§ II. On the Notion, Division, and Directive Force of Conscience Properly So Called

Conscience can be taken both physically and morally. Conscience taken physically, or physiological conscience, is the cognitive faculty of returning to one's own acts. Conscience taken morally, or moral conscience, imports a judgment about the morality of our acts; and it is twofold, antecedent and consequent, according as it regards an act, or respectively an omission, to be placed or already placed. Antecedent conscience commands, forbids, or permits an act to be placed. Consequent conscience approves or reproves an act already placed, and consequently causes joy or remorse (St. Thomas, De verit., q. 17, a. 1). But it is clear that the morality of an action does not depend on consequent conscience, which follows the act, but on antecedent conscience alone; in other words, this latter, not the former, is the rule of morality. Hence our discussion concerns antecedent conscience alone.

I. Notion. Conscience, moral and antecedent, is a dictate of the practical intellect by which someone judges that a particular action is commanded, prohibited, or free for him (St. Alphonsus, I, 2; cf. St. Thomas, I, q. 79, a. 13; De veritate, q. 17, a. 2). It is said:

1. A dictate, because conscience is an act, not a faculty or a habit.

2. Of the practical intellect, that is, of the intellect insofar as it directs to operation what it apprehends. This belongs to the practical intellect, which "knows truth as the speculative intellect does, but orders the known truth to work" (St. Thomas, I, q. 79, a. 11, ad 2).

3. A particular action; for conscience is not a judgment about the morality of an act considered in general and in the abstract, but about the morality of an act viewed in particular and in the concrete (St. Thomas, De veritate, q. 17, a. 2; St. Alphonsus, I, 2).

4. For him, namely, conscience judges about the morality of an act insofar as it belongs to the one judging himself, or insofar as it must be placed or omitted by the one judging himself, or can be placed or omitted at will.

5. Commanded, etc. That is, moral conscience does not judge about the utility or pleasantness of an act, but about its morality, that is, about the moral necessity or moral liberty of placing or omitting the act.

Corollary I. Conscience is the conclusion of a syllogism, at least a virtual one. The major proposition states some law. The minor proposition compares some act with the law; for example: Theft is illicit. But the taking of this thing would be theft. Therefore the taking of this thing is illicit for me.

Corollary II. Conscience differs from synderesis, from moral science, from casuistic science, from prudence, and from the last practical judgment.¹ Synderesis (Greek synteresis, that is, preservation) is the natural habit preserving the first and general practical principles, for example: good is to be done, evil is to be fled. Moral science is an acquired habit which concerns general conclusions deduced from first principles; for example: to each person his own must be left; but theft takes away from one's neighbor what is his; therefore theft must be rejected. Casuistic science is an acquired habit which applies the conclusions of moral science to particular cases considered in the abstract. But conscience applies general conclusions to particular cases, and to these as considered in the concrete, insofar as here and now they are to be brought into practice. Prudence is a habit which directs the intellect in deducing and applying conclusions. But conscience is the very act itself of applying conclusions to particular cases considered in the concrete. Finally, the last practical judgment dictates only that something is to be done or omitted; but it does not speak about the morality of the action or omission.

¹ Judgments formed in order to operation are distinguished into speculative, speculative-practical, and practical-practical. Speculative judgments regard the truth which founds the morality of a consequent act, for example the existence of some fact, as: Today is Sunday; or the value of an act, as: A sacrament administered in this way is invalid; etc. Speculative-practical judgments regard the morality of an act, but only in common, as: Mass is to be heard on Sunday. Practical-practical judgments concern the morality of an act in particular and constitute conscience properly so called, as: Today Mass is to be heard by me.

II. Division. Conscience is divided:

1. By reason of its relation to truth, into true or right¹ and false or erroneous, according as the morality which is predicated of a particular action is really present in the action or is not present in it (St. Alphonsus, I, 3).

An erroneous conscience is called vincibly or invincibly erroneous, according as the error can or cannot be driven out by moral diligence.

2. By reason of the morality which is judged to be present in the act, into commanding, prohibiting, and permitting conscience, according as something is judged to be commanded, prohibited, or free.

3. By reason of the state of the mind, into certain, opinionative, and doubtful conscience. Certain conscience is that by which someone judges firmly, that is, without prudent fear concerning the opposite, about the morality of a particular action. It is distinguished into two: directly and indirectly certain. The former rests on motives which show the objective morality of the action. The latter arises from a general, reflex, and certain principle, which is applied to an act about whose objective morality there is only doubt or opinion.² Opinionative conscience is that by which someone judges weakly, that is, with prudent fear concerning the opposite, about the morality of a particular action. Doubtful conscience is one which hesitates uncertainly concerning the morality of a particular action and suspends assent (p. 205; St. Alphonsus, I, 20).

