PHYSICS that God made the world after so and so many ages had passed This does not mean that we cannot set a date for creation, but we have to so by counting backwards from the present, not, impossibly, counting forward from the Wrst moment of eternity Scripture tells us, in fact, that the world was created less than six thousand years ago (DCD IX 4, 12 11) Philoponus, Critic of Aristotle There was a well-known series of arguments, deriving from Aristotle, to the eVect that the universe cannot have had a beginning Augustine was aware of some of these arguments, and attempts to counter them, but a deWnitive attack on Aristotle’s reasoning was Wrst made by John Philoponus Philoponus’ work Against Aristotle, On the Eternity of the World survives only in quotations gleaned from the commentaries of his adversary Simplicius, but the fragments are substantial enough to enable his argumentation to be reconstructed with conWdence.2 The Wrst part of the work is an attack on Aristotle’s theory of the quintessence, namely the belief that in addition to the four elements of earth, air, Wre, and water with their natural motions upward and downward, there is a Wfth element, ether, whose natural motion is circular The heavenly and sublunar regions of the universe, he argues, are essentially of the same nature, composed of the same elements (books 1–3) Aristotle had argued that the heavens must be eternal because all things that come into being so out of a contrary, and the quintessence has no contrary because there is no contrary to a circular motion (De Caelo 270a 12–22) Philoponus pointed out that the complexity of planetary motions could not be explained simply by appealing to a tendency of celestial substance to travel in a circle More importantly, he denied that everything comes into being from a contrary Creation is bringing something into being out of nothing; but that does not mean that non-being is the material out of which creatures are constructed, in the way that timber is the material out of which ships are constructed It simply means that there is no thing out of which it is created The eternity of the world, The reconstruction has been carried out by Christian Wildberg, who has translated the reconstructed text as Philoponus: Against Aristotle on the Eternity of the World (London: Duckworth, 1987) 179