2395. Sinfulness of All Lies.—But though lies are unequal in sinfulness, it remains that no lie, even the smallest (such as are called fibs or white lies), is ever justified, even by the greatest good (Job, xiii. 7), for a lie is intrinsically evil, and the end does not justify the means.
(a) A lie is a sin, because it is an abuse of speech and other signs given by God for the manifestation of truth; because it is an unfriendly and unsocial act, tending to the disruption of kindly relations between men; because it is directly opposed to truth, the proper and distinctive good of the human mind. Even the pagans have regarded liars with contempt and considered lies as disgraceful, and even those who lay no claim to virtue feel gravely insulted if called liars. In many places the Scriptures forbid lying (Exod., xxiii. 7; Levit., Xix. 11; Prov., xii. 22; Ecclus., xx. 26; Col., iii. 9), and St. Paul especially (Eph., iv. 25) is very clear on this point: “Putting away lying, speak ye the truth every man with his neighbor, for we are members one of another.” The Fathers and the theologians are generally agreed that no necessity, not even the danger of death, excuses a lie, any more than it excuses theft or adultery. If God could approve of even one lie, would not that approval undermine our faith in His own veracity? Surely we have no implicit confidence in one who helps to deceive us even in a small matter.
(b) A lie, considered precisely as a lie, seems from its nature to be only a venial sin, for the disorder of using signs against one’s mind is not serious, and the harm done society by mere denial of truth is not necessarily grave (the case would be otherwise if truth could be denied on principle as a lawful thing). Even pious persons do not regard harmless lies as very sinful (see 2143, 2386). Hence, as jocose and officious lies have no other malice than that of untruthfulness and as the malice is lessened by the intention, they are generally venial; but some extrinsic circumstance (such as scandal, the fact that one lies habitually and without scruple, or disastrous results) may render them mortal. Pernicious lies have another malice besides that of untruthfulness, and accordingly the case with them is different.
2396. When Lying Entails No Formal Sin.—Lies are sometimes free from all formal sin on account of ignorance (as in the case of children or uninstructed persons, who think they may use lies in case of great difficulty) or on account of irresponsibility (as in the case of certain defectives who seem to be born liars).
2397. Pernicious Lies.—Pernicious lies are mortal sins from their nature, but may become venial from the imperfection of the act or the lightness of the matter. For a pernicious lie sins not against truth only, but also against justice or charity. Hence, it is said that the liar destroys his own soul (Wis., i. 11), that a lie is abominated and hated by the Lord (Prov., vi. 17, xii. 22), that it has the devil for its father (John, viii. 44), that it brings down divine vengeance (Ps. v. 7) and will receive its portion in the pool of fire and brimstone (Apoc., xxi. 8). This sin is committed in two ways, as follows:
(a) a lie is pernicious when its matter is harmful, as being contrary to sound doctrine, good morals or true science. Hence, a preacher sins gravely if the substance of his pulpit teaching is mendacious (e.g., if in a sermon he enunciates or defends erroneous principles of conduct), venially if he lies about accidentals (e.g., if he gives the wrong chapter or verse for a text); a scientist, a physician, a jurist, or the like is similarly guilty of a pernicious lie when he misleads the public by unreliable information. A penitent in the confessional and a witness in court lie perniciously if their statements about relevant matters are untrue, for the one injures the Sacrament and the other injures public justice; but if the lie is about some matter of slight importance, the sin is venial, unless there is no other matter in the confession, or the testimony is under oath;
(b) a lie is also pernicious when the intention of the liar is to injure God or his neighbor, even though the matter itself is not opposed to true doctrine or is not official testimony. Examples are found in those who lie in a humorous way in order to injure or sadden others.
2398. Concealment of the Truth.—Truthfulness is offended not only by the declaration of falsity (i.e., of what is not in the mind), but also by the unlawful concealment of the truth (i.e., of what is in the mind). The truth is concealed either negatively or positively.
(a) There is negative concealment of the truth, when one has recourse to silence or evasion. Everyone admits that this kind of concealment is lawful when there is no obligation to give information, or when there is an obligation not to give it. Thus, a person who is besieged by newspaper reporters does not feel obligated to answer all their questions; a person who is interrogated by curious individuals about his business or financial affairs, does not feel guilty if he evades their questions by changing the subject, or by asking them similar questions, or by putting them off till a more convenient time, etc.
(b) There is positive concealment of the truth, when one gives a reply in language that is obscure to the listener or obscure in itself. If the listener has no right to the truth, it is not wrong to speak to him in words which he will not understand (e.g., in technical or scientific terms); for if he is deceived, he can blame only his own impertinence or dullness. The case is more difficult, however, if the reply is obscure in itself, that is, if use is made of ambiguity or mental reservation.