Some questions on the soul, Part II

In a recent post I responded to a reader’s question about the Aristotelian-Thomistic understanding of the soul.  Another reader asks another question.  Let me set out some background before addressing it.  From the Aristotelian-Thomistic point of view, strictly intellectual activity -- as opposed, say, to sensation or imagination -- is not corporeal.  This is the key to the soul’s immortality.  A human being is the sort of thing that carries out both non-corporeal and corporeal activities.  Though less than an angel, he is more than an ape, having a metaphysical foot, as it were, in both the immaterial and material camps.  That means that when his corporeal operations go, as they do upon death, it doesn’t follow that he goes.  He limps along, as it were, reduced to the non-corporeal side of his nature.  This reduction is drastic, for a great deal of what we do -- not only walking, talking, breathing, and eating, but seeing, hearing, smelling, and so forth -- depends on the body.

 
Even intellectual activity depends in part on the body.  Though not sufficient for intellectual activity, neural processes are, in the normal case, necessary for it.  As Aquinas writes, “the soul united to the body can understand only by turning to the phantasms, as experience shows” (Summa Theologiae I.89.1).  Consider, for example, the way that even when you grasp geometrical abstractions like triangularity -- which you cannot strictly picture before your mind’s eye, since any triangle you picture will have limiting features that aren’t true of triangularity per se -- you make use of mental imagery as an aid to intellection.  Consider also that intellectual activity can be severely impaired or even undermined entirely by brain damage.  For sensation and imagination are corporeal functions. 

This brings us to the reader’s question.  He writes:

[B]rain damage inhibits the exercise of the intellectual power.  In other words, as long as soul and body are united, you need a good functioning brain to engage in intellectual activities; therefore it seems the intellect is dependent on the brain… 

[So] it does seem to be a contradiction to say that the intellect can function independently of the brain after abstraction occurs.  How can [one] say that the intellect can function independently of the brain but yet is inhibited in its power when the brain is damaged?  It would seem that the power of intellection cannot be achieved independent of the brain, which of course would ruin [the] argument… for its survival after bodily death.   

End quote.  There are really two issues here which need to be disentangled.  One is the question of the intellect’s survival of death, the other concerns its operation after death.  Now the facts the reader calls attention to don’t affect the former question.  Remember, the Thomist allows that in the intellect’s normal state, corporeal activity is necessary for its operation -- it’s just not sufficient for it, which is why intellectual activity is essentially incorporeal.  Even if corporeal activity were necessary full stop, and not just under normal conditions, it wouldn’t follow that the Thomist’s arguments for the intellect’s immateriality are undermined.  Hence it wouldn’t follow that the soul does not survive death.  What would follow is only that it would be inert after death.  So the reader is just mistaken to think that the dependence of intellectual activity on the brain threatens to “ruin [the] argument… for its survival after bodily death.”  At most it threatens the claim that the intellect can function after death.  A proponent of the “soul sleep” theory of personal immortality could happily accept that, and argue that the intellect functions again only when the body is restored to it at the resurrection.

Now of course, the Thomist does not accept the “soul sleep” theory.  He holds that the intellect does function after death.  How can this be?  Remember that I said that corporeal activity is necessary for the intellect’s operation under normal conditions.  But as Aquinas argues in the article linked to above, it is not necessary full stop.  The intellect functions one way when it is in its normal state -- that is, when conjoined to the body -- but in another way under the abnormal circumstances when we are no longer “in the flesh.” 

Is this an ad hoc move?  Not at all.  To see why not, consider some parallel cases.  In normal circumstances a tree needs to be rooted firmly in the ground if it is going to survive.  That’s what roots are for, after all -- to root the tree to the ground so as to provide it stability and take in nutrients.  Knock it over so that it is torn out by the roots and it will die.  But there are, of course, abnormal circumstances wherein it can survive without being rooted to the ground -- namely when it is nourished hydroponically instead.  Similarly, normally a human being cannot be nourished without a properly functioning digestive system.  Destroy the stomach, say, and a human being will in normal circumstances die.  But of course there are abnormal circumstances in which nourishment can occur without a stomach -- via intravenous feeding.  Examples can easily be multiplied: In normal circumstances, you cannot walk without properly functioning legs; in unusual circumstances you can (e.g. when fitted with prosthetics).  In normal circumstances you cannot hear when the various parts of the ear are not functioning properly; in unusual circumstances you can (e.g. via an artificial tympanic membrane).  And so forth. 

All these cases involve interventions in the natural course of things.  In the natural course of things, such-and-such is necessary, and we remedy the loss of such-and-such by supplementing nature.  And that’s what happens, in Aquinas’s view, vis-à-vis the intellect after death.  In the natural course of things, the intellect cannot operate without input from sensation and imagination.  Hence if it is to operate after death it needs some supplement to make up for what it has lost.  Of course, unlike hydroponics, artificial limbs, etc., we can’t provide the sort of metaphysical supplement required in this case.  But God can.  As Aquinas says in the article linked to, “the soul in that state understands by means of participated species arising from the influence of the Divine light.”

Here’s an analogy that might help.  Think of the intellect as like a church’s stained glass windows.  The images are there in the windows whether you see them or not, but you can’t see them if the church is dark.  Light is necessary.  It might come from inside the church, such as from the lamps that illuminate the church at night.  Or it might come from outside the church, such as from the sun.  Now, the deliverances of sensation and imagination, to which the intellect has recourse when in the body, are like the light that illuminates the stained glass windows from within.  The divine illumination by which the intellect operates after death, by contrast, is like the sunlight that illuminates the stained glass from without.  Or, to mix metaphors, it is like a kind of cognitive manna that comes from above when, after death, you’re quite thoroughly “fresh out of flesh.”