed since the beginning of the universe, and will always exist, allowing for no variability. The only way to change this is if there were a way to change the initial conditions of the Big Bang, which is not possible.

Sabine Hossenfelders has some remarks about this in the video as well.

00:00 - Is Randomness built into the Universe?

02:33 - What is Determinism?

04:03 - Download Opera

05:46 - Is quantum mechanics really deterministic?

06:50 - How Bohmian mechanics works

08:29 - What did Bell's inquality prove?

09:19 - Nonlocal vs local hidden variables

10:07 - What is Superdeterminism vs determinism

12:20 - Merits of Superdeterminism

14:23 - Problems with Superdeterminism

17:16 - Sabine's rebuttal

19:05 - What's your input?