  When al-Kindi comes to argue explicitly against the eternity of the world, he uses Philoponus’ strategy of using Aristotle against himself. Aristotle famously held that there can be no such thing as an actual infinite. Thus, for instance, the body of the world cannot be infinitely large. Because the cosmos is finite in spatial magnitude, argues al-Kindi, nothing predicated of the body of the cosmos can be infinite. Since time is one of the things predicated of this body, time must be finite; therefore the world is not eternal.