 The study of nature was a search for answers to the question “why?” before and independently of Aristotle. A critical examination of the use of the language of causality by his predecessors, together with a careful study of natural phenomena, led Aristotle to elaborate a theory of causality. This theory is presented in its most general form in Physics II 3 and in Metaphysics V 2. In both texts, Aristotle argues that a final, formal, efficient or material cause can be given in answer to a why-question.