Article III: On Opinative or Probable Conscience

95. Notions and certain principles placed outside controversy. - Opinative or probable conscience, properly, is that which, on account of reasons absolutely grave and relatively graver, judges, although not firmly but with grave fear of the opposite, that some action here and now to be placed is licit or illicit. It can arise either because the conclusion is deduced by means of an uncertain but probable principle, or because the application of a certain principle to this particular case is uncertain, but only probable. In either case a certain conscience is lacking.

Such a conscience, of itself, is not the rule of acting prudently, because it is not a certain conscience; and therefore it must be laid aside either by further inquiry and the acquisition of direct certitude, or, if that cannot be had by moral diligence, by the acquisition of indirect certitude by force of a reflex principle. And indeed:

1. in practically practical probabilities, if in the given circumstances a practically certain conscience cannot in any way be had, man is held to choose the part of the law and to do what is safer, even if the law more probably does not exist, lest, namely, he expose himself to the danger of sinning, as was said in n. 89;

2. likewise in speculatively practical probabilities concerning the validity of an act, if there is question of an end absolutely to be obtained and of the value of an act perhaps necessary for the imposed end, man is held to do what is safer, lest he incur the danger of not obtaining the end, according to what was said in n. 90;

3. on the contrary, in speculatively practical probabilities concerning the mere honesty of an action, a certain conscience must be formed by force of some reflex principle. But concerning the reflex principle to be employed moralists do not agree altogether perfectly, since they dispute whether the less safe can be chosen even if it is more probable that the obligation is present.

96. Thesis. In the state of a true and strictly so-called speculatively practical opinion concerning the mere honesty and dishonesty of an action, remaining after diligent examination, man must, before he acts, form a practically certain conscience by force of a reflex principle; and this is different in the different opinions of theologians. According to the Probabilists, he can always do this from the principle: An uncertain law does not oblige, and so licitly do that which is less safe, even if it is more probable that the obligation exists or has not ceased; unless, however, it is very notably more probable, because then the law is practically certain (as was said in n. 80). According to the Probabiliorists and Equiprobabilists, not always; for if the law is certainly more probable, it must be observed, since it is now, as it were, practically certain, according to the principle: In uncertainties, the more truthlike is to be done.

It is proved: 1. Man must, before he acts, form for himself a certain conscience from a reflex principle, because this alone is the rule of acting (n. 78), and in the case it cannot be had except indirectly from a reflex principle.

2. He must act more safely and observe the law in the case in which it is very notably more probable, because then the law is equivalently or, as it were, practically certain, and the principle is valid: The more truthlike is to be done, as all now admit (n. 80).

3. On the contrary, he can do the less safe thing if liberty is more probable, from the principle: An uncertain law does not oblige, because in the case the law is more than strictly doubtful; in this all now agree.

4. One point remains controverted, namely, if the law is simply but certainly more probable, whether the principle An uncertain law does not oblige can be employed, or that other one must be employed: In doubts, the more truthlike is to be done.

The whole point of the controversy is situated in this: whether every opinion understood in the strictly so-called philosophical sense always is equivalent to practical certitude broadly so called.

A. The Probabilists deny this, and therefore they say: if it is only more probable that the law exists, although the reasons for the law are graver, nevertheless they are not practically certain, because grave reasons remain against it; and therefore it is certain that the law is uncertain, and we judge certainly that it does not oblige. This being posited, they form for themselves a certain conscience thus:

"That which, all things having been diligently considered, is not prohibited, is licit.

"But this action here and now to be placed certainly is not prohibited to me:

"for it is certain that an uncertain law does not oblige;

"but, although I rather think that this law exists and now obliges, and I adhere to this opinion, nevertheless I do not think this with certitude, even broadly so called, and therefore the law is uncertain for me;

"therefore it is certain that in the case it does not oblige me.

"Therefore this action here and now to be placed, all things having been diligently considered, is certainly licit for me."

B. On the contrary, the Equiprobabilists distinguish:

Either the opinion is a little more probable and the excess of reasons is slight; and then in practice it is doubtfully more probable, and almost or morally equally probable, in which case it is judged doubtful, and does not oblige on account of the principle: A doubtful law does not oblige. And then they form for themselves a certain conscience by a process similar to that above.

Or it is certainly more probable even by one degree (moral); and this in practice is impossible unless it is notably more probable and the excess of reasons is notable. Then, however, it is practically certain with certitude broadly so called and imperfect (n. 80). This the Probabiliorists also acknowledge.

The Probabilists observe, however, that many degrees of probability are found between equal probability, or strict doubt, and practical certitude; but it would be strange if in practice we could distinguish none of them with certitude, so that opinion would either be equivalent to doubt or equivalent to certitude, and in practice there would be no middle state between strict doubt and certitude. This seems incredible, they say, and it is nothing other than to eliminate one of the more principal states of mind.

