If, however, with Augustine (De Verb. Dom., Serm. lxxi) we understand the sin against the Holy Ghost to denote final impenitence, it does not regard the question in point, because this sin against the Holy Ghost requires persistence in sin until the end of life.
Reply Obj. 1: Movement both in good and in evil is made, for the most part, from imperfect to perfect, according as man progresses in good or evil: and yet in both cases, one man can begin from a greater (good or evil) than another man does. Consequently, that from which a man begins can be perfect in good or evil according to its genus, although it may be imperfect as regards the series of good or evil actions whereby a man progresses in good or evil.
Reply Obj. 2: This argument considers the sin which is committed through certain malice, when it proceeds from the inclination of a habit.
Reply Obj. 3: If by impenitence we understand with Augustine (De Verb. Dom., Serm. lxxi) persistence in sin until the end, it is clear that it presupposes sin, just as repentance does. If, however, we take it for habitual impenitence, in which sense it is a sin against the Holy Ghost, it is evident that it can precede sin: for it is possible for a man who has never sinned to have the purpose either of repenting or of not repenting, if he should happen to sin. _______________________
QUESTION 15
OF THE VICES OPPOSED TO KNOWLEDGE AND UNDERSTANDING
(In Three Articles)
We must now consider the vices opposed to knowledge and understanding. Since, however, we have treated of ignorance which is opposed to knowledge, when we were discussing the causes of sins (I-II, Q. 76), we must now inquire about blindness of mind and dulness of sense, which are opposed to the gift of understanding; and under this head there are three points of inquiry:
(1) Whether blindness of mind is a sin?
(2) Whether dulness of sense is a sin distinct from blindness of mind?
(3) Whether these vices arise from sins of the flesh? _______________________