19. Existence of the Last End.—Every deliberate act proceeds from the will, and, since the will pursues good as its goal, it follows that every deliberate act is done for some good or end. But, if this end is an imperfect good, it is desired not for itself but as leading up to a perfect good, that is, to one which will leave nothing beyond it to be desired; in other words, the intermediate end is willed on account of a last end. Hence, all that a man wills, he wills directly or indirectly on account of a last end. All men desire their own happiness and perfection; but not all understand in what beatitude consists, since some aim ultimately at finite goods.
20. Nature of the Last End.—As man’s Last End is that object which will make him perfectly happy, it cannot consist: (a) in external goods, such as wealth, honors, fame, glory and power, since one might have all these and yet be very unhappy; (b) in goods of the body, such as health, beauty, pleasure and strength, since all these things are passing, and moreover satisfy only a part, and that the lower part, of man; (c) in goods of the soul, such as wisdom or virtue, since man’s intellect is never content with particular truth, nor his will with particular good, the former always reaching out for the highest truth, the latter for the highest good. Hence, the Last End of man is the Infinite Good, or God “who satisfieth thy desire” (Psalm cii. 5).
21. Attainment of the Last End.—God being supersensible, the act by which He is attained cannot be any operation of the senses, but must be an act of the higher powers. Man possesses his Last End through the vision of God, from which result beatific love and every good that is compatible with the glorified state. For “we see now through a glass in a dark manner, but then face to face” (I Cor., xiii. 12); and there shall be “glory and honor and peace to everyone that worketh good” (Rom, ii. 10).
Art. 2: ACTS AS HUMAN
(_Summa Theologica_, I-II, qq. 6-17.)
22. Human acts are a means to man’s Last End, inasmuch as they are meritorious—i.e., labors that deserve a recompense (I Cor., iii. 8), struggles that deserve a crown (II Tim., ii. 5). But works are not meritorious unless they are one’s own (human) and good (moral); and, since the reward is supernatural, they must also be the fruit of grace. Hence, we shall speak of acts in the following order: (a) acts as human and free (Art. 2); (b) acts as morally good (Art. 3); (c) acts as supernaturally meritorious (Art. 4).
23. Definition.—Those acts are called human of which a man is the master, and he is master of his actions in virtue of his reason and his will, which faculties make him superior to non-human agents that act without reason and freedom. Hence, the following kinds of acts done by a human being are not called human: (a) those that are not under the control of the mind, because one is permanently or temporarily without the use of reason or without knowledge (e.g., the acts done by the insane; by those who are unconscious or delirious, under the influence of hypnotism or drugs, distracted or carried away by vehement fear, anger, etc.; by infants and uninstructed persons); (b) those that are not under the control of the will, even though they are known (e.g., automatic acts, such as the acts of the vegetative powers, growth, circulation of the blood; pathological acts, such as convulsions; acts done under external violence).
24. Knowledge Requisite for a Human Act.—An act is human, or voluntary, when it is deliberately desired; and, since nothing can be deliberately desired unless it is known, an act done without knowledge is not human or voluntary. Thus, a delirious patient does not will the language he uses, for his mind is confused and he does not understand what he is saying.
25. The condition of a person without knowledge is ignorance, which is defined as the absence of knowledge in one who is capable of knowing. Ignorance is of various kinds. From the viewpoint of that which is not known (i.e., of the object of the ignorance), there is ignorance of the substance of an act and ignorance of the quality of an act. For example, Titus driving rapidly in the dark runs over and kills a pet animal of his neighbor, but knows nothing of this happening (ignorance of the substance of the act); Balbus, a child, fires a pistol at his playmate, not knowing that this causes death (ignorance of the physical quality of an act), and that it is the sin of murder (ignorance of the moral quality of an act).
26. With reference to the will of the person who is ignorant, three kinds of ignorance may be distinguished.