Before you begin this lesson, you are in potential of understanding it. If you do not read closely enough, you will still be in potential. We’re doing two chapters this week; actually, doing one short one and starting one very long one, which we’ll wrap up next week.
1 The truth of this statement clearly emerges from what was said above.
2 For, whatever is sometimes in act and sometimes in potentiality is measured by time. But the intellect of a separate substance is above time, as we have just shown. Therefore, it is not sometimes in act of understanding and sometimes not.
3 Moreover, there is always actually present in every living substance some vital operation with which it is endowed by its very nature, although other operations are sometimes present potentially. Thus, the process of nourishment is perpetual in animals, but not sensation. Now, as preceding considerations make clear, separate substances are living substances, and the only vital operation which they have is understanding. It follows that they are by their very nature always actually understanding.
4 Then, too, the philosophers teach that the separate substances move the heavenly bodies by their intellect. But the movement of the heavenly bodies is always continuous. Therefore, the act of understanding exercised by separate substances is continuous and perpetual.
5 And the same conclusion follows even if that teaching is denied, because separate substances are higher than the heavenly bodies; so that, if the proper operation of a heavenly body, namely, its movement, is continuous, for all the more reason will the proper operation of separate substances, namely, understanding, be continuous.
6 Furthermore, whatever sometimes operates and sometimes does not operate is moved either through itself or by accident. Changes occurring in the sensible part of our nature, then, are responsible for the fact that we are sometimes understanding and sometimes not understanding, as Aristotle observes in Physics VIII . But separate substances are not moved through themselves, since they are not bodies, nor are they moved by accident, because they are not united to bodies; so that in them understanding, which is their proper operation, is not intermittent, but continuous.
Notes Angels are always up and running.
1 Now, if separate substances understand those things which are intelligible through themselves, as was shown, and if separate substances are intelligible through themselves, since, as we have also seen, freedom from matter makes a thing intelligible through itself, then it follows that separate substances have separate substances as the proper objects of their understanding. Each of them, therefore, knows both itself and others.
Notes So much for privacy.
2 Indeed, each separate substance knows itself otherwise than the possible intellect knows itself. For the possible intellect exists as in potency in intelligible being, and becomes in act through the intelligible species, just as prime matter is actualized in sensible being by a natural form.
Now, nothing is known, so far as it is only in potentiality, but so far as it is in act. That is why the form is the principle of the knowledge of the thing which becomes in act through the form. And the cognitive power likewise is rendered actually cognitive through some species. Thus, our possible intellect knows itself, thanks only to the intelligible species whereby it becomes in act in intelligible being; and for this reason Aristotle says in De anima III  that the human intellect “is itself knowable in the same way as other things are,” namely, through species derived from phantasms, as through proper forms. But separate substances by their very nature enjoy intelligible being actually; so that each of them knows itself through its essence, and not through the species of another thing.
3 Now, as the likeness of the thing known is in the knower, so in every case is the knowledge. But, one separate substance is like another as regards the nature of the genus that such substances have in common, while they differ from each other in species, as was made clear above. It would then seem to follow that the one separate substance knows the other, not according to the proper nature of the species, but only as regards the common nature of the genus.
4 Some therefore say that one separate substance is the efficient cause of another. Now, in every efficient cause there must be the likeness of its effect, and, similarly, in every effect the likeness of its cause must be present; for every agent produces its like.
Thus, in the higher separate substance there exists the likeness of the lower, as in the cause resides the likeness of the effect; and in the lower is the likeness of the higher, as in the effect dwells the likeness of its cause.
Now, in non-univocal causes the likeness of the effect exists in the cause in a higher mode, while the likeness of the cause is in the effect in a lower mode. But the higher separate substances must be non-univocal causes of the lower ones, since the former, placed in diverse grades, are not of one species. Therefore, a lower separate substance knows a higher substance in a lower way, according to the mode of the substance knowing and not of the substance known; whereas the higher knows the lower in a higher way. This is expressed as follows in the work On Causes [VIII]: “An intelligence knows what is below it and what is above it, according to the mode of its substance, because the one is the cause of the other.”
Notes This is played out in human classrooms everywhere. Once again, inequality reigns.
5 But, since it was shown above that separate intellectual substances are not composed of matter and form, they cannot be caused except by way of creation. We have also proved that to create belongs to God alone. One separate substance, therefore, could not be the cause of another.
6 It has been demonstrated, moreover, that all the principal parts of the universe are created immediately by God. Hence, one of them is not caused by another. Now, each of the separate substances is a principal part of the universe, much more than the sun or the moon; since each of them has the nature of a species all its own, which is nobler than that of any corporeal things. Therefore, one separate substance is not caused by another, but all are immediately from God.
Notes Angels cannot make baby angels.
7 So, according to what was said above, each of the separate substances knows God, by its natural knowledge, after the manner of its substance; and through this knowledge they are like God as their cause. But God knows them as their proper cause, possessing in Himself the likeness of them all. Not in this way, however, could one separate substance know another, since one is not the cause of another.
Notes Chapters 8–20 next week.