Philosophy, by simply changing the name, can start the argument over again. How different is free will and what is within our control? Epictetus to Dan Dennett to Sam Harris. How different is that which each define? Well Sam tries to measure it, but what he measures is part body, beyond our control or power, so he finds we little or no free will.
Epictetus starts by defining what we have complete control of, our mind from input acceptance decision to output decision, bounded by our beliefs, values, and reality. Reality includes our talent and skill stack, our temperament. Our assents, positive and negative impulse, opinion, reason or logic, are all that is ours. We can, also, over time change our beliefs, likes and dislikes, some rationally, but one our beliefs become fixed, change takes time. Also what is marginally out of our power, hidden behind beliefs, likes and dislikes, will vary, person to person. It is those individual differences that make up the diverse population with different behaviors we see today.
We are bounded by reality on one side, and each persons reality is different. Some of us do not tolerate cold, others of us do not tolerate heat. Each persons skill stack is different, as unique as a fingerprint. Yet each of us has control of our thinking, our ability to accept or reject an incoming proposition, as long as that preposition does not conflict with our beliefs. If it conflicts with their beliefs, then it conflicts with their learned beliefs, for all beliefs are just learned, which often people have never rationally examined.
Some of what we learned is just wrong. We do not know what part or which "fact". We just do not know. Which or what. Some facts do not stand the logic test, other the total lack of evidence makes it unlikely, even inconceivable to some. So one wall of our free will or control is movable by adding or subtracting beliefs. This may be why AA and the like work, they change our beliefs and place behaviors out of our control. Oh well, who knows.
Free will, or within our power or control, is what personal responsibility is based on. So if instinct is to eat, we are not responsible for overeating; if what we eat is within our free will, our overeating is within our responsibility. Likely, is in that zone of partial control, where our free will permits the body to have input. We can use our power of impulse to move ourselves into a food free environment, but others may contaminate our environment or we wait too long, instinct takes over, and we lose control. Staying out of places where we lose control may be the best control some of us have if instinct is in overdrive.