That it is not impossible for the Potential and the Active Intellect to be united in the one Substance of the Soul

SOME one perhaps may think it impossible for one and the same substance, that of our soul, to be in potentiality to receive all intellectual impressions (which is the function of the potential intellect), and to actualise those impressions (which is the function of the active intellect); since nothing acts as it is in potentiality to receive, but only as it is in actual readiness to act. But, looking at the matter rightly, no inconvenience or difficulty will be found in this view of the union of the active and potential intellect in the one substance of the soul. For a thing may well be in potentiality in one respect and in actuality in another; and this we find to be the condition of the intellectual soul in its relation to phantasms, or impressions in phantasy. For the intellectual soul has something in actuality, to which the phantasm is in potentiality;* For the substance of the human soul has the attribute of immateriality: but it is not thereby assimilated to this or that definite thing; and yet such assimilation is requisite for our soul to know this or that thing definitely, since all cognition takes place by some likeness of the object known being stamped on the knowing mind.Metaph. I, Appendix): hence the little intellectual light that is connatural to us is sufficient for us to understand with. But that the intellectual light connatural to our soul is sufficient to produce the action of the active intellect, will be clear to any one who considers the necessity for positing such an intellect. Our soul is found to be in potentiality to intelligible objects as sense to sensible objects: for as we are not always having sensations, so we are not always understanding.* But if this Platonic position were true, the absolutely better objects of intelligence should be better also relatively to us, and be better understood by us, which is manifestly not the case: for things are more intelligible to us which are nigher to sense, though in themselves they are less excellent objects of understanding. Hence Aristotle was moved to lay down the doctrine, that the things which are intelligible to us are not any self-existent objects of understanding, but are gathered from objects of sense. Hence he had to posit some faculty to do this work of making terms of understanding: that faculty is the active intellect. The active intellect therefore is posited to make terms of understanding proportionate to our capacity. Such work does not transcend the measure of intellectual light connatural to us. Hence there is no difficulty in attributing the action of the active intellect to the native light of our soul, especially as Aristotle compares the active intellect to light (De anima, III, v, 2).

2.76 : That the Active Intellect is not a separately Subsisting Intelligence, but a Faculty of the Soul
2.78 : That it was not the Opinion of Aristotle that the Active Intellect is a separately Subsistent Intelligence, but rather that it is a Part of the Soul