A. The Opinion of Avicenna

6. There is here the opinion of Avicenna On the Soul p.5 ch.6.“Either we will say that the ‘intelligible forms’ are things per se existing, each of which is a species and a thing per se existing, but the intellect sometimes looks at them and sometimes turns away from them and later turns back to them... Or [we will say that] from the acting principle there flows into the soul form after form according to the request of the soul...and when later the soul turns from the principle, the flowing ceases; which if it were so, the soul would have to learn again every time just as at the start. We will say, therefore, that the last part of this division is true... , and so that ‘learning’ is nothing but the perfect aptitude of joining oneself to the agent intelligence until understanding comes to be from it. For when what coheres with the sought-for understanding passes ‘into the mind of him who is learning’ and the soul turns itself to look at it (now this looking at is the turning of the soul to the principle giving the understanding), the soul is wont to be conjoined with the intelligence and the virtue of simple understanding flows therefrom, which is followed by the flow of ordering; but if the soul turns away from the first principle, the forms come to be in potency, but in proximate potency. For when Plato is said to be ‘knowing intelligibles’, the sense is that, when he wishes, he will recall the forms to his mind; and the sense too of this is that, when he wishes, he can be joined to the agent intelligence so that understanding is formed in him by it. For this way of ‘understanding in potency’ is the virtue which acquires understanding for the soul whenever it wishes - because, whenever it wishes, it will be joined to the intelligence from which flows into it the understood form, which form is understanding most truly attained.” ²³ Look at it.a, b

a. a[Interpolation] because the superior intelligence is cause of the inferior as to being and as to knowledge, and so on by descending from the supreme intelligence; and at last a certain separate intelligence, superior to the intellective soul, causes in it intellectual knowledge (or an intelligible species), and thus the soul understands through actual intellectual conversion to that intelligence.

b. b[Interpolation] because the species of things flow from the separate intelligence for men’s having natural knowledge, so that - according to him - it is natural for our intellect to be turned to the separate intelligence so that it may understand (which whether it is true is plain from Reportatio IA d.3 nn.139, 153-155).

7. Against the opinion of Avicenna the argument is made [by Aquinas] that then [sc. if the soul had to turn to the separate intelligence to have intelligible species of things] the soul would be united to the body in vain, because this would be for no perfection of the united soul; for it is not for the perfection of it in itself, because form is not for matter but the reverse (Physics 2.9.200a24-34); nor is it for its perfection in operating, because it could have when not united intelligible species from the intelligence just as when united.

8. This reason [n.7] seems at fault because it seems to conclude that a blessed soul would in vain be united to the body; because this uniting is not for any perfection necessary to its operation, for it has an operation in which it neither receives nor will receive anything from the body.

9. Besides, according to some of them [sc. followers of Aquinas], the soul understands insofar as it is above the body - therefore it does not belong to it to understand insofar as it is united to the body; therefore neither is it united per se because of any perfection that might be necessary for its operation, namely for understanding.

10. The stated position [sc. of Avicenna, n.6] is rejected in another way:

First because all our knowledge arises from the senses (Posterior Analytics 2.19.100a3-8), and when a sense is lacking the science is lacking that accords with that sense (Posterior Analytics 1.18.81a38-b9, Metaphysics 1.9.993a7-8, Physics 2.1.193a7-9); for someone born blind cannot have a determinate knowledge of colors. But all this would be false if the intelligible species were impressed on the soul by the intelligence.

11. Further, if no habitual knowledge remained when the act of understanding does not remain [sc. as Avicenna supposed], then it would follow that the intellect was always equally in essential potency to understanding. For although some facility would be generated from the acts for turning the intellect toward understanding, yet because a form would never be possessed by which the intellect could understand (which would be the first act making it to be in accidental potency), but there would always be need to receive de novo such a form whereby it could operate - then in the intellect when not understanding would always be an essential potency for the act of understanding (because the intellect would always be in that potency to the form which is the principle of intellection), although an intellect possessing the acquired habit (consequent to act) could more easily acquire that form than another intellect not possessing it. Hence, although one passive thing is more disposed to undergoing the process than another, yet both are in essential potency before they receive the form; just as, if a piece of wood (when it was not heating) were not hot, and one piece of wood were dry and another damp, then although the dry piece would be more easily receptive of heat and the damp one with more difficulty, yet each (when not heating) would be in essential potency to heating. So it is here.