s
making one mortal sin dispositively.

Reply Obj. 2: The same movement of the sensuality which preceded the
consent of reason can never become a mortal sin; but the movement of
the reason in consenting is a mortal sin.

Reply Obj. 3: Disease of the body is not an act, but an abiding
disposition; wherefore, while remaining the same disease, it may
undergo change. On the other hand, venial sin is a transient act,
which cannot be taken up again: so that in this respect the
comparison fails.

Reply Obj. 4: A disposition that becomes a habit, is like an
imperfect thing in the same species; thus imperfect science, by being
perfected, becomes a habit. On the other hand, venial sin is a
disposition to something differing generically, even as an accident
which disposes to a substantial form, into which it is never changed.
________________________

FIFTH ARTICLE [I-II, Q. 88, Art. 5]

Whether a Circumstance Can Make a Venial Sin to Be Mortal?

Objection 1: It would seem that a circumstance can make a venial sin
mortal. For Augustine says in a sermon on Purgatory (De Sanctis,
serm. xli) that "if anger continue for a long time, or if drunkenness
be frequent, they become mortal sins." But anger and drunkenness are
not mortal but venial sins generically, else they would always be
mortal sins. Therefore a circumstance makes a venial sin to be mortal.

Obj. 2: Further, the Master says (Sentent. ii, D, 24) that
delectation, if morose [*See Q. 74, A. 6], is a mortal sin, but that
if it be not morose, it is a venial sin. Now moroseness is a
circumstance. Therefore a circumstance makes a venial sin to be
mortal.

Obj. 3: Further, evil and good differ more than venial and mortal
sin, both of which are generically evil. But a circumstance makes a
good act to be evil, as when a man gives an alms for vainglory. Much
more, therefore, can it make a venial sin to be mortal.

_On the contrary,_ Since a circumstance is an accident, its quantity
cannot exceed that of the act itself, derived from the act's genus,
because the subject always excels its accident. If, therefore, an act
be venial by reason of its genus, it cannot become mortal by reason
of an accident: since, in a way, mortal sin infinitely surpasses the
quantity of venial sin, as is evident from what has been said (Q. 72,
A. 5, ad 1; Q. 87, A. 5, ad 1).

_I answer that,_ As stated above (Q. 7, A. 1; Q. 18, A. 5, ad 4; AA.
10, 11), when we were treating of circumstances, a