Question F: At what point does mortal sin begin in sins of thought?

1. Spontaneous emotional reactions are a determined aspect of sentient nature—they cannot be prevented. In themselves they no more have the character of human acts than do reflexes, such as being startled by a loud noise. Nor is their character altered by their duration, intensity, or recurrence. Thus there can be no personal sin in the mere experience of an emotional reaction (see S.t., 1–2, q. 74, a. 4; q. 89, a. 5). For example, a person working in the prolife movement who feels hatred toward abortionists is not guilty of personal sin by reason of that feeling as such; one who notices an attractive individual of the opposite sex and feels sexual desire has not committed sin merely by feeling desire.

2. At the same time, the psychologically normal play of emotion is not beyond moral criticism. In the fallen human condition, normal emotion has the character of concupiscence. It not only lacks but resists reasonable integration into the pattern of a humanly good life (see S.t., 1–2, q. 82, a. 3; q. 89, a. 3; 2–2, q. 164, a. 1). In this way the effect of original sin on human emotionality inclines to sin (see DS 1515/792).

3. Moreover, each individual’s emotional reactions can be badly conditioned by inappropriate habituation in childhood and by personal sins. The resulting lack of emotional integration is a privation in the existential domain and so is sin of a sort. But such sin cannot be mortal, because the usual conditions for mortal sin are not met; there is no choice contrary to conscience.

4. In confronting situations, courses of action (proposals for possible choice) come spontaneously to mind. There can be no mortal sin in the mere coming to mind of proposals, no matter what they are. Furthermore, one naturally begins—without any actuation of the will beyond simple willing, for which we have no responsibility—to consider the good and bad aspects of any proposal which comes to mind. In itself, this spontaneous beginning of deliberation can involve no sin either.

5. However, one who begins deliberating about a morally unacceptable proposal is in a condition of temptation. Temptation as such is not sin.¹¹ Without committing any sin, one can be drawn into this process and compelled to terminate it by choosing between doing what is right and doing what is wrong. Jesus himself “in every respect has been tempted as we are, yet without sinning” (Heb 4.15). One can be tempted without the slightest evil will, because temptation can arise due to the natural and good functioning of practical reasoning itself and due to the intelligible goodness present even in choices it would be wrong to make.

6. It might be supposed that there must be something wrong in proceeding to begin deliberating about a possibility one recognizes as morally wrong to adopt. However, while this sequence can involve venial sin, it need not involve sin at all. This is so because practical reason naturally and necessarily begins to consider the case for and against any proposal which comes to mind. True, a person can block such consideration—but only when the possibility of blocking it comes to mind. It comes quickly to the mind of a virtuous person, but not so quickly to someone whose thought processes are not so well integrated with morally upright commitments (see S.t., 1–2, q. 74, a. 6, ad 3).

In many cases, incipient deliberation about a possibility which initially is thought to be morally wrong leads to—and is absolutely necessary to achieve—insight into the morally right thing to do. For incipient deliberation can lead to conscientious reflection which will make it clear that in reality the adoption of the possibility which at first seemed wrong is not so. For instance, not keeping a promise, which might initially seem wrong, can be found to be obligatory. Again, incipient deliberation often leads to the replacement of the possibility one should not adopt by a possibility which is upright. For example, an unmarried young couple who begin to deliberate about fornicating can replace the unacceptable possibility with the upright plan to get married.

7. Thus deliberation can occur, desires and wishes can come to mind, and one can experience some emotional satisfaction in imagining acts which it would be wrong to choose—all without making any choice. All these things can occur without mortal sin.

8. If one ought not to have such thoughts, desires, wishes, and experiences of satisfaction but has them due to some prior sin, then they are sinful. But only venially so, unless they are voluntary by executive willing consequent upon some prior, unrepented mortal sin. Likewise, one can sin in failing to turn one’s attention to other matters. But unless the failure follows by executive willing from an unrepented mortal sin, one commits only venial sin until there is a wrong choice.

9. The qualification with respect to executive willing is important. Often, temptations and sins of thought occur after one has freely chosen to adopt a mortally sinful proposal. A person who deliberately seeks sexual excitement from pornographic entertainment or who has decided to take revenge on another by inflicting serious harm might, for instance, experience subsequent temptations and sinful thoughts. Even if these do not proceed from additional distinct choices, they can share in the character of mortal sin to the extent that they unfold the previous mortally sinful choice in subsequent actuations of the will.

