494. 14. Adulteries of the third and fourth degree are sinful evils according to the measure and nature of the intellect and will in them, whether they are committed in act or not. It can be seen from the discussion of them above (nos. 490-493) that adulteries of the reason or intellect, which are those of the third degree, and adulteries of the will, which are those of the fourth degree, are grave, consequently are sinful evils, according to the nature of the intellect and will in them. That is because a person is the person he is in consequence of his will and intellect; for from these two spring not only all actions which occur in the mind but also all actions which occur in the body. Who does not know that the body does not act on its own, but that the will does by means of the body, or that the mouth does not speak on its own, but that the thought does by means of the mouth? Consequently, if the will were to be taken away, instantly the action would cease, or if the thought were to be taken away, instantly the mouth's speaking would cease.

It is clearly apparent from this that adulteries committed in act are grave according to the measure and nature of the intellect and will in them. That these same evils are similarly grave even if not committed in act follows from these words of the Lord:

...it was said by those of old, "You shall not commit adultery." But I say to you that (if anyone) looks at (another's) woman so as to lust for her, (he) has already committed adultery with her in his heart. (Matthew 5:27-28)

To commit adultery in the heart is to do so in the will.

[2] There are many considerations which induce an adulterer to refrain from being an adulterer in act, while yet remaining so in will and intellect. For there are some who refrain from adulterous relationships as regards the act because they are afraid of the civil law and its penalties; because they are afraid of losing reputation and thus respect; because they are afraid of diseases resulting from such relationships; because they are afraid of being railed at by their wives at home and of having no peace in their lives on account of it; because they are afraid the husband or a relative will take revenge; so also because they are afraid of being beaten by the servants; because they are too poor, or too stingy; or because they are too feeble owing either to illness, or to their abusing themselves, or to age, or to impotence, and fear being disgraced on account of it.

If anyone refrains from adulteries in act for these and like reasons, and yet sanctions them in will and intellect, he is still an adulterer. For he nevertheless believes that they are not sins, and in his spirit makes them not unlawful in the eyes of God; and thus he commits them in spirit, even if he does not in body before the world. Therefore after death, when he becomes a spirit, he speaks openly in favor of them.

490. 10. Adulteries of the third degree are adulteries of the reason, which are committed by people who intellectually persuade themselves that they are not sinful evils. Everyone knows that he is endowed with a will and intellect, for whenever he speaks, he says, this is what I want, and this is what I think. Yet despite that he does not distinguish between these two faculties, but makes one to be the same as the other. The reason for it is that he reflects only on such things as are matters of thought from the intellect, and not on such things as are matters of love from the will; for the latter are not visible to his sight in the way that the former are. Nevertheless, one who does not distinguish between the will and intellect cannot distinguish between evil things and good, and so cannot know anything at all about the guilt of sin.

Who, however, does not know that good and truth are two distinct things, as are love and wisdom? And whenever he is possessed of rational light, who cannot therefore conclude that there are two elements in man which separately receive and incorporate these into them; and that one is the will and the other the intellect, for the reason that what the will receives and reproduces is referred to in terms of good, and what the intellect receives is referred to in terms of truth? For what the will loves and does is called good, and what the intellect perceives and thinks is called truth.

[2] Now the marriage between good and truth was discussed in the first part of this work, and we presented there a number of points having to do with the will and intellect and the various attributes and characteristics of each - points which I am inclined to suppose even those people understand who have not had any distinct thought concerning the intellect and will; for human reason is such that it understands truths in the light of truth, even if it has not discerned them before. So, then, to make the differences between the intellect and will still more clearly perceptible, I will cite some of these points here, in order that it may be known what adulteries of the reason or intellect are, and afterward what adulteries of the will are. Let the following serve to provide a concept of them:

[3] 1. The will by itself accomplishes nothing on its own, but whatever it does it does through the intellect.

2. Conversely, too, the intellect by itself accomplishes nothing on its own, but whatever it does it does from the will.

3. The will flows into the intellect, and not the intellect into the will; but the intellect makes known what is good and what is evil and advises the will, in order that it may choose between the two and do that which it prefers.

4. After that a twofold conjunction of the two takes place, one in which the will operates inwardly and the intellect outwardly, the other in which the intellect operates inwardly and the will outwardly.

The last is what distinguishes adulteries of the reason, which we are considering here, from adulteries of the will, which we take up next.

There is a distinction between them, because one is more grave than the other. For adultery of the reason is not as grave as adultery of the will. That is because in adultery of the reason, the intellect operates inwardly and the will outwardly; but in adultery of the will, the will operates inwardly and the intellect outwardly, and the will is the person himself, while the intellect is the person only as an extension of the will. Whatever operates inwardly also predominates over that which operates outwardly.