only a venial sin, while others have held it to be a mortal sin, and this opinion is more common and more probable. For we must take note that since every delectation results from some action, as stated in _Ethic._ x, 4, and again, that since every delectation may be compared to two things, viz. to the operation from which it results, and to the object in which a person takes delight. Now it happens that an action, just as a thing, is an object of delectation, because the action itself can be considered as a good and an end, in which the person who delights in it, rests. Sometimes the action itself, which results in delectation, is the object of delectation, in so far as the appetitive power, to which it belongs to take delight in anything, is brought to bear on the action itself as a good: for instance, when a man thinks and delights in his thought, in so far as his thought pleases him; while at other times the delight consequent to an action, e.g. a thought, has for its object another action, as being the object of his thought; and then his thought proceeds from the inclination of the appetite, not indeed to the thought, but to the action thought of. Accordingly a man who is thinking of fornication, may delight in either of two things: first, in the thought itself, secondly, in the fornication thought of. Now the delectation in the thought itself results from the inclination of the appetite to the thought; and the thought itself is not in itself a mortal sin; sometimes indeed it is only a venial sin, as when a man thinks of such a thing for no purpose; and sometimes it is no sin at all, as when a man has a purpose in thinking of it; for instance, he may wish to preach or dispute about it. Consequently such affection or delectation in respect of the thought of fornication is not a mortal sin in virtue of its genus, but is sometimes a venial sin and sometimes no sin at all: wherefore neither is it a mortal sin to consent to such a thought. In this sense the first opinion is true.
But that a man in thinking of fornication takes pleasure in the act thought of, is due to his desire being inclined to this act.
Wherefore the fact that a man consents to such a delectation, amounts to nothing less than a consent to the inclination of his appetite to fornication: for no man takes pleasure except in that which is in conformity with his appetite. Now it is a mortal sin, if a man deliberately chooses that his appetite be conformed to what is in itself a mortal sin. Wherefore such a consent to delectation in a mortal sin, is itself a mortal sin, as the second opinion maintains.
Reply Obj. 1: Consent to delectation may be not only in the lower reason, but also in the higher reason, as stated above (A. 7).
Nevertheless the lower reason may turn away from the eternal types, for, though it is not intent on them, as regulating according to them, which is proper to the higher reason, yet, it is intent on them, as being regulated according to them: and by turning from them in this sense, it may sin mortally; since even the acts of the lower powers and of the external members may be mortal sins, in so far as the direction of the higher reason fails in directing them according to the eternal types.
Reply Obj. 2: Consent to a sin that is venial in its genus, is itself a venial sin, and accordingly one may conclude that the consent to take pleasure in a useless thought about fornication, is a venial sin. But delectation in the act itself of fornication is, in its genus, a mortal sin: and that it be a venial sin before the consent is given, is accidental, viz. on account of the incompleteness of the act: which incompleteness ceases when the deliberate consent has been given, so that therefore it has its complete nature and is a mortal sin.
Reply Obj. 3: This argument considers the delectation which has the thought for its object.
Reply Obj. 4: The delectation which has an external act for its object, cannot be without complacency in the external act as such, even though there be no decision to fulfil it, on account of the prohibition of some higher authority: wherefore the act is inordinate, and consequently the delectation will be inordinate also.
Reply Obj. 5: The consent to delectation, resulting from complacency in an act of murder thought of, is a mortal sin also: but not the consent to delectation resulting from complacency in the thought of murder.
Reply Obj. 6: The Lord's Prayer is to be said in order that we may be preserved not only from venial sin, but also from mortal sin.
Whether There Can Be Venial Sin in the Higher Reason As Directing the Lower Powers?
Objection 1: It would seem that there cannot be venial sin in the higher reason as directing the lower powers, i.e. as consenting to a sinful act. For Augustine says (De Trin. xii, 7) that the "higher reason is intent on considering and consulting the eternal law." But mortal sin consists in turning away from the eternal law. Therefore it seems that there can be no other than mortal sin in the higher reason.
Obj. 2: Further, the higher reason is the principle of the spiritual life, as the heart is of the body's life. But the diseases of the heart are deadly. Therefore the sins of the higher reason are mortal.