10. When one’s present experience and thinking do not follow upon a prior, unrepented mortally sinful choice, a mortal sin of thought begins only when the usual conditions for mortal sin are fulfilled. One must be aware of a grave moral obligation to do something (for example, to focus attention on some innocent matter) or not to do something (for example, not to continue deliberating about an immoral proposal), and one must choose contrary to the awareness.

The following example will illustrate the preceding distinctions. A businessman who has lost a contract to a competitor might think of a legal but gravely unjust way to destroy the competitor’s business. Hatred and an angry desire for revenge could make the plan attractive, and the businessman might elaborate it in detail, taking considerable satisfaction in the prospect of his competitor’s downfall.

Under what conditions does the businessman commit a sin of thought? At what point will the sin be mortal? Four possibilities should be distinguished.

First, this entire process could occur without any personal sin. This would be so if it unfolded spontaneously, without dependence on any prior personal sin, although conditioned by the concupiscence which results from original sin. When the businessman reflects in conscience that he is entertaining a gravely wrong possibility and that he ought to set aside these thoughts and desires, he has experienced temptation but commits no sin provided he chooses to follow this judgment of conscience.

Second, the process described might result from some personal sin, yet not unfold in the course of living out an unrepented mortally sinful choice. Perhaps the businessman has accepted the grasping and merciless standards of the world in which he moves, yet without ever deliberately violating his conscience in a grave matter. Or perhaps he is simply not as conscientious as he should be in guarding his thoughts. In such cases, even before sufficient reflection and consent, there will be venial sin. Venial sin in these cases involves only the derivative modes of voluntariness (see 9‑G). Many classical moralists, who overlooked these modes of voluntariness, would find only temptation and imperfection here, but St. Thomas rightly teaches that there can be a privation of moral rectitude in sensuality itself (see S.t., 1–2, q. 74, a. 3). Thus, the moral defect in spontaneous thoughts and desires for revenge can be venial sin of a genuine though analogous sort insofar as the defect is in some way voluntary.

Third, the process described might unfold in the mind of a man who has made and not repented a mortally sinful commitment to succeed in business and destroy his competition by every expedient means. In this case, his developing plan and desire for revenge unfolds in the course of executing this prior, mortally sinful choice. Even without any new and specific judgment of conscience that the revenge would be wrong and choice contrary to such a judgment, his mortal sin continues in the executive willing with which he entertains vengeful plans and desires.

Fourth, the process described might unfold into a mortal sin of thought in the mind of a businessman who is not guilty of any relevant, unrepented mortal sin. In this case, there will be no mortal sin until he chooses contrary to a judgment of genuine conscience that the wish and plan for revenge is gravely wrong and ought to be set aside. Without sufficient reflection and choice at odds with it, there can be no mortal sin of thought, no matter how grave the injustice, how detailed the planning, and how intense the hatred and desire for revenge.

Thomas expressly holds (S.t., 1–2, q. 74, a. 8) with respect to delectatio morosa that the mortal sin is in the choice: “When one thinks about fornication and delights in the activity, this occurs because his affections are bent to the act of fornication itself. When one consents to this type of delight it is equivalent to consent to affection for fornication. Nobody delights in a thing unless it suits his desire. If one deliberately chooses (ex deliberatione eligat) to fix his desire on something that is gravely sinful, it is a mortal sin.”

11. Choosing is a conscious act; one cannot make a choice without knowing it. Moreover, one cannot make a choice and an instant later forget having made it. A person uncertain of having made a choice a moment before can be sure he or she did not make it.

12. Of course, unreflective people often have no clear understanding of what choices are and cannot recognize their own choices in reflex awareness after having made them. Such people should not be given false reassurance—for instance, by telling them: “Unless you know you have made a choice, you have not sinned mortally.” They can sin mortally without being able to point to anything they would call the “choice.”

13. It is possible to make a choice and later forget having made it. However, there is no need for anxiety and minute introspection concerning possible sins of thought on the part of people who try constantly to avoid mortal sin and regularly examine their consciences, if, upon doing so some time after a temptation, they find themselves not clearly aware of having committed such a sin.

11. On temptation, see St. Francis de Sales, Introduction to the Devout Life, part 4, 3–10.