Third Theory.—viz., that of Aristotle, his followers, and commentators. Aristotle maintains, like the adherents of the second theory, that a corporeal object cannot be produced without a corporeal substance. He goes, however, farther, and contends that the heavens are indestructible. For he holds that the Universe in its totality has never been different, nor will it ever change: the heavens, which form the permanent element in the Universe, and are not subject to genesis and destruction, have always been so; time and motion are eternal, permanent, and have neither beginning nor end; the sublunary world, which includes the transient elements, has always been the same, because the materia prima is itself eternal, and merely combines successively with different forms; when one form is removed, another is assumed. This whole arrangement, therefore, both above and here below, is never disturbed or interrupted, and nothing is produced contrary to the laws or the ordinary course of Nature. He further says—though not in the same terms—that he considers it impossible for God to change His will or conceive a new desire; that God produced this Universe in its totality by His will, but not from nothing. Aristotle finds it as impossible to assume that God changes His will or conceives a new desire, as to believe that He is non-existing, or that His essence is changeable. Hence it follows that this Universe has always been the same in the past, and will be the same eternally. This is a full account of the opinions of those who consider that the existence of God, the First Cause of the Universe, has been established by proof. But it would be quite useless to mention the opinions of those who do not recognize the existence of God, but believe that the existing state of things is the result of accidental combination and separation of the elements, and that the Universe has no Ruler or Governor. Such is the theory of Epicurus and his school, and similar philosophers, as stated by Alexander [Aphrodisiensis]; it would be superfluous to repeat their views, since the existence of God has been demonstrated whilst their theory is built upon a basis proved to be untenable. It is likewise useless to prove the correctness of the followers of the second theory in asserting that the heavens are transient, because they at the same time believe in the Eternity of the Universe, and so long as this theory is adopted, it makes no difference to us whether it is believed that the heavens are transient, and that only their substance is eternal, or the heavens are held to be indestructible, in accordance with the view of Aristotle. All who follow the Law of Moses, our Teacher, and Abraham, our Father, and all who adopt similar theories, assume that nothing is eternal except God, and that the theory of Creatio ex nihilo includes nothing that is impossible, whilst some thinkers even regard it as an established truth.