I think your mistake is to take “free will” to be something that exists or could exist (ie: in the same realm as physical forces). Which is, of course, just as “outside of physics” as the concept of a spirit or God.
“Free will” is a cultural-linguistic construct. How could it be anything else? The very concepts of discrete individuals, let alone agency, is effectively arbitrary as far as physical forces are concerned.
The “things” that free will concern are already many, many layers of abstractions (and cultural-linguistic construction) away from the individual deterministic interactions of what we currently understand to be physics.
And, like all abstractions, these are leaky and imprecise. So trying to model or analyse their behavior in terms of deterministic physical interactions has always seemed misguided to me.
Let's also think about Quantum Mechanics. It says the world is non-deterministic. A photon basically has FREE WILL to decide which slit it goes through in the double-slit experiment.
The Laws of Physics cannot dictate whether Schrodinger's cat dies because an atomic reaction happens, only that there is a specific probability for that happening.
So if the world is not deterministic neither are human brains. Physics cannot dictate what the brains think, it can only dictate what the probabilities for some neuron pathways opening or closing are.
“Free will” is a cultural-linguistic construct. How could it be anything else? The very concepts of discrete individuals, let alone agency, is effectively arbitrary as far as physical forces are concerned.
The “things” that free will concern are already many, many layers of abstractions (and cultural-linguistic construction) away from the individual deterministic interactions of what we currently understand to be physics.
And, like all abstractions, these are leaky and imprecise. So trying to model or analyse their behavior in terms of deterministic physical interactions has always seemed misguided to me.