Against this the Equiprobabilists object with St. Alphonsus:¹ That which is certainly more probable is notably more probable, otherwise the intellect could not certainly and evidently, i.e., without any hesitation, affirm that it is more probable. But that which is notably more probable is practically certain (n. 80).

¹ Cf. St. Alphonsus, Th. M., book I, nn. 56, 67, 77; and Diss. of the year 1762.

The Probabilists answer that the principle is not always and necessarily true, because, as it seems, a man of keen mind can certainly perceive that one thing is more probable than another, although nevertheless it is only a little, or at least not so notably, more probable. Yet often for many questions and minds that principle is verified; whence the fact that something is certainly more probable will ordinarily be a sign that it is notably more probable. Therefore present-day Probabilists, as being moderate (at least with their principles considered), and Equiprobabilists differ little in practice. For the former teach that a notably more probable law must be observed; the latter, however, teach that a certainly more probable law must be observed, but add that such a law does not exist unless it is notably more probable.

Hence it is clear that in practice this dispute is of lesser importance.

97. It is pleasing to relate various arguments and responses of the controversy, by which the question can in some way be judged.

I. The Equiprobabilists and Probabiliorists say: When something is certainly more probable, the contrary is no longer probable, and consequently we do not licitly do it.

The Probabilists respond, by distinguishing: The contrary is no longer probable in the strict and philosophical sense, i.e., worthy that we adhere to it by our judgment, granted; it is not probable in the broad and moral sense, i.e., founded on grave reasons, I subdistinguish: if the reasons are sought from the same principles on which the more probable opinion is founded, or if this latter notably exceeds it, granted; otherwise, I deny.

The objection contends that the probability of one proposition is elided by the probability of the other more probable proposition. But the elision of one probability by another does not consist in this, that one is destroyed by the other, but in this, that the other takes away its power of moving the intellect to prudent speculative assent. Yet the less probable opinion keeps its power of moving the intellect at the same time to judge that the opposite more probable opinion is not certain.

And St. Alphonsus himself at one time confessed this: "Our authors rightly respond that it is false: that the greater probability elides the lesser, unless that lesser probability is drawn from the same principle, or unless the probable opinion has for itself so convincing an argument that the contrary seems truly improbable, or no longer gravely and certainly probable."1 2 Nevertheless we acknowledge that the Holy Doctor afterward no longer held this, but rather taught the contrary.

II. The very recent Equiprobabilists argue: In all things we are held sincerely to tend toward truth and conformity with the objective order and the eternal law, or with the divine reason and will establishing this order; and consequently, if it is impossible to arrive at that conformity certainly, we must tend as much as we can and embrace what comes nearer to it: in uncertainties, namely, the more truthlike is to be chosen. But he who chooses what he judges less probable does not sincerely tend toward truth and the eternal law, because he does not do this as much as he can. Therefore he does not do what he ought, and he sins.

a) To this some observe that the argumentation, if it is right, also proves - which nevertheless the Equiprobabilists deny - that one must adhere to an opinion a little more probable, because in it there is greater hope of conforming oneself to objective truth and to the eternal law. Indeed, logically it leads to tutiorism: for if there is an obligation to tend as much as we can toward conformity with a law prescribing good, which does not oblige for always, there will be a much greater obligation of tending toward conformity with a law prohibiting evil, which obliges for always. But this we shall never obtain better than by doing what is safer.

But, setting this aside, the Probabilists respond briefly thus:

In all things we are held sincerely to tend toward truth and conformity with the eternal law, I distinguish: i.e., we must endeavor to know the law and observe it once it is known as morally certain, granted; when we cannot know the law as morally certain, we must choose and do what is more probable, I deny. He does not sincerely tend toward truth and law who does not make serious efforts to know the law, granted; he who seriously endeavors but cannot know it certainly, denied.

b) But since the matter is of greater moment, a fuller response can also be brought forward. Before we hand it down, it must be noted: a) with St. Alphonsus,² with respect to us the eternal law is not a proper law, but only the natural law, i.e., our reason (which is a participation in us of the eternal law), obliges us; whence in the major of the argument nothing else is said except that in all things we are held to follow reason, and if it says nothing certain, we are held to follow what is more probable; b) the major can be understood of direct principles alone of reason and of the eternal law, or also of indirect and reflex principles. This being posited, the Probabilists respond thus:

² Th. M., I, n. 72. "The eternal law with respect to men is not a proper law; for the proper law with regard to them is natural law." Cf. n. 77.

1. If there is question of direct and reflex principles together, nothing is stated except what all admit, namely, that we cannot act except that which certainly seems licit or conformable to law, i.e., we cannot act except with a certain conscience (directly or indirectly) concerning the honesty of the action; which conscience, nevertheless, can also be formed from indirect principles.

