Part — Wouters, Manual of Moral Theology
Part I. Summary Doctrine of the Human Act
I. Notion of a human act. A human act is an act which proceeds from the deliberate will of man. For "those actions alone are properly called human which are proper to man insofar as he is man. Now man differs from irrational creatures in this, that he is master of his acts. Hence those actions alone are properly called human of which man is master. But man is master of his acts through reason and will; hence free choice is said to be a faculty of will and reason. Therefore those actions are properly called human which proceed from deliberate will" (St. Thomas, I-II, q. 1, a. 1; St. Alphonsus, V, I).
Other acts, which do indeed proceed from man, but not from the will, or not from deliberate will, are called acts of man. Such are, for example, the first thought of the intellect, the desire for beatitude, and the beatific love of the saints (St. Alphonsus, V, II).
II. Intrinsic principles of the human act. As follows from the definition handed down, the intrinsic principles of the human act are intellect and free will, or, as others prefer, intellect, will, and liberty: the intellect deliberates; the will, once deliberation has been placed, freely chooses.
III. Division of human acts. Human acts are distinguished:
Into elicited and commanded acts. Elicited acts are those elicited by the will itself, such as the act of loving. Commanded acts are those elicited by another faculty from the command of the will, such as the act of walking; likewise acts elicited by the will, but from the command of a preceding act of the will. Acts of this kind can be called both elicited and commanded, as when someone detests sin from charity toward God.
Into internal and external acts, according as they are completed by the internal powers alone, as thought is, or proceed to the external powers, as the act of speaking does.
Into commanded, forbidden, and free acts. Of free acts, some are simply permitted, some are advised, and some are dissuaded.
Into good and bad acts, according as they agree with the divine law or differ from it (n. 60). Good acts are distinguished into natural and supernatural acts, according as they are elicited by the powers of nature alone or with the help of grace.
Into valid and invalid acts, according as they produce or do not produce the effect for which they are destined. Then, of valid acts, some are irrescindable or firm, while others are rescindable or infirm (St. Alphonsus, V, III and IV).