Article I: On True Conscience

S. Th. I-II, q. 19, a. 3; Q. D. de Veritate 17, a. 3.

53. State of the question. - Inquiry having been made for attaining conscience concerning the morality of an act, there can arise from it a threefold state or species of conscience from the part of the object or rectitude: for by reason of conformity with law, conscience is true or erroneous according as it dictates truth or falsity. True, namely, if it dictates that what is really licit or illicit is licit or illicit; erroneous if it exhibits something as licit which really is illicit, or vice versa: this, moreover, is invincibly erroneous if here and now it cannot be overcome by moral diligence; vincibly erroneous if by moral diligence it can be overcome here and now, but voluntarily is not overcome, whether directly from lack of industry, or indirectly from negligence.

Hence it is asked whether each of these consciences is a sufficient rule for acting prudently, or practically true.

54. Thesis. True conscience is per se a rule for acting prudently which we can follow; indeed it is obligatory, if it is commanding or prohibiting, so that we are held to conform ourselves to it both negatively, by not acting against it, and positively, by acting according to it.

It is explained: True conscience a) is that which from true principles dictates that something in particular is licit or illicit which really is such;

b) it is a rule for acting safely, so that we can always conform ourselves to it, and by acting according to it we ourselves act well;

c) sometimes, namely if it commands or prohibits, we are also held to conform ourselves to it.

It is proved: Conscience, because it intimates and applies the law, is the proximate rule of human acts, upon which their morality depends. But true conscience applies the law: namely, it is a faithful herald. Therefore the act which is conformed to that rule is prudent and morally good, and the act which departs from that rule is morally evil.

It is confirmed: 1) True conscience is, as it were, the promulgation of law in relation to a particular act, made to us through reason. But we are bound to follow a law certainly known. Therefore.

2. Whence Scripture, Rom. XIV, 23: Everything that is not from faith (good faith, de bonne foi; uit goeder trouw) is sin; that is, what is not conformed to conscience, or what is not from persuasion or the judgment of conscience, is sin.

55. Sense of the doctrine. - True conscience is called a) a prudent rule per se, that is, from its own nature, because it faithfully exhibits the law as it is in itself; whence it is simply right and under every respect, formally and materially, and consequently it is a rule absolutely and in every event; and therefore an act conformed to it is per se prudent and good;

b) it is an obligatory rule if it is commanding or prohibiting: for if it counsels or permits, to act against it is not illicit, because we are not bound to do or omit what is commanded or prohibited by no law, although nevertheless it is illicit to contemn conscience counseling, even if we are not bound to fulfill it. But we can always act according to true conscience; indeed, we have the right so to act.

1. "We are said not to be bound to counsels. He who passes over a counsel does not sin, provided contempt is absent." Q. D. De Veritate 17, a. 4.

56. Formation of true conscience. - True conscience is formed by a ratiocination rightly deduced from true principles. Its major, which enunciates the universal principle, is from synderesis, for example: Evil is to be avoided; the minor, which regards the particular fact, is from reason rightly estimating all its circumstances, for example: to take this sum of Peter's money, without his knowledge, here and now, without any reason, is evil (for example, because prohibited by God, or by human law, or dishonorable, etc.). For rightly forming this minor, reason can use both moral science insofar as it applies the general rule to the particular act, and prudence for rightly estimating all circumstances, through eubulia. The conclusion is the very judgment of conscience: therefore to take this money of Peter, without his knowledge, here and now, without any reason, is illicit for me and to be avoided. This conclusion is enunciated through synesis.

Thus, therefore, true conscience can be formed:

"What is evil or prohibited by the law of God is to be avoided.

"But to have intercourse with this unmarried (or married, or related, or sacred) woman here and now is evil or prohibited by the law of God.

"Therefore to have intercourse with this woman here and now is to be avoided."

This ratiocination is not always formed explicitly, but more often is present implicitly.