2. If there is question of direct principles alone, I respond: In all things we are held sincerely to tend toward conformity with right reason and the eternal law and the divine will, and if we cannot conform to them certainly, we are held to do this as much as we can, I distinguish: if there is question of truth to be sought and of acts of the intellect, granted; for it would be absurd, for example, in dogmatic and speculative questions to choose what is less probable, or not to inquire what is more probable; and similarly it would be absurd in moral questions not first to seek, as far as morally possible, direct certitude concerning the existence of the law, as was said in n. 88. If there is question of acts of the will and of things to be done, I subdistinguish: if right reason, the eternal law, the will of God certainly prescribe, granted; if they do not prescribe, or not certainly, denied.

For right reason and the eternal law do not always oblige that we conform ourselves to them, but if they prescribe; and the will of God obliges only if He wills us to will something; moreover it is required that we know this certainly. Besides, as was said, since the same reason and eternal law also dictate that an uncertain law does not oblige, if we do not follow an uncertain law although more probable, we shall still be conformed to the eternal law and to reason according to higher principles through a reflex judgment.

III. They insist: The will, in order to operate prudently, must follow the judgment of the intellect. But the will following the less probable opinion does not follow the judgment of the intellect, but rather brings force and compulsion upon the intellect, so that it does not follow its own judgment, but is bent away from the part which appears more truthlike to a part which it does not have as true, contrary to its own nature.

It can be answered: There is a confusion between the speculative and practical order. The will cannot rightly and without fault bend the intellect to adhering to the less probable part as true - as certain Probabilists erroneously said - but it is not held to observe the more probable law, because this is not certain. And yet it follows the judgment of the intellect, which not only judges that such reasons are graver and that one must adhere to them, but at the same time judges that they are not certain, and consequently that the law does not oblige. And the will is conformed to this judgment of the intellect and to the higher law, and thus it brings no force upon the intellect.³

³ More recent Probabilists defend their system as if its necessary and only foundation were the principle: Under the influence of the will, the intellect can both physically and also reasonably and prudently restrain the judgment, namely, assent to the more founded opinion, and adhere to the less founded. This principle the adversaries very easily prove to be contrary to all sound philosophy, unheard of among the older scholastics, repugnant to psychological experience, and opposed to right reason and prudence; whence they boast that they overturn Probabilism without much effort. The older Probabilists spoke otherwise and more wisely, saying that the intellect prudently, indeed necessarily, cannot embrace anything except that which appears more founded; but that a law even truthlikely existing does not oblige, because for that reason it does not become morally certain. Let Laymann be heard, Th. M., book I, tr. 1, c. 5, n. 6: "Although every part of a question, if it is probable, can produce the assent of those opining, speaking absolutely, nevertheless it cannot do this in every intellect. For if the opposite part of the question seems more probable to you, or if you perceive greater weights of reasons on that side, although you can then restrain every assent, nevertheless, on the hypothesis that you wish to assent to one part or the other, it is necessary that you assent to the more probable; but to the other, which appears less probable to you, you then cannot assent. For if you assent to the less probable, or judge it true, by that very fact you judge the opposite false; which cannot happen while that opposite appears to you more probable or more truthlike, because the judging intellect according to specification is not altogether free, but is determined by the reasons and motives of the proposed object. Nor is St. Thomas opposed to this doctrine, I-II, q. 17, a. 6, where he says that, in those things apprehended which do not convince the intellect, it is in our power to assent or dissent. For this is true absolutely, because the intellect can be moved by command of the will so that, omitting the consideration of the reasons for one part of the question, it considers and evaluates the reasons occurring for the opposite part. But with the hypothesis standing, or in the composite sense, while, I say, one part of a contradiction appears more truthlike than the opposite part, the intellect cannot dissent from the former and assent to the latter, because that would be done without reason, indeed against reason..." And n. 7: "These things... show that it is licit to follow a probable opinion in acting. But that this can be done, even if to the one acting himself speculatively it appears less probable, and the opposite more probable, must be shown from this, that that speculative opining, by the very fact that it is uncertain and perhaps false, cannot be the rule of operation. Consequently the one acting must follow another rule, and that a certain one; namely, that in doubtful questions concerning morals anyone can operate according to an opinion which learned men defend as probable and safe in practice. Nor indeed does he then act against his own conscience, since conscience is not some speculative opining, but a practical certain judgment concerning what is to be done." In the same way Suarez, De Vol. et invol., disp. X, sect. 1, n. 5; Lessius, de Act. Hum., q. 17, a. 6; Pallavicini, in I-II, disp. 8, q. 6, a. 4, n. 9; Vasquez, in I-II, disp. 67, c. 1, n. 4.

From the arguments brought forward each one will be able to form some judgment for himself. But as to practice, as we have said, it does not matter much which system is chosen, provided that Probabilism is understood as truly moderate and is contained within the just limits of sound prudence.

98. Practical observations. - 1. Some Probabilists understand a solidly probable opinion relatively to the opposite. And these agree in substance with the Equiprobabilists and can be called moderate Probabilists.1 Others hold every opinion absolutely and in itself probable to be solidly probable, without caring about relative probability. Namely, they deny that the use of a probable opinion must be confined within limits, and that the part to which another, however much even evidently more probable, is opposed becomes illicit.2 This is absolute Probabilism, which opens the way to Laxism.

