[I-II.q.18.a.1.arg.1] It would seem that every human action is good, and that none is evil. For Dionysius says (Div. Nom. iv) that evil acts not, save in virtue of the good. But no evil is done in virtue of the good. Therefore no action is evil.

[I-II.q.18.a.1.arg.2] Further, nothing acts except in so far as it is in act. Now a thing is evil, not according as it is in act, but according as its potentiality is void of act; whereas in so far as its potentiality is perfected by act, it is good, as stated in Metaph. ix, 9. Therefore nothing acts in so far as it is evil, but only according as it is good. Therefore every action is good, and none is evil.

[I-II.q.18.a.1.arg.3] Further, evil cannot be a cause, save accidentally, as Dionysius declares (Div. Nom. iv). But every action has some effect which is proper to it. Therefore no action is evil, but every action is good.

[I-II.q.18.a.1.sc] Our Lord said (John 3:20): "Every one that doth evil, hateth the light." Therefore some actions of man are evil.

[I-II.q.18.a.1.co] We must speak of good and evil in actions as of good and evil in things: because such as everything is, such is the act that it produces. Now in things, each one has so much good as it has being: since good and being are convertible, as was stated in the I, 5, 1,3. But God alone has the whole plenitude of His Being in a certain unity: whereas every other thing has its proper fulness of being in a certain multiplicity. Wherefore it happens with some things, that they have being in some respect, and yet they are lacking in the fulness of being due to them. Thus the fulness of human being requires a compound of soul and body, having all the powers and instruments of knowledge and movement: wherefore if any man be lacking in any of these, he is lacking in something due to the fulness of his being. So that as much as he has of being, so much has he of goodness: while so far as he is lacking in goodness, and is said to be evil: thus a blind man is possessed of goodness inasmuch as he lives; and of evil, inasmuch as he lacks sight. That, however, which has nothing of being or goodness, could not be said to be either evil or good. But since this same fulness of being is of the very essence of good, if a thing be lacking in its due fulness of being, it is not said to be good simply, but in a certain respect, inasmuch as it is a being; although it can be called a being simply, and a non-being in a certain respect, as was stated in the I, 5, 1, ad 1. We must therefore say that every action has goodness, in so far as it has being; whereas it is lacking in goodness, in so far as it is lacking in something that is due to its fulness of being; and thus it is said to be evil: for instance if it lacks the quantity determined by reason, or its due place, or something of the kind.

[I-II.q.18.a.1.ad.1] Evil acts in virtue of deficient goodness. For it there were nothing of good there, there would be neither being nor possibility of action. On the other hand if good were not deficient, there would be no evil. Consequently the action done is a deficient good, which is good in a certain respect, but simply evil.

[I-II.q.18.a.1.ad.2] Nothing hinders a thing from being in act in a certain respect, so that it can act; and in a certain respect deficient in act, so as to cause a deficient act. Thus a blind man has in act the power of walking, whereby he is able to walk; but inasmuch as he is deprived of sight he suffers a defect in walking by stumbling when he walks.

[I-II.q.18.a.1.ad.3] An evil action can have a proper effect, according to the goodness and being that it has. Thus adultery is the cause of human generation, inasmuch as it implies union of male and female, but not inasmuch as it lacks the order of reason.

[I-II.q.18.a.2.arg.1] It would seem that the good or evil of an action is not derived from its object. For the object of any action is a thing. But "evil is not in things, but in the sinner's use of them," as Augustine says (De Doctr. Christ. iii, 12). Therefore the good or evil of a human action is not derived from their object.

[I-II.q.18.a.2.arg.2] Further, the object is compared to the action as its matter. But the goodness of a thing is not from its matter, but rather from the form, which is an act. Therefore good and evil in actions is not derived from their object.

[I-II.q.18.a.2.arg.3] Further, the object of an active power is compared to the action as effect to cause. But the goodness of a cause does not depend on its effect; rather is it the reverse. Therefore good or evil in actions is not derived from their object.

[I-II.q.18.a.2.sc] It is written (Hosea 9:10): "They became abominable as those things which they loved." Now man becomes abominable to God on account of the malice of his action. Therefore the malice of his action is according to the evil objects that man loves. And the same applies to the goodness of his action.

