ARTICLE II: RULES FOR JUDGING THE PROBABILITY OF OPINIONS

55. • Reason alone constitutes the probability of opinions. Nevertheless, the authority of Doctors is of such great strength that it is sometimes equated with intrinsic probability, insofar as the Doctors are presumed to have diligently weighed the opinion which they hold and to have taught it on account of good reasons. Hence extrinsic probability is to be esteemed more from the merit and erudition of the Doctors, and also from their study and diligence in investigating the truth of the matter, than from their number.¹

Wherefore, for judging the probability of opinions, the following rules should be attended to.

56. • Who can judge concerning the probability of opinions.

1° Concerning intrinsic probability, only learned men and those versed in moral matters can judge; for many times to men indeed talented, but little instructed in moral science, that will seem evident which experts judge false.²

2° Concerning extrinsic probability, a moderately learned man can judge, if, rightly understanding the state of the question, he finds the asserted opinion as probable from Doctors greater than every exception, that is, entirely approved among theologians.

3° The unlearned, who are not able of themselves to consult Doctors, can stand by the testimony of preachers and confessors whom they judge upright, prudent, and learned.³

57. • When an opinion is to be held as probable.

1° Unless a certain and convincing reason militates against some opinion, certainly probable is to be held both that which, the Church tolerating it, is commonly asserted as probable by theologians generally or by most theologians; and that which five Doctors strong in authority simply teach, or which some Doctor of the Church holds; and then finally that which some great theologian testifies to be probable. Now he is esteemed a great theologian who possesses the greatest authority among theologians on account of his distinguished doctrine, prudence, and probity. Such are: Suarez, Soto, Azor, Cano, Sylvius, Cajetan, Bannez, Navarrus, Paludanus, Toletus, Sylvester, Lessius, Sanchez, Angelus, Vasquez, Armilla, Valentia, Laymann, Molina, de Lugo, Castropalaus, Bonacina, Emmanuel Sa, Pontius, Cabassutius, Collet, Roncaglia, the Salmanticenses, Petrocorensis, Abelly, Cardenas, Coninck, Gamachaeus, Isambert, and others, whose learning, how great it is, is known everywhere; besides St. Thomas, St. Bonaventure, St. Antoninus, or Scotus, whose authority indeed must be preferred to others.¹ To these, mentioned in the last place, St. Alphonsus must be added, whose authority alone is so great that an opinion which he holds as probable must be held as extrinsically such.

2° The authority of a few Doctors who discuss some question expressly is to be preferred to the sayings of many others who write about it in passing. Indeed, sometimes, although rarely, the authority of one Doctor will be able to constitute an opinion probable, and even more probable, against the common opinion of others, if that author is very learned, upright, prudent, free from party zeal, and not a lover of novelties, and if he brings forward a valid reason which the others have not considered or have not sufficiently solved, while he himself conveniently solves the opposed reasons.

3° "Of Casuists who wrote after the condemned propositions, greater account is to be had than of the more ancient, in those things which regard the very opinions branded, or which are akin to them."²

4° Concerning particular cases not discussed by theologians, for a learned and God-fearing man that opinion is sufficiently probable which he knows that he himself has diligently examined, both by carefully weighing the reasons and by consulting the learned, and which he judges, without inordinate affection, to be such; for probability is not to be restricted to public doubts.

For the rules for discerning the judgment of St. Alphonsus concerning the value of sentences, see p. LXXXVIII sq.