There is also a twofold system of Equiprobabilism. Some, the milder, say that St. Alphonsus never intended to found a new system substantially different from moderate Probabilism, but willed to confine it within just limits by positing the restriction: that which is certainly more probable is very notably more probable, and therefore is practically certain. Hence he never enunciated the axiom of the Probabiliorists, In doubts, the more truthlike is to be chosen, as absolutely true, nor as a properly so-called reflex principle, but only as an expression of this doctrine: in morals, when we cannot arrive at perfect certitude, we are held to be content with certitude broadly so called and to choose the more probable, not indeed everything that is more probable, but what is certainly more probable, because that comes nearest to perfect practical certitude. And thus they understand St. Alphonsus when he says, Th. M., book I, n. 56: "Where truth cannot clearly be found, we are held to embrace at least that opinion which comes nearer (altogether) to the truth, such as is the opinion (certainly) more probable." And these do not differ as to substance from the moderate Probabilists.1 - But the more recent are stricter,2 and affirm that the principle of the Probabiliorists, In doubts, the more truthlike is to be chosen, is a reflex principle by which conscience certainly must be formed in the state of opinion, even if the certainly more probable opinion were not certain with certitude broadly so called; yet this hypothesis is not verified in practice. And these, in principle, approach more nearly to Probabiliorism.

Indeed there is also a twofold Probabiliorism. Some are milder, as the older authors and among the more recent Billuart, and do not depart so very much in various practical solutions from the Equiprobabilists and moderate Probabilists; others are stricter, as Concina and Patuzzi, and wholly approach Tutiorism.

2. They rather often say that Probabilism cannot be brought into practice because it is not certain, since several theologians are opposed to it. But the same could be objected against Equiprobabilism, since the Probabiliorists contradict it. This argument, however, is valid only for those who think that they see certainly that Probabilism (or Equiprobabilism) is false or illicit. For others it is not valid, because they can act according to Probabilism from the authority of the greater part of the moralists of our time, or even perhaps form for themselves, from a certain ratiocination, a practically certain conscience in this matter. For the principle An uncertain law in practice of itself does not oblige seems sufficiently certain (n. 92). Whence this principle, in a state of positive doubt or mere opinion, can be applied to form a certain conscience, unless a certain higher law of charity, religion, justice, etc., obliges (n. 91). The Equiprobabilists and Probabiliorists contend that in the state of opinion the higher law obliges: In uncertainties the more truthlike is to be chosen; yet they do not prove this sufficiently, with certitude. Until they prove it, liberty, or the right of applying the principle An uncertain law does not oblige, remains practically certain.

3. Formerly certain authors placed as the foundation of Probabilism the axiom: He who acts probably, acts prudently. But:

a) This is not a primary principle having force of itself in the formation of an indirectly certain conscience; for prudence requires that we act only with a certain conscience of honesty. But it can be valid as a consequence of the primary principle: probability, namely, is a condition so that a certain conscience can prudently be formed from the more general principle: A doubtful law does not oblige, - The condition of the possessor is better, - or: In doubts the more truthlike is to be done. Probability is the reason by which through discourse we come to a certain conclusion.

b) Nor is it valid absolutely concerning every probability; for to act prudently, a slender, or doubtful probability, or one considered absolutely without comparison to the opposite reasons, does not suffice. For it can happen that a reason probable in itself absolutely, from comparison with much graver opposite reasons, loses solid probability or becomes doubtfully probable (n. 74).

c) Nor is it valid without restriction, because in doubts concerning the validity of an act or the necessity of a means one must not act probably, but more safely (n. 90).

Hence a threefold mode of Probabilism is altogether to be rejected: 1) both that one which rested on the sole principle: He who acts probably acts prudently; 2) and laxer Probabilism, which also admits light probabilities, or absolute Probabilism, which necessarily leads to the use of a light probability; 3) and unlimited Probabilism, which posits no restriction and does not exclude from the use of probability cases concerning validity and the necessity of a means to the end.

4. From canon 15 Probabilism is to be applied to ecclesiastical laws, not indeed in doubts of fact, but in a case of doubt of law.⁴ But from this an argument cannot be drawn and a conclusion made that the same is valid for natural and divine law, because the obligation of ecclesiastical law alone, not of natural and divine law, depends wholly upon the intention of the Church.

⁴ Some have interpreted this more laxly, as if it were enough to doubt approved authors, even if the agent himself judged the benign interpretation of the canon to be false, and thus it were clear to him that there was no doubt of law! Indeed they add: received interpretations of some authors, after some time, found a usual interpretation from which one must not depart. But for a usual interpretation the consensus of some authors does not suffice; all the conditions necessary for juridical custom are required, among which first is the general observance of subjects. Besides, how is such a general usage possible for rarely occurring cases, to which nevertheless they intend to apply their rule? - But if the said interpretation were valid, laws from day to day would always become more lax.