Obj. 3: Further, a venial sin becomes a mortal sin if it be done out of contempt. But it would seem impossible to commit even a venial sin, deliberately, without contempt. Since then the consent of the higher reason is always accompanied by deliberate consideration of the eternal law, it seems that it cannot be without mortal sin, on account of the contempt of the Divine law.
_On the contrary,_ Consent to a sinful act belongs to the higher reason, as stated above (A. 7). But consent to an act of venial sin is itself a venial sin. Therefore a venial sin can be in the higher reason.
_I answer that,_ As Augustine says (De Trin. xii, 7), the higher reason "is intent on contemplating or consulting the eternal law"; it contemplates it by considering its truth; it consults it by judging and directing other things according to it: and to this pertains the fact that by deliberating through the eternal types, it consents to an act or dissents from it. Now it may happen that the inordinateness of the act to which it consents, is not contrary to the eternal law, in the same way as mortal sin is, because it does not imply aversion from the last end, but is beside that law, as an act of venial sin is. Therefore when the higher reason consents to the act of a venial sin, it does not turn away from the eternal law: wherefore it sins, not mortally, but venially.
This suffices for the Reply to the First Objection.
Reply Obj. 2: Disease of the heart is twofold: one which is in the very substance of the heart, and affects its natural consistency, and such a disease is always mortal: the other is a disease of the heart consisting in some disorder either of the movement or of the parts surrounding the heart, and such a disease is not always mortal. In like manner there is mortal sin in the higher reason whenever the order itself of the higher reason to its proper object which is the eternal law, is destroyed; but when the disorder leaves this untouched, the sin is not mortal but venial.
Reply Obj. 3: Deliberate consent to a sin does not always amount to contempt of the Divine law, but only when the sin is contrary to the Divine law.
Whether Venial Sin Can Be in the Higher Reason As Such?
Objection 1: It would seem that venial sin cannot be in the higher reason as such, i.e. as considering the eternal law. For the act of a power is not found to fail except that power be inordinately disposed with regard to its object. Now the object of the higher reason is the eternal law, in respect of which there can be no disorder without mortal sin. Therefore there can be no venial sin in the higher reason as such.
Obj. 2: Further, since the reason is a deliberative power, there can be no act of reason without deliberation. Now every inordinate movement in things concerning God, if it be deliberate, is a mortal sin. Therefore venial sin is never in the higher reason as such.
Obj. 3: Further, it happens sometimes that a sin which takes us unawares, is a venial sin. Now a deliberate sin is a mortal sin, through the reason, in deliberating, having recourse to some higher good, by acting against which, man sins more grievously; just as when the reason in deliberating about an inordinate pleasurable act, considers that it is contrary to the law of God, it sins more grievously in consenting, than if it only considered that it is contrary to moral virtue. But the higher reason cannot have recourse to any higher tribunal than its own object. Therefore if a movement that takes us unawares is not a mortal sin, neither will the subsequent deliberation make it a mortal sin; which is clearly false.
Therefore there can be no venial sin in the higher reason as such.
_On the contrary,_ A sudden movement of unbelief is a venial sin. But it belongs to the higher reason as such. Therefore there can be a venial sin in the higher reason as such.
_I answer that,_ The higher reason regards its own object otherwise than the objects of the lower powers that are directed by the higher reason. For it does not regard the objects of the lower powers, except in so far as it consults the eternal law about them, and so it does not regard them save by way of deliberation. Now deliberate consent to what is a mortal sin in its genus, is itself a mortal sin; and consequently the higher reason always sins mortally, if the acts of the lower powers to which it consents are mortal sins.
