Question 51 — Of the Cause of Habits, as to Their Formation

We must next consider the cause of habits: and first, as to their formation; second, as to their increase; third, as to their diminution and corruption. Under the first head there are four points of inquiry:

(1) Whether any habit is from nature?

• (2) Whether any habit is caused by acts?
• (3) Whether any habit can be caused by one act?
• (4) Whether any habits are infused in man by God?