Aquinas’s Logic of Temptation

This is useful for understanding the relation of body and soul in Aquinas for several reasons. First, the spiritual governs the corporeal, so temptation comes through the body. Second, the movements of appetite make perception more acute, or the body prepares the soul’s cognition. Third, imagination produces appetite, or the soul prepares the body, at least in part.

Summa Theologica, I-II.80.2

Hence, the entirety of the devil’s interior operation seems to focus on the imagination and sentient appetite.


By moving the two of them, he is able to induce a man to sin, since he can operate in such a way as

to present certain imagined forms to the imagination, and he can likewise

bring it about that the sentient appetite is excited with some passion.


For it was explained in the First Part (ST 1, q. 110, a. 3) that a corporeal nature naturally obeys a spiritual nature with respect to local motion.


Hence, the devil, too, is able to cause everything that can arise from the local motion of lower bodies, unless he is held back by God’s power.


Now the fact that forms are represented to the imagination follows sometimes from local motion.

For in De Somno et Vigilia the Philosopher says, “When an animal sleeps and the blood descends to the sentient principle in a large quantity, the movements or impressions that are left by sensible motions and that are conserved in the sensible species descend at the same time and move the apprehensive principle in such a way that the impressions appear in the way they would if the sentient principle were at that time being affected by the exterior things themselves.”

Hence, this sort of local motion on the part of the humors or [animal] spirits can be procured by demons whether the man in question is asleep or awake, and in this way it follows that the man imagines certain things.


Similarly, the sentient appetite is likewise excited toward certain passions in accord with certain determinate movements of the heart and [animal] spirits; hence, the devil can likewise operate to effect this.


And from the fact that certain passions are excited in the sentient appetite, it follows that the man perceives more acutely the sensible movement or tendency that is traced back, in the way just explained, to the apprehensive principle;

for as the Philosopher says in the same book, “Lovers are moved to the apprehension of the beloved even by a slight similarity.”


Again, because the passion is excited, it happens that what is proposed to the imagination is judged to be something that should be pursued;

for someone who is in the grips of a passion (ei qui a passione detinetur) is such that what he is inclined toward by the passion seems good to him. And it is in this way that the devil induces a man interiorly to sin.

A Letter from Carl Jung to Bill Wilson (Bill W.)

The following was written by the famous psychologist, Carl Jung to “Bill W.”, founder of alcoholics anonymous. Kent Dunnington takes up this thread in his Addiction and Virtue and compares addiction to misplaced charitas, citing Aquinas that there is one way in which we are not finite, “we have unlimited desire.” (Paul Wadell, The Primacy of Love, 61.)

Dear Mr. Wilson

Your letter has been very welcome indeed.

I had no news from Roland H. anymore and often wondered what has been his fate. Our conversation which he has adequately reported to you had an aspect of which he did not know. The reason that I could not tell him everything was that those days I had to be exceedingly careful of what I said. I had found out that I was misunderstood in every possible way. Thus I was very careful when I talked to Roland H. But what I really thought about was the result of many experiences with men of his kind.

His craving for alcohol was the equivalent, on a low level, of the spiritual thirst of our being for wholeness, expressed in medieval language: the union with God.*

How could one formulate such an insight in a language that is not misunderstood in our days?

The only right and legitimate way to such an experience is that it happens to you in reality and it can only happen to you when you walk on a path which leads you to higher understanding. You might be led to that goal by an act of grace or through a personal and honest contact with friends, or through a higher education of the mind beyond the confines of mere rationalism. I see from your letter that Roland H. has chosen the second way, which was, under the circumstances, obviously the best one.

I am strongly convinced that the evil principle prevailing in this world leads the unrecognized spiritual need into perdition, if it is not counteracted either by real religious insight or by the protective wall of human community. An ordinary man, not protected by an action from above and isolated in society, cannot resist the power of evil, which is called very aptly the Devil. But the use of such words arouses so many mistakes that one can only keep aloof from them as much as possible.

These are the reasons why I could not give a full and sufficient explanation to Roland H., but I am risking it with you because I conclude from your very decent and honest letter that you have acquired a point of view above the misleading platitudes one usually hears about alcoholism.

You see, “alcohol” in Latin is “spiritus” and you use the same word for the highest religious experience as well as for the most depraving poison. The helpful formula therefore is: spiritus contra spiritum.

Thanking you again for your kind letter

I remain

Yours sincerely

C. G. Jung

Aquinas on Reason

[2] There is a twofold mode of truth in what we profess about God. Some truths about God exceed all the ability of the human reason. Such is the truth that God is triune. But there are some truths which the natural reason also is able to reach. Such are that God exists, that He is one, and the like. In fact, such truths about God have been proved demonstratively by the philosophers, guided by the light of the natural reason.

[3] That there are certain truths about God that totally surpass man’s ability appears with the greatest evidence. Since, indeed, the principle of all knowledge that the reason perceives about some thing is the understanding of the very substance of that being (for according to Aristotle ‘what a thing is’ is the principle of demonstration), it is necessary that the way in which we understand the substance of a thing determines the way in which we know what belongs to it. Hence, if the human intellect comprehends the substance of some thing, for example, that of a stone or of a triangle, no intelligible characteristic belonging to that thing surpasses the grasp of the human reason. But this does not happen to us in the case of God. For the human intellect is not able to read a comprehension of the divine substance through its natural power. For, according to its manner of knowing in the present life, the intellect depends on the sense for the origin of knowledge; and so those things that do not fall under the senses cannot be grasped by the human intellect except in so far as the knowledge of them is gathered from sensible things. Now, sensible things cannot lead the human intellect to the point of seeing in them the nature of the divine substance; for sensible things are effects that fall short of the power of their cause. Yet, beginning with sensible things, our intellect is led to the point of knowing about God that He exists, and other such characteristics that must be attributed to the First Principle. There are, consequently, some intelligible truths about God that are open to the human reason; but there are truths that absolutely surpass its power.

Aquinas, Summa Contra Gentiles, I.3.2-3. (emphasis mine)