2740. Integral Confession.—The completeness or integrity of confession is twofold.
(a) Material completeness consists in the declaration of all mortal sins committed and not yet confessed and absolved. This kind of completeness is sometimes impossible, and therefore unnecessary. For completeness is obligatory in virtue of a positive law of Christ, and positive laws do not bind in case of impossibility (361).
(b) Formal completeness consists in the declaration of all the mortal sins which here and now, all things considered, one can and should mention. This kind of completeness is necessary for a valid and fruitful confession, because the law of Christ calls for a complete confession, as far as possible, and formal completeness is possible. Since he who is obliged by a law is also obliged to use the means to keep the law, those who are going to confession should examine their consciences beforehand, unless this is impossible or unnecessary. The time and diligence to be given this examination depends on the person and his circumstances; but all should be careful about it, while avoiding scrupulosity, and should also remember that contrition is even more important than confession.
2741. Manner of Confession.—Completeness of confession as regards mortal sins extends to the following points:
(a) the theological and the lowest moral species of a sin (197 sqq.) must be given, for otherwise the confessor does not understand the case before him. He who has committed a mortal theft does not satisfy by confessing a venial theft; he who is guilty of the specific sin of calumny does not satisfy by the generic accusation of sins of the tongue. But impossibility excuses, as when the penitent has only a general recollection about a sin;
(b) the number of the sins must be given exactly or, if this is impossible, approximately. He who unintentionally exaggerates the number or tells a sin of which he is not guilty, is not bound to correct this, but he who unintentionally lowers the number to a notable extent should tell in his next confession what was omitted (see 202 sqq.);
(c) the circumstances that change the species of a sin must be declared, for example, the fact that the person who was scandalized was one’s subject, that the person who was treated disrespectfully was one’s superior, that the amount stolen was large (see 72);
(d) the external act that completed an internal sin must be declared, and hence he who committed impurity does not confess properly by saying that he gave consent to impure desires (see 89-93).
2742. Disputed Cases.—(a) Circumstances that Notably Aggravate a Sin without Changing Its Species.—For the obligation of confessing these circumstances, it is argued that, if the confessor does not know them, he is unable to guide the penitent properly. Against obligation, it is argued that the species of the sin gives the confessor sufficient knowledge, and that the obligation of confessing aggravating circumstances would make the burden too heavy for the penitent. But all admit that _per accidens_ there may be a duty of confessing a circumstance of this kind, as when it makes a sin reserved, or consists in an occasion of sin or evil habit, or when it produces a great change in reference to satisfaction (e.g., the theft of $10,000 is quite different from the theft of $1000).
(b) As to the Imputable External Effects of a Sin.—One opinion is that these must be confessed, since they are willed in their cause (96, 102); another opinion is that they need not be confessed since they are not sins, but results that followed on a sin; a third opinion answers that they must be confessed if the evil will was not retracted before they happened, but otherwise not. All agree, however, that the sinner in this case should confess that he sinned with foresight of the consequence, and that he should confess the consequence itself if there is attached to it something that should be known to the confessor (e.g., censure, irregularity, etc.).