CT 84: Incorruptibility of the Human Soul

In the previous section, Thomas discussed the nature of the human intellect, and its division into the possible intellect, a kind of storehouse of things we’ve understood in the past, and the agent intellect, our capacity to actively bring these things to mind. Now he’s moving on from this to the incorruptibility of the human soul. He says,

A necessary consequence of the foregoing doctrine is that the intellect whereby man understands is incorruptible.

By “incorruptible,” Thomas means that the intellect cannot pass away, cannot die. Natural things are generated, they come to be, and they are corrupted, they pass away. They are born, and they die. The intellect does not. Thomas goes on to show this in several ways.

Every being acts in a way that is conformable to its existence. The intellect has an activity which it does not share with the body, as we have proved. This shows that it can act by itself. Hence it is a substance subsisting in its own being. But, as was pointed out above, intellectual substances are incorruptible. Accordingly the intellect whereby man understands is incorruptible.

As shown previously, the action of the intellect is immaterial; and since every being’s action is conformable with its existence, the intellect’s existence must be immaterial as well—it “subsists in its own being.” That is, it’s an intellectual substance, and such cannot die.

Again, the proper subject of generation and corruption is matter. Hence a thing is immune to corruption to the extent that it is free from matter. Things composed of matter and form are per se corruptible; material forms are corruptible indirectly (per accidens), though not per se. Immaterial forms, which are above material conditions, are wholly incorruptible. The intellect by its very nature is elevated completely beyond matter, as its activity shows: we do not understand anything unless we separate it from matter. Consequently the intellect is by nature incorruptible.

Looked at another way, to be corruptible is to be material. A material object is composed of matter and form; the form gives form to the matter. An oak tree is matter with the form of an oak tree. Oak trees can die; and thus, indirectly, the tree’s form can die as well. Oak trees have no intellect, and no immaterial activity, and so the form must pass away with the matter.

But the intellect is an immaterial form, as it deals with forms as separated from matter and must be immaterial to do so.

Moreover, corruption cannot take place without contrariety; for nothing is corrupted except by its contrary. This is why the heavenly bodies, which do not admit of contrariety, are incorruptible. But all contrariety is far removed from the nature of the intellect, so much so that things which are contraries in themselves, are not contraries in the intellect. The intelligible aspect of contraries is one, inasmuch as one thing is understood in terms of another. Thus it is impossible for the intellect to be corruptible.

This last bit I had to think about for a while. “…nothing is corrupted except by its contrary.” What on earth does that mean?

Two propositions, A and B, are contraries if they cannot both be true. An oak tree exists; it dies; it no longer exists. There is no longer an oak tree. Those two statements are certainly contrary: there is an oak tree here, there is not an oak tree here. But I still think there’s something I’m missing about contraries and corruption.

But the point that Thomas is making about contraries is that although the propositions A and B cannot both be true in reality, and cannot coexist in fact, they can coexist perfectly well in my intellect. I am quite capable of holding both propositions in my mind at once—in fact, I must do so just to note that they are contraries. Thus, “contrariety is far removed from the nature of the intellect.” And since corruption requires contrariety, the intellect cannot be corruptible.

5 Responses to “CT 84: Incorruptibility of the Human Soul”

  1. Brandon says:

    Every change (including corruption) is in Aristotelian terms a replacement of one form by a contrary form so, as Aquinas says elsewhere, all corruption is from a contrary to a contrary. A way to think about the contraries is to think of it in terms of the introduction of a flaw. A flaw is contrary to what it makes imperfect; and corruption occurs when something, e.g., health, is diminished by the introduction of a flaw, e.g., sickness.

  2. Aha! Yes, that makes sense. Any change has to be a change from something that is to something that is not, or something that is not to something that is, or there’d be no change. And matter is the principle of change.

    Of course, that would seem to indicate that intellect is unchanging, which doesn’t appear to be Thomas’s intent.

  3. Brandon says:

    Elsewhere, Thomas does discuss the various senses in which the intellect is unchanging and changing, so it’s possible that he just thinks that that sort of discussion would be too much of a digression here. The point, I take it, is that the intellect itself cannot be changed into something else by one contrary pushing out the other contrary (since it is by its very nature able to take contrary forms simultaneously), although, of course, it can take on and lose new and old forms. An analogy might be made to those people who argued that matter was eternal. Obviously they can’t mean that matter never loses its forms and takes on new ones; but rather, that matter itself always remains, whatever forms it gains or loses. So here: the intellect can lose or gain accidental forms like habits and dispositions, but this is the sort of change that presupposes that the intellect continues through the change. What is at issue when we talk about corruptibility of the intellectual soul is whether the intellect itself can be gained or lost.

    By the way, by sheer accident, doing something else, I came across the poem by the early modern poet Sir John Davies in his poems on the immortality of the soul, which I thought was an interesting coincidence:

    She Hath No Contrary

    Perhaps her cause may cease, and she may die;
    God is her cause, His Word her Maker was;
    Which shall stand fixt for all eternitie
    When Heauen and Earth shall like a shadow passe.

    Perhaps some thing repugnant to her kind,
    By strong antipathy, the Soule may kill;
    But what can be contrary to the minde,
    Which holds all contraries in concord still ?

    She lodgeth heat, and cold, and moist, and dry,
    And life, and death, and peace, and war together;
    Ten thousand fighting things in her doe lye,
    Yet neither troubleth, or disturbeth either.

  4. Brandon says:

    Whoops! Sorry about the missing tag!

  5. Serendipity strikes again!