[I-II.q.18.a.2.co] as stated above (Article 1) the good or evil of an action, as of other things, depends on its fulness of being or its lack of that fulness. Now the first thing that belongs to the fulness of being seems to be that which gives a thing its species. And just as a natural thing has its species from its form, so an action has its species from its object, as movement from its term. And therefore just as the primary goodness of a natural thing is derived from its form, which gives it its species, so the primary goodness of a moral action is derived from its suitable object: hence some call such an action "good in its genus"; for instance, "to make use of what is one's own." And just as, in natural things, the primary evil is when a generated thing does not realize its specific form (for instance, if instead of a man, something else be generated); so the primary evil in moral actions is that which is from the object, for instance, "to take what belongs to another." And this action is said to be "evil in its genus," genus here standing for species, just as we apply the term "mankind" to the whole human species.

[I-II.q.18.a.2.ad.1] Although external things are good in themselves, nevertheless they have not always a due proportion to this or that action. And so, inasmuch as they are considered as objects of such actions, they have not the quality of goodness.

[I-II.q.18.a.2.ad.2] The object is not the matter "of which" (a thing is made), but the matter "about which" (something is done); and stands in relation to the act as its form, as it were, through giving it its species.

[I-II.q.18.a.2.ad.3] The object of the human action is not always the object of an active power. For the appetitive power is, in a way, passive; in so far as it is moved by the appetible object; and yet it is a principle of human actions. Nor again have the objects of the active powers always the nature of an effect, but only when they are already transformed: thus food when transformed is the effect of the nutritive power; whereas food before being transformed stands in relation to the nutritive power as the matter about which it exercises its operation. Now since the object is in some way the effect of the active power, it follows that it is the term of its action, and consequently that it gives it its form and species, since movement derives its species from its term. Moreover, although the goodness of an action is not caused by the goodness of its effect, yet an action is said to be good from the fact that it can produce a good effect. Consequently the very proportion of an action to its effect is the measure of its goodness.

[I-II.q.18.a.3.arg.1] It would seem that an action is not good or evil from a circumstance. For circumstances stand around [circumstant] an action, as being outside it, as stated above (Question 7, Article 1). But "good and evil are in things themselves," as is stated in Metaph. vi, 4. Therefore an action does not derive goodness or malice from a circumstance.

[I-II.q.18.a.3.arg.2] Further, the goodness or malice of an action is considered principally in the doctrine of morals. But since circumstances are accidents of actions, it seems that they are outside the scope of art: because "no art takes notice of what is accidental" (Metaph. vi, 2). Therefore the goodness or malice of an action is not taken from a circumstance.

[I-II.q.18.a.3.arg.3] Further, that which belongs to a thing, in respect of its substance, is not ascribed to it in respect of an accident. But good and evil belong to an action in respect of its substance; because an action can be good or evil in its genus as stated above (Article 2). Therefore an action is not good or bad from a circumstance.

[I-II.q.18.a.3.sc] the Philosopher says (Ethic. ii, 3) that a virtuous man acts as he should, and when he should, and so on in respect of the other circumstances. Therefore, on the other hand, the vicious man, in the matter of each vice, acts when he should not, or where he should not, and so on with the other circumstances. Therefore human actions are good or evil according to circumstances.

[I-II.q.18.a.3.co] In natural things, it is to be noted that the whole fulness of perfection due to a thing, is not from the mere substantial form, that gives it its species; since a thing derives much from supervening accidents, as man does from shape, color, and the like; and if any one of these accidents be out of due proportion, evil is the result. So it is with action. For the plenitude of its goodness does not consist wholly in its species, but also in certain additions which accrue to it by reason of certain accidents: and such are its due circumstances. Wherefore if something be wanting that is requisite as a due circumstance the action will be evil.

[I-II.q.18.a.3.ad.1] Circumstances are outside an action, inasmuch as they are not part of its essence; but they are in an action as accidents thereof. Thus, too, accidents in natural substances are outside the essence.

[I-II.q.18.a.3.ad.2] Every accident is not accidentally in its subject; for some are proper accidents; and of these every art takes notice. And thus it is that the circumstances of actions are considered in the doctrine of morals.

[I-II.q.18.a.3.ad.3] Since good and being are convertible; according as being is predicated of substance and of accident, so is good predicated of a thing both in respect of its essential being, and in respect of its accidental being; and this, both in natural things and in moral actions.

