Thomas Aquinas, Disputed Questions on Truth (De Veritate)

1. No one is bound to do anything except by some law. But man does not make the law for himself. Therefore, since conscience arises from the act of man, it does not bind.

2. One is not bound to follow the counsels. But conscience operates as a counsel, for conscience seems to precede choice in the way counsel does. Therefore, conscience does not bind.

3. One is bound only by something superior. But the conscience of a man is not superior to the man himself. Therefore, a man is not bound by his conscience.

4. The same thing binds and frees [from an obligation]. But conscience cannot free a man [from an obligation]. Therefore, it cannot bind him, either.

To the Contrary:

1'. The Gloss on Ecclesiastes (7:23), "Your conscience knows," says: "No one who is guilty is set free by this judge." But the command of a judge is binding. Therefore, the dictate of conscience binds.

2'. On Romans (14:23), "All that is not of faith . . . ," Origen says: "The Apostle desires that I say, think, or do nothing against conscience." Therefore, conscience binds.

REPLY:

Conscience is certainly binding. But, to see how it binds, we must bear in mind that binding, taken metaphorically from corporeal things and applied to spiritual, means imposing necessity. For he who is bound must necessarily stay in the place where he is bound, and the power to go off to other places is taken away from him. Hence, it is clear that binding has no place in things which have internal necessity. For we cannot say that fire is bound to rise, although it is necessary for it to rise. Binding, then, has place only in things which are necessary with a necessity imposed by something else.

Now, there is a twofold necessity which can be imposed by an outside agent. One is the necessity of coercion, through which someone with absolute necessity does that which the agent forces him to do. Otherwise, it is not properly called coercion, but inducement. The other necessity is conditional, on the presupposition, that is, of an end to be attained. In this way, necessity is so imposed on one that, if he does not do a certain thing, he will not receive his reward.

The first necessity, that of coercion, has no place in movements of the will, but only in physical things, because by its nature the will is free from coercion. The second necessity, however, can be imposed on the will, so that one must, for example, choose this means if he is to acquire this good, or avoid this evil. For, in such matters, avoiding evil is considered equivalent to achieving some good, as is clear from the Philosopher.

Moreover, as necessity of coercion is imposed on physical things by means of some action, so, too, it is by means of some action that conditional necessity is imposed on the will. But the action by which the will is moved is the command of the one ruling or governing. Consequently, the Philosopher says that by means of his command the king is the source of movement.

Similarly, too, where the will is concerned, the relation between the command of a ruler and the imposition of the kind of obligation by which the will can be bound is like the relation between physical action and the binding of physical things through the necessity of coercion. However, the action of a physical agent never imposes necessity on another thing except by the contact of its action with the object on which it is acting. So, no one is bound by the command of a king or lord unless the command reaches him who is commanded; and it reaches him through knowledge of it.

Hence, no one is bound by a precept except through his knowledge of the precept. Therefore, one who is not capable of the knowledge of a precept is not bound by the precept. Nor is one who is ignorant of a precept bound to carry out that precept except in so far as he is required to know it. If, however, he is not required to know it, and does not know it, he is in no way bound by the precept. Thus, as in physical things the physical agent acts only by means of contact, so in spiritual things a precept binds only by means of knowledge. Therefore, just as it is the same power by which touch acts and by which the power of the agent acts, since touch acts only by the power of the agent and the power of the agent acts only through the mediation of touch, so it is the same power by which the precept binds and by which knowledge binds, since the knowledge binds only through the power of the precept, and the precept only through the knowledge. Consequently, since conscience is nothing else but the application of knowledge to an act, it is obvious that conscience is said to bind by the power of a divine precept.

Answers to Difficulties:

1. Man does not make the law for himself, but through the act of his knowledge, by which he knows a law made by someone else, he is bound to fulfill the law.

2. Counsel has two meanings. Sometimes, counsel is nothing other than the action of reason inquiring about things to be done. In this sense, the relation of counsel to election is the same as that of a syllogism or question to a conclusion, as is clear from the Philosopher. Taken in this sense, counsel is not opposed to precept, for we take counsel in this way about matters of precept. Hence, obligation can arise from such counsel. It is in this sense that counsel is found in conscience in so far as it is applied to one function of conscience, when, namely, it makes an investigation into some action.

In the other sense, counsel is called persuasion or inducement to do something when it does not have compelling force. In this sense, counsel is opposed to precept. Friendly exhortations are of this sort, and, sometimes, conscience proceeds from that type of counsel. For the knowledge of this counsel is sometimes applied to a particular act. But, since conscience does not bind except in virtue of that which is in conscience, conscience which follows from counsel cannot bind in any other way than the counsel itself. Consequently, one is bound not to despise it, but he is not obliged to follow it.

3. Although man is not higher than himself, the one whose precept he knows is higher than man. This is how he is bound by his conscience.

4. When a man sins in making the error itself, a false conscience is not enough to excuse him. This is the case when he makes a mistake about things which he is required to know. However, if the error is about things which he is not required to know, he is excused by his conscience, as is clear when one sins from ignorance of a fact, as when one approaches another's wife, whom he thinks is his own.