1. Thus, besides those who in the Order of Preachers adhered to Probabilism, also Suarez, Vasquez, Lugo, Lessius, Laymann, Sylvius, Palaus, Viva, Abelly, Reuter, Voit, and several recent authors.

2. Lacroix, Arsdékin, Illsung, Ballerini, Bucceroni are cited.

1. Thus, for example, Scavini and the older disciples of St. Alphonsus, Aertnijs and de Caigny.

2. Among others, Dubois, Janssen, Ter Haar and Wouters of the C.SS.R.

99. Concerning the system of compensation it must be observed:

1. The twofold compensation, of probability and at the same time of the gravity of the law, is very difficult to estimate in practice; whence it is not a system apt to be a practical rule of acting and of forming conscience for all, even those sufficiently cultivated.

2. Not only does an inconvenience arise from the free positing of an act probably prohibited, namely, the danger of materially violating the law and frustrating the end intended by the legislator; but a greater one arises from the imposition of all uncertain precepts, namely, the deprivation of liberty and the danger lest men, on account of their weakness, fall rather into formal sins. Whence one could judge that, in a case of a solidly probable opinion, there is always a sufficiently compensating reason for the danger of materially transgressing an uncertain law.⁵

⁵ Thus in the new edition (5th) of the Tractatus de Conscientia from the Mechlin Theology, p. 81 sq. Article IV.

3. The proposition an uncertain law does not oblige seems sufficiently proved, so that of itself it can always be brought into practice, unless there is question of the value of an act and the obtaining of an end.

Yet something true is had in that system, not insofar as it hands down the due rule of acting and of forming conscience, but insofar as it admonishes prudence in the application of the rule, namely: for practice, in the application of any system whatever, all the circumstances of the subject must be considered in order to see whether it is expedient, or whether greater evils are not to be feared. But this only proves that the principles concerning the formation of conscience in such or such a state are to be subjected to the more general principles concerning human acts which govern the whole moral matter.

100. What system of probability it is licit to use. - Here the following things are to be attended to:

1. In the direction of his own moral life, each one can use probable opinions according to the mode of one of the three systems: Probabiliorism, Equiprobabilism, or Probabilism. For although of itself and generally it will be more conformable to reason and more prudent to follow Probabiliorism rather than Equiprobabilism, and Equiprobabilism rather than Probabilism, nevertheless ordinarily we are not held to act more prudently and more safely (this belongs to counsel and perfection), but only safely and prudently. But Equiprobabilism or Probabilism in practice is sufficiently safe and prudent, because it removes the danger of sinning formally, unless for those who certainly saw that such a system was false, in which case they would have to follow the stricter system.

2. In the direction of others, we cannot impose, but only persuade to, our own system, or one or another probable opinion, because priests are not legislators and do not command; unless per accidens, if the other consents in this, or if otherwise some particular danger would follow for him.

3. Hence in practice the three systems do not differ so very much as to application, if the morals of the faithful of the whole Church are considered. We have already seen that what is certainly more probable is rather often notably more probable and practically certain for all (n. 96). Moreover, what some call more probable, others call less probable; what some call less probable, others hold equally or more probable; what appears equally probable to some, appears less probable to others. Besides, if one inspects not only what is strictly licit, but also what is expedient or more fitting, as often happens in practice, the differences will be still smaller.

The sole difference is for those who, from conviction, hold some system as practically certain and judge all opinions by themselves. Indeed even in them it easily happens that after some time an opinion which previously they had held less probable already appears more probable, or vice versa. And therefore the question concerning a determinate mode of forming a certain conscience is not of such great moment as it seems at first sight and as several theologians affirm, calling it a "moral system," and placing it at the threshold of moral theology as if it dominated all the treatises, whereas nevertheless the doctrine concerning human acts, as being more fundamental, rules all the others.⁶

⁶ Sometimes, on account of extrinsic circumstances, the question could seem of greater moment: thus, on account of sharp disputes, in the time of St. Alphonsus.

4. Therefore it is understood that the Church has abstained from a formal judgment concerning the systems, and has been content to reprove the two extreme doctrines of Laxism and Rigorism; for in practice, as to forming the morals of the faithful, confessors do not differ so very much.

5. Nor is it strange if, in the Middle Ages, such determinate systems are not found; for this belongs rather to the art of the direction of souls than to moral science. Various reflex principles were indeed known: In uncertainties, the more truthlike is to be chosen; - A doubtful law does not oblige; - The condition of the possessor is better; - In uncertainties one must stand for that for which the presumption stands; - In doubts one must act more safely, etc. These were applied by some rather than others in doubts of conscience for various cases and circumstances, so that in some way a conscience might prudently be formed as certain, without the matter being expounded systematically, or one determinate mode predominating or being imposed on all. And therefore all the systems can bring forward something from the authors of the Middle Ages in their favor; nevertheless none is found there complete and formed. But from the sixteenth century onward they endeavored to reduce those principles to one supreme principle from which, in any case, in any matter, the practical doubt might easily be solved.