With regard to its own object it has a twofold act, viz. simple _intuition,_ and _deliberation,_ in respect of which it again consults the eternal law about its own object. But in respect of simple intuition, it can have an inordinate movement about Divine things, as when a man suffers a sudden movement of unbelief. And although unbelief, in its genus, is a mortal sin, yet a sudden movement of unbelief is a venial sin, because there is no mortal sin unless it be contrary to the law of God. Now it is possible for one of the articles of faith to present itself to the reason suddenly under some other aspect, before the eternal law, i.e. the law of God, is consulted, or can be consulted, on the matter; as, for instance, when a man suddenly apprehends the resurrection of the dead as impossible naturally, and rejects it, as soon as he had thus apprehended it, before he has had time to deliberate and consider that this is proposed to our belief in accordance with the Divine law. If, however, the movement of unbelief remains after this deliberation, it is a mortal sin. Therefore, in sudden movements, the higher reason may sin venially in respect of its proper object, even if it be a mortal sin in its genus; or it may sin mortally in giving a deliberate consent; but in things pertaining to the lower powers, it always sins mortally, in things which are mortal sins in their genus, but not in those which are venial sins in their genus.
Reply Obj. 1: A sin which is against the eternal law, though it be mortal in its genus, may nevertheless be venial, on account of the incompleteness of a sudden action, as stated.
Reply Obj. 2: In matters of action, the simple intuition of the principles from which deliberation proceeds, belongs to the reason, as well as the act of deliberation: even as in speculative matters it belongs to the reason both to syllogize and to form propositions: consequently the reason also can have a sudden movement.
Reply Obj. 3: One and the same thing may be the subject of different considerations, of which one is higher than the other; thus the existence of God may be considered, either as possible to be known by the human reason, or as delivered to us by Divine revelation, which is a higher consideration. And therefore, although the object of the higher reason is, in its nature, something sublime, yet it is reducible to some yet higher consideration: and in this way, that which in the sudden movement was not a mortal sin, becomes a mortal sin in virtue of the deliberation which brought it into the light of a higher consideration, as was explained above.
QUESTION 75 OF THE CAUSES OF SIN, IN GENERAL (In Four Articles) We must now consider the causes of sin: (1) in general; (2) in particular. Under the first head there are four points of inquiry: (1) Whether sin has a cause?
(2) Whether it has an internal cause?
(3) Whether it has an external cause?
(4) Whether one sin is the cause of another?
Whether Sin Has a Cause?
Objection 1: It would seem that sin has no cause. For sin has the nature of evil, as stated above (Q. 71, A. 6). But evil has no cause, as Dionysius says (Div. Nom. iv). Therefore sin has no cause.
Obj. 2: Further, a cause is that from which something follows of necessity. Now that which is of necessity, seems to be no sin, for every sin is voluntary. Therefore sin has no cause.
Obj. 3: Further, if sin has a cause, this cause is either good or evil. It is not a good, because good produces nothing but good, for "a good tree cannot bring forth evil fruit" (Matt. 7:18). Likewise neither can evil be the cause of sin, because the evil of punishment is a sequel to sin, and the evil of guilt is the same as sin.
Therefore sin has no cause.
_On the contrary,_ Whatever is done has a cause, for, according to Job 5:6, "nothing upon earth is done without a cause." But sin is something done; since it a "word, deed, or desire contrary to the law of God." Therefore sin has a cause.
_I answer that,_ A sin is an inordinate act. Accordingly, so far as it is an act, it can have a direct cause, even as any other act; but, so far as it is inordinate, it has a cause, in the same way as a negation or privation can have a cause. Now two causes may be assigned to a negation: in the first place, absence of the cause of affirmation; i.e. the negation of the cause itself, is the cause of the negation in itself; since the result of removing the cause is the removal of the effect: thus the absence of the sun is the cause of darkness. In the second place, the cause of an affirmation, of which a negation is a sequel, is the accidental cause of the resulting negation: thus fire by causing heat in virtue of its principal tendency, consequently causes a privation of cold. The first of these suffices to cause a simple negation. But, since the inordinateness of sin and of every evil is not a simple negation, but the privation of that which something ought naturally to have, such an inordinateness must needs have an accidental efficient cause. For that which naturally is and ought to be in a thing, is never lacking except on account of some impeding cause. And accordingly we are wont to say that evil, which consists in a certain privation, has a deficient cause, or an accidental efficient cause. Now every accidental cause is reducible to the direct cause. Since then sin, on the part of its inordinateness, has an accidental efficient cause, and on the part of the act, a direct efficient cause, it follows that the inordinateness of sin is a result of the cause of the act. Accordingly then, the will lacking the direction of the rule of reason and of the Divine law, and intent on some mutable good, causes the act of sin directly, and the inordinateness of the act, indirectly, and beside the intention: for the lack of order in the act results from the lack of direction in the will.