[I-II.q.18.a.4.arg.1] It would seem that the good and evil in human actions are not from the end. For Dionysius says (Div. Nom. iv) that "nothing acts with a view to evil." If therefore an action were good or evil from its end, no action would be evil. Which is clearly false.

[I-II.q.18.a.4.arg.2] Further, the goodness of an action is something in the action. But the end is an extrinsic cause. Therefore an action is not said to be good or bad according to its end.

[I-II.q.18.a.4.arg.3] Further, a good action may happen to be ordained to an evil end, as when a man gives an alms from vainglory; and conversely, an evil action may happen to be ordained to a good end, as a theft committed in order to give something to the poor. Therefore an action is not good or evil from its end.

[I-II.q.18.a.4.sc] Boethius says (De Differ. Topic. ii) that "if the end is good, the thing is good, and if the end be evil, the thing also is evil."

[I-II.q.18.a.4.co] The disposition of things as to goodness is the same as their disposition as to being. Now in some things the being does not depend on another, and in these it suffices to consider their being absolutely. But there are things the being of which depends on something else, and hence in their regard we must consider their being in its relation to the cause on which it depends. Now just as the being of a thing depends on the agent, and the form, so the goodness of a thing depends on its end. Hence in the Divine Persons, Whose goodness does not depend on another, the measure of goodness is not taken from the end. Whereas human actions, and other things, the goodness of which depends on something else, have a measure of goodness from the end on which they depend, besides that goodness which is in them absolutely.

Accordingly a fourfold goodness may be considered in a human action. First, that which, as an action, it derives from its genus; because as much as it has of action and being so much has it of goodness, as stated above (Article 1). Secondly, it has goodness according to its species; which is derived from its suitable object. Thirdly, it has goodness from its circumstances, in respect, as it were, of its accidents. Fourthly, it has goodness from its end, to which it is compared as to the cause of its goodness.

[I-II.q.18.a.4.ad.1] The good in view of which one acts is not always a true good; but sometimes it is a true good, sometimes an apparent good. And in the latter event, an evil action results from the end in view.

[I-II.q.18.a.4.ad.2] Although the end is an extrinsic cause, nevertheless due proportion to the end, and relation to the end, are inherent to the action.

[I-II.q.18.a.4.ad.3] Nothing hinders an action that is good in one of the way mentioned above, from lacking goodness in another way. And thus it may happen that an action which is good in its species or in its circumstances is ordained to an evil end, or vice versa. However, an action is not good simply, unless it is good in all those ways: since "evil results from any single defect, but good from the complete cause," as Dionysius says (Div. Nom. iv).

[I-II.q.18.a.5.arg.1] It would seem that good and evil in moral actions do not make a difference of species. For the existence of good and evil in actions is in conformity with their existence in things, as stated above (Article 1). But good and evil do not make a specific difference in things; for a good man is specifically the same as a bad man. Therefore neither do they make a specific difference in actions.

[I-II.q.18.a.5.arg.2] Further, since evil is a privation, it is a non-being. But non-being cannot be a difference, according to the Philosopher (Metaph. iii, 3). Since therefore the difference constitutes the species, it seems that an action is not constituted in a species through being evil. Consequently good and evil do not diversify the species of human actions.

[I-II.q.18.a.5.arg.3] Further, acts that differ in species produce different effects. But the same specific effect results from a good and from an evil action: thus a man is born of adulterous or of lawful wedlock. Therefore good and evil actions do not differ in species.

[I-II.q.18.a.5.arg.4] Further, actions are sometimes said to be good or bad from a circumstance, as stated above (Article 3). But since a circumstance is an accident, it does not give an action its species. Therefore human actions do not differ in species on account of their goodness or malice.

[I-II.q.18.a.5.sc] According to the Philosopher (Ethic ii. 1) "like habits produce like actions." But a good and a bad habit differ in species, as liberality and prodigality. Therefore also good and bad actions differ in species.

[I-II.q.18.a.5.co] Every action derives its species from its object, as stated above (Article 2). Hence it follows that a difference of object causes a difference of species in actions. Now, it must be observed that a difference of objects causes a difference of species in actions, according as the latter are referred to one active principle, which does not cause a difference in actions, according as they are referred to another active principle. Because nothing accidental constitutes a species, but only that which is essential; and a difference of object may be essential in reference to one active principle, and accidental in reference to another. Thus to know color and to know sound, differ essentially in reference to sense, but not in reference to the intellect.

