The Four causes is simply four different ways of asking the question ‘why’. One can ask about (1) The material constitution (From what?) (2) The form (What was it?).. (3) The precipitating cause (By What?) and (4) The purpose (In aid of what?).
The Four causes is simply four different sorts of explanatory factor that ought to have better been called the four becauses since they are concerned to distinguish, not the different varieties of cause and effect, but rather the different senses in which the question 'Why?' can be asked.