101. The use of probable opinions must be regulated with the greatest prudence, so that it may be conformable to right reason; for it easily provides occasion for abuse, so that Probabilism, or even Equiprobabilism, degenerates into Laxism, if merely probable opinions without selection are also applied to cases in which a determinate end must be attained absolutely, or if doubtfully or lightly probable opinions are too easily admitted as truly and solidly or almost equally probable, as happened in the seventeenth century and even today sometimes occurs.⁷

⁷ Th. M. fundamentalis, n. 384.

Now, 1) to avoid the first, one must carefully attend in practice whether there is not present a case concerning the validity of an act or the necessity of a means for an end absolutely to be obtained, because such cases occur much more frequently than appears at first sight.

2. To avoid the other, it is asked: what opinion in practice can be held as seriously and sufficiently probable?

To solve this question one must know that, by reason of the principle or motive on which it rests, probability is intrinsic if it rests on reasons taken from the very nature of the thing to be examined (properties, causes, effects, inconveniences of the opposite part); or extrinsic if it rests on the authority of others. The latter supposes the former, and lasts so long as the former can be presumed; for we therefore admit what others affirm because we hold them learned and truthful. But if it is established that they are in error or rest on altogether weak foundations, their authority for this case vanishes.⁸

⁸ "The intrinsic force of reasons must principally be attended to; for extrinsic authority does nothing other than bring a presumption of intrinsic force." St. Alphonsus, Th. M., book I, n. 80.

Now, a) concerning intrinsic probability, not indeed of fact but of doctrine, only the learned can rightly judge, and indeed not the moderately learned, but those very versed in moral matters. For them, that is probable which, all things having been duly and diligently considered, and the reasons on the opposite side compared with one another, appears as uncertain and yet resting on grave reasons.

b) Concerning extrinsic probability, the learned and the unlearned can judge. For the latter, that is probable or even practically certain which is said to them by a learned man (especially if he has authority for directing morals, for example, by a pastor or confessor), if there is no serious reason for doubting his skill or the probability of his statement. For since they cannot weigh the reasons, they act prudently by following the judgment of him concerning whose knowledge and truthfulness they have no reason for doubting. Hence St. Thomas, II-II, q. 4, a. 8 ad 2: "someone of little knowledge is made more certain concerning what he hears from someone scientific than concerning what seems to him according to his own reason." But if a reason for doubting is present, for example because the unlearned person sees that it is against common doctrine or the mode of acting, he is held to inquire further.

c) For the moderately learned, i.e., not only for theologians, but also for pastors and confessors, extrinsic probability must be judged not so much from the number of authors as from their merit: authors must not so much be counted as weighed.⁹ On this let Tanquerey be heard, conformably to the warning of Benedict XIV:

⁹ They ask whether a "probably probable opinion" is sufficiently probable so that we may licitly act according to it. If the obvious sense is taken, so that the word probably is taken in the same sense as probable (as it must be taken in the same context), it is illicit, because "probability concerning the probability of an opinion does not pour probability into the opinion itself." Thus Marc and Beaudoin. But if probably is taken in the strict philosophical sense, for that which is much more probable or as it were practically certain, it could be sustained, and Noldin (n. 27) and Vermeersch (n. 363) seem to understand it thus.

"Confessors especially are held to apply themselves to this kind of study... Wherefore Benedict XIV admonishes them 'that in a doubtful matter, they not rely upon their own opinion, but, before they decide the case, consult very many books, especially those whose doctrine is more solid, and then come down into that opinion which reason persuades and authority confirms' (Const. apost. de praep. ad Iub. a. 1750, § 21). a) Namely, they should not rely upon their own opinion, which is often fallacious: for more wisdom is found in the judgment of many than in that of one. b) They should consult very many books, more easily to guard against the same inconvenience: for what could escape one author does not so easily escape many, especially if they do not belong to the same school, but to diverse schools; for experience establishes how easily authors of the same school, without further examination, confidently repeat the opinions and arguments of their predecessors! c) Moreover, they should choose those books whose doctrine is more solid, which, namely, by knowledge, prudence, and piety, have gained for themselves a greater reputation, and have weighed the matter expressly, not in passing... d) They should come down into that opinion which reason persuades and authority confirms. Whence, insofar as it can be done, both intrinsic reasons and extrinsic authorities must be attended to: the arguments brought forward should be critically weighed with attention to the circumstances of places and times; and generally speaking, the authority of theologians should not be esteemed more than the weight of the reasons which they bring forward. Nevertheless, if by the common doctrine of all schools some conclusion is confirmed, by that very fact it has great probability, even independently of the arguments brought forward; nor must one depart from it unless a new reason is brought into the open which until now was unknown."¹⁰

¹⁰ "Extrinsic probability must be estimated 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; for ten or more authors can hold some opinion whose authority contributes scarcely anything more to its probability than the authority of one, whom perhaps they followed without examination and discussion of the matter." Thus Aertnijs, Th. M., t. I, n. 62, from the Diss. of St. Alphonsus, a. 1763, nn. 84-88.