Now in human actions, good and evil are predicated in reference to the reason; because as Dionysius says (Div. Nom. iv), "the good of man is to be in accordance with reason," and evil is "to be against reason." For that is good for a thing which suits it in regard to its form; and evil, that which is against the order of its form. It is therefore evident that the difference of good and evil considered in reference to the object is an essential difference in relation to reason; that is to say, according as the object is suitable or unsuitable to reason. Now certain actions are called human or moral, inasmuch as they proceed from the reason. Consequently it is evident that good and evil diversify the species in human actions; since essential differences cause a difference of species.

[I-II.q.18.a.5.ad.1] Even in natural things, good and evil, inasmuch as something is according to nature, and something against nature, diversify the natural species; for a dead body and a living body are not of the same species. In like manner, good, inasmuch as it is in accord with reason, and evil, inasmuch as it is against reason, diversify the moral species.

[I-II.q.18.a.5.ad.2] Evil implies privation, not absolute, but affecting some potentiality. For an action is said to be evil in its species, not because it has no object at all; but because it has an object in disaccord with reason, for instance, to appropriate another's property. Wherefore in so far as the object is something positive, it can constitute the species of an evil act.

[I-II.q.18.a.5.ad.3] The conjugal act and adultery, as compared to reason, differ specifically and have effects specifically different; because the other deserves praise and reward, the other, blame and punishment. But as compared to the generative power, they do not differ in species; and thus they have one specific effect.

[I-II.q.18.a.5.ad.4] A circumstance is sometimes taken as the essential difference of the object, as compared to reason; and then it can specify a moral act. And it must needs be so whenever a circumstance transforms an action from good to evil; for a circumstance would not make an action evil, except through being repugnant to reason.

[I-II.q.18.a.6.arg.2] Further, that which is accidental does not constitute the species, as stated above (Article 5). But it is accidental to an action to be ordained to some particular end; for instance, to give alms from vainglory. Therefore actions are not diversified as to species, according to the good and evil which are from the end.

[I-II.q.18.a.6.arg.3] Further, acts that differ in species, can be ordained to the same end: thus to the end of vainglory, actions of various virtues and vices can be ordained. Therefore the good and evil which are taken from the end, do not diversify the species of action.

[I-II.q.18.a.6.sc] It has been shown above (Question 1, Article 3) that human actions derive their species from the end. Therefore good and evil in respect of the end diversify the species of actions.

[I-II.q.18.a.6.co] Certain actions are called human, inasmuch as they are voluntary, as stated above (Question 1, Article 1). Now, in a voluntary action, there is a twofold action, viz. the interior action of the will, and the external action: and each of these actions has its object. The end is properly the object of the interior act of the will: while the object of the external action, is that on which the action is brought to bear. Therefore just as the external action takes its species from the object on which it bears; so the interior act of the will takes its species from the end, as from its own proper object.

Now that which is on the part of the will is formal in regard to that which is on the part of the external action: because the will uses the limbs to act as instruments; nor have external actions any measure of morality, save in so far as they are voluntary. Consequently the species of a human act is considered formally with regard to the end, but materially with regard to the object of the external action. Hence the Philosopher says (Ethic. v, 2) that "he who steals that he may commit adultery, is strictly speaking, more adulterer than thief."

[I-II.q.18.a.6.ad.1] The end also has the character of an object, as stated above.

[I-II.q.18.a.6.ad.2] Although it is accidental to the external action to be ordained to some particular end, it is not accidental to the interior act of the will, which act is compared to the external act, as form to matter.

[I-II.q.18.a.6.ad.3] When many actions, differing in species, are ordained to the same end, there is indeed a diversity of species on the part of the external actions; but unity of species on the part of the internal action.

[I-II.q.18.a.7.arg.1] It would seem that the species of goodness derived from the end is contained under the species of goodness derived from the object, as a species is contained under its genus; for instance, when a man commits a theft in order to give alms. For an action takes its species from its object, as stated above (2,6). But it is impossible for a thing to be contained under another species, if this species be not contained under the proper species of that thing; because the same thing cannot be contained in different species that are not subordinate to one another. Therefore the species which is taken from the end, is contained under the species which is taken from the object.

