 Just as Aristotle is “the First Teacher” for the philosophers, so his doctrine of the four causes is the starting point for their accounts of causation. In Physics, Aristotle introduces this doctrine as ancillary to the study of natural change: We must proceed to consider the character and number of causes, he says, because to know a thing is to grasp the “why” of it, and this is to grasp its primary cause. He then posits four types of causes to explain natural change (whether substantial, i.e., coming to be and passing away, or accidental, i.e., change of quantity, quality or place). In works of natural philosophy and metaphysics, Arabic authors defend Aristotle’s view that we must posit four (and only four) types of causes: material, formal, efficient and final. Generally speaking, they maintain that each type of cause contributes to the goal of explanation and that the four causes together are sufficient for explanation.