Whether Sin Diminishes Natural Good
We proceed to the first article thus:
1. It seems that sin does not diminish natural good. For the sin of a man is no worse than the sin of a devil, and Dionysius says that what is naturally good in devils remains intact after they sin (4 Div. Nom., lect.19). It follows that sin does not destroy the natural good in man.
2. Again, that which is prior is not changed by an alteration in that which is consequential to it. Thus a substance remains the same when its attributes are altered. Now nature is prior to voluntary action. It follows that nature is not changed, nor the good of nature thereby diminished, by any derangement of voluntary action which results from sin.
3. Again, sin is an action, and diminution a passion. Now an agent cannot possibly be affected by its own action, although it may act on one thing and be affected by another. It follows that one who sins cannot diminish the good of his own nature by his own sin.
4. Again, no accident acts upon the subject to which it belongs, since what is acted upon is potentially something, whereas the subject of an accident is already the actuality of which its accident is an accident. Now sin occurs in the good of nature as an accident in its subject. It follows that sin does not diminish the good of nature, since to diminish anything is in a sense to act upon it.
On the other hand: according to a gloss by another, Bede expounds Luke 10:30 thus -- |a certain man going down from Jerusalem to Jericho (that is, incurring the defect of sin) was stripped of his raiment and wounded in his natural powers.| It follows that sin diminishes the good of nature.
I answer: by natural good we may mean three things. We may mean the constitutive principles of nature itself, together with the properties consequential to them, such as the powers of the soul, and the like. Secondly, we may mean the inclination to virtue. This is a good of nature, since a man possesses it naturally, as we said in Q.63, Art.1. Thirdly, we may mean the gift of original justice, which was bestowed on the whole of human nature when it was bestowed on the first man. The constitution of human nature is neither destroyed nor diminished by sin. The gift of original justice was totally lost through the sin of our first parent. The natural inclination to virtue, finally, is diminished by sin. Actions generate an inclination to similar actions, as we said in Q^.51, Art.2, and the inclination to one of two contraries is bound to be diminished by an inclination to the other. Now sin is the contrary of virtue. The good of nature which consists in the inclination to virtue is therefore bound to be diminished by the very fact that a man sins.
On the first point: anyone who reads his words can see that Dionysius is speaking of the primary good of nature, which consists of being, living, and understanding.
On the second point: although it is prior to voluntary action, nature includes the inclination to voluntary action of some kind. Hence although nature itself is not changed by any alteration in its voluntary action, its inclination is changed in respect of its direction to an end.
On the third point: voluntary action is the outcome of diverse powers, of which some are active and others passive. Hence it may either cause something in him who acts voluntarily, or take something away from him, as we said when discussing the formation of a habit (Q.51, Art.2).
On the fourth point: an accident does not act upon its subject in the sense of producing an effect in it. But it does act on it formally, in the sense in which whiteness makes things white. There is therefore nothing to prevent sin diminishing the good of nature by being itself the diminution of it, as a derangement of action. It must be said, however, that the derangement of the soul is due to the circumstance that there is both activity and passivity in its actions. The sensitive appetite is moved by a sensible object, and also inclines the reason and the will, as we said in Q.77, Art.1, and Q.80, Art.2. Disorder arises through an object acting on one power which acts on another power and deranges it, not through an accident acting upon its own subject.