Reply Obj. 1: Sin signifies not only the privation of good, which privation is its inordinateness, but also the act which is the subject of that privation, which has the nature of evil: and how this evil has a cause, has been explained.
Reply Obj. 2: If this definition is to be verified in all cases, it must be understood as applying to a cause which is sufficient and not impeded. For it happens that a thing is the sufficient cause of something else, and that the effect does not follow of necessity, on account of some supervening impediment: else it would follow that all things happen of necessity, as is proved in _Metaph._ vi, text. 5.
Accordingly, though sin has a cause, it does not follow that this is a necessary cause, since its effect can be impeded.
Reply Obj. 3: As stated above, the will in failing to apply the rule of reason or of the Divine law, is the cause of sin. Now the fact of not applying the rule of reason or of the Divine law, has not in itself the nature of evil, whether of punishment or of guilt, before it is applied to the act. Wherefore accordingly, evil is not the cause of the first sin, but some good lacking some other good.
Whether Sin Has an Internal Cause?
Objection 1: It would seem that sin has no internal cause. For that which is within a thing is always in it. If therefore sin had an internal cause, man would always be sinning, since given the cause, the effect follows.
Obj. 2: Further, a thing is not its own cause. But the internal movements of a man are sins. Therefore they are not the cause of sin.
Obj. 3: Further, whatever is within man is either natural or voluntary. Now that which is natural cannot be the cause of sin, for sin is contrary to nature, as Damascene states (De Fide Orth. ii, 3; iv, 21); while that which is voluntary, if it be inordinate, is already a sin. Therefore nothing intrinsic can be the cause of the first sin.
_On the contrary,_ Augustine says (De Duabus Anim. x, 10, 11; Retract. i, 9) that "the will is the cause of sin."
_I answer that,_ As stated above (A. 1), the direct cause of sin must be considered on the part of the act. Now we may distinguish a twofold internal cause of human acts, one remote, the other proximate. The proximate internal cause of the human act is the reason and will, in respect of which man has a free-will; while the remote cause is the apprehension of the sensitive part, and also the sensitive appetite. For just as it is due to the judgment of reason, that the will is moved to something in accord with reason, so it is due to an apprehension of the senses that the sensitive appetite is inclined to something; which inclination sometimes influences the will and reason, as we shall explain further on (Q. 77, A. 1).
Accordingly a double interior cause of sin may be assigned; one proximate, on the part of the reason and will; and the other remote, on the part of the imagination or sensitive appetite.
But since we have said above (A. 1, ad 3) that the cause of sin is some apparent good as motive, yet lacking the due motive, viz. the rule of reason or the Divine law, this motive which is an apparent good, appertains to the apprehension of the senses and to the appetite; while the lack of the due rule appertains to the reason, whose nature it is to consider this rule; and the completeness of the voluntary sinful act appertains to the will, so that the act of the will, given the conditions we have just mentioned, is already a sin.
Reply Obj. 1: That which is within a thing as its natural power, is always in it: but that which is within it, as the internal act of the appetitive or apprehensive power, is not always in it. Now the power of the will is the potential cause of sin, but is made actual by the preceding movements, both of the sensitive part, in the first place, and afterwards, of the reason. For it is because a thing is proposed as appetible to the senses, and because the appetite is inclined, that the reason sometimes fails to consider the due rule, so that the will produces the act of sin. Since therefore the movements that precede it are not always actual, neither is man always actually sinning.
Reply Obj. 2: It is not true that all the internal acts belong to the substance of sin, for this consists principally in the act of the will; but some precede and some follow the sin itself.
Reply Obj. 3: That which causes sin, as a power produces its act, is natural; and again, the movement of the sensitive part, from which sin follows, is natural sometimes, as, for instance, when anyone sins through appetite for food. Yet sin results in being unnatural from the very fact that the natural rule fails, which man, in accord with his nature, ought to observe.
