I. According to the Philosophers

3. According to Aristotle’s meaning, since every passive power of matter is a power for contradictories, from Metaphysics 9.8.1050b6-27, and since, ibid., any eternal thing is necessary and so not potential in any way to contradictories, and since the heaven according to him is eternal, the consequence, according to him, is that there is nothing in the heaven that is in potency to contradictories; and as a result the heaven does not have matter, because if it did have matter it would be formally corruptible, as fire is; for given that there was no agent outside it that could corrupt it (‘because it does not have a contrary’ [Averroes Metaphysics 12 com.41]), this would not take from it its having within itself a principle of corruption, namely matter (whereby a thing is able to be and not to be), as fire does. And on this point Averroes in his treatise the Substance of the World seems to grasp Aristotle’s intention better than others who posit matter in the heavens.

4. However to demonstrate the incorruptibility in themselves of the heavens (which is the supposition here) one must proceed along the way of Aristotle in On the Heaven 1.2.268b13-269a32, 3.270a12-b25, and herein show that the heaven is not composed of any elementary nature. When this incorruptibility has been shown, the absence of matter will be shown, unless an incorruptible form could necessarily actuate a matter able of itself to lack the form, so that the disposition of incorruptibility would not be necessary on the part of both but only on the part of matter and, conversely, the heaven would be contingent as far as concerns the part of its matter; accordingly, where the necessity is not on the part of both extremes, it is not similar to the necessary inherence of some accident in a subject.

5. But if you say [e.g. Henry of Ghent] that celestial matter does not have the same idea as matters do that are susceptive of diverse forms, and for this reason it cannot of itself be changed from one form to another - this seems unacceptable:a

First, it seems indeed difficult to assign why there is this difference of idea in this matter and in that, because then there would beb two first matters of different ideas; the consequent is false, therefore the antecedent is too. Proof of the falsity of the consequent: there are not two first ends nor two first efficient causes of different idea; therefore likewise there are not two first matters of different idea.

a. a[Interpolation] Against the statement that ‘there is no matter of the same idea here and there’.

b. b[Interpolation] I prove by reason that positing that there is a matter of a different idea here and there is impossible, because if there were then it would follow that there will be...

6. Second, given this difference, the matter in the heavens is at least in potency to this form and to privation of this form, so that this matter is of itself in potency to contradictories although what potency to form it is in is not set down; but, as things are, matter is not the per se reason for corruptibility insofar as it is in potency to a form other than the one it has, but insofar as it is in potency to the privation of the form it has.

7. Likewise, the Philosopher only posits matter because of potentiality for change; in the heavens there is no potentiality for change save in ‘where’.

8. If it be said [e.g. Richard of Middleton] that the matter in the heaven is not in potency to contradictories, because the form of heaven completes the whole appetite of the matter, on the contrary: no form completes the whole appetite of its matter in respect of some other form save because it gives the matter an act opposed to privation of the form; but the form of heaven does not give an act opposed to privation of the form of fire;     therefore a privation of the form of fire remains there. Proof of the minor: no form gives an act opposed to privation of any form whatever unless it contains in itself all forms, at least virtually; but the form of heaven does not thus contain all forms, because it does not contain the intellective soul; therefore etc     .

9. From this follows further that, according to the philosophers, the heaven would not be formally alive, because then either the heaven would essentially be only a soul, and that an intellective one (because the philosophers only posited an intellective soul there), and thus the intellect would by itself be a quantity (which is unintelligible, for the heaven, as is plain, is formally a quantum), or there will be there, besides the soul that is of the essence of the heaven, something else that is per se perfectible by a soul, and thus there would be a passive potency there and a potency for contradictories, and so the heaven would not be eternal and necessary; hence, whether the Philosopher [On the Heaven 2.2.285a29-30] or the Commentator [Averroes On the Heaven 2 com.61, Metaphysics 8 com.12, com.41, Substance of the World ch.2] posits that the heaven is alive formally with a soul that is per se of the essence of the heaven, he seems at once to abandon the first position initially held [n.3].

10. Whatever may be true about Averroes, let us not say that Aristotle abandoned the first position; nor do his words compel us to impute this to him, because wherever he speaks of ‘soul’ he may be expounded as to the condition whereby the soul is a mover, not whereby it is a form, because the soul is the properly moving intelligence of this sphere, joined to it as the proper mover of it (there is only one such for one thing; this was proved by Avicenna, who openly distinguishes between the first produced intelligence and the soul of the first sphere, but there is no necessity for so much plurality).

11. In favor of this conclusion there is the Philosopher in Physics 8.5.257b12-13 who distinguishes what is ‘moved of itself’ into two parts, one of which is a moved only and the other is a mover only. This distinguishable thing is composed of two units, namely the mover and the movable, and the former truly moves and the latter truly is moved; but in us the soul does not move but is only the reason of moving, therefore it is moved per accidens since it is the form of the moved - the mover in the heaven is moved neither per se nor per accidens.