/summa/XP/XPII/XP_Q1:
We must now consider each single part of Penance, and (1) Contrition; (2) Confession; (3) Satisfaction. The consideration about Contrition will be fourfold: (1) What is it? (2) What should it be about? (3) How great should it be? (4) Of its duration; (5) Of its effect.
Under the first head there are three points of inquiry:
(1) Whether Contrition is suitably defined?
(2) Whether it is an act of virtue?
(3) Whether attrition can become contrition?