[I-II.q.18.a.7.arg.2] Further, the last difference always constitutes the most specific species. But the difference derived from the end seems to come after the difference derived from the object: because the end is something last. Therefore the species derived from the end, is contained under the species derived from the object, as its most specific species.

[I-II.q.18.a.7.arg.3] Further, the more formal a difference is compared to genus, as form to matter. But the species derived from the end, is more formal than that which is derived from the object, as stated above (Article 6). Therefore the species derived from the end is contained under the species derived from the object, as the most specific species is contained under the subaltern genus.

[I-II.q.18.a.7.sc] Each genus has its determinate differences. But an action of one same species on the part of its object, can be ordained to an infinite number of ends: for instance, theft can be ordained to an infinite number of good and bad ends. Therefore the species derived from the end is not contained under the species derived from the object, as under its genus.

[I-II.q.18.a.7.co] The object of the external act can stand in a twofold relation to the end of the will: first, as being of itself ordained thereto; thus to fight well is of itself ordained to victory; secondly, as being ordained thereto accidentally; thus to take what belongs to another is ordained accidentally to the giving of alms. Now the differences that divide a genus, and constitute the species of that genus, must, as the Philosopher says (Metaph. vii, 12), divide that genus essentially: and if they divide it accidentally, the division is incorrect: as, if one were to say: "Animals are divided into rational and irrational; and the irrational into animals with wings, and animals without wings"; for "winged" and "wingless" are not essential determinations of the irrational being. But the following division would be correct: "Some animals have feet, some have no feet: and of those that have feet, some have two feet, some four, some many": because the latter division is an essential determination of the former. Accordingly when the object is not of itself ordained to the end, the specific difference derived from the object is not an essential determination of the species derived from the end, nor is the reverse the case. Wherefore one of these species is not under the other; but then the moral action is contained under two species that are disparate, as it were. Consequently we say that he that commits theft for the sake of adultery, is guilty of a twofold malice in one action. On the other hand, if the object be of itself ordained to the end, one of these differences is an essential determination of the other. Wherefore one of these species will be contained under the other.

It remains to be considered which of the two is contained under the other. In order to make this clear, we must first of all observe that the more particular the form is from which a difference is taken, the more specific is the difference. Secondly, that the more universal an agent is, the more universal a form does it cause. Thirdly, that the more remote an end is, the more universal the agent to which it corresponds; thus victory, which is the last end of the army, is the end intended by the commander in chief; while the right ordering of this or that regiment is the end intended by one of the lower officers. From all this it follows that the specific difference derived from the end, is more general; and that the difference derived from an object which of itself is ordained to that end, is a specific difference in relation to the former. For the will, the proper object of which is the end, is the universal mover in respect of all the powers of the soul, the proper objects of which are the objects of their particular acts.

[I-II.q.18.a.7.ad.1] One and the same thing, considered in its substance, cannot be in two species, one of which is not subordinate to the other. But in respect of those things which are superadded to the substance, one thing can be contained under different species. Thus one and the same fruit, as to its color, is contained under one species, i.e. a white thing: and, as to its perfume, under the species of sweet-smelling things. In like manner an action which, as to its substance, is in one natural species, considered in respect to the moral conditions that are added to it, can belong to two species, as stated above (1, 3, ad 3).

[I-II.q.18.a.7.ad.2] The end is last in execution; but first in the intention of the reason, in regard to which moral actions receive their species.

[I-II.q.18.a.7.ad.3] Difference is compared to genus as form to matter, inasmuch as it actualizes the genus. On the other hand, the genus is considered as more formal than the species, inasmuch as it is something more absolute and less contracted. Wherefore also the parts of a definition are reduced to the genus of formal cause, as is stated in Phys. ii, 3. And in this sense the genus is the formal cause of the species; and so much the more formal, as it is more universal.

[I-II.q.18.a.8.arg.1] It would seem that no action is indifferent in its species. For evil is the privation of good, according to Augustine (Enchiridion xi). But privation and habit are immediate contraries, according to the Philosopher (Categor. viii). Therefore there is not such thing as an action that is indifferent in its species, as though it were between good and evil.

