Summa Theologiae Moralis, vol. I: De Principiis

S. Th. I-II, q. 1 and q. 21.

47. The notion of a human act. — After the treatise on the ultimate end, we must consider human acts by which we ought to attain it.

According to St. Thomas, who first among all wrote a distinct treatise on human acts¹:

1) Those actions alone are properly called human, which are proper to man insofar as he is man, or which proceed from man acting insofar as he differs from irrational creatures, not only as to substance but also as to the mode of operating.

But it differs in its mode of operating from irrational creatures inasmuch as it acts freely, and so it is the master of its own acts.

2) Whence those actions alone are called properly human of which man is the master.

He is master of his own acts through the deliberation of reason and the choice of the will.

3) Those actions, therefore, are properly called human which proceed from deliberate will. But other actions which are done by a man are called acts of man; and although some are human as to substance, e.g., the necessary actions of the intellect and will, they are not, however, such as to the mode of operating, nor are they properly human since they are not of a man acting as a man (q. 1, a. 1).

An act of man can therefore be defined as an act which proceeds from the deliberate will of man (q. 1, a. 1), or an act which is voluntary, proceeding from reason (Q. D. de Malo 2, a. 6)^1.

Hinc: 1) They are not human a) acts (of vegetative or sensitive life) which man has in common with brutes, both as to substance and as to mode of operating, such as eating, seeing, walking, feeling without deliberation; b) acts of one who is incapable of deliberating: an infant, one fully sleeping, one delirious, the drunk, or the insane, one perfectly dependent on the influence of hypnotism; c) acts of one who can deliberate but acts without any deliberation, e.g., by a man fully distracted: they are called first-first movements. 2) Acts which are proper to man as to substance, such as understanding, willing, laughing, weeping, wondering, speaking, are nevertheless not human unless they are done from deliberation; on the contrary, acts common with brutes, such as eating, drinking, stroking one’s beard, walking, are human if they are done from deliberation. 3) Beatific love, although it is an act proper to man as to substance, is nevertheless not so as to mode of operating, because it is not free; hence it is not a human act^2.

48. Properties of the human act. — Human acts are so called insofar as they are performed in the manner proper to humans; they are also called free insofar as they proceed from free will, — moral insofar as they are conformable or nonconformable with the rules of morals: the inclination toward the ultimate end, right reason, law, and accordingly they have the character of rightness or of sin; — imputable insofar as they can be attributed to a human being as author and master, who must render an account of them, and thus they are worthy of praise or blame, praiseworthy or culpable^3; — meritorious insofar as they are referred

^{2 3 4}

to another in whose benefit or harm they redound, whether of a singular person, or of a community, or of God the ruler of the universe and ultimate end. All those acts are really the same, although they are distinguished in reason insofar as they are considered under a different respect⁵ (q. 21).

49. Division of the treatise.— The treatise is divided into 3 parts:

1st treats of human acts according to their material or physical and psychological being: A. on the condition of human acts: 1º on the subjective element of a human act: a) on the voluntary, both in itself, — both positive and negative, direct and indirect, — both in itself and in its cause; b) on the impediments of the voluntary, i.e., on violence, on fear, on concupiscence, on ignorance; c) on the free; d) on the impediments of the free, namely, on passion, on habit, on more remote impediments; — 2º on the objective element of a human act: a) on the object, b) on the circumstances. B. on the division of human acts: a) on elicited acts; b) on commanded acts.

2nd Part treats of human acts according to their formal or moral being: A. on the morality of human acts in general; 1º on the essence of morality and its species; 2º on the foundations of morality: a) on the intrinsic distinction between good and evil; b) on the subjective criterion or norm of morality; c) on the objective criterion and ultimate foundation of morality.

d) on the errors to be noted in this matter; e) on the cognitive faculty of morality; 3° on the principles or sources of morality in general; 4° on the specific distinction between a good and an evil act; 5° on the specific distinction among various good or evil acts a) from the object, b) from the circumstances, c) from the end.

B. on the morality of human acts in particular: 1° on the goodness and malice of the interior act; 2° on the goodness and malice of the exterior act; 3° on the goodness and malice of the external effect; 4° on the goodness and malice of the passions; 5° on the goodness and malice of the other circumstances.

3rd Part treats of human acts according to their supernatural and meritorious being: 1) on supernatural merit; 2) on the conditions of merit.

50. The treatise is theological and philosophical at once. — In the customary division, the first part is rather philosophical, providing the notions necessary for understanding the rest; the third is wholly theological, as dealing with the supernatural element; the second is at once theological and philosophical, because it is drawn not from reason alone but also from revelation: for this, by divine oral tradition and partly by the sacred Scriptures, teaches us even more certainly the most universal moral principles and their immediate and more general conclusions, from which the whole moral science is deduced. Whence to declare, confirm, explain, and apply these belongs to theology as much as to philosophy.

51. Importance of the treatise. — The treatise is the most principal of all, because it is;

1. more universal, since it hands down the most general notions and principles of the whole moral science to be applied in all its parts; and therefore
2. more fundamental, because on it is built up the edifice of the whole moral science: for this latter treats only of human acts, and all other things—whether ends, or means, or rules or counsels, or virtues or vices—it considers only insofar as they pertain to human acts; whence the treatise is entitled on the acts themselves human according to themselves. Hence
3. it is more necessary: for it is impossible to acquire for oneself a knowledge—not a common or merely historical one of moral matters, but a scientific one, founded on reasoning—unless the doctrine on human acts be well understood and rightly applied.