Section 3: Probabilism and Other Systems of Morals

We now come to a consideration of the systems that have been devised for the purpose of insuring practical certainty in cases of speculative doubt, or, if we may express the same thought somewhat differently, to satisfy oneself whether an act, the morality of which is speculatively uncertain, is practically allowed or forbidden. 1. STATE OF THE QUESTION. —In all cases where a definite decision has to be made under conditions which do not admit of full certainty regarding the existence of a law or obligation, a man may act safely with what is called a probable conscience (conscientia probabilis ). Such doubtful cases owe their existence to the fact that law cannot regulate the actions of men in every detail, nor adequately express the will of the lawgiver, and hence a sphere is left open in which man may use his own judgment.

In every "case of conscience" there are two opposing opinions: one in favor of the law (opinio pro lege), the other in favor of liberty (opinio pro libertate). Neither is certain, but both are more or less probable (probabiles). Note that the discussion of such cases by Catholic moralists never turns on the question, which is the more perfect course to pursue? but merely, what is licit or not? In other words, in trying to solve so-called cases of conscience, theologians do not ask: "Which of the two actions is the more perfect?" but "Which of the two is one obliged to perform under pain of sin?" For example: I am uncertain whether or not to-day is a day of fasting. I have reasons for thinking that it is. But these reasons are merely probable. What am I to do if I cannot obtain reliable information? Am I obliged to fast? Or may I, on the strength of the reasons I have for thinking it is not a fast-day, absolve myself from the duty of keeping the fast? The question at issue is plainly one of licitness, not of greater perfection, for no one disputes that to fast would be the more perfect act.

2. GENERAL PRINCIPLE. —Aside from Laxism, it is a general principle that in case of doubt the pars tutior must be chosen, i. e., that course of action must be followed which most effectively excludes the danger of sin. Abstractly and objectively considered, the opinion in favor of the law (opinio pro lege) is the safer (opinio tutior scil. a periculo peccandi) for the reason that by following it one can best avoid the risk of sin. That the pars tutior must be followed in all cases is the teaching of Rigorism. The so-called Probabilistic systems, on the contrary, contend that the opinio pro lege does not always furnish moral certainty, that such certainty may also be afforded by the opinio pro libertate, and that in case of doubt one may, for good reasons (probabilitas), safely follow the latter.

The controversy thus narrows itself down to the question which of the two opposing opinions, —that favoring the law or that favoring liberty, —is safer to follow in case of doubt.

is not permitted to act upon a mere opinion, but when direct certitude is unattainable, should try to reach reflex certitude by earnest consideration and careful comparison. The conscience or dictate of conscience based upon such an opinion is called probabilis. The relation of the different conflicting opinions is determined according to the degrees of intrinsic or extrinsic probability which each can claim.

The difference between intrinsic and extrinsic probability is that intrinsic probability rests upon reasons contained within the opinion itself, whereas extrinsic probability is based on authority.

A probable opinion (opinio probabilis) may be based either on intrinsic or extrinsic grounds, provided these are good and solid.

If two contrary opinions have the same degree of probability they are called aequiprobabiles.

A more probable opinion (opinio probabilior) is one that rests on weightier reasons than its opposite, which in that case is still probable, but less so (minus probabilis, or simply probabilis).

When a probable opinion rests on such solid grounds that it is almost a certainty, it is called most probable (probabilissima). Its opposite can not, of course, be solidly probable, but, in the language of the schools, may be parum vel tenuiter probabilis.

From what we have said it follows that the probability of an opinion is measured by the weight of the intrinsic and extrinsic arguments on which it rests. The authority which creates extrinsic probability is that of theological experts or confessors.

4. THE SCOPE OF PROBABILISM. —Though, as we have seen, the claims of liberty may in all cases be asserted against those of the law, the sphere of liberty in Moral Theology is nevertheless greatly restricted, for the reason that the safer side (pars tutior) must always be chosen where it is absolutely necessary to attain a definite end, and where following an opinio probabilis or even probabilior would involve danger of frustration.¹ This is the case whenever faith or religion are involved, especially in the administration of the Sacraments,² in medical and surgical prescriptions, and when there is an obligation to protect the interests of one's fellowmen.³

¹ Cfr. J. P. Gury, Compendium Theologiae Moralis, Lyons and Paris, 1850, Vol. I, n. 55-56: saria "It is not lawful to follow a probable, or even a more probable, opinion after abandoning the safer one whenever there is an absolute obligation to attain some determinate end which the use of a probably unsuitable means would place in danger; therefore the safer course must then be followed."