[I-II.q.18.a.8.arg.2] Further, human actions derive their species from their end or object, as stated above (06; 1, 3). But every end and every object is either good or bad. Therefore every human action is good or evil according to its species. None, therefore, is indifferent in its species.

[I-II.q.18.a.8.arg.3] Further, as stated above (Article 1), an action is said to be good, when it has its due complement of goodness; and evil, when it lacks that complement. But every action must needs either have the entire plenitude of its goodness, or lack it in some respect. Therefore every action must needs be either good or bad in its species, and none is indifferent.

[I-II.q.18.a.8.sc] Augustine says (De Serm. Dom. in Monte ii, 18) that "there are certain deeds of a middle kind, which can be done with a good or evil mind, of which it is rash to form a judgment." Therefore some actions are indifferent according to their species.

[I-II.q.18.a.8.co] As stated above (2,5), every action takes its species from its object; while human action, which is called moral, takes its species from the object, in relation to the principle of human actions, which is the reason. Wherefore if the object of an action includes something in accord with the order of reason, it will be a good action according to its species; for instance, to give alms to a person in want. On the other hand, if it includes something repugnant to the order of reason, it will be an evil act according to its species; for instance, to steal, which is to appropriate what belongs to another. But it may happen that the object of an action does not include something pertaining to the order of reason; for instance, to pick up a straw from the ground, to walk in the fields, and the like: and such actions are indifferent according to their species.

[I-II.q.18.a.8.ad.1] Privation is twofold. One is privation "as a result" [privatum esse], and this leaves nothing, but takes all away: thus blindness takes away sight altogether; darkness, light; and death, life. Between this privation and the contrary habit, there can be no medium in respect of the proper subject. The other is privation "in process" [privari]: thus sickness is privation of health; not that it takes health away altogether, but that it is a kind of road to the entire loss of health, occasioned by death. And since this sort of privation leaves something, it is not always the immediate contrary of the opposite habit. In this way evil is a privation of good, as Simplicius says in his commentary on the Categories: because it does not take away all good, but leaves some. Consequently there can be something between good and evil.

[I-II.q.18.a.8.ad.2] Every object or end has some goodness or malice, at least natural to it: but this does not imply moral goodness or malice, which is considered in relation to the reason, as stated above. And it is of this that we are here treating.

[I-II.q.18.a.8.ad.3] Not everything belonging to an action belongs also to its species. Wherefore although an action's specific nature may not contain all that belongs to the full complement of its goodness, it is not therefore an action specifically bad; nor is it specifically good. Thus a man in regard to his species is neither virtuous nor wicked.

[I-II.q.18.a.9.arg.1] It would seem that an individual action can be indifferent. For there is no species that does not, cannot, contain an individual. But an action can be indifferent in its species, as stated above (Article 8). Therefore an individual action can be indifferent.

[I-II.q.18.a.9.arg.2] Further, individual actions cause like habits, as stated in Ethic. ii, 1. But a habit can be indifferent: for the Philosopher says (Ethic. iv, 1) that those who are of an even temper and prodigal disposition are not evil; and yet it is evident that they are not good, since they depart from virtue; and thus they are indifferent in respect of a habit. Therefore some individual actions are indifferent.

[I-II.q.18.a.9.arg.3] Further, moral good belongs to virtue, while moral evil belongs to vice. But it happens sometimes that a man fails to ordain a specifically indifferent action to a vicious or virtuous end. Therefore an individual action may happen to be indifferent.

[I-II.q.18.a.9.sc] Gregory says in a homily (vi in Evang.): "An idle word is one that lacks either the usefulness of rectitude or the motive of just necessity or pious utility." But an idle word is an evil, because "men . . . shall render an account of it in the day of judgment" (Matthew 12:36): while if it does not lack the motive of just necessity or pious utility, it is good. Therefore every word is either good or bad. For the same reason every other action is either good or bad. Therefore no individual action is indifferent.

[I-II.q.18.a.9.co] It sometimes happens that an action is indifferent in its species, but considered in the individual it is good or evil. And the reason of this is because a moral action, as stated above (Article 3), derives its goodness not only from its object, whence it takes its species; but also from the circumstances, which are its accidents, as it were; just as something belongs to a man by reason of his individual accidents, which does not belong to him by reason of his species. And every individual action must needs have some circumstance that makes it good or bad, at least in respect of the intention of the end. For since it belongs to the reason to direct; if an action that proceeds from deliberate reason be not directed to the due end, it is, by that fact alone, repugnant to reason, and has the character of evil. But if it be directed to a due end, it is in accord with reason; wherefore it has the character of good. Now it must needs be either directed or not directed to a due end. Consequently every human action that proceeds from deliberate reason, if it be considered in the individual, must be good or bad.

