sphericity, which is substantial and particular, an instance of the universal "sphericity," but not
identical with it. I do not think the language of the passages I quoted would readily support this
interpretation. And it would be open to the objection that the particular sphericity would, on
Aristotle's view, be unknowable, whereas it is of the essence of his metaphysics that, as there
comes to be more of form and less of matter, things become gradually more knowable. This is
only consistent with the rest of his views if the form can be embodied in many particular things. If
he were to say that there are as many forms that are instances of sphericity as there are spherical
things, he would have to make very radical alterations in his philosophy. For instance, his view
that a form is identical with its essence is incompatible with the above suggested escape.
The doctrine of matter and form in Aristotle is connected with the distinction of potentiality and
actuality. Bare matter is conceived as a potentiality of form; all change is what we should call
"evolution," in the sense that after the change the thing in question has more form than before.
That which has more form is considered to be more "actual." God is pure form and pure actuality;
in Him, therefore, there can be no change. It will be seen that this doctrine is optimistic and
teleological: the universe and everything in it is developing towards something continually better
than what went before.
The concept of potentiality is convenient in some connections, provided it is so used that we can
translate our statements into a form in which the concept is absent. "A block of marble is a
potential statue" means "from a block of marble, by suitable acts, a statue is produced." But when
potentiality is used as a fundamental and irreducible concept, it always conceals confusion of
thought. Aristotle's use of it is one of the bad points in his system.
Aristotle's theology is interesting, and closely connected with the rest of his metaphysics--indeed,
"theology" is one of his names for what we call "metaphysics." (The book which we know under
that name was not so called by him.)
There are, he says, three kinds of substances: those that are sensible and perishable, those that are
sensible but not perishable, and those that are neither sensible nor perishable. The first class
includes plants and animals, the second includes the heavenly bodies (which Aristotle