² Cfr. Gury, op. cit., Vol. I, n. 57, 1 and 4: "In those things which are necessary for salvation by necessity of means, you are compelled to act more safely; for so great an end must be attained absolutely before all others, entirely by necessity, and therefore safe and certain means must be employed. Accordingly, in matters pertaining to that end or to religion, probability being rejected, the safer opinion must necessarily be followed. Hence the following proposition, under no. 4, was condemned by Innocent XI: 'An unbeliever who does not believe will be excused from unbelief when led by a less probable opinion.' [See Denzinger-Bannwart, n. 1154]. Indeed, in such a case it would not be lawful to use even a more probable opinion after setting aside the safer one. A minister of a sacrament, where its validity is at issue, unless a defect is supplied or a case of necessity presses, is bound to follow the safer course insofar as he morally can, abandoning the less safe course, whether probable or even more probable, because otherwise he would expose the sacrament to the danger of nullity and his neighbor to the danger of spiritual harm. Hence the following proposition was deservedly condemned by Innocent XI under no. 1: 'It is not unlawful in conferring sacraments to follow a probable opinion concerning the validity of the sacrament, abandoning the safer opinion.' " (Denzinger-Bannwart, n. 1151).

³ Gury, op. cit., Vol. I, n. 57, 2-3: "A hunter who fears that by firing a bullet at a wild animal he may perhaps injure some man cannot fire it, even if he judges it more probable that the danger is absent; for if the danger is perhaps present, it cannot be removed by the contrary probability, even though greater. A physician and a surgeon are bound to employ the safer medicines and means which can be had here and now, because by an implicit contract they have bound themselves to attain the end insofar as this can be done. The same must likewise be said of all others who have contracted an obligation toward their neighbor." —Cfr. the Propositiones Damnat. sub Innocentio XI., n. 2: "I judge it probable that a judge can render judgment according to an opinion that is even less probable." (Denzinger-Bannwart, n. 1152).

Hence Probabilism may be applied only when there is question of the mere morality, i. e., the licitness or illicitness, of an act or omission (sola actionis honestas). In all other cases the pars tutior must be chosen. This is no argument in favor of Tutiorism, however, nor an exception to the general rule of Probabilism, because in such cases there is always present a direct speculative certitude, whereas Probabilism was expressly devised for cases in which no speculative certitude can be attained.

Absolute Tutiorism or Rigorism (tutiorismus absolutus sive rigidus) is based on the principle that the opinion which favors the law must be followed always, and that it is never lawful to follow a probable opinion, even though it be probabilissima, in favor of liberty.⁴ This system is untenable because it misconceives the problem at issue, ⁵ and has been formally condemned by the Church.⁶

⁴ Tutiorism was adopted by the Jansenists. Its foremost defender was the Irish theologian Joan Sinnichius (+ 1666).

⁵ Cfr. 1 Macc. II, 31 sqq.; IX, 44; 2 Mace. V, 25; VI, 11; Matth. XXIV, 20.

⁶ See the Prop. damn, ab Alexandro VIII. (Dec. 7, 1690), n. 3: "It is not lawful to follow an opinion, even the most probable among probable opinions." (Denzinger-Bannwart, n. 1293).

In order to escape ecclesiastical condemnation a certain school of Rigorist theologians modified the fundamental tenet of Tutiorism by saying that one may decide in favor of liberty only if the opinion favoring that side is most probable (probabilissima). This system does not differ substantially from absolute Tutiorism and is useless for the solution of difficult cases of conscience. Its principal representatives are the Jansenists M. Steyaert († 1701) and J. Obstraet († 1720), Henry a Sancto Ignatio († 1719), and Cardinal H. S. Gerdil († 1802). ⁷ 6. LAX PROBABILISM OR LAXISM (probabilismus absolutus sive excessivus). —This system maintains that the opinion which favors liberty may be followed always, even when it enjoys but a slight or doubtful degree of probability (tenuiter vel dubie). The Church rejects Laxism for the reason that this system is incompatible with the dignity of the moral law.⁸

⁷ A sketch of Card. Gerdil's life will be found in the Cath. Encyclopedia, Vol. VI, p. 471.

⁸ Cfr. the Prop. Damnat. sub Innocentio XI, n. 3: "Generally, whenever, relying upon either intrinsic or extrinsic probability, however slight, provided the bounds of probability are not exceeded, we do something, we always act prudently." (Denzinger-Bannwart, n. 1153).

