ARTICLE IV: VARIOUS SYSTEMS CONCERNING THE USE OF PROBABLE OPINION

61. • Since in practical doubt concerning the honesty of an action we cannot act honestly, and since that doubt very often cannot be directly overcome by reasons proper to individual cases, there must certainly be given from elsewhere some means of laying aside the doubt, so that, resting upon a certain conscience, we can act rightly. Now it is manifest that this means cannot consist except in some certain principle.² Therefore the state of the question here is:

In the concurrence of two opinions concerning the honesty of an action, of which one, the less safe, favors liberty, while the other, the safer, favors the law, what in this doubt is the certain universal rule to be followed for acting rightly?

This question is of such great moment that upon its solution depends the whole system of Moral Theology, whatever system may be chosen. For doubts of this kind occur many times in the individual matters of Moral Theology, since in it especially the application of laws to particular cases is treated, which is often uncertain.

But now, to solve this celebrated question, theologians have entered upon various ways. Some, namely, of excessive rigor in favor of the law; others, of excessive benignity in favor of liberty; and others finally have held the middle way between each extreme. Hence several systems have come forth, which we here briefly review:

62. Systems. - I. Rigorism or strict Tutiorism, according to which it is not lawful to follow a sentence favoring liberty unless it is morally certain; otherwise the safer part must always be followed. This is a condemned system.

II. Mitigated Tutiorism, according to which it is not lawful to follow the less safe sentence unless it is most probable.

III. Probabiliorism (another mitigated Tutiorism), according to which it is prohibited to follow an opinion favoring liberty unless it is more probable than the opposite one for the law.

IV. Equi-probabilism, according to which, in the concurrence of two opinions equally or almost equally probable, while doubt stands concerning the existence of the law, it is lawful to follow the opinion favoring liberty; but in doubt concerning the cessation of a certain law, the opinion favoring the law must be followed. This is the system of St. Alphonsus.

Since the followers also of simple Probabilism in our age are accustomed to distinguish their system by the title of Moderate Probabilism, and thus, by the celebrated name of Alphonsus, cover a doctrine altogether diverse from the doctrine of the Holy Doctor, for the sake of greater clarity we have preferred in this edition to call the Alphonsian system by the name Equi-probabilism; the more so because authors today commonly use that term, and the Saint himself (for example, H. A. Tr. I. 75) calls his system "my system of the equally probable opinion."

V. Simple Probabilism, according to which it is right to follow an opinion less probable and favoring liberty in the concurrence even of a notably more probable one for the law; and it is lawful promiscuously to follow a probable opinion that is less safe, even in doubt concerning the cessation of a certain law.

The followers of simple Probabilism are divided into two classes; for some, although they favor liberty, nevertheless say that in doubt both concerning the cessation and concerning the existence of a law, the law must be followed when the opinion favoring liberty is certainly less probable. Thus Martinet and certain more recent authors. Others teach that it is lawful to follow an opinion less probable and favoring liberty, even if it is evident that the opposite one is more probable. Thus Lacroix and other Probabilist authors of the eighteenth century almost commonly, and also Gury in the later editions of his Compendium, and Ballerini.

VI. Laxism, according to which it is lawful to follow a sentence favoring liberty, even if it is only doubtfully or slightly probable. This system also is condemned.

Therefore, excepting I and VI, the remaining systems can be maintained without the Church's condemnation. Yet among them we judge that only Equi-probabilism, which claims St. Alphonsus for itself as its principal author and as a second quasi-parent (Vind. P. I, p. 74. - Ed. 2a, T. I, p. 509), holds the middle way and for this reason is true.