I tried to read Prof. 't Hooft's new paper The Cellular Automaton Interpretation of Quantum Mechanics A View on the Quantum Nature of our Universe, Compulsory or Impossible? and encountered difficulty about the motivation for introducing ontological states and cogwheel models.
Suppose quantum mechanics is deterministic, the probabilistic nature in the Born's rule must be an artifact. Namely the Born's rule somehow likes throwing a classical dice. The probability comes from our incomplete knowledge and limited computational power.
In another paper, How a wave function can collapse without violating Schroedinger's equation, and how to understand Born's rule, it is stated that
According to our ontological theory of quantum mechanics, the probabilities generated by Born’s rule, are to be interpreted exactly in the same terms. If we do not know the initial state with inﬁnite accuracy then we won’t be able to predict the ﬁnal state any better than that.
I am fine with all that. However, in the "The Cellular Automaton Interpretation of Quantum Mechanics", if I understood correctly, Prof. 't Hooft constructed a series cogwheel models to show these deterministic models exhibit Schrodinger equation.
My question is, what is the motivation for introducing ontological states and cogwheel model? Would the Schrodinger equation itself to be sufficient, since it is already deterministic anyway? If one wants to get rid of Bell's inequality, Schrodinger equation seems to be sufficient (Related post, Why was quantum mechanics regarded as a non-deterministic theory? ). And even tried to derive Born's rule?
If one feels the Schrodinger equation is insufficient, i.e. there is something behind it, why the object behind Schrodinger equation is so essential? I think I missed some important aspect in his paper... (Presumably I did not read it carefully enough)