Excessively lax propositions were taught by J. Sanchez († about 1620), ⁹ F. Amicus, S.J. (+ 165 1),¹⁰ St. Bauny, SJ. († 1649),¹¹ Thos. Tamburini, S.J. († 1675),¹² J. Caramuel, Ord. Cist. († 1682),¹³ J. Cardenas, SJ. († 1684),¹⁴ A. Diana, Ord. Theat. († 1663),¹⁵ Z. Pasqualigo, Ord. Theat. († 1664), ¹⁶ A. Escobar y Mendoza, S.J. († 1669), ¹⁷ M. de Moya, S.J. († 1684), ¹⁸ and others.

⁹ John Sanchez must not be confounded with Thomas Sanchez, S.J. (+ 1610). Cfr. Hurter, Nomenclator Lit. Theol. Cath., Vol. III, 3rd ed., pp. 592, 893.

¹⁰ See the Catholic Encyclopedia, Vol. I, p. 429.

¹¹ V. supra, p. 63.

¹² On Tamburini see the Cath. Encyclopedia, Vol. XIV, p. 441.

¹³ Ibid., Vol. III, pp. 329 sq.

¹⁴ Ibid., Vol. III, pp. 332 sq.

¹⁵ Ibid., Vol. IV, p. 773.

¹⁶ Hurter, Nomenclator Lit. Theol. Cath., Vol. IV, 3rd ed., col. 298 sqq.

¹⁷ V. supra, p. 62.

¹⁸ Father Matthew de Moya was professor of Moral Theology in Murcia, Alcala, and Madrid. Under the nom de plume "Amadaeus Guimenius" he wrote a book entitled Adversus Quorundam Expostulationes contra Nonnullas Jesuitarum Opiniones Morales (Palermo 1657), in which he showed that the lax doctrines attributed to the Jesuits in a libelous pamphlet, Teatro Jesuitico, Apologetico Discurso con Saludables y Seguras Doctrinas Necessarias a los Principes y Senores de la Tierra, by Francisco de la Piedad (also a pseudonym), were taught long before by other writers. Both the Teatro and Moya's reply were put on the Index, where they remain even after the Leonine revision.

7. PROBABILIORISM. —This theory contends that if a man is in doubt regarding the existence of a law, he must nevertheless obey the same and may follow the opinion in favor of liberty only if that opinion is certainly more probable (certe probabilior) than its opposite. Hence the axiom, "In dubio stricto seu aequali pars tutior sequenda est," i. e., as long as the conscience is strictly in doubt, that is to say, while it suspends judgment without inclining either way, the law must be obeyed.

This principle is theoretically incontrovertible but useless for practical purposes, and therefore no longer has any followers. While all Catholic moralists admit that a man may safely follow Probabiliorism, most of them maintain that this system is of no value in the solving of doubtful cases precisely for the reason that in such cases no opinio probabilior is attainable. In practice Probabiliorism leads to Tutiorism, and "solves" only those cases of conscience which in reality are no "cases" at all, because the greater probability in favor of one side or the other can be easily perceived.

The most eminent defenders of this system are: Cardinal Cajetan († 1534),¹⁹ Alexander Natalis († 1724), ²⁰ Vincent Baronius († 1674),²¹ C. R. Billuart († 1757),²² D. Concina († 1756),²³ V. Contenson († 1674),²⁴ P. M. Gazzaniga († 1799),²⁵ J. B. Gonet († 1681),²⁶ J. V. Patuzzi († 1769), ²⁷ —all Dominicans —and the Jesuits Thyrsus Gonzalez de Santalla († 1705),²⁸ M. de Elizalde († 1678),²⁹ P. G. Antoine († 1743),³⁰ and P. Collet († 1770).³¹

¹⁹ On Cardinal Cajetan (Tommaso de Vio Gaetani) see the Cath. Encyclopedia, Vol. III, pp. 145 sqq.

²⁰ On Alexander Natalis (Noel Alexandre), ibid., Vol. I, pp. 296 sq.

²¹ Not to be confounded with the famous Jesuit Cardinal Cesare Baronius. Brief sketches of both in the Catholic Encyclopedia, Vol. II, pp. 304 sq.

²² V. supra, p. 57.

²³ V. supra, p. 60.

²⁴ V. Cath. Encyc., IV, 330.

²⁵ V. Cath. Encyclopedia, Vol. VI, p. 401.

²⁶ V. supra, p. 60.

²⁷ V. supra, p. 60.

