As is often the case in the thought of Averroes, the central propositions he discusses are derived from Aristotle. He follows Aristotle in identifying four causes of change:
- The material cause, which depends on the matter from which the object that changes is formed.
- The efficient cause, which is an agent causing change.
- The formal cause, a movement which alters the arrangement or shape of something.
- The final cause, an intentional cause which permits a thing to become what it is supposed to be.
Although these causes are not all applicable all the time, they are certainly not mutually exclusive. Aristotle and Averroes both prefer explanations in which a move from potential to actuality is explained by all four causes. For instance, suppose a man plants an apple seed in the ground. The seed then grows into an apple tree. The man himself is the efficient cause. The material cause is the matter from which the appleseed and the environment around it are formed.
The formal cause would be a description of the biological processes allowing seeds to grow into trees. The final cause is whatever power in nature "intends" seeds to grow into trees. While the last cause could be stated as God, Averroes's Aristotelianism has made his work the subject of debate in the Islamic world. Other Muslim philosophers and theologians have argued that God is the cause of everything, and that Averroes is therefore wrong to follow Aristotle in separating the four causes.