102. Practical rules. - Recent theologians almost all hand down the same rules. Generally in practice, that doctrine can be judged certainly or at least seriously or gravely probable which, with the Church tolerating it:

a) either is commonly or by most authors asserted as such, although not as more probable;

b) or that which some great theologian2 (for example, St. Thomas, St. Antoninus, Cajetan, Sylvius, Banez, Suarez, Lugo, the Salmanticenses, St. Alphonsus, etc.) testifies3 to be probable, i.e., rightly to be held as such by others;

c) or that which five or six grave and approved authors, namely, men distinguished by probity and knowledge,4 i.e., those whose doctrine, prudence, probity, and faith are everywhere acknowledged, hold absolutely as true; - or assert to be truly probable, if this is not very much called back into doubt by others.

On the contrary, that doctrine is improbable or only thinly, lightly, or doubtfully, and not sufficiently probable:

1. which even many theologians have held, if it is reformed by a decree of the Church, or if to someone on account of most grave reasons it seems certainly false;

2. which one or another author hands down, but several contradict;

3. which five or six authors only hold as probable, if as to this assertion their authority is doubtful, either because against them stands a grave reason which they have not solved, or because others strongly contradict, or because it is not sufficiently established whether they have carefully examined the question; for often they call an opinion probable solely because it is held as such by another;¹¹

¹¹ "The doctors judge an opinion doubtfully probable: 1. if there is doubt concerning the gravity of the reasons; 2. if wise men commonly doubt concerning that probability; 3. if the authority of the doctors who affirm or hold the opinion as probable is doubtful; 4. if the reason of the doctor who defends it does not seem sufficiently firm; 5. if it is a singular opinion brought forth by an author, without his bringing forward a sufficient reason; 6. if one or another hands it down, but several contradict." Ballerini-Palmieri, Opus theol. mor., book I, de consc., q. 113.

4. a fortiori something is not probable because it is taught by one recent author; whence Alexander VII condemned the proposition (27): "If a book is by some younger and modern author, the opinion must be judged probable, so long as it is not established that it has been rejected by the Apostolic See as improbable" (cf. St. Thomas, Quodl. III, 10).

Yet an exception is made:

a) a general one: if one very learned, prudent, and diligent in examination, and not a lover of novelties, brings forward valid reasons which others have not considered or have not sufficiently solved, and he himself conveniently solves the opposite reasons;¹²

¹² Cf. St. Alphonsus, diss. of the year 1755, n. 117; and diss. of the year 1763, n. 86.

b) a special one, for St. Alphonsus: from the decree of the Sacred Penitentiary, 5 July 1831, a confessor,¹³ while administering the sacrament of Penance, can safely in conscience follow all the opinions of St. Ligorio, even if he does not examine the reasons, but solely because he himself teaches them. And the same is valid a fortiori concerning St. Thomas. - This, however, must not be understood without discretion: for it is not valid for opinions which the author himself, in the case St. Alphonsus, reformed; nor, a fortiori, for those which the Church reformed; nor for opinions contrary to a just civil law or to a new ecclesiastical law; nor for those which appear certainly false to someone.

¹³ Even he who has sworn to defend Probabiliorism, as was answered on 19 Dec. 1855.

The aforesaid rules must not be extended more broadly but must be urged strictly, and the more strictly because in our days so many theological writings and responses are published that much more easily than before five or six recent authors are found to assert the sufficient probability of some opinion, especially if they are of the same school, all the more because rather often they do nothing except copy out another recent author.

103. Practical corollaries. - 1. A lightly probable opinion is not to be attended to except in extreme necessity, in which, more certain remedies failing, even extreme and lightly probable things are to be attempted in order to attain the end; for in those circumstances this is now the safer thing.

2. In a practical doubt, probability for acting does not suffice, but one must have certitude; whence one must inquire concerning the truth, and otherwise act more safely. Hence, as to the observance of ecclesiastical law:

a) while the hour of the precept is positively doubtful, one must inquire concerning it, even if diverse clocks indicate differently, for diverse clocks do not suffice to remove a practical doubt. Only in the case in which certitude will be impossible can, from custom, diverse clocks be held as diverse probable opinions;¹⁴

¹⁴ Vermeersch, Th. M., t. I, n. 370.

b) where two foods, of which one is prohibited and the other permitted, can no longer be distinguished, an insoluble practical doubt is present; wherefore one must act more safely and abstain from both - unless there is present so grave an inconvenience; but then it will be licit, not on account of the doubt, but on account of the inconvenience.¹⁵ 3

¹⁵ Ibid.

