Father Pegues concludes his discussion of human happiness by explaining how one attains ultimate happiness: “Man can come to possess God, his Supreme Good, and to enjoy Him, by an act of his intellect which is moved to this by his will.” The act whereby God is reached by the intellect as He is in Himself is called the “vision of God.” It is in this vision that the perfect happiness of man consists. “On earth and in this life it is impossible for man to come to possess the vision of God which is his perfect happiness, for the conditions of this life and the miseries thereof are incompatible with such fullness of happiness.”
“Man can only attain to the vision of God which constitutes his perfect happiness by the help of God from whom he receives it. God will not confer this boon upon man unless by merit he make himself worthy to receive it.” By performing virtuous acts, a person can merit during his earthly life to receive from God the beatific vision, which is his eternal happiness. Virtuous acts are “acts which man performs by his own free will in conformity with God’s will under the action of grace.”
St. Thomas Aquinas in his Treatise On Human Acts (Summa Theologica I-II, 6-21) elaborates upon the conditions that make human acts meritorious. One must perform them “spontaneously and with the knowledge that he is their cause.” They must be performed “without constraint or force.” And one must take into account the circumstances that accompany a human act. These are circumstances of person, object, effect produced, place, motive, means employed, and time. The most important of these is the motive for which a person acts.
Human acts are always produced by the will: either by the will alone, or by some human faculty or external bodily member acting under impulse of the will. “The will of man is the central point of all those acts that constitute his life as a rational being, and have direct bearing upon the reward of his life which is the gain or the loss of the happiness of heaven.”
The goodness of the object, the end, and the circumstances of an act “is derived from the relation that all these things have with right reason.” Right reason is “the reason enlightened by all the lights that come from God, or which at least is not knowingly at variance with them.” When a person “wills or chooses something in conformity with right reason for an object or an end of which right reason approves, and of which all the accompanying circumstances accord with right reason,” then it is considered a good act.
Quotations from Thomas Pegues, Catechism of the “Summa Theologica” of Saint Thomas Aquinas, trans. Aelred Whitacre (New York: Benziger, 1922).