Question One: On the Obligation and Means of Forming a Sufficiently Certain Conscience

S. Th. I-II, q. 91, a. 3, ad 3; q. 96, a. 1, ad 3; II-II, q. 47, a. 9, ad 2; q. 70, a. 2; Quodl. VIII, a. 13.

78. Thesis. A certain conscience is the rule altogether required for acting prudently and licitly, by which, namely, a man prudently forms for himself a certain judgment that the action to be placed here and now is licitly and honorably placed.

Now a certain conscience is that which, formally in itself and in all the principles from which it is immediately formed, excludes fear of the opposite, and therefore firmly and without fear of erring dictates that something in particular is licit or illicit. We say that such a conscience is required as the rule of acting.

It is proved: 1) from Scripture, Rom. XIV, 23: Everything that is not from faith is sin. But everything that is done from an uncertain conscience is not from faith or from certain persuasion; therefore it is sin;

2. from reason: He who, uncertain whether his action is evil and prohibited by God, or prudently fearing lest it be prohibited and evil, nevertheless acts, wills to place the action even if it really is evil and prohibited, and thus has an evil will, and contemns the law of God, and exposes himself to the proximate danger of sinning formally and sins (I, n. 214).

Hence a) one acting with an uncertain conscience violates the obligation of inquiring into the truth concerning the existence of a precept, for every precept first of all obliges to knowledge of itself;

b) he prudently fears that by his operation he is sinning formally; therefore he voluntarily casts himself into the proximate danger of sinning;

c) whence it is never licit to act in a practical doubt concerning the honesty of the action.

79. A conscience broadly or indirectly certain suffices. - For acting prudently and licitly there suffices:

1. When certitude strictly so called is lacking, certitude broadly so called. For certitude, says St. Thomas, is not to be sought in the same way in all things, but in each matter according to its proper mode. Now human actions are particular and contingent things, in which ordinarily absolute certitude, which takes away every solicitude, is not given. Therefore probable certitude suffices, which ordinarily and in the greater number of cases attains the truth, and sometimes, in the fewer cases, fails of the truth.¹ - But if strict certitude were required, says St. Alphonsus,² the yoke of God would be heavy and hard and unbearable, would incite to straits and desperation, and thus would expose one to the danger of sinning.

¹ Thus II-II, q. 47, a. 9, ad 2; and q. 70, a. 2; likewise I-II, q. 91, a. 3, ad 3, and q. 96, a. 1, ad 3; commentary on Aristotle, I Ethics, lect. 3. - Likewise St. Antoninus, Summa Theol., p. I, tit. 3, c. 10, § 10, speaks of "the certitude of a probable conjecture," which arises "from probable conjectures, broad and figurative, bearing more toward one part than toward the other." - Certain persons, such as Arendt (Crisis Apol. Aequiprob., pp. 59, 77, 231 sq.), have interpreted these things as if they were valid only concerning moral certitude which is concerned with facts, but not concerning the conclusions of moral science, for which they demand stricter certitude. But this interpretation is opposed to St. Thomas, who in his Commentary on Aristotle also speaks of principles: "It is manifest that moral matter is varied and difform, not having certitude in every way. And because according to the art of demonstrative science principles must be conformed to conclusions, it is agreeable and desirable, when making a treatment of such matters, i.e., of matters so variable, and proceeding from similar things, to show the truth 1) indeed roughly, i.e., by applying universal and simple principles to singular and composite things in which there is act... 2) it is necessary to show the truth figuratively, i.e., verisimilarly; and this is to proceed from the proper principles of this science. For moral science is about voluntary acts; but the motive of the will is not only the good, but the apparent good. 3) It is necessary that, since we are about to speak of those things which happen for the most part, i.e., of voluntary acts which the will does not produce from necessity, but perhaps inclined more to one than to another, we also proceed from such things, so that the principles may be conformed to the conclusions." In the same way St. Alphonsus, Th. M., book I, n. 56: "Where the truth cannot be found clearly, we are bound to embrace at least that opinion which comes nearer to the truth."

² St. Alphonsus, Th. M., book I, n. 82 sq.

It should nevertheless be noted that from the aforesaid doctrine it cannot be concluded that every probability properly so called, i.e., every more truthlike opinion, constitutes probable certitude, but only that which comes nearer to certitude, or, as they say, a vehement opinion, which is only with some or slight doubting.

