Computationally even relatively simple biological molecules can’t be emulated exhaustively – they exceed the computational power of the entire Universe (if it were a computer that is), thus purely first principles descriptions of any complex system are a nonsense. “Determinism” assumes infinite computational ability – Laplace’s Demon – but such just doesn’t obtain in the physical Universe.
So where has free-will vanished to, when even simple biomolecules are beyond deterministic prediction? It’s not free-will that’s threatened, but simplistic Determinism. Everything derived from “no free-will” is just cant and tendentious posturing. Human behaviour can’t be predicted in an absolute deterministic sense, even if we were just classical computers in essence. So give up the whole line of “there’s no free-will” – it’s meaningless from a scientific and human-level point of view. Only a God’s eye-view can make an utterly deterministic computation… and guess what? He’s not sharing the results with us!
Here’s the thing. Turing’s Non-halting proof means there’s no way of knowing in advance what a bit of not very complex software is going to do – will it continue forever or will it stop? Why should humans be any less complex and any less beyond prediction?
You might think “Well that doesn’t mean that the program’s future behaviour is not determined by its previous states.”
But by what do you mean “determined”? And who can judge whether it is or isn’t 100% “determined” or partially stochastic or partially “random”? In principle you can’t! So “determined” is operationally meaningless. It serves no descriptive purpose for complex systems. Doesn’t mean that non-determined things can’t exhibit statistical regularities – radioactive decay is inherently unpredictable, but it’s still layfully obeying the Law of Large Numbers and so forth. But what it does mean is the ideas of “freedom” and “free will” aren’t meaningless because lower level laws are inherently deterministic either. The evolution of a system down a particular branch of probable outcomes (one of Everett’s Many Worlds) is no more predictable than its evolution down any other branch, yet the ensemble of Possible Worlds is governed by quantum mechanics, a deterministic theory.
Freedom, free-will and Determinism.