A perplexed conscience is had when someone apprehends sin on both sides, and can neither form a safe conscience for himself nor abstain from choosing one side, as if someone judges, and persists in that opinion, that he sins whether by hearing Mass he leaves a sick person alone, or by remaining with the sick person he neglects Mass (St. Alphonsus, I, 10).

¹ Others call that conscience right which is prudently formed, whether it is true or false.

² Indirectly certain conscience is usually called probable conscience (St. Alphonsus, I, 40).

III. Directive force of conscience. 1. Certain conscience, whether true or false, or erroneous,¹ is the rule of morality; or it brings it about that an action has, with respect to the one judging it, that morality which is judged to be present in it. In other words, one who firmly judges that a particular action must be placed by him, or omitted by him, or is free for him, is in reality either bound to place it or omit it, or is free. For certain conscience involves a firm judgment about the ordinance of God the Best and Greatest concerning a particular action. But the mode or manner of acting must be conformed to such a judgment, whether it is true or false. For neglect of the aforesaid conformity would involve neglect of the divine ordinance itself (St. Thomas, De veritate, q. 17, a. 4, c. and ad 3; I, q. 79, a. 13; I-II, q. 19, a. 5; cf. St. Alphonsus, I, 5).

2. Certain conscience enjoys the force described above not from itself, but from the power of divine law. The reason is that the power of obliging, or of morally binding, cannot belong except to a superior. But a man's conscience is not superior to the man himself. "Conscience," says St. Bonaventure, "is like God's herald and messenger; and what it says, it does not command from itself, but commands as if from God, as a herald does when he publishes the edict of the king"² (cf. St. Thomas, De veritate, q. 17, a. 3).

3. Uncertain conscience, that is, opinionative or doubtful conscience, of itself lacks directive force, because direction necessarily takes place toward one thing, and therefore must proceed from a conscience which itself is determined to one thing. But uncertain conscience is not determined to one thing, but is disposed about different things. What must be done by one who is uncertain will be explained in n. 221.

Corollary I. One who acts against a certain conscience commanding or forbidding, whether true or false, commits as much and such a sin as he apprehends in the act. "A human act is judged virtuous or vicious according to the good apprehended toward which the will is borne, and not according to the material object of the act" (St. Thomas, Quodl. 3, art. 27).

Corollary II. One who apprehends the malice of an act, but thinks nothing, not even confusedly, about grave or light malice, sins only lightly. Nevertheless, commonly there is present, and therefore it is presumed that there is had, sufficient advertence and consent, though confused, to grave malice: first, if the matter is manifestly grave; second, if there is question of a man little concerned about the quantity of sin.

Corollary III. One who from an erroneous conscience judges that he sins, whether by not fulfilling a precept which he physically cannot fulfill, or by suffering an evil, for example rape, which he cannot prevent, does not sin. For there is physical impotence, and therefore the voluntary is lacking.

Corollary IV. One who apprehends sin on both sides should, if he can, form a safe conscience for himself by seeking the truth and by prudently solving the doubt, should it perhaps persist, with the help of a reflex principle. If he can neither form a certain conscience for himself nor abstain from choosing, let him choose what appears the lesser evil.³ If each appears equal, let him choose at will. If nevertheless he judges that he sins, he is still free from sin, because liberty is lacking and no one sins necessarily.

If he chooses what appears graver, he indeed sins, but only in proportion to the apprehended excess; since as regards the total malice he is not free, but he freely embraces the excess.

¹ Others add: provided it is invincibly erroneous. But certain conscience is necessarily here and now invincibly erroneous; for such a conscience supposes that here and now not even a suspicion of error is suggested. Hence such a conscience, if it commands or prohibits something, obliges, even if a vincibly erroneous conscience preceded it; if it permits something, it renders that thing licit here and now to the one so judging, although the erring person perhaps was not without fault led to such a conscience and therefore sinned before.

² In II Sent., dist. 39, a. 1, q. 3.

³ Of itself, that is, other things being equal, the transgression of a natural precept is to be guarded against more than that of a positive precept; of a divine precept more than of a human one; of a negative precept more than of an affirmative one.