Summa Theologica, Part I (Prima Pars) From the Complete...

Obj. 4: Further, the subject of whiteness is called white. Therefore also the subject of evil is evil. If, therefore, evil is in good as in its subject, it follows that good is evil, against what is said (Isa. 5:20): "Woe to you who call evil good, and good evil!"

I answer that, As was said above (A. 1), evil imports the absence of good. But not every absence of good is evil. For absence of good can be taken in a privative and in a negative sense. Absence of good, taken negatively, is not evil; otherwise, it would follow that what does not exist is evil, and also that everything would be evil, through not having the good belonging to something else; for instance, a man would be evil who had not the swiftness of the roe, or the strength of a lion. But the absence of good, taken in a privative sense, is an evil; as, for instance, the privation of sight is called blindness.

Now, the subject of privation and of form is one and the same—viz. being in potentiality, whether it be being in absolute potentiality, as primary matter, which is the subject of the substantial form, and of privation of the opposite form; or whether it be being in relative potentiality, and absolute actuality, as in the case of a transparent body, which is the subject both of darkness and light. It is, however, manifest that the form which makes a thing actual is a perfection and a good; and thus every actual being is a good; and likewise every potential being, as such, is a good, as having a relation to good. For as it has being in potentiality, so has it goodness in potentiality. Therefore, the subject of evil is good.

Reply Obj. 3: Evil is not in the good opposed to it as in its subject, but in some other good, for the subject of blindness is not "sight," but "animal." Yet, it appears, as Augustine says (Enchiridion 13), that the rule of dialectics here fails, where it is laid down that contraries cannot exist together. But this is to be taken as referring to good and evil in general, but not in reference to any particular good and evil. For white and black, sweet and bitter, and the like contraries, are only considered as contraries in a special sense, because they exist in some determinate genus; whereas good enters into every genus. Hence one good can coexist with the privation of another good.

Obj. 3: Further, evil, as long as it lasts, hurts, and takes away good. But that from which something is always being removed, is at some time consumed, unless it is infinite, which cannot be said of any created good. Therefore evil wholly consumes good.

I answer that, Evil cannot wholly consume good. To prove this we must consider that good is threefold. One kind of good is wholly destroyed by evil, and this is the good opposed to evil, as light is wholly destroyed by darkness, and sight by blindness. Another kind of good is neither wholly destroyed nor diminished by evil, and that is the good which is the subject of evil; for by darkness the substance of the air is not injured. And there is also a kind of good which is diminished by evil, but is not wholly taken away; and this good is the aptitude of a subject to some actuality.

The diminution, however, of this kind of good is not to be considered by way of subtraction, as diminution in quantity, but rather by way of remission, as diminution in qualities and forms. The remission likewise of this habitude is to be taken as contrary to its intensity. For this kind of aptitude receives its intensity by the dispositions whereby the matter is prepared for actuality; which the more they are multiplied in the subject the more is it fitted to receive its perfection and form; and, on the contrary, it receives its remission by contrary dispositions which, the more they are multiplied in the matter, and the more they are intensified, the more is the potentiality remitted as regards the actuality.

Therefore, if contrary dispositions cannot be multiplied and intensified to infinity, but only to a certain limit, neither is the aforesaid aptitude diminished or remitted infinitely, as appears in the active and passive qualities of the elements; for coldness and humidity, whereby the aptitude of matter to the form of fire is diminished or remitted, cannot be infinitely multiplied. But if the contrary dispositions can be infinitely multiplied, the aforesaid aptitude is also infinitely diminished or remitted; yet, nevertheless, it is not wholly taken away, because its root always remains, which is the substance of the subject. Thus, if opaque bodies were interposed to infinity between the sun and the air, the aptitude of the air to light would be infinitely diminished, but still it would never be wholly removed while the air remained, which in its very nature is transparent. Likewise, addition in sin can be made to infinitude, whereby the aptitude of the soul to grace is more and more lessened; and these sins, indeed, are like obstacles interposed between us and God, according to Isa. 59:2: "Our sins have divided between us and God." Yet the aforesaid aptitude of the soul is not wholly taken away, for it belongs to its very nature.

