As in so many other aspects of his philosophy, Averroes' concept of God takes its point of departure from Aristotle. The ancient Greek philosopher argued that God was the “unmoved mover” on which the eternal motions of the heavens ultimately depended.
According to Aristotle, God was not an efficient cause in the way that a carpenter, say, is the efficient cause of a wooden chair. This is because efficient causation involves change, and God, if He is to act as an unmoved mover, cannot change and cannot be in motion. As the motion that the unmoved mover causes is eternal, then it follows that the unmoved mover must Himself be eternal. This eternal substance is what Aristotle understands as God.
Averroes's own understanding of God is heavily influenced by that of Aristotle, despite the fact that Aristotle was a pagan and Averroes was a Muslim. Nevertheless, Averroes genuinely believed that Aristotle's notion of God as the unmoved mover and as the final cause of the universe was actually beneficial to Islam, because it supplemented the teachings of the Qu'ran with science and common-sense.
Even so, Averroes's understanding of God was highly controversial among many of his fellow Muslims, as it involved rejecting the traditional notion of God as the efficient cause of the universe. Averroes does not believe that God is the creator of the universe in the same way that, as we saw earlier, a carpenter is the creator of a wooden chair. God's agency is that of final, not efficient, causality. In other words, the universe, and everything in it, is God's ultimate purpose.