Cause

In one sense, then, (1) that out of which a thing comes to be and which persists, is called ’cause’, e.g. the bronze of the statue, the silver of the bowl, and the genera of which the bronze and the silver are species.

In another sense (2) the form or the archetype, i.e. the statement of the essence, and its genera, are called ‘causes’ (e.g. of the octave the relation of 2:1, and generally number), and the parts in the definition.

Again (3) the primary source of the change or coming to rest; e.g. the man who gave advice is a cause, the father is cause of the child, and generally what makes of what is made and what causes change of what is changed.

Again (4) in the sense of end or ‘that for the sake of which’ a thing is done, e.g. health is the cause of walking about. (‘Why is he walking about?’ we say. ‘To be healthy’, and, having said that, we think we have assigned the cause.) The same is true also of all the intermediate steps which are brought about through the action of something else as means towards the end, e.g. reduction of flesh, purging, drugs, or surgical instruments are means towards health. All these things are ‘for the sake of’ the end, though they differ from one another in that some are activities, others instruments.

This then perhaps exhausts the number of ways in which the term ’cause’ is used.

In order to make this clear, we must observe that as there are few kinds of causes; matter is not a principle of action, but is the subject that receives the effect of action. On the other hand, the end, the agent, and the form are principles of action, but in a certain order. For the first principle of action is the end which moves the agent; the second is the agent; the third is the form of that which the agent applies to action (although the agent also acts through its own form); as may be clearly seen in things made by art. For the craftsman is moved to action by the end, which is the thing wrought, for instance a chest or a bed; and applies to action the axe which cuts through its being sharp.