It has been shown that according to Aristotle, and according to all that defend his theory, the Universe is inseparable from God; He is the cause, and the Universe the effect; and this effect is a necessary one; and as it cannot be explained why or how God exists in this particular manner, namely, being One and incorporeal, so it cannot be asked concerning the whole Universe why or how it exists in this particular way. For it is necessary that the whole, the cause as well as the effect, exist in this particular manner, it is impossible for them not to exist, or to be different from what they actually are. This leads to the conclusion that the nature of everything remains constant, that nothing changes its nature in any way, and that such a change is impossible in any existing thing. It would also follow that the Universe is not the result of design, choice, and desire; for if this were the case, they would have been non-existing before the design had been conceived. We, however, hold that all things in the Universe are the result of design, and not merely of necessity; He who designed them may change them when He changes His design. But not every design is subject to change; for there are things which are impossible, and their nature cannot be altered, as will be explained. Here, in this chapter, I merely wish to show by arguments almost as forcible as real proofs, that the Universe gives evidence of design; but I will not fall into the error in which the Mutakallemim have so much distinguished themselves, namely, of ignoring the existing nature of things or assuming the existence of atoms, or the successive creation of accidents, or any of their propositions which I have tried to explain, and which are intended to establish the principle of Divine selection. You must not, however, think that they understood the principle in the same sense as we do, although they undoubtedly aimed at the same thing, and mentioned the same things which we also will mention, when they treated of Divine Selection. For they do not distinguish between selection in the case of a plant to make it red and not white, or sweet and not bitter, and determination in the case of the heavens which gave them their peculiar geometrical form and did not give them a triangular or quadrilateral shape. The Mutakallemim established the principle of determination by means of their propositions, which have been enumerated above (Part I., chap. lxxiii.). I will establish this principle only as far as necessary, and only by philosophical propositions based on the nature of things. But before I begin my argument, I will state the following facts: Matter is common to things different from each other; there must be either one external cause which endows this matter partly with one property, partly with another, or there must be as many different causes as there are different forms of the matter common to all things. This is admitted by those who assume the Eternity of the Universe.