Tags
Neuroscientists have pinpointed the origin of “free will” inside the human brain.
Actually, they found the part of the brain that processes our perception of having the ability to decide to control our movement. This is interesting, but tells us nothing about whether human beings have agency or whether that agency is merely a sense of agency coupled to a biochemical determinism in the physical body.
memoirandremains 
It’s unnecessary to look inside the head to observe human agency. We see each other going about, doing things, and causing this or that to happen. It is an empirical observation.
Free will is when a person decides for themselves what they will do, free of coercion or other undue influence. This too is something we empirically observe, every time we walk into a restaurant and see people perusing the menu and placing their orders.
Reliable cause and effect, in itself, is neither coercive nor undue. Thus it poses no threat to free will. Specific causes, such as someone holding a gun to the head and telling you to do something against your will, are meaningful and relevant constraints upon our ability to decide for ourselves what we will do.
But not reliable causation in itself. Every freedom that we have, to do anything at all, requires a deterministic universe, one where the results of our actions are reliable enough to be predicted. Free will requires a deterministic universe.
Choosing what we will do requires reliable mental processes running upon the hardware of the brain. Disrupt that process through illness or injury impairs our ability to choose.
Choosing itself is a deterministic process, where our decision is causally determined by our own goals and reasons, our own thoughts and feelings.
There is no contradiction between the two facts (1) that our choice is reliably caused (determinism), and (2) that it is reliably caused by us (free will).
When you say “determinism”, I assume you mean a “soft determinism”; the need for predictability and regularity — as opposed to a hard determinism where choice is a mere illusion.
If I need an adjective now for determinism, because of all the false versions floating around, then it would not be “soft”. I find it much easier if we presume “perfect” determinism at the outset, where every event that ever occurs, from the motion of the planets to the thoughts running through your head right now, were causally necessary from any prior point in eternity.
I hope that helps.
Okay that makes sense
A question – and I am not seeking to be argumentative – how does that understanding differ from fatalism? You don’t seem to be arguing for fatalism; but, I am not certain how you would distinguish it.
Fatalism shifts our control to external forces, “the Fates”. Hard determinism is just soft fatalism, shifting our control to “prior causes” and the “laws of Nature”. But both are incorrect. Correct determinism incorporates our causal agency, our control and our choices, into the overall scheme of causation. What we choose to do will be causally necessary, but it will still be us deciding what we will do.
Turns out we are not separate from reliable causation. We are each unique packages of reliable cause and effect, biologically purposed to survive, thrive, and reproduce, and with the intelligence required to imagine alternate futures, estimate the outcome of our choices, and decide for ourselves what we will inevitably do.