Free will is a bit of an oxymoron, as will is to affect and without cause, there is no effect.

The purpose of all the neurological hard and software between the sense and motor functions, is to better strategize future actions. Otherwise it just slows our reaction times.

The mind is a model making process, so the assumption is there is some grand, overall map, model, frame out there, be it the mind of God, math, or any number of other beliefs and ideologies.

Yet models are necessarily a small subset of the larger reality. Too much information and they revert back to noise, but any thing less than total information and they are not complete. They break down over infinities and disappear at equilibrium.

As mobile organisms, this sentient interface our body has with its situation functions as a sequence of perceptions, in order to navigate, so our sense of time is as the present going past to future, but the evident reality is that activity and the resulting change turns future to past. Tomorrow becomes yesterday, because the earth turns.

There is no dimension of time, because the past is consumed by the present, to inform and drive it. Causality and conservation of energy. Cause becomes effect.

The reason why this is overlooked, is because the process of education, building that larger civilizational model, is a function of learning from one's elders, as they learned from their's, going back to the dawn of civilization. So this narrative flow is as foundational to our systems of building knowledge, as the earth is the center of our view of the cosmos.

So the future is not determined, because the act of determination only occurs as the present. The future is simply not fully computed.