2. When direct certitude concerning the material and objective honesty of the action is lacking, indirect certitude concerning its formal honesty suffices: for then it is not required that someone be certain that there is no law which prohibits the action, but that, even if there is a law, he is excused from it. The reason is that often another certitude, direct certitude, cannot be obtained in practice, since the doubts are insoluble for us, and yet man generally must act. Now no one is held to the impossible, nor does God demand more than the human condition bears: thus Cajetan. - Moreover, the truth of an opinion is one thing, the use of an opinion and the honesty of the action another; and therefore the principles and reasons by which we judge of the truth of a thing, the probability of an opinion, doubt, etc., for example whether a war is just, a marriage valid, are one thing; those by which we judge of the honesty of an action are another, for example whether in such a perhaps unjust war, when a superior commands, it is licit to fight, or whether one doubting about the validity of a marriage can render the conjugal debt.³

³ St. Alphonsus, Th. M., book I, n. 25.

80. Practical certitude varies according to the diversity of matter, person, and circumstances, so that greater certitude is required in matters of great moment, in persons of greater knowledge, and in circumstances which require greater diligence or more easily admit error. Thus the counsel of one learned man or pastor is prudence for a countryman or laborer, not for a theologian; and greater care is required that someone act prudently in administering a sacrament than in observing an ecclesiastical law.

"Therefore," says d'Annibale, Summula Theol. M. I, n. 131, "as civil judgments, though of one small coin, so also penal judgments, though capital, are concluded by the testimony of two, namely because no one calls witnesses of his own offense. And in those things in which it is of no interest to the witnesses to lie (e.g., when it is asked whether someone was baptized), credence is given even to one trustworthy witness. But in those things which admit no witness, we use presumptions, for example when there is doubt whether a wife has brought forth an adulterine child; and each one is believed to have been duly baptized or ordained, although the intention of him who baptized or ordained lies hidden."

But from the agreement now made by all more recent theologians after St. Alphonsus, to practical certitude, which excludes every reasonable and prudent doubt, there is equivalent:

1. An opinion absolutely most probable, which in itself and by force of the reasons upon which it is founded in reality attains the highest grade of probability, although it does not exclude every prudent doubt, but only grave doubt or doubt of some moment:1 for against this there is opposed only a sentence slenderly or rather doubtfully probable; but in moral matters a little is reckoned as nothing, and slender probability as none.⁴, 3

⁴ Cf. St. Alphonsus, Th. M., book I, n. 76; book III, n. 562; and Dissertation of the year 1765, n. 8.

Nor does it obstruct that by acting without certitude someone exposes himself to the danger of sinning; for in the case there is not a proximate danger, but almost none and wholly remote, and only of sinning materially. Thus the Theologians teach against the Tutiorists, who for acting licitly always demanded direct and perfect certitude, which doctrine Alexander VIII condemned, namely, prop. 2: It is not licit to follow an opinion even the most probable among probable ones; - and against the Laxists, who said that the least probability sufficed, even an opinion doubtfully or slenderly probable, whom Innocent XI condemned, prop. 3: Generally, when relying upon probability, whether intrinsic or extrinsic, however slender, provided one does not go outside the bounds of probability, we do something, we always act prudently.

2. Likewise, generally, an opinion much, very, or notably more probable: for then the opposite is only a little, lightly, doubtfully, imprudently, and no longer solidly, gravely, seriously, prudently probable.

Thus they teach against the mitigated Tutiorists, who required at least the most probable opinion; and against the laxer Probabilists, who said that an opinion much or far less, or even almost lightly probable, was sufficient, such as that opinion which says that for satisfying the precept of hearing Mass the presence during the whole time of the sacrifice suffices, the consecration however being omitted, because communion is the more principal part; or even the hearing of two parts, if the consecration and communion do not pertain to the same Mass.

We have said: generally; because in matters of greatest moment men are accustomed to seek greater certitude, such as the sacraments and eternal salvation; - and on the contrary in extreme necessity they are also accustomed to use slender probability: for in extremes, extreme things must be attempted.

3. Likewise, generally, an opinion uniquely but very probable, to which no grave reason is opposed: on account of a reason similar to the preceding case.

For with such probability prudent men are accustomed to direct themselves, unless there is question of matters of greatest moment. Thus right reason judges a penitent to be duly disposed, if no grave reason is opposed.1

1. Practical perfect certitude, namely, excludes every prudent doubt, even slight. Imperfect certitude excludes every grave prudent doubt, or one of some moment; whence someone can prudently doubt: it is more prudent; but he is not bound, because a slight reason ought not to be attended to.

