Neither predetermined choices nor random choices are free choices. Therefor, neither a deterministic universe, nor a universe where atoms sometimes randomly swerve, can host free will1, or so the argument goes. I will argue that determinism is fully compatible with free will.
Firstly, because a universe like ours is a chaotic system, a deterministic universe is only computable2, not predictable. That is, you could compute the next state if the current state was known. But you cannot jump ahead in time and calculate, unless you go at it step by step simulating every atom3.
Secondly, atoms don’t make choices nor desire things. But atoms in certain configurations can learn to recognize cats in videos. And atoms in a brain-like4 configurations can learn to model the world, imagine futures, to guess5 what its options are, to weight consequences of each option against desires — and then choose. Moreover, as we do so, we feel like something, we are conscious, we are aware.
Because choices and awareness go hand in hand and no choice can be predicted unless simulated step by step, atom by atom, we can say that we have aware will. Nobody can predict our choices, unless by letting us be aware6 and let us make those choices. The rest of the argument will show aware will is the same as free will.
Thought Experiment
As a thought experiment, imagine a deity7 who blesses some people with the gift of free will. On their 7th birthday, this deity shows them all the beauty of the universe and beyond. Grants them temporarily perfect knowledge; grants them free will. And asks them to select some things they really want. Then rewires the 7 year old brain accordingly. The next day, these children are no longer a product of the causal chain8, are no more a victim of determinism, no longer part of the “whole show”9, but are free.
As these kids grow up, go through life learning, experiencing, self-reflecting, will they be different from the rest of us? Circumstances will still shape them as it shapes us. They will make choices, and how the future unfolds still depends on those choices. Same for us. At age 30, nobody can tell the difference between the people who were given free will at age of 7 and the rest of us.
Layering Violation
Atoms don’t make choices, that is the wrong layer to be analyzing the the situation from. Choices are made by minds that can imagine futures, guess their options, and have goals and preferences by which to weight those options. The universe doesn’t give those things to minds, nor forces them on minds. Instead, minds learn them.
Places in the universe where there are minds are profoundly different than places where there are none. It is not the universe that is in control of this, but minds. How the future unfolds around a mind is very much dependent on the choices such a mind makes. And they do so in a way indistinguishable from a truly free mind.
A deterministic universe, or something fairly close to it10, is required for our brains to exist and function. But such a universe has no predetermined choices. While it will only unfold in one way, that unfolding fundamentally depends on the minds inside on the predictions they make and options they choose as they are aware.