²⁸ Gonzales was the thirteenth general of the Society of Jesus, and while holding that office, published his famous Fundamentum Theologiae Moralis, i. e. Tractatus Theologicus de Recto Usu Opinionum (Rome 1694). It is reproduced in Migne's Cursus Theologiae, Vol. XI. —Cfr. J. Salsmans, S.J., in the Catholic Encyclopedia, Vol. VI, pp. 635 sq.; Döllinger-Reusch, Geschichte der Moralstreitigkeiten in der römisch-kath. Kirche, Nördlingen 1889, Vol. I, pp. 120 sqq. —For an account of the controversies that raged about the decree of Innocent XI on Probabilism see J. Brucker S.J., in the Paris Études Religieuses, 1901-02, and F. Ter Haar, Das Decret Innocenz XI. über den Probabilismus, Paderborn 1904. —Latin text of the decree given by the latter, pp. 29 sqq. and by Lehmkuhl, Prob. Vind., pp. 81 sqq. For an English translation see p. 230, note 40, infra.

²⁹ V. Hurter, Nomenclator Lit. Theol. Cath., Vol. IV, 3rd ed., col. 286 sq.

³⁰ V. supra, p. 58.

³¹ Cfr. Buchberger, Kirchl. Handlexikon, I, 964.

8. SIMPLE OR COMMON PROBABILISM (probabilismus simplex sive benignus, communis sive latus). —This system teaches that whenever there is doubt concerning the mere lawfulness or unlawfulness of an act, it is permissible to follow a solidly probable opinion in favor of liberty, even though the opposing view be more probable (probabilior). But why may a more probable opinion be relinquished in favor of a less probable one? To this Probabilism answers as follows: If the opinion favoring liberty is truly and solidly probable (vere et solide probabilis), it must be because the law is doubtful or insufficiently promulgated (lex dubia aut non sufficienter pr omul gat a). Now a doubtful law is not binding (lex dubia non obligat), and therefore one is at liberty.

But this statement of the Probabilist position does not remove the logical and moral objection that Probabilism permits men to follow a less probable opinion (sententia minus probabilis sic cognita et iudicata) even though its opposite is perceived to be more probable.

"The wise practicians who established the moral system of the Jesuits," says a Protestant ethicist, "correctly perceived that probability plays a part in moral conduct, and that to reject Probabilism absolutely, would betray a hasty judgment. Were man permitted to follow the axiom, 'Quod dubitas, ne feceris' and to act only when he knows for certain and without doubt that he is right, he would frequently be unable to act at all; nor would abstention from action help him out of the difficulty, for the mere omission of an act also entails consequences and is equivalent to a definite decision of the will, which may be either right or wrong That a certain mode of procedure is absolutely right in all circumstances, and its opposite absolutely wrong, can be asserted only from the standpoint of an omniscient intelligence. Man is a short-sighted creature and can act only if he has the courage to make a false move and to do something which may prove objectively wrong, and which he would not do were he better informed. Nevertheless, his conscience absolves him from guilt if he has acted to the best of his knowledge and understanding in accordance with the most probable opinion. The only thing we reject in the teaching of the Jesuits is that they base probability preferably on authority and allow a man to follow an opinion which he himself must admit to be less probable." ³²

³² Ch. Sigwart, Vorfragen der Ethik, 2nd ed., Tübingen 1907, pp. 40 sq. —Cfr. Mandonnet, Le Decret d'Innocent XI. contre le Probabilisme, Paris 1903, pp. 79 sqq., 99 sqq.

"There can be no doubt," says St. Alphonsus, "that the Tutiorists in their excessive rigorism do much damage; but on the other hand the Probabilists, who follow an opinion which they recognize as less probable (but which I no longer regard as probable because the law in its moral sense is sufficiently promulgated), are also to blame for the loss of many souls." ³³ Neither the Fathers nor the early Schoolmen give any general rule for determining moral obligation in doubtful cases. But from the way in which they decided controversies it is evident that they were guided by the principle that a doubtful law does not bind. Thus St. Gregory of Nazianzus addressed the following challenge to a Novatian writer who had denounced second marriage as illicit: "Either prove that you are right, or if you are unable to bring proof, do not pass judgment. If the matter is in doubt, let humanity and convenience prevail." ³⁴ The first theologian who reduced Probabilism to a formula and attempted to demonstrate it systematically was Bartholomew de Medina, O. P. († 1581). In his commentaries on the Second and Third Parts of the Summa of St. Thomas, this learned writer, who is usually called "the Father of Probabilism," defends the proposition: "We are permitted to follow a probable opinion even if its opposite is more probable." ³⁵ This thesis was favorably received by the majority of Catholic moralists and met with no ex professo opposition until Father Andrew Bianchi, S.J., attacked it in his treatise De Opinionum Praxi Disputatio, published at Genoa in 1642.³⁶ The bitterest opponents of simple Probabilism were the Jansenists, especially Blaise Pascal, who, in his famous Lettres a un Provincial (1656), attacked Probabilism with vigor and grace of style. The result was that many theologians adopted Probabiliorism. In the ensuing conflict, which lasted nearly two centuries, Probabilism received its hardest blows from the Dominicans. Alexander VII (1665), Innocent XI (1679), and Alexander VIII (1690) censured a series of propositions which were mostly taken from the writings of Probabilistic authors.³⁷ At the instance of the last-mentioned Pope, a general chapter of the Dominicans, held at Rome in 1656, advised all members of that Order to espouse Probabiliorism.³⁸ Father Thyrsus Gonzalez, General of the Jesuits, tried to banish Probabilism from the Society by publishing an anti-Probabilistic work, Fundamentum Theologiae Moralis.³⁹ The so-called decree of Innocent XI, of June 26, 1680 (which in reality was merely a protocol of the Holy Office), strongly approved of his action.⁴⁰

