Superdeterminism is a bit odd in that it rejects even effective free will, at least in very specific circumstances. Let’s say you set up an experiment where the observer is given the free choice to measure a particle in a particular way. If you were Laplace’s demon and could see the precise state of the initial particle, that information alone would be sufficient to predict the choice the observer will make because they would be guaranteed to be pre-correlated with that value.

It would be like Final Destination where, just by looking at a single variable in a single particle, you would know with absolute certainty what conscious decision the observer would make ahead of time, and all their complex brain chemistry and stuff becomes unnecessary to predict what decision they will make, because you will know with certainty what the orientation of the measurement must be. You could try everything to stop them and change their mind and even fight them, but you’d find yourself entirely unable to change it, because the laws of physics would guarantee the particle would be measured on that particular choice of orientation.

You might be able to get around this by arguing that the these variables are fundamentally unobservable and hidden from us so that you still have effective free will, but then the model becomes pointless. Hossenfelder has suggested she thinks a hidden variable model should be testable and she thinks it may be possible to find patterns in the quantum noise and violations of the Born rule under specific circumstances. If these variables become even partially knowable then even effective free will, at least in certain very contrived circumstances, becomes doomed.

That is kind of the weirdest thing about it.