3. A fortiori it is illicit voluntarily to bring about an insoluble practical doubt concerning the law and nevertheless not to observe it, although, once the doubt has arisen involuntarily, it can be licit not to observe it. Hence if someone does not know whether midnight is at hand or has passed, he is held first to inquire into the truth; if he neglects this, he will sin unless he acts more safely and observes the doubtful law. Thus one who is uncertain, for example, cannot drink unless by renouncing communion on the following day; and if he has drunk, he is held to abstain from it, unless nevertheless after the fact it is established certainly that it had not yet been midnight. On the contrary, he who has drunk in good faith, thinking nothing about the hour, and in the morning doubts whether he is fasting, is not held to observe the law and will be able to communicate.

4. In the direction of one's own life, for each one (unless someone were a Probabiliorist) it is of itself licit, in the same matter, now to follow one solidly probable opinion, now another solidly probable opinion opposed to the former, successively or in diverse cases or acts; because each is sufficiently safe and secure. For example, in one case he can accept the inheritance of an informal testament because, before the judge's sentence concerning nullity, it is probably valid, and, in another case, pursue the annulment of another informal testament to be declared by a judge, because it is null.

Nevertheless per accidens it is illicit, by reason of scandal, or by reason of simultaneity, namely if someone uses opposite opinions at the same time, in the same case and act, or in the same individual thing and action, so that from this a certain obligation or the right of a third party is certainly violated. Thus, for example, someone cannot accept an inheritance from an informal testament because it is valid, and refuse the burdens to be fulfilled under the pretext that the same testament is null; for it is certain that he who takes the inheritance must also take upon himself the annexed burdens.

Likewise it is illicit to reason thus: it is probable that it is not yet midnight of the feast of Pentecost; therefore it is probable that I can take a collation and communicate in the morning. But it is also probable that it is midnight; therefore I can eat meat, and from the prior opinion communicate in the morning. For in no way can it be probable that I can eat meat and communicate in the morning, because for this it would be required that it be probable that it is midnight and at the same time that it is not.

Likewise, supposing two probable opinions, of which one says that today one must fast, the other that today one need not fast but tomorrow, it would not be licit today to embrace the second opinion and not fast, and tomorrow to embrace the first opinion and again not fast, because certainly the same numerically one law is violated. The same would hold for one who on Thursday, having heard twelve at night on one clock, omitted compline because he was no longer held to recite, and wished to eat meat because he had not yet heard the twelfth hour on another clock.

3. Almost thus Lehmkuhl, Th. M., I, n. 205; Noldin, Th. M., I, n. 243; Vermeersch, Th. M., I, n. 374; Th. Mechl. M. gen., ed. 5, n. 20, II. In the same way a priest could not consume a doubtfully consecrated host before the consumption of the most Precious Blood, lest he voluntarily induce a state of doubt concerning the natural fast with danger of violating the law.

1. Do not say: even in the first case, where there are two testaments, some right is certainly violated. - That indeed would be true if one testament were held valid of itself, and another invalid of itself; but not if one, before the sentence of the judge, is judged probably to retain validity, and another after the sentence is altogether invalid, because by the intervention of the judge the invalidating law obtains its full force.

104. Observation. - The rules indicated above generally are accustomed to be handed down by the more recent theologians,¹⁶ even Probabilists; but not all always sufficiently regard them in practice, nor apply them constantly, by which it happens that even laxer opinions are sometimes judged probable.

¹⁶ Thus, for example, Lehmkuhl, Ballerini, Aertnijs, Genicot, Noldin.

Specifically, a) by saying of certain opinions that "they perhaps are probable," or that "they do not dare to confess that they are altogether improbable," they implicitly suggest to readers that those who follow them are not to be condemned, whereas on the contrary according to what has been explained they ought to conclude that the opinions are little and doubtfully probable, and consequently not sufficiently and practically probable, nor generally able to found a rule of acting prudently.

b) In the past century, a certain theologian of a sufficiently great name, while the stricter opinion seemed certainly more probable, strove with all his strength through rational arguments to show that the more benign one was nevertheless intrinsically probable; and, on the contrary, while that one did not seem to rest on valid arguments, he tried to heap up a long series of authors for the extrinsic probability nevertheless to be preserved for it against everything. This is not sincerely to seek the truth.

c) Similarly, what service does it render if a theologian of the best reputation shows well that a certain too benign opinion has no probability for itself, indeed is false; and nevertheless he does not cease to acknowledge some extrinsic probability for it in practice, because some five or six authors said it was probable? But some authors do not make serious extrinsic probability, unless they are truly distinguished, have carefully examined the matter, and do not pronounce from the authority of others alone. But if it is established that the opinion is not founded, by that very fact the probability of the opinion vanishes.

Such a procedure hinders every progress of moral science, which would be reduced to reciting the opinions of authors, without their probability ever being able to cease, unless by the intervening judgment of the Church.