Full context:   In Physics II.3, I.7-9 and Metaphysics V.2, Aristotle holds that there are four kinds of answers to "why" questions: The four "causes" are not mutually exclusive. For Aristotle, several, preferably four, answers to the question "why" have to be given to explain a phenomenon and especially the actual configuration of an object. For example, if asking why a table is such and such, an explanation in terms of the four causes would sound like this: This table is solid and brown because it is made of wood (matter); it does not collapse because it has four legs of equal length (form); it is as it is because a carpenter made it, starting from a tree (agent); it has these dimensions because it is to be used by humans (end).