If, however, it does not proceed from deliberate reason, but from some act of the imagination, as when a man strokes his beard, or moves his hand or foot; such an action, properly speaking, is not moral or human; since this depends on the reason. Hence it will be indifferent, as standing apart from the genus of moral actions.

[I-II.q.18.a.9.ad.1] For an action to be indifferent in its species can be understood in several ways. First in such a way that its species demands that it remain indifferent; and the objection proceeds along this line. But no action can be specifically indifferent thus: since no object of human action is such that it cannot be directed to good or evil, either through its end or through a circumstance. Secondly, specific indifference of an action may be due to the fact that as far as its species is concerned, it is neither good nor bad. Wherefore it can be made good or bad by something else. Thus man, as far as his species is concerned, is neither white nor black; nor is it a condition of his species that he should not be black or white; but blackness or whiteness is superadded to man by other principles than those of his species.

[I-II.q.18.a.9.ad.2] The Philosopher states that a man is evil, properly speaking, if he be hurtful to others. And accordingly, because he hurts none save himself. And the same applies to all others who are not hurtful to other men. But we say here that evil, in general, is all that is repugnant to right reason. And in this sense every individual action is either good or bad, as stated above.

[I-II.q.18.a.9.ad.3] Whenever an end is intended by deliberate reason, it belongs either to the good of some virtue, or to the evil of some vice. Thus, if a man's action is directed to the support or repose of his body, it is also directed to the good of virtue, provided he direct his body itself to the good of virtue. The same clearly applies to other actions.

[I-II.q.18.a.10.arg.1] It would seem that a circumstance cannot place a moral action in the species of good or evil. For the species of an action is taken from its object. But circumstances differ from the object. Therefore circumstances do not give an action its species.

[I-II.q.18.a.10.arg.2] Further, circumstances are as accidents in relation to the moral action, as stated above (Question 7, Article 1). But an accident does not constitute the species. Therefore a circumstance does not constitute a species of good or evil.

[I-II.q.18.a.10.arg.3] Further, one thing is not in several species. But one action has several circumstances. Therefore a circumstance does not place a moral action in a species of good or evil.

[I-II.q.18.a.10.sc] Place is a circumstance. But place makes a moral action to be in a certain species of evil; for theft of a thing from a holy place is a sacrilege. Therefore a circumstance makes a moral action to be specifically good or bad.

[I-II.q.18.a.10.co] Just as the species of natural things are constituted by their natural forms, so the species of moral actions are constituted by forms as conceived by the reason, as is evident from what was said above (Article 5). But since nature is determinate to one thing, nor can a process of nature go on to infinity, there must needs be some ultimate form, giving a specific difference, after which no further specific difference is possible. Hence it is that in natural things, that which is accidental to a thing, cannot be taken as a difference constituting the species. But the process of reason is not fixed to one particular term, for at any point it can still proceed further. And consequently that which, in one action, is taken as a circumstance added to the object that specifies the action, can again be taken by the directing reason, as the principal condition of the object that determines the action's species. Thus to appropriate another's property is specified by reason of the property being "another's," and in this respect it is placed in the species of theft; and if we consider that action also in its bearing on place or time, then this will be an additional circumstance. But since the reason can direct as to place, time, and the like, it may happen that the condition as to place, in relation to the object, is considered as being in disaccord with reason: for instance, reason forbids damage to be done to a holy place. Consequently to steal from a holy place has an additional repugnance to the order of reason. And thus place, which was first of all considered as a circumstance, is considered here as the principal condition of the object, and as itself repugnant to reason. And in this way, whenever a circumstance has a special relation to reason, either for or against, it must needs specify the moral action whether good or bad.

[I-II.q.18.a.10.ad.1] A circumstance, in so far as it specifies an action, is considered as a condition of the object, as stated above, and as being, as it were, a specific difference thereof.

