(b) Debate is unlawful in its manner when a disputant does not argue according to the rules, appeals to prejudice or ignorance, uses an insulting tone or unparliamentary language, etc.
1357. The Sin of Contention.—Contention is a sin when its aim is the concealment or discomfiture of the truth. (a) From its nature this kind of contention is a mortal sin, for it is the external expression of internal discord in matters about which charity requires concord and the same speech. Hence, the Apostle numbers contention among the works of the flesh that exclude from the kingdom of God (Gal, v. 20). (b) From the lightness of the matter or the imperfection of the consent, this kind of contention is very often, if not usually, only a venial sin, or no sin at all. Examples: A person argues against what he knows is true, but the matter is trivial (e.g., his weight); or he is distracted by the heat of dispute or the tactics of the other party.
1358. Mortal sin is not committed by contention, therefore, unless the truths against which one contends are of a serious kind. Such truths are: (a) truths of a religious or moral character, such as the doctrines of faith and the commandments of God; (b) natural truths of a universal character, the knowledge of which pertains to the perfection of the intellect, such as first principles; (c) natural truths of a particular character in which important rights are involved. Example: An historian who writes against some deservedly revered person of the past, or a lawyer who attempts to prove against an accused what he knows is not a fact, are guilty of the sin of contention.
1359. Hence, one may be defending one kind of truth and contending against another kind of truth at the same time. St. Paul, accordingly, makes the distinction between announcement of the truth out of charity and announcement of the truth out of contention (Philip, i, 15 sqq.). (a) The truth is defended out of charity when one does not use truth as a means for the defense of error; (b) it is defended out of contention when one makes use of it as a means for the propagation of error. Thus, while St. Paul was imprisoned at Rome in 61, certain personal enemies preached Christ, but at the same time spoke or hinted falsehoods against St. Paul in order to undermine his authority or add to the bitterness of his captivity. Similarly, if one defends the truth to make oneself appear different or better than one is, one speaks from contention.
1360. Ways in which one is guilty of the mortal sin of contention: (a) when one contends formally against the truth, that is, when one knows the truth and intends to overcome it or suppress it; (b) when one contends virtually against the truth, that is, when one is so bent on carrying one’s point that one does not care whether it is true or false. Thus, the Sophists aimed to win, right or wrong.
1361. When the aim of contention is the overthrow of error: (a) in itself, such contention is good and praiseworthy, and at times necessary; (b) by reason of circumstances, it may be a venial or a mortal sin. Examples: A dispute on a matter that is unbecoming, such as which of the disputants is greater (Luke, xxii. 24); dispute with greater warmth than the case requires; a dispute that leads to scandal or other evil consequences, as in religious controversies (I Tim., ii. 14).
1362. The Causes of Sinful Contention.—(a) The cause of that which is principal in contention—namely, the departure from the truth held by another and the stand made for error—is envy, pride and vainglory, as said above (see 1854) concerning discord. (b) The cause of that which is secondary in contention—namely, the wrangling or bawling manner and the shouts or screams of the contenders—is anger.
1363. The sins in act against the peace of charity are the following: (a) schism which is opposed to the peace of the spiritual society, the Church; (b) war, which is opposed to international peace, and sedition, which is opposed to national peace; (c) fighting, which is opposed to peace between individuals.
1364. Schism.—Schism (etymologically, a split, rent) is defined: “A voluntary separation of oneself from the unity of the Church.”
(a) Schism is a voluntary separation, that is, a separation intended for its own sake. Every sinner in a sense separates himself from unity, for sin divides one from God (Is., lix. 2); but it is only the schismatic who expressly intends separation as such. Other sinners expressly intend some inordinate gratification. Moreover, schism is not the same thing as the state of the unbaptized, who have not separated themselves from unity, or of the excommunicated, whom the Church herself rejected from her body on account of some sin other than schism.