Whether Sin Has an External Cause?
Objection 1: It would seem that sin has no external cause. For sin is a voluntary act. Now voluntary acts belong to principles that are within us, so that they have no external cause. Therefore sin has no external cause.
Obj. 2: Further, as nature is an internal principle, so is the will.
Now in natural things sin can be due to no other than an internal cause; for instance, the birth of a monster is due to the corruption of some internal principle. Therefore in the moral order, sin can arise from no other than an internal cause. Therefore it has no external cause.
Obj. 3: Further, if the cause is multiplied, the effect is multiplied. Now the more numerous and weighty the external inducements to sin are, the less is a man's inordinate act imputed to him as a sin. Therefore nothing external is a cause of sin.
_On the contrary,_ It is written (Num. 21:16): "Are not these they, that deceived the children of Israel by the counsel of Balaam, and made you transgress against the Lord by the sin of Phogor?" Therefore something external can be a cause of sin.
_I answer that,_ As stated above (A. 2), the internal cause of sin is both the will, as completing the sinful act, and the reason, as lacking the due rule, and the appetite, as inclining to sin.
Accordingly something external might be a cause of sin in three ways, either by moving the will itself immediately, or by moving the reason, or by moving the sensitive appetite. Now, as stated above (Q.
9, A. 6; Q. 10, A. 4), none can move the will inwardly save God alone, who cannot be a cause of sin, as we shall prove further on (Q.
79, A. 1). Hence it follows that nothing external can be a cause of sin, except by moving the reason, as a man or devil by enticing to sin; or by moving the sensitive appetite, as certain external sensibles move it. Yet neither does external enticement move the reason, of necessity, in matters of action, nor do things proposed externally, of necessity move the sensitive appetite, except perhaps it be disposed thereto in a certain way; and even the sensitive appetite does not, of necessity, move the reason and will. Therefore something external can be a cause moving to sin, but not so as to be a sufficient cause thereof: and the will alone is the sufficient completive cause of sin being accomplished.
Reply Obj. 1: From the very fact that the external motive causes of sin do not lead to sin sufficiently and necessarily, it follows that it remains in our power to sin or not to sin.
Reply Obj. 2: The fact that sin has an internal cause does not prevent its having an external cause; for nothing external is a cause of sin, except through the medium of the internal cause, as stated.
Reply Obj. 3: If the external causes inclining to sin be multiplied, the sinful acts are multiplied, because they incline to the sinful act in both greater numbers and greater frequency. Nevertheless the character of guilt is lessened, since this depends on the act being voluntary and in our power.
Whether One Sin Is a Cause of Another?
Objection 1: It would seem that one sin cannot be the cause of another. For there are four kinds of cause, none of which will fit in with one sin causing another. Because the end has the character of good; which is inconsistent with sin, which has the character of evil.
In like manner neither can a sin be an efficient cause, since "evil is not an efficient cause, but is weak and powerless," as Dionysius declares (Div. Nom. iv). The material and formal cause seems to have no place except in natural bodies, which are composed of matter and form. Therefore sin cannot have either a material or a formal cause.
Obj. 2: Further, "to produce its like belongs to a perfect thing," as stated in _Meteor._ iv, 2 [*Cf. _De Anima_ ii.]. But sin is essentially something imperfect. Therefore one sin cannot be a cause of another.
Obj. 3: Further, if one sin is the cause of a second sin, in the same way, yet another sin will be the cause of the first, and thus we go on indefinitely, which is absurd. Therefore one sin is not the cause of another.
_On the contrary,_ Gregory says on Ezechiel (Hom. xi): "A sin that is not quickly blotted out by repentance, is both a sin and a cause of sin."
