This assumes the functionality of brains can be fully captured as a deterministic mathematical function, but the function of the brain may well depend on nondet

This assumes the functionality of brains can be fully captured as a deterministic mathematical function, but the function of the brain may well depend on nondeterministic quantum states that can't be reduced to stateless functions: https://en.wikipedia.org/wiki/Quantum_mind https://en.wikipedia.org/wiki/Quantum_mind