That which first moves a circular motion is impartible, or without parts.
_Demonstration._—For let A be that which moves the first motion: for
it is necessary that there should be something of this kind, because
everything which is moved is moved by something. But A, if it is that
which first moves, will be immoveable: for that which is immoveable is
the leader of all things which are moved. And, since it moves a perpetual
motion, it will possess an infinite power of moving; for finite powers
have also finite energies: for energy proceeds from power. So that if
its energy is infinite, its power also will be infinite. Hence, that
which first moves a circular motion, must necessarily either be body,
or incorporeal. But if body, it is either finite or infinite. There is
not however an infinite body. And if it is a finite body, it will not
possess an infinite power. But the powers of things bounded according to
magnitude are finite, as has been demonstrated. Hence, that which first
moves a circular motion, is not a body. It is therefore incorporeal, and
possesses infinite power.