_I answer that,_ Forasmuch as a sin has a cause on the part of the act of sin, it is possible for one sin to be the cause of another, in the same way as one human act is the cause of another. Hence it happens that one sin may be the cause of another in respect of the four kinds of causes. First, after the manner of an efficient or moving cause, both directly and indirectly. Indirectly, as that which removes an impediment is called an indirect cause of movement: for when man, by one sinful act, loses grace, or charity, or shame, or anything else that withdraws him from sin, he thereby falls into another sin, so that the first sin is the accidental cause of the second. Directly, as when, by one sinful act, man is disposed to commit more readily another like act: because acts cause dispositions and habits inclining to like acts. Secondly, after the manner of a material cause, one sin is the cause of another, by preparing its matter: thus covetousness prepares the matter for strife, which is often about the wealth a man has amassed together. Thirdly, after the manner of a final cause, one sin causes another, in so far as a man commits one sin for the sake of another which is his end; as when a man is guilty of simony for the end of ambition, or fornication for the purpose of theft. And since the end gives the form to moral that one sin is also the formal cause of another: because in the act of fornication committed for the purpose of theft, the former is material while the latter is formal.
Reply Obj. 1: Sin, in so far as it is inordinate, has the character of evil; but, in so far as it is an act, it has some good, at least apparent, for its end: so that, as an act, but not as being inordinate, it can be the cause, both final and efficient, of another sin. A sin has matter, not _of which_ but _about which_ it is: and it has its form from its end. Consequently one sin can be the cause of another, in respect of the four kinds of cause, as stated above.
Reply Obj. 2: Sin is something imperfect on account of its moral imperfection on the part of its inordinateness. Nevertheless, as an act it can have natural perfection: and thus it can be the cause of another sin.
Reply Obj. 3: Not every cause of one sin is another sin; so there is no need to go on indefinitely: for one may come to one sin which is not caused by another sin.
QUESTION 76 OF THE CAUSES OF SIN, IN PARTICULAR (In Four Articles) We must now consider the causes of sin, in particular, and (1) The internal causes of sin; (2) its external causes; and (3) sins which are the causes of other sins. In view of what has been said above (A.
2), the first consideration will be threefold: so that in the first place we shall treat of ignorance, which is the cause of sin on the part of reason; secondly, of weakness or passion, which is the cause of sin on the part of the sensitive appetite; thirdly, of malice, which is the cause of sin on the part of the will.
Under the first head, there are four points of inquiry: (1) Whether ignorance is a cause of sin?
(2) Whether ignorance is a sin?
(3) Whether it excuses from sin altogether?
(4) Whether it diminishes sin?
Whether Ignorance Can Be a Cause of Sin?
Objection 1: It would seem that ignorance cannot be a cause of sin: because a non-being is not the cause of anything. Now ignorance is a non-being, since it is a privation of knowledge. Therefore ignorance is not a cause of sin.
Obj. 2: Further, causes of sin should be reckoned in respect of sin Now ignorance seems to savor of _turning away_ from something.
Therefore it should not be reckoned a cause of sin.
Obj. 3: Further, every sin is seated in the will. Now the will does not turn to that which is not known, because its object is the good apprehended. Therefore ignorance cannot be a cause of sin.
_On the contrary,_ Augustine says (De Nat. et Grat. lxvii) "that some sin through ignorance."
_I answer that,_ According to the Philosopher (Phys. viii, 27) a moving cause is twofold, direct and indirect. A direct cause is one that moves by its own power, as the generator is the moving cause of heavy and light things. An indirect cause, is either one that removes an impediment, or the removal itself of an impediment: and it is in this way that ignorance can be the cause of a sinful act; because it is a privation of knowledge perfecting the reason that forbids the act of sin, in so far as it directs human acts.
Now we must observe that the reason directs human acts in accordance with a twofold knowledge, universal and particular: because in conferring about what is to be done, it employs a syllogism, the conclusion of which is an act of judgment, or of choice, or an operation. Now actions are about singulars: wherefore the conclusion of a practical syllogism is a singular proposition. But a singular proposition does not follow from a universal proposition, except through the medium of a particular proposition: thus a man is restrained from an act of parricide, by the knowledge that it is wrong to kill one's father, and that this man is his father. Hence ignorance about either of these two propositions, viz. of the universal principle which is a rule of reason, or of the particular circumstance, could cause an act of parricide. Hence it is clear that not every kind of ignorance is the cause of a sin, but that alone which removes the knowledge which would prevent the sinful act.