2. Hence several theologians distinguish strict or perfect practical certitude and broader or imperfect practical certitude. Palmieri notes well (Op. theol. mor. of Ballerini, I, de Consc., at n. 117): Just as Philosophers rightly distinguish true and strict certitude, which excludes every fear, and an opinion most probable, which is certitude broadly so called or practical certitude, which excludes prudent fear; so Moralists wished to distinguish practical certitude (which they call strict or perfect), and opinion below this most probable certitude, which therefore does not exclude every prudent fear. Whence according to St. Alphonsus, slender probability is opposed to certitude: "Slender probability does not prevent true certitude from being had to the contrary, understanding this even of moral (practical) certitude strictly so called" (Dissertation of the year 1765); - and doubtful probability is opposed to a most probable opinion. Opinion below practical certitude but most probable is nevertheless equivalent to this and, speaking broadly, is called moral certitude: for this certitude admits several degrees. Cf. St. Alphonsus, Th. M., book I, nn. 40 and 82. - The Probabilists also admit this, of whom one witness, De Lugo, may suffice: "For the sake of clarity we can distinguish two grades of moral (i.e., practical) certitude. The first is the certitude which excludes every prudent fear, and this is proper moral (practical) certitude. The second is certitude less properly so called, which does not exclude every prudent fear, but only prudent (positive) doubt about that object, or a prudent probable judgment about the contrary object," de Fide, disp. 1, n. 316. Yet all these can be understood under the one name of certitude broadly so called.

3. St. Alphonsus, Th. M., book I, n. 56.

1. St. Alphonsus, Th. M., book I, nn. 56 and 57, and Dissertation of the year 1762, n. 2. There is a difference between an opinion most probable, and one notably more probable or uniquely probable, because the first is equivalent to certitude considered absolutely and in itself, but the others if they are considered comparatively to the opposite.

81. A conscience broadly or indirectly certain is reduced to an altogether certain conscience. - He who has only a broadly or indirectly certain conscience can form for himself an altogether certain practical judgment from a reflex principle, for example in this way:

"That which, all things having been diligently considered, appears licit to me with certitude broadly so called or indirect certitude, this here and now is altogether certain to be done licitly by me, because in moral matters strict certitude is not possible nor consequently required.

"But, all things having been diligently considered, this appears licit to me with certitude broadly so called or indirect certitude.

"Therefore this here and now is altogether certain to be done licitly by me."

Hence a double ratiocination can be distinguished: the direct, from principles prudently admitted, which is not altogether certain; and the reflex, from reflex principles, which is an altogether certain judgment of conscience. Such a judgment is not explicitly required, but it suffices to make it implicitly.

They object: 1) A reflex principle cannot do more than a direct principle; therefore it does not render conscience certain.

Resp.: I distinguish: A reflex principle cannot do more than a direct principle, as to the truth of the thing, opinion, or sentence, granted; as to the honesty of the action, denied.

2. Thus conscience would be at the same time doubtful and certain.

Resp.: Not precisely the conscience itself would be doubtful and certain, but human reason would be doubtful and certain, yet according to diverse respects: doubtful as to the truth in itself, certain as to the honesty of the action.

3. Probable opinion, even if it is most probable, always knows with fear and doubt; therefore it excludes a certain conscience.

Resp.: I distinguish: it always knows with speculative fear and doubt, granted; with practical fear and doubt, denied.

82. Observation. - Since conscience ought to be certain and true, it is understood in what sense the axiom is to be understood: Practice differs from speculation. For although practice differs from merely speculative science, which is occupied only with the truth of the thing, nevertheless it cannot differ from speculation which has practice itself as its object and tends to direct it, as certain priests say under a species of pretext, who are unable to give the reason for their practice, and misuse the said axiom as a cloak of their lack of skill or even of a laxer conscience. For moral science treats of human acts even when considered with all their circumstances; and practice ought to be conformed to this, since it is the measure, exemplar, and rule according to which practice ought to be directed. But those who assert that the principles of moral science are impossible in practice, and that a confessor cannot always follow them, proclaim this absurdity: that conscience is not the application of moral science, that a practical conclusion is given without a practical principle, and a reasonable manner of acting without a reasonable motive.

But the aforesaid prejudice, which always returns in the mind and mouth of certain men, comes from this, that men insufficiently versed in the knowledge and application of moral theology do not rightly apply the principles and thus come to an impossibility. For either they infer the conclusion or solution of a case, which they impose upon theology, from an illegitimate principle which does not contain the conclusion and which therefore is declared impossible in practice; - or the case is not rightly set forth with all its circumstances, and then, as the premise, a principle is posited which does not correspond to the circumstances, and the conclusion will be narrower or laxer and impossible in practice; - or finally, the case with all its circumstances is apprehended, but from the various principles that one is not chosen which corresponds to the case, and again the conclusion can be impossible. But let these bad applications not be attributed to moral science itself.

Nevertheless, for right application in practice, speculative knowledge of moral science does not suffice; there is also need of experience and use, whereby, namely, someone may acquire for himself the art, and the aptitude and facility, of rightly estimating all circumstances and applying precisely those principles which correspond to these. Whence it is far more difficult to reduce principles into practice than to learn them. And if such a sense is attributed to the axiom, according to this it has a certain truth.