Front Page Titles (by Subject) QUESTION LXXVI.: OF THE CAUSES OF SIN IN PARTICULAR. - Aquinas Ethicus: or, the Moral Teaching of St. Thomas, vol. 1 (Summa Theologica - Prima Secundae, Secunda Secundae Pt.1)
Return to Title Page for Aquinas Ethicus: or, the Moral Teaching of St. Thomas, vol. 1 (Summa Theologica - Prima Secundae, Secunda Secundae Pt.1)
The Online Library of Liberty
A project of Liberty Fund, Inc.
QUESTION LXXVI.: OF THE CAUSES OF SIN IN PARTICULAR. - St. Thomas Aquinas, Aquinas Ethicus: or, the Moral Teaching of St. Thomas, vol. 1 (Summa Theologica - Prima Secundae, Secunda Secundae Pt.1) 
Aquinas Ethicus: or, the Moral Teaching of St. Thomas. A Translation of the Principal Portions of the Second part of the Summa Theologica, with Notes by Joseph Rickaby, S.J. (London: Burns and Oates, 1892).
About Liberty Fund:
The text is in the public domain.
Fair use statement:
OF THE CAUSES OF SIN IN PARTICULAR.
Article I.—Can ignorance be a cause of sin?1
R. A moving cause is of two sorts: one ordinary, and another incidental. The ordinary cause moves by its own power; the incidental cause by removing the obstacle to the action of another. In this latter way it is that ignorance may be a cause of sin; for ignorance is a privation of that knowledge that perfects the reason and hinders a sinful act, inasmuch as reason has the guidance of human acts, which guidance we must observe takes effect through a twofold knowledge, one general and one particular. For, thinking over a course of action to be adopted, a man uses a syllogism, the conclusion of which is a judgment, or choice, or activity: but actions are singular: hence the conclusion of the syllogism of conduct is singular. But a singular proposition is not drawn as a conclusion from a general one except by means of another singular proposition. Thus a man is kept from a deed of parricide by knowing that a father ought not to be killed, and by further knowing that this individual is his father. Ignorance of either the general principle or of the particular circumstance may cause a deed of parricide. Hence clearly it is not any and every ignorance on the part of the sinner that causes sin, but that ignorance only which takes away the knowledge that was a bar to the act of sin.
§ 3. The will cannot go out to that which is altogether unknown, but it can will what is partly known and partly unknown; and in this way ignorance is a cause of sin, as when one knows that the person whom he is killing is a man, but does not know that it is his father;1 or as when one knows that some action is pleasurable, but does not know that it is a sin.
Article II.—Is ignorance a sin?
R. Ignorance differs from nescience in this, that nescience means a simple negation of knowledge; but ignorance denotes a privation of knowledge in the case of a person lacking knowledge of matters which he is naturally apt to know. Of these matters there are some which a man is bound to know, those, namely, without the knowledge of which he cannot fulfil his duty. Hence all alike are bound to know the articles of faith and the general precepts of law: particular individuals are bound also to know what concerns their special state or office. But there are some things which a man is not bound to know, though a man has a natural aptitude to know them, as the theorems of geometry. Now it is manifest that whoever neglects to have or to do what he is bound to have or to do, sins by a sin of omission. Hence ignorance through negligence of what a man is bound to know, is a sin; but it is not imputed to a man as negligence if he does not know what he could not have known. This ignorance is called invincible, because it cannot be overcome by an effort. Such ignorance is not a sin; but vincible ignorance is a sin, if it is of what one is bound to know, not if it is of what one is not bound to know.
§ 1. Under the head of word, deed, or desire against the law of God, are to be understood also the opposite negations, in so far as omission bears the character of sin; and thus negligence, by which ignorance is sinful, is contained under the definition of sin, inasmuch as something is omitted which ought to have been said, done, or desired, in order to the acquiring of due knowledge.
§ 3. As in a sin of transgression the sin consists not only in the act of the will, but also in the act willed, which is commanded by the will, so in a sin of omission not only the act of the will is a sin, but also the omission itself, inasmuch as it is in some sort voluntary; and in this way mere neglect to know, or mere inconsiderateness, is a sin.
§ 5. As in other sins of omission a man sins for that time only for which the affirmative precept obliges him to act, so is it also with the sin of ignorance. An ignorant person is not in the act of sinning continually, but then only when it is time to acquire a knowledge which he is bound to have.
Article IV.—Does ignorance diminish sin?
R. Because all sin is voluntary, ignorance is capable of diminishing sin so far as it diminishes voluntariness: but if it does not diminish voluntariness, it will in no way diminish sin. Now, as for the ignorance that is a total excuse from sin, as being a total taking away of voluntariness, plainly that does not diminish sin, but takes it away altogether. Again, the ignorance which is not a cause of sin, but a concomitant of sin, neither diminishes sin nor increases it.1 That ignorance then alone can diminish sin, which is a cause of sin and yet not a total excuse from sin. Such ignorance is sometimes directly and of itself voluntary, as when one of his own choice remains in ignorance upon some point, in order that he may sin more freely. Such ignorance seems to increase the voluntariness and the sinfulness of the action: for by reason of the will being bent on sinning, the man is ready to endure the disadvantage of ignorance to gain freedom to sin. Sometimes, however, the ignorance which is a cause of sin is not directly voluntary, but indirectly and incidentally: as when one will not labour at study, and thence comes to be ignorant; or when one will drink wine to excess, and thereby gets drunk and wants discretion: such ignorance diminishes voluntariness and consequently sinfulness. For when a thing is not known to be a sin, it cannot be said that the will directly and of itself goes out upon the sin, but only incidentally; hence there is less contempt and consequently less sin.
§ 2. Sin added to sin makes more sins, but not always greater sin; because it may be that the two sins do not coincide to make one and the same sin, but keep their plurality. It may also happen, if the first diminishes the second, that both together are not so grievous as the one alone would have been. Thus homicide is a more grievous sin if committed by a sober man than by a drunken man, notwithstanding that in the latter case there are two sins: because drunkenness takes off more than the amount of its own gravity from the gravity of the sin that ensues upon it.
§ 4. As the Philosopher says, “the drunkard deserves to be fined double,” for the double sin that he commits of drunkenness and the sin thence ensuing. Nevertheless, on account of the ignorance that goes along with it, drunkenness diminishes the ensuing sin, and that, perhaps, to a greater amount than is represented by the gravity of the drunkenness itself. Or it may be answered that the saying is adapted to the enactment of a certain lawgiver, Pittacus, who ordered an assault to be punished the more if it was committed in drunkenness, not considering the allowance that should be made for drunkards, but going upon expediency; because more breaches of the peace are committed by drunken men than by sober men, as is evident from the Philosopher.
[1 ]That is, of material sin, or objective transgression. How far the sin done in ignorance may be formal and imputable to the agent, is inquired in art. 3. (Trl.)
[1 ]The Roman soldiers, of whom our Saviour said, “They know not what they do,” knew that they were carrying out the sentence on Him with needless cruelty, but not, perhaps, that He was a just man; others, who knew Him to be a just man, did not know that He was the Son of God; which the priests and elders of the people were in a position to know Him to be, were it not that their eyes were blinded that they should not see (St. John xii. 40), through their own culpable ignorance. (Trl.)
[1 ]See q 6. art. 8. (Trl.)