Reply Obj. 2: The aforesaid aptitude is a medium between subject and act. Hence, where it touches act, it is diminished by evil; but where it touches the subject, it remains as it was. Therefore, although good is like to itself, yet, on account of its relation to different things, it is not wholly, but only partially taken away.

Reply Obj. 3: Some, imagining that the diminution of this kind of good is like the diminution of quantity, said that just as the continuous is infinitely divisible, if the division be made in an ever same proportion (for instance, half of half, or a third of a third), so is it in the present case. But this explanation does not avail here. For when in a division we keep the same proportion, we continue to subtract less and less; for half of half is less than half of the whole. But a second sin does not necessarily diminish the above mentioned aptitude less than a preceding sin, but perchance either equally or more.

Therefore it must be said that, although this aptitude is a finite thing, still it may be so diminished infinitely, not per se, but accidentally; according as the contrary dispositions are also increased infinitely, as explained above. _______________________

Objection 1: It would seem that evil is not adequately divided into pain and fault. For every defect is a kind of evil. But in all creatures there is the defect of not being able to preserve their own existence, which nevertheless is neither a pain nor a fault. Therefore evil is inadequately divided into pain and fault.

Obj. 3: Further, temptation is an evil, but it is not a fault; for "temptation which involves no consent, is not a sin, but an occasion for the exercise of virtue," as is said in a gloss on 2 Cor. 12; not is it a pain; because temptation precedes the fault, and the pain follows afterwards. Therefore, evil is not sufficiently divided into pain and fault.

I answer that, Evil, as was said above (A. 3), is the privation of good, which chiefly and of itself consists in perfection and act. Act, however, is twofold; first, and second. The first act is the form and integrity of a thing; the second act is its operation. Therefore evil also is twofold. In one way it occurs by the subtraction of the form, or of any part required for the integrity of the thing, as blindness is an evil, as also it is an evil to be wanting in any member of the body. In another way evil exists by the withdrawal of the due operation, either because it does not exist, or because it has not its due mode and order. But because good in itself is the object of the will, evil, which is the privation of good, is found in a special way in rational creatures which have a will. Therefore the evil which comes from the withdrawal of the form and integrity of the thing, has the nature of a pain; and especially so on the supposition that all things are subject to divine providence and justice, as was shown above (Q. 22, A. 2); for it is of the very nature of a pain to be against the will. But the evil which consists in the subtraction of the due operation in voluntary things has the nature of a fault; for this is imputed to anyone as a fault to fail as regards perfect action, of which he is master by the will. Therefore every evil in voluntary things is to be looked upon as a pain or a fault.

Reply Obj. 1: Because evil is the privation of good, and not a mere negation, as was said above (A. 3), therefore not every defect of good is an evil, but the defect of the good which is naturally due. For the want of sight is not an evil in a stone, but it is an evil in an animal; since it is against the nature of a stone to see. So, likewise, it is against the nature of a creature to be preserved in existence by itself, because existence and conservation come from one and the same source. Hence this kind of defect is not an evil as regards a creature.

Reply Obj. 3: Temptation, as importing provocation to evil, is always an evil of fault in the tempter; but in the one tempted it is not, properly speaking, a fault; unless through the temptation some change is wrought in the one who is tempted; for thus is the action of the agent in the patient. And if the tempted is changed to evil by the tempter he falls into fault.

Reply Obj. 4: In answer to the opposite argument, it must be said that the very nature of pain includes the idea of injury to the agent in himself, whereas the idea of fault includes the idea of injury to the agent in his operation; and thus both are contained in evil, as including the idea of injury. _______________________

Obj. 2: Further, that is the greater evil which is opposed to the greater good. But pain, as was said above (A. 5), is opposed to the good of the agent, while fault is opposed to the good of the action. Therefore, since the agent is better than the action, it seems that pain is worse than fault.

I answer that, Fault has the nature of evil more than pain has; not only more than pain of sense, consisting in the privation of corporeal goods, which kind of pain appeals to most men; but also more than any kind of pain, thus taking pain in its most general meaning, so as to include privation of grace or glory.