³³ Letters, III, 355.

³⁴ Orat., 39, n. 19 (Migne, P.G., XXXVI, 358): "Either prove that the matter is so, or, if you cannot do this, do not condemn. But if the matter is doubtful, let humanity and mildness prevail." —Cfr. Chr. Lupus, Dissertatio de Antiquitate, Auctoritate et Legitimo Usu Sententiae Probabilis (Opera Omnia, Venice 1729, Vol. XI, pp. 1 sqq.).

³⁵ "If an opinion is probable, it is lawful to follow it, even though the opposite opinion is more probable." (Expositio s. Scholastica Commentaria in D. Thomae S. Theol., 1a 2ae, qu. 19, art. 6, Salamanca 1577. For a sketch of B. de Medina's life see D. J. Kennedy, O. P., in the Catholic Encyclopedia, Vol. X, pp. 143 sq. Modern writers are divided as to Medina's teaching on Probabilism. Echard (followed by Billuart) maintains that Medina's system differed greatly from Probabilism as expounded by its later defenders. H. Hurter, S.J., says of him: "He was numbered among the leading cultivators of Scholastic and moral theology of his age, and from this also gained a certain renown; he is said to have anticipated the system of Probabilism." (Nomenclator Literarius Theologiae Catholicae, Vol. III, 3rd ed., Innsbruck 1907, col. 144). Cfr. Döllinger-Reusch, Geschichte der Moralstreitigkeiten, Vol. I, pp. 28 sqq.; Ter Haar, De Systemate Mor., pp. 17 sqq.; A. Schmitt, Zur Geschichte des Probabilismus, Innsbruck 1904, pp. 43 sqq.

³⁶ Andrea Bianchi, S.J., is perhaps better known by his Latin name, Blancus. He died at Genoa, March 29, 1657. His treatise De Opinionum Praxi Disputatio was published under the pseudonym "Candidus Philalethes." It is Tutioristic in tendency. —Cfr. Döllinger-Reusch, Geschichte der Moralstreitigkeiten, Vol. I, pp. 31 sqq., 51 sqq.; Ter Haar, De Syst. Mor., pp. 18 sqq.

³⁷ For a list of these condemned propositions see Denzinger-Bannwart, n. 1101, 1151, 1289, 1291; A. Rohling, Medulla Theol. Mor., pp. 479 sqq., St. Louis 1875.

³⁸ Cfr. Döllinger-Reusch, Geschichte der Moralstreitigkeiten, Vol. I, pp. 42 sqq.

³⁹ V '. supra, p. 225, n. 10. —Cfr. A. Lehmkuhl, S.J., Prob. Vind., pp. 83 sqq.; A. Koch, "Neue Dokumente zu dem Thyrsus Gonsalez'- Streit," in the Theol. Quartalschrift of Tübingen, 1905, pp. 95 sqq.

