Appendix 5. (fn. 328).
Impartiality, a duty imposed upon writers by the more general obligation of love for truth (cf. 443), obliges me to differ in this study from St. Alphonsus de Liguori, for whom I have the highest respect and devotion. Careful consideration will show, however, that if I criticise certain occasional, logical slips found in his works, I do not depart from the spirit of his basic teaching. If the Saint sometimes erred in his reasoning, his great holiness helped him to amend and abandon his unconscious mistake. An example will help to clarify the situation.
In the passage cited, St. Alphonsus teaches as certain and outside controversy that a person sins if he posits an act which he considers doubtfully sinful; he sins lightly if the doubtful act is lightly sinful; mortally if the doubtful act is mortally sinful.
If we keep this perfectly correct teaching firmly in mind, it soon becomes clear that what St. Alphonsus teaches immediately afterwards contradicts his premise. He asks: 'What sin is committed by a person who is certain, without doubt, that his action is evil, but doubts whether it is gravely or lightly evil?' It is clear that the moral condition of this person is worse than that of the one above who doubts whether his action is evil. The first does not desire a certain evil; the second wants to carry out an act which he knows is certainly evil. In the first case, an action which could be lawful is desired, although sin is present because the action could also be gravely sinful; in the second case, an action is done which could be as gravely sinful as in the first case, but which can never be lawful. In both cases, grave sin would be present if both persons exposed themselves to the danger of sinning gravely. In addition, there is also the certainty of at least venial sin in the second case, while the first case could, of itself, be immune from all sin.
Liguori, however, after deciding for mortal sin in the first case, seems almost to absolve the second person from sin. But his conclusion, which is so qualified that it falls within the bounds of sound teaching, lacks logical connection with what has already been said. He asks: 'What is the state of one who knows a thing is wrong but doubts whether it is mortally or venially wrong, and acts with such a doubt?.' He replies: 'Some . . . with Navarrus, Gregory of Valencia, Luis de Granada and many others, hold it sufficiently probable that he sins only venially.' This is the bare reply. But he then adds (and we should consider this carefully): 'Provided this person does not advert even confusedly to the danger of sinning gravely, nor to his obligation of examining the matter, and provided that the object is not certainly of itself grave sin.' Nor is Saint Alphonsus content with the qualifications of other theologians: 'And I might add, provided the person concerned has a delicate conscience' (De Consc. n. 23).
The qualifications surrounding the solution to the problem seem to destroy the very hypothesis which gave rise to the problem. In fact, if a person does not advert even confusedly to the danger of sinning gravely, nor to the obligation of examining the matter, how can he doubt whether his action is mortal or venial sin? If he doubts whether it is mortal sin, he must necessarily advert to the danger of sinning gravely. The other qualifications, 'provided the object is not certainly of itself grave sin' and 'provided the person concerned has a delicate conscience' have no connection with the question about serious sin in a person who is uncertain whether his action is grave or light sin. These qualifications are only prudential indications helpful to the confessor when he has to decide the state of his penitent.
In order to understand St. Alphonsus correctly we must remember that he is often writing for confessors. He does not intend to judge matters in themselves but, by means of the indications he offers, to help the prudent confessor form his own judgment. It is one thing to judge a matter when all the circumstances are known, it is another when only certain circumstances are known, as in the case of the confessor who cannot see his penitent's heart. The confessor's judgment has to be based on what the penitent tells him and on all he knows about the character of the penitent. Knowing that a person's conscience has been formed delicately, the confessor can prudently conjecture that if the penitent's confessed doubt about sinning gravely were truly doubt, he would not have committed that sin. In this case, the penitent would not in fact be doubtful whether a sin were grave or light, but at most would have a slight, idle fear about the gravity of the sin. This changes the question. The penitent is no longer one who doubts, but a person who fears without any foundation for fear.