[I-II.q.18.a.10.ad.2] A circumstance, so long as it is but a circumstance, does not specify an action, since thus it is a mere accident: but when it becomes a principal condition of the object, then it does specify the action.

[I-II.q.18.a.10.ad.3] It is not every circumstance that places the moral action in the species of good or evil; since not every circumstance implies accord or disaccord with reason. Consequently, although one action may have many circumstances, it does not follow that it is in many species. Nevertheless there is no reason why one action should not be in several, even disparate, moral species, as said above (07, ad 1; 1, 3, ad 3).

[I-II.q.18.a.11.arg.1] It would seem that every circumstance relating to good or evil, specifies an action. For good and evil are specific differences of moral actions. Therefore that which causes a difference in the goodness or malice of a moral action, causes a specific difference, which is the same as to make it differ in species. Now that which makes an action better or worse, makes it differ in goodness and malice. Therefore it causes it to differ in species. Therefore every circumstance that makes an action better or worse, constitutes a species.

[I-II.q.18.a.11.arg.2] Further, an additional circumstance either has in itself the character of goodness or malice, or it has not. If not, it cannot make the action better or worse; because what is not good, cannot make a greater good; and what is not evil, cannot make a greater evil. But if it has in itself the character of good or evil, for this very reason it has a certain species of good or evil. Therefore every circumstance that makes an action better or worse, constitutes a new species of good or evil.

[I-II.q.18.a.11.arg.3] Further, according to Dionysius (Div. Nom. iv), "evil is caused by each single defect." Now every circumstance that increases malice, has a special defect. Therefore every such circumstance adds a new species of sin. And for the same reason, every circumstance that increases goodness, seems to add a new species of goodness: just as every unity added to a number makes a new species of number; since the good consists in "number, weight, and measure" (I, 5, 5).

[I-II.q.18.a.11.sc] More and less do not change a species. But more and less is a circumstance of additional goodness or malice. Therefore not every circumstance that makes a moral action better or worse, places it in a species of good or evil.

[I-II.q.18.a.11.co] As stated above (Article 10), a circumstance gives the species of good or evil to a moral action, in so far as it regards a special order of reason. Now it happens sometimes that a circumstance does not regard a special order of reason in respect of good or evil, except on the supposition of another previous circumstance, from which the moral action takes its species of good or evil. Thus to take something in a large or small quantity, does not regard the order of reason in respect of good or evil, except a certain other condition be presupposed, from which the action takes its malice or goodness; for instance, if what is taken belongs to another, which makes the action to be discordant with reason. Wherefore to take what belongs to another in a large or small quantity, does not change the species of the sin. Nevertheless it can aggravate or diminish the sin. The same applies to other evil or good actions. Consequently not every circumstance that makes a moral action better or worse, changes its species.

[I-II.q.18.a.11.ad.1] In things which can be more or less intense, the difference of more or less does not change the species: thus by differing in whiteness through being more or less white a thing is not changed in regard to its species of color. In like manner that which makes an action to be more or less good or evil, does not make the action differ in species.

[I-II.q.18.a.11.ad.2] A circumstance that aggravates a sin, or adds to the goodness of an action, sometimes has no goodness or malice in itself, but in regard to some other condition of the action, as stated above. Consequently it does not add a new species, but adds to the goodness or malice derived from this other condition of the action.

[I-II.q.18.a.11.ad.3] A circumstance does not always involve a distinct defect of its own; sometimes it causes a defect in reference to something else. In like manner a circumstance does not always add further perfection, except in reference to something else. And, for as much as it does, although it may add to the goodness or malice, it does not always change the species of good or evil.

The Summa Theologica of St. Thomas AquinasSecond and Revised Edition, 1920Literally translated by Fathers of the English Dominican ProvinceOnline Edition Copyright © 2009 by Kevin Knight Nihil Obstat. F. Innocentius Apap, O.P., S.T.M., Censor. Theol.Imprimatur. Edus. Canonicus Surmont, Vicarius Generalis. Westmonasterii.APPROBATIO ORDINISNihil Obstat. F. Raphael Moss, O.P., S.T.L. and F. Leo Moore, O.P., S.T.L.Imprimatur. F. Beda Jarrett, O.P., S.T.L., A.M., Prior Provincialis AngliæMARIÆ IMMACULATÆ - SEDI SAPIENTIÆ