⁴⁰ Cfr. Mandonnet, Decret d' Innocent XL, pp. 73 sqq.; T er Haar, Das Dekret Innozenz' XI, pp. 29 sqq.; G. Arendt, S.J., De Conciliationis Tentamine nuper Iterate Aequiprobabilistas inter et Probabilistas, Rome 1902 (cfr. the Civiltà Cattolica, 1902, quad. 1253, pp. 574 sqq.). The "decree," the authentic text of which was published Apr. 19, 1902, by the Secretary of the Holy Office, reads: "A report having been made by Father Laurea of a letter directed by Father Thyrsus Gonzalez, S.J., to Our Most Holy Lord; the Most Eminent Lords said that the Secretary of State must write to the Apostolic nuncio of the Spains [directing him] to signify to the said Father Thyrsus that His Holiness, having received his letter favorably, and having read it with approval, has commanded that he [Thyrsus] shall freely and fearlessly preach, teach, and defend with his pen the more probable opinion, and also manfully attack the opinion of those who assert that in a conflict of a less probable opinion with a more probable, known and estimated as such, it is allowed to follow the less probable; and to inform him that whatever he does and writes on behalf of the more probable opinion will be pleasing to His Holiness. Let it be enjoined upon the Father General of the Society of Jesus, as by order (de ordine) of His Holiness, not only to permit the Fathers of the Society to write in favor of the more probable opinion and to attack the opinion of those who assert that in a conflict of a less probable opinion with a more probable, known and estimated as such, it is allowed to follow the less probable; but also to write to all the universities of the Society, [informing them] that it is the mind of His Holiness that whosoever chooses may freely write in favor of the more probable opinion, and may attack the aforesaid contrary [opinion]; and to order them to submit entirely to the command of His Holiness." (Cfr. J. M. Harty in the Cath. Encyclopedia, Vol. XII, p. 445).

The present status of Probabilism may be described as It has never been either officially approved or officially censured by the Church, but was and is tolerated ⁴¹ and upheld by the majority of Jesuit theologians, though it is not the official teaching of the Society.⁴²

⁴¹ Cfr. Ter Haar, Das Decret Innocenz XL, pp. 177 sqq.

⁴² For some of the leading arguments for and against Probabilism see J. M. Harty in the Cath. Encyclopedia, Vol. XII, pp. 444 sq.

Lately J. de Caigny, C.SS.R., published several books ⁴³ for the purpose of reconciling Probabilism with Æquiprobabilism. His arguments were met by G. Arendt, S.J.⁴⁴ 9. ÆQUIPROBABILISM (probabilismus moderatus). —Æquiprobabilism takes middle ground between Probabiliorism and simple Probabilism. It teaches that unless the opinions for and against the existence of a law have equal or nearly equal probability, it is not permissible to choose in favor of liberty. The leading principle of this system, which it shares with Probabiliorism, is this:

⁴³ Apologetica, etc. (see p. 235, infra); De Gemino Probabilismo Licito Dissertatio Exarata Conciliationis Gratia; De Genuino Morali Systemate S. Alphonsi Dissertatio Irenico-Critica.

⁴⁴ Apologeticae de Aequiprobabilismo Alphonsiano Historico-Philosophicae Dissertationis a R. P. J. Caigny, C.SS.R., Exaratae Crisis iuxta Principia Angelici Doctoris Instituta. Freiburg i. B. (Herder). —Fr. Lehmkuhl says towards the conclusion of his little book, Probabilismus Vindicatus (p. 126): "What I have said more often I now repeat: I recognize only a slight theoretical difference, and either no practical difference or scarcely any, between moderate or equiprobabilism and probabilism."

"In obscure matters the certainly more likely side, or the more probable side known and judged as such, is to be followed in favor of the law." However, if the opinions for and against the existence of a law have equal or nearly equal probability, and there is consequently a state of real doubt, it is permissible to follow the less safe opinion. Hence the axiom, "Lex stricte dubia non obligat. In other words, when there is doubt as to the existence of a law, liberty is in possession. When there is doubt in regard to the cessation of a law, the law remains in possession. Consequently, whereas simple Probabilism teaches that a man may always follow the opinion favoring liberty, if that opinion is based on good and solid grounds (opinio vere ac solide probabilis), even though he knows that the opposite opinion is more probable, Æquiprobabilism maintains that the less safe opinion may be followed only when it is quite or nearly as probable (aeque aut fere aeque probabilis) as its opposite, and only when there is question of an obligation arising, not ceasing.

/Equiprobabilism is regarded by some as an advance over simple Probabilism, in so far as it sets up a practical instead of a purely logical probability. ⁴⁵ The extrinsic reasons in favor of Æquiprobabilism are summed up by Archbishop Simar as follows: "This theory is the fruit of long scientific debates and has in its favor the presumption that, by dint of logical development, it is the golden mean between the two conflicting extremes of absolute Probabilism and Tutiorism. The followers of St. Alphonsus may point to the official declaration of the Church that, unlike Tutiorism and several forms of Probabilism, his teaching has never been censured. To these advantages must be added the great personal authority of the Saint, which deserves to be the more highly regarded because the problem in question was for him a vital one, which he investigated with the utmost conscientiousness and zeal, and also for the further reason that the conviction at which he finally arrived has stood the test of pastoral experience and triumphantly resisted innumerable attacks." ⁴⁶ The most prominent representatives of Æquiprobabilism are the Jesuits Christopher Rassler (+ about 1730) and Antony Mayr († 1749), Eusebius Amort of the Canons Regular of St. Augustine († 1775),⁴⁷ St. Alphonsus de' Liguori, founder of the Redemptorist Order,⁴⁸ Bishop Martin of Paderborn, Archbishop Simar of Cologne, and the moral theologians of the Congregation of the Most Holy Redeemer.48a

