The question of free will can in principle be settled by answering the question of whether anything could turn out differently due to the act of a will which is not itself determined by prior events.
Allow me to pose the following thought experiment.
Suppose there was a “god” in the Deistic sense, who set everything in motion, and started the Big Bang. Suppose also that this being was somehow able to control the exact initial condition of the Big Bang. I am not sure if the uncertainty principle would apply in such a case, but for the moment assume that this being was not constrained by the uncertainty principle, and was able to determine the exact conditions of the Big Bang.
Would it be possible, in principle, for this being to determine every event which would happen in the future history of the universe? If quantum uncertainty would not allow for an exact prediction, would the being be able to determine the general course of events, such as knowing that intelligent life would arise on earth?
To put it another way, suppose we had two universes started by two Big Bangs, identical in every respect. Would the future histories of these universes be identical, assuming the same physical laws we observe in our universe apply in both identical universes?
If there was another universe that started with the exact initial conditions as ours, would another me exist, typing this identical thought in exactly the same sequence, etc?
Furthermore, assume that humanity develops to the point where it can create a Big Bang within our own universe. Would it be possible, in principle, to set the conditions of this event in such a way that an world would form which supported life, and on which intelligent beings would arise?
If we could do such a thing, we would be the gods of those beings!