Again, that for the sake of which, or the end, belongs to the same department of knowledge as the means. For if a thing undergoes a continuous change toward some end, that last stage 10 is actually that for the sake of which. The arts, therefore, which govern the matter and have knowledge are two, namely the art which uses the product and the art which directs the production of it. For the helmsman knows and prescribes what sort of form a helm should have, the other from what wood it should be made and by means of what operations. In the products of art, however, we make the material with a view to the function, whereas in the products of nature the matter is there all along.
Man is begotten by man and by the sun as well.
The mode of existence and essence of the separable it is the business of first philosophy to define. Chapter 3 Now that we have established these distinctions, we must proceed to consider causes, their character and number. So clearly we too must do this as regards both coming to be and passing away and every kind of natural change, in order that, knowing their principles, we may try to refer to these principles each of our problems. In one way, then, that out of which a thing comes to be and which persists, is called a 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. Again, 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.