It is unjust to charge that Probabilism and the allied systems permit man to act on the strength of a mere opinion and thus dispense him from the duty of regulating his life in accordance with the dictates of conscience, which must be the highest rule and measure of all morality. Probabilism, Probabiliorism, and Æquiprobabilism were all devised for the express purpose of enabling man to follow the voice of conscience in doubtful cases.⁴⁹ So far from undermining morality, these systems, as a whole, deserve great credit for having safeguarded the important principle of liberty against the attacks and snares of the Jansenists, Rigorists, and Talmudists.

⁴⁵ Cfr. St. Alphonsus, Theol. Mor., I, n. 58: "For acting lawfully probability alone does not suffice, but moral certainty concerning the uprightness of the action is required." —Cfr. op. cit., I, 54: "If the opinion which stands for the law appears certainly more probable, we are bound altogether to follow it and cannot then embrace the opposite opinion which stands for liberty. The reason is that, in order to act lawfully, we must seek and follow the truth in doubtful matters; but where the truth cannot be clearly found, we are bound to embrace at least that opinion which approaches nearer to the truth, such as the more probable opinion." (Ed. Gaude, I, 25). —Cfr. Ter Haar, Das Decret Innocenz' XI, pp. 8 sqq.

⁴⁶ Th. H. Simar, Lehrbuch der Moraltheologie, 3rd ed., p. 143. — The translator of this work thinks it but fair to note, however, that Lehmkuhl and others hold that St. Alphonsus never held Aequiprobabilistic principles. Lehmkuhl (Theol. Mor., ed. 11a, Vol. I, p. 118) illustrates the difference between the Saint's teaching and that of the Aequiprobabilists as follows: EQUIPROBABILISM says: With probability alone that a law exists, an obligation does not exist. With probability alone that a law has ceased, the obligation has not ceased. ST. ALPHONSUS says: With probability alone that a law exists, an obligation does not exist; with probability alone that a law has ceased, the obligation has ceased. —For an able defense of the Probabilist position see the same author's Probabilismus Vindicatus, Freiburg 1906.

⁴⁷ Cfr. Ter Haar, De Systemate Mor., pp. 20 sqq., 52 sqq. —On Amort, see the Cath. Encyclopedia, Vol. I, pp. 434 sq. He was one of the foremost theologians of the 18th century. (Thos. J. Shahan, Cath. Encycl., Vol. I, p. 434). 48a See L. Wouters, C.SS.R., De Systemate Morali Dissertatio, new edition, "ad novum ius accommodata," Wittem (Holland), 1918.

⁴⁸ Æquiprobabilism "gained vigor and persistence from the teaching of St. Alphonsus, who began his theological career as a Probabiliorist, subsequently defended Probabilism, ... and finally, about 1762, embraced Æquiprobabilism. In a new dissertation he laid down the two propositions that it is lawful to act on the less safe opinion, when it is equally probable with the safe opinion, and that it is not lawful to follow the less safe opinion when the safe opinion is notably and certainly more probable. In the sixth edition (1767) of his 'Moral Theology' he again expressed these views, and indeed towards the end of his life frequently declared that he was not a Probabilist." (Cath. Encyc., Vol. XII, pp. 442 sq.; cfr. Irish Theol. Quarterly, Vol. VI, No. 24). —On the systema compensationis seu rationis sufficientis, which d'Annibale ascribes to Potton, O. P., and which has been latterly espoused by Prummer and some French moralists, see Vermeersch, Theol. Mor., I, pp. 306 and 313; K. Neuner, O. Cap., in the Kath. Kirchenstg. of Salzburg, 1924, No. 26.

⁴⁹ Cfr. Joseph Mausbach, Catholic Moral Teaching and its Antagonists, pp. 69 sqq.; A. Meyenberg, Die kath. Moral, 2nd ed., pp. 161 sqq.; Ter Haar, Vcn. Innoc. XL de Probabilismo Decrcti Histona, Rome 1904, pp. 126 sqq.

