A. About the Opinion of Aristotle

54. About the first point the answer is sufficiently plain from his intention, in diverse places, that he thought the motion of the heaven would last perpetually. For this he posited one reason, in Metaphysics 12.8.1074a17-23, as follows: “If it is necessary to reckon that every impassible substance has been allotted the best end, there will be no other impassible substance besides these,” besides these that are active causes of local motion.

55. From this the argument goes: if the best end of a separate substance is in causing the local motion of a celestial body, and if any such substance cannot lack its end, then it cannot not move.

56. This reasoning is derided by some [Richard of Middleton] who do not understand it as the Philosopher posed it, because even according to the Philosopher, Ethics 10.8.1178b7-8, Metaphysics 11.7.1064a33-b5, the perfection of these separate substances consists in speculation of truth; so their end even according to him is not, the way he seems to take it here, to move a body

57. But the procedure in this objection begins from an equivocation:

For the end in one way is the end that perfects, and thus is beatitude in the intellect or the will posited as the internal end of a separate substance, and the object of that act is posited as the external end (and this is what Aristotle himself understood in the Ethics, ibid.); and this end is the end simply.

58. In another way the end is said to be the ultimate result of the perfection of a thing, although it not be perfective of the thing. And in this way the Philosopher would say that not only are those separate substances perfect in themselves, but that from the fullness of their perfection it is necessary that they communicate that perfection to others; and thus are they allotted not only a first end but a second. This second end cannot be had without the motion of some celestial body.

59. This reasoning [n.55], thus understood [nn.57-58], can be formulated as follows: the most perfect substance does not lack anything that belongs to substance from the perfection of substance, whether that is the intrinsic perfection of it or the communication of its perfection outwardly; but to substance from the perfection of substance belongs that it not only be perfected in itself but that it communicate its perfection to another - by producing it; therefore this belongs most of all to impassible substances.

60. But they cannot produce any substance save by moving the heaven. This Aristotle himself supposes as having been made clear, in Metaphysics 7.2.1028b18-21, against the ideas of Plato.

61. That this is the mind of Aristotle and of the philosophers is accepted by Avicenna in his Metaphysics 1 ch.3, where he maintains that, in one way, metaphysics is useful for the other sciences because it directs and rules them (in which way too it can be conceded that a lord is useful to a servant, according to Avicenna there). But conversely, when taking ‘utility’ properly, it only belongs to another thing in view of an end; and in this way are the other sciences useful to metaphysics, and the servant useful to the lord. Therefore in the same way it will be possible, since ‘utility’ is equivocal, for ‘end’ also to be equivocal, so that to utility said in the first way there correspond the end that is the term and not the end that consummates, and to utility said in the second way there correspond the end of perfection.

Hence no philosopher posits that a necessity of externally acting belongs to the separate substances as if the things produced were to perfect the producing substances in some way; but that it is from the fullness of the perfection of those substances that they necessarily diffuse themselves to other substances.

62. The second reason of the Philosopher is as follows: anything that is permanent and sempiternal in relation to anything else that is permanent and sempiternal always and necessarily is disposed in the same way (the proof of this is that a relation between certain things cannot vary save by variation in one or other extreme; the extremes are thus [invariable] extremes if the sempiternal things are invariable). But the Intelligence that moves [the heaven] is a certain permanent and sempiternal substance, and the heaven is likewise; therefore, the sempiternal thing here has the same disposition to the other thing, as mover to moved.

63. If you object, “so when will a different disposition of the sempiternal to anything else begin?” - I reply: according to Aristotle, the first difference is in the parts of the uniform sempiternal motion (or uniform as a whole according to him); for because the motion is uniform from the uniform relation of a movable to a mover, therefore it has new different parts, and from this difference of parts another difference or variety can follow in the substances that are generated in this way. And thus from uniform causes, namely the Intelligence and the heaven and their being in uniform relation to each other, some uniform thing consisting of different parts, as motion, is first caused, and by means of that motion other things simply different are caused.

64. The third reason: whatever is in beings is either simply necessary in being or is for the most part or for the least part or open to either side. In the heavens nothing is open to either side nor for the least part, because both these would be marks of imperfection repugnant to such a body. Nor is anything there for the most part, because then sometimes the opposite would chance to be, albeit for the least part, which has never been seen (for never has the opposite of anything belonging to those regular motions come aboutThe observation at any rate of irregularities among the regularities has led to the replacement of this philosophical and Aristotelian system of necessities with our modern quantum mechanical and Einsteinian relative system of necessities. There is still necessity and still system, but a different system. The possibility of thinking a different system, however, was provided, not so much by different observations, as by the theologians next discussed who thought that this system, however consistent with observations, was not inevitable but optional and could, by divine omnipotence, be otherwise. ³⁶); therefore, whatever is there is simply necessary.