Consequently if a man's will be so disposed that he would not be restrained from the act of parricide, even though he recognized his father, his ignorance about his father is not the cause of his committing the sin, but is concomitant with the sin: wherefore such a man sins, not "through ignorance" but "in ignorance," as the Philosopher states (Ethic. iii, 1).
Reply Obj. 1: Non-being cannot be the direct cause of anything: but it can be an accidental cause, as being the removal of an impediment.
Reply Obj. 2: As knowledge, which is removed by ignorance, regards sin as turning towards something, so too, ignorance of this respect of a sin is the cause of that sin, as removing its impediment.
Reply Obj. 3: The will cannot turn to that which is absolutely unknown: but if something be known in one respect, and unknown in another, the will can will it. It is thus that ignorance is the cause of sin: for instance, when a man knows that what he is killing is a man, but not that it is his own father; or when one knows that a certain act is pleasurable, but not that it is a sin.
Whether Ignorance Is a Sin?
Objection 1: It would seem that ignorance is not a sin. For sin is "a word, deed or desire contrary to God's law," as stated above (Q. 71, A. 5). Now ignorance does not denote an act, either internal or external. Therefore ignorance is not a sin.
Obj. 2: Further, sin is more directly opposed to grace than to knowledge. Now privation of grace is not a sin, but a punishment resulting from sin. Therefore ignorance which is privation of knowledge is not a sin.
Obj. 3: Further, if ignorance is a sin, this can only be in so far as it is voluntary. But if ignorance is a sin, through being voluntary, it seems that the sin will consist in the act itself of the will, rather than in the ignorance. Therefore the ignorance will not be a sin, but rather a result of sin.
Obj. 4: Further, every sin is taken away by repentance, nor does any sin, except only original sin, pass as to guilt, yet remain in act.
Now ignorance is not removed by repentance, but remains in act, all its guilt being removed by repentance. Therefore ignorance is not a sin, unless perchance it be original sin.
Obj. 5: Further, if ignorance be a sin, then a man will be sinning, as long as he remains in ignorance. But ignorance is continual in the one who is ignorant. Therefore a person in ignorance would be continually sinning, which is clearly false, else ignorance would be a most grievous sin. Therefore ignorance is not a sin.
_On the contrary,_ Nothing but sin deserves punishment. But ignorance deserves punishment, according to 1 Cor. 14:38: "If any man know not, he shall not be known." Therefore ignorance is a sin.
_I answer that,_ Ignorance differs from nescience, in that nescience denotes mere absence of knowledge; wherefore whoever lacks knowledge about anything, can be said to be nescient about it: in which sense Dionysius puts nescience in the angels (Coel. Hier. vii). On the other hand, ignorance denotes privation of knowledge, i.e. lack of knowledge of those things that one has a natural aptitude to know.
Some of these we are under an obligation to know, those, to wit, without the knowledge of which we are unable to accomplish a due act rightly. Wherefore all are bound in common to know the articles of faith, and the universal principles of right, and each individual is bound to know matters regarding his duty or state. Meanwhile there are other things which a man may have a natural aptitude to know, yet he is not bound to know them, such as the geometrical theorems, and contingent particulars, except in some individual case. Now it is evident that whoever neglects to have or do what he ought to have or do, commits a sin of omission. Wherefore through negligence, ignorance of what one is bound to know, is a sin; whereas it is not imputed as a sin to man, if he fails to know what he is unable to know. Consequently ignorance of such like things is called "invincible," because it cannot be overcome by study. For this reason such like ignorance, not being voluntary, since it is not in our power to be rid of it, is not a sin: wherefore it is evident that no invincible ignorance is a sin. On the other hand, vincible ignorance is a sin, if it be about matters one is bound to know; but not, if it be about things one is not bound to know.
Reply Obj. 1: As stated above (Q. 71, A. 6, ad 1), when we say that sin is a "word, deed or desire," we include the opposite negations, by reason of which omissions have the character of sin; so that negligence, in as much as ignorance is a sin, is comprised in the