Medieval philosophy is the synthesis of philosophy and religion, or revelation. In Ibn Tufayl's Hayy Ibn Yaqzan, Hayy is a perfect example of how reason and revelation are used to determine the ways of the world. While trying to determine whether the world was created or eternal, Hayy believes he cannot resolve this question. Reason cannot prove that the universe was created or eternal. However, he determines that whatever the origin of the world, “the world must have a non-corporeal cause” (Tufayl, 2009, p. 131). Hayy supports this conclusion by first stating that if the world was created in time, then a creator who was not created must be the Cause. Then he supports his conclusion by asserting that if the world is eternal, then the universe must have an infinite force that causes the universe to move. Finally, Hayy supports his conclusion by establishing the characteristics of the First Cause which is at the origin either of creation or of the infinite movement of the universe. These characteristics include a non-physical body, an eternal being, infinite perfection, knowledge and goodness. In this article I will first discuss Hayy's conclusion that there must be a first cause if the world was created. I will then discuss Hayy's conclusion that there must be a first cause if the world is eternal. Finally, I will discuss Hayy's conclusion about the characteristics that this First Cause must contain. The first reason Hayy concludes that there is a First Cause is that if the world was created in time, then an uncreated creator must have created it. . Hayy decided that for the universe to be created in time, there had to be a point in time when the universe came into being from nothing. This meant that there must have been a time before the universe... middle of paper ... argument that the universe is eternal, the First Cause must have knowledge of how to keep the universe moving. In the argument that the universe is created, the First Cause must know how to create the universe. The Creator must also know the creators of the universe in which he created. He must know how to create every creature so that it survives in the universe. The last characteristic that the First Cause must have is goodness. In either case, the First Cause must be good to give parts of itself to a universe that are not necessary for its own survival. In the medieval philosophical tale Hayy Ibn Yaqzan, Hayy does not know whether the universe is eternal or created. He states that he cannot resolve this question because reason cannot prove that the universe was created or eternal. Nevertheless,