Schopenhauer: If a cannonball got a will, it would think it willed to fly, and it would be right.
What else would it want?
It would take the cannon, the order to shoot, the pulling the trigger, etc. as mere conditions for its decision; the explosion of the powder would not be something determining its action a tergo but an instrument to its intention, just as gravity is an instrument of one using a diving board or a paperweight.
It is true that if all is a determined flow then there are no selves within it but only the illusion of choice; and if there is pure unconditioned choice there is no pre-determination or prediction either. Some sort of middle position is the only one that can preserve experience, but it’s not at all clear how to flesh this out. A hylomorphism of nature and self is probably the only way to inaugurate a research program.
Determinism or predicatability is an idealization of activity without a self. It is opposed to the belief that selves transcend all possible conditions and are utterly self-making spirits. Rationalism and pure self-creative relativism are thus two extremes that either need to be blended or transcended.