READINGS. —On the moral systems in general: K. Werner, System der Ethik, Vol. I, pp. 430 sqq. —W. Wilmers, S.J., Lehrbuch der Religion (ed. Lehmkuhl), 6th ed., pp. 537 sqq. —F. X. Linsenmann, Lehrbuch der Moraltheologie, pp. 114 sqq. —F. A. Göpfert, Moraltheologie, Vol. I, 6th ed., pp. 168 sqq. —Thos. Slater, S.J., A Manual of Moral Theology, Vol. I, pp. 68 sqq. —J. M. Harty in the Catholic Encyclopedia, Vol. XII, pp. 441 sqq. —M. Cronin, The Science of Ethics, Vol. I, pp. 478 sq. —A. Tanquerey, S.S., Synopsis Theologiae Moralis, Vol. II, Tournai 1905, pp. 213 sqq. —C. Gaudé, C.SS.R., De Morali Systemate S. Alphonsi, Rome 1894.

On Probabilism: F. Ter Haar, De Systemate Morali Antiquerum Probabilistarum Dissertatio Historic o-Critica, Paderborn 1894, pp. 77 sqq. —P. F. Mandonnet, O.P., Le Décret d' Innocent XI contre le Probabilisme, Paris 1903, pp. 99 sqq. —A. Lehmkuhl, S.J., Probabilismus Vindicatus, Freiburg 1906, pp. 16 sqq. —L. Wouters, C.SS.R., De Minus probabilismo, Amsterdam, 2nd ed., 1908, pp. 17 sqq. —J. L. Jansen, Geschichte und Kritik im Dienste der "Minus probabilis," Paderborn 1906, pp. 14 sqq. —F. Mentré, Courot et la Renaissance du Probabilisme au XIXe Siècle, Paris 1908. —Chr. Lupus, Dissertatio de Antiquitate, Auctoritate et Legitimo Usu Sententiae Probabilis (Opera Omnia, XI, Venice 1729). —Dinneen, De Probabilismo Dissertatio, Dublin 1898. —J. M. Harty in the Catholic Encyclopedia, Vol. XII, pp. 443 sqq. —Jos. Rickaby, Moral Philosophy, pp. 152 sqq. —W. McDonald, The Principles of Moral Science, Dublin 1904, pp. 215 sqq. —A. Vermeersch, S.J., Theol. Mor., Vol. I, pp. 303 sqq.

On Probabiliorism: Thyrsus Gonzalez, Fundamentum Theologiae Moralis, i. e. Tractatus Theologicus de Recto Usu Opinionum, Rome 1694. —J. M. Harty in the Catholic Encyclopedia, Vol. XII, pp. 442 sq. —J. Biederlack, S.J., in the Innsbruck Zeitschrift für kath. Theologie, 1890, pp. 186 sqq. —L. Wedff, "S. Alphonse est-il Probabilioriste?" in the Revue Thomiste, Paris 1904, pp. 129 sqq., 477 sqq. —A. Tanquerey, S.S., Synopsis Theologiae Moralis, Vol. II, pp. 220 sqq.

On Æquiprobabilism: Vindiciae Alphonsianae seu Doctoris Ecclesiae S. Alphonsi de Ligorio Doctrina Moralis Vindicata a Plurimis Oppugnatoribus A. P. Ballerini cura et studio quorundam Theologorum e Congregatione SS. Redemptoris, 2 vols., 2nd ed., Bruxelles 1874. —J. De Caigny, C.SS.R., Apologetica de Æquiprobabilismo Alphonsiano, Tournai 1894. —G. Arendt, S.J., Apologeticae de Æquiprobabilismo Alphonsiano Historico-Philosophicae Dissertationis a R. P. J. de Caigny Exaratae Crisis iuxta Principia Angelici Doctoris, Freiburg 1897, pp. 65 sqq. —IDEM, Æquiprobabilismus ab Ultimo Fundamento Discussus, Rome 1909. —Vindiciae Ballerinianae seu Gustus Recognitionis Vindiciarum Alphonsianarum. Insunt Dissertationes Ballerini de Systemate S. Alphonsi et Altera Dissertatio de Probabilismo et Æquiprobabilismo eiusdem, Bruges 1873. —A. Ballerini, S.J., Opus Theologiae Moralis (ed. Palmieri), Vol. I, 3rd ed., pp. 606 sqq. —Le Bachelet, La Question Ligorienne, Paris 1899, pp. 25 sqq. —J. M. Harty in the Catholic Encyclopedia, Vol. XII, p. 445. —Berthe-Castle, C.SS.R., Life of St. Alphonsus de' Liguori, Dublin 1905. —A. Tanquerey, S.S., Synopsis Theologiae Moralis, Vol. II, pp. 223 sqq. —Sabetti-Barrett, S.J., Compendium Theologiae Moralis, 27th ed., New York 1919, pp. 163 sqq.