  Regarding the second question, the idea that God is an agent cause of being may likewise seem at first to be a departure from Aristotle. But in fact Neoplatonist authors like Ammonius had explicitly argued that Aristotle’s God was an efficient cause of being, not just a final cause of motion. And a passage in On the Quantity of Aristotle’s Books — the aforementioned discussion of Koran 36: 79–82 — understands creation on the model of Aristotelian change, in which something passes from one contrary to another. In the case of creation, one contrary is “non-being” and the other “being.” Al-Kindi’s discussion of this has parallels in ninth century theological discussions of creation (see Adamson 2003). But his main source, surprisingly, is Ammonius’ student John Philoponus, a Christian Neoplatonist who had also spoken of creation as bringing something to be “from non-being.” What separates al-Kindi and Philoponus from Aristotle is their idea that this kind of “change” from non-being to being requires no subject. For example, for there to be a change from non-white to white, there must be some subject or substrate for both the privation of the whiteness and the whiteness itself (for instance the fence that goes from being non-white to being white when it is painted). God, by contrast, can bring about being ex nihilo, with no subject for the change. Al-Kindi emphasizes also that God’s creative act requires no time to be realized.