use, and final
cause, all melt into the single conception of form. In the first
place, the formal cause and the final cause are the same. For the
formal cause is the essence, the concept, the Idea, of the thing. Now
the final cause, or the end, is simply the realisation of the Idea of
the thing in actuality. What the thing aims at is the definite
expression of its form. It thus aims at its form. Its end, final
cause, is thus the same as its formal cause. Secondly, the efficient
cause is the same as the final cause. For the efficient cause is the
cause of becoming. The final cause is the end of {274} the becoming,
it is what it becomes. And, in Aristotle's opinion, what causes the
becoming is just that it aims at the end. The striving of all things
is towards the end, and exists because of the end. The end is thus
itself the cause of becoming or motion. That is to say, the final
cause is the real efficient cause. We may see this better by an
example. The end or final cause of the acorn is the oak. And it is the
oak which is the cause of the acorn's growth, which consists
essentially in a movement by which the acorn is drawn towards its end,
the oak. We may see this even more definitely in the case of human
productions, because here the striving towards an end is conscious,
whereas in nature it is unconscious or instinctive. The efficient
cause of the statue is the sculptor. It is he that moves the brass.
But what moves the sculptor, and causes him to act upon the brass, is
the idea of the completed statue in his mind. The idea of the end, the
final cause, is thus the real ultimate cause of the movement. Only, in
the case of human production, the idea of the end is actually present
in the sculptor's mind as a motive. In nature there is no mind in
which the end is conscious of itself, but nevertheless nature moves
towards the end, and the end is the cause of the movement. Thus the
three causes named all melt into a single notion, which Aristotle
calls the form of the thing. And this leaves only the material cause
unreduced to any other. So we are left with the single antithesis of
matter and form.

Now as matter and form are the fundamental categories of Aristotle's
philosophy, by means of which he seeks to explain the entire universe,
it is essential that we should thoroughly understand their
characteristics. {275} First of all, matter and form are inseparable.
We think of them as separate in order to understand them cle