Question II. Good and Bad Habits

Having considered human acts and the passions, we now pass to a consideration of the principles from which acts proceed proximately. These principles are, first, the faculties, powers or forces of the soul (such as the intellect, will, sense, appetite, and vegetative powers); and, secondly, the habits which permanently modify the faculties. For some faculties may be turned in various directions, either favorably or unfavorably, as regards their ends, and it is the stable bent given to a faculty that is called a habit. Thus, the intellect may be directed towards its end, which is truth, by the habit of knowledge; or away from that end by the habit of ignorance. Likewise, the will may be directed towards or away from its end, which is good, by virtue or vice. The faculties are treated in Psychology, but the habits, since they turn the faculties towards good or evil, must be considered in Moral Theology, as well as in philosophy.