  The historical Aristotle did argue that the world is eternal and that whatever is eternal is necessary [On Generation and Corruption 338a1–4, Physics 203b 29, Metaphysics 1050b8–15]. His medieval followers took this to mean that while the world is ontologically dependent on God, there is no moment when it first comes to be and therefore does not owe its existence to a decision to create. As we might say, it exists not because of anything God does but simply because of what God is. Because God’s nature does not change, according to this position, neither does the existence or fundamental structure of the world. The most important consequence of this view is that God does not exercise free choice, which is to say that according to the Aristotelian alternative, the world is governed by necessity.