[r2_pilot]

Specifically, free will can't affect chemistry or physics, because what, to you, is free will, to me, is chemical reactions that lead to your body making movements. Since no known process is capable of altering these reactions, ergo you have no free will(defined as the ability to make choices outside of external interference, whatever that even means). Calvinism is relevant because they purport to believe in the same God you do, yet have wildly different and incompatible theories of mind that make no sense to you. As an outside observer all I can say is that either you or they are wrong, and it's likely you both are.

[freedomben]

Agreed, and to expand slightly, we do know that our brains are constructed on top of neurons, and neurons are way too big to be affected by quantum-level events. There's countless literature describing people who have had accidents or illnesses that damage parts of their brain and change personalities (typically without the patient being aware of any change and in most cases being in adamant denial about it), and we can now pinpoint quite precisely what many parts of the brain do. We even have AI that can now "read minds" to an extent based on measuring neural activity. The idea of "free will" is highly suspect given the deterministic nature of our brains. There are still some God of the Gaps arguments that try to save free will, but IMHO you have to really want to save it in order to accept many of those arguments. It's deeply uncomfortable to consider, but our brains are deterministic.

This is not my field at all so don't take my word for any of it, but I highly recommend people interested in this read or watch Robert Sapolsky's work. His books "Behave" and "Determined" are utterly fascinating and get very, very deep into this in a way that is challenging but understandable for a non-Neurologist.