  We prove that superdeterministic models of quantum mechanics are
conspiratorial in a mathematically well-defined sense, by further development
of the ideas presented in a previous article $\mathcal{A}$. We consider a Bell
scenario where, in each run and at each wing, the experimenter chooses one of
$N$ devices to determine the local measurement setting. We prove, without
assuming any features of quantum statistics, that superdeterministic models of
this scenario must have a finely-tuned distribution of hidden variables.
Specifically, fine-tuning is required so that the measurement statistics depend
on the measurement settings but not on the details of how the settings are
chosen. We quantify this as the overhead fine-tuning $F$ of the model, and show
that $F > 0$ (corresponding to `fine-tuned') for any $N >1$. The notion of
fine-tuning assumes that arbitrary (`nonequilibrium') hidden-variables
distributions are possible in principle. We also show how to quantify
superdeterministic conspiracy without using nonequilibrium. This second
approach is based on the fact that superdeterministic correlations can mimic
actual signalling. We argue that an analogous situation occurs in equilibrium
where, for every run, the devices that the hidden variables are correlated with
are coincidentally the same as the devices in fact used. This results in
extremely large superdeterministic correlations, which we quantify as a drop of
an appropriately defined formal entropy. Nonlocal and retrocausal models turn
out to be non-conspiratorial according to both approaches.
