Quantum physicist have all but proven that at the quantum level, the smallest particles that make up our universe only come into physical reality when observed by a conscious being, or better put, by a chain of conscious beings leading all the way up to the ultimate consciousness, which from the Christian viewpoint, is God Himself.
Quantum physicists have also theorized that the universe is made up of 10-11 dimensions. We as human beings experience only four (width, depth, height, and time). The fifth dimension would include the scope of history as a unified, completed whole. God who exists in these higher dimensions outside of our space time continuum would thus have observed everything at once bringing the whole of history into physical reality immediately. Therefore, from God’s perspective the future is just as real and settled in His mind as the past and present, although we still experience time here moment by moment.
This dovetails perfectly with Isaiah 46:9-10, “Remember the former things of old: for I am God, and there is none else; I am God, and there is none like me, Declaring the end from the beginning, and from ancient times the things that are not yet done, saying, My counsel shall stand, and I will do all my pleasure:”
So in this sense, the future is predetermined, and it is settled according to the counsel and pleasure of God.