The first part of part 2 of the Summa, consisting of 114 questions, offers an extensive discussion of man, who is said to have been made in God’s image. The first 5 questions, each of which is subdivided into various Articles, deal with man’s last end, the things in which man’s happiness consists, what happiness is, the things that are required for happiness, and the attainment of happiness.
First, in contrast to irrational animals, man has the faculty and will of reason. The will, also known as the rational appetite, seeks to achieve both its end and the good, and so all acts, being guided by the will, are for an end.
Second, man’s happiness does not consist of wealth, honor, fame, glory, power, the goods of the body, or pleasure. In fact, man’s happiness cannot consist in any created good at all, since the ultimate object of man’s will, the universal good, cannot be found in any creature but rather only in God, who is the source of all good.
Third, happiness is man’s supreme perfection, and each thing is perfect insofar as it is actual. Man’s final and complete happiness can consist only in contemplating the Divine Essence, although the possibility of this contemplation remains withheld from us until we are in the world to come. As long as man desires and seeks something, he remains unhappy. The intellect seeks the essence of a thing. For example, knowing an effect, such as a solar eclipse, the intellect is aroused and is unsatisfied until it discovers the cause of the eclipse. Indeed, the intellect desires to understand the essence of the cause. For this reason, the intellect is unsatisfied to know merely that the First Cause, that is, God, exists. The intellect seeks to penetrate farther to the very essence of the First Cause itself.
Fourth, the things required for happiness must derive from the way in which man is constituted and designed for a purpose, since happiness consists in man’s attainment of that final purpose. Perfect knowledge of the intelligible end, actual attainment of the end, and delight in the presence of the end attained must all coexist in happiness. Happiness in this life, which is necessarily imperfect, requires rectitude of the will, the existence of the body, and certain external goods and consists in the use of the intellect either speculatively or practically (i.e., with respect to morality). Perfect happiness, which is possible only in the life to come, consists in contemplation of the Divine Essence, which is goodness.
Finally, man is capable of attaining happiness, that is, of seeing God, and one person can be happier than another insofar as she is better inclined to enjoy him. Happiness excludes the presence of evil, though, and since evil is present in this world, it is impossible for man to be happy in this life. Furthermore, man cannot attain perfect happiness because he is incapable of seeing God in this life. Imperfect happiness can be lost, but perfect happiness cannot. Neither man nor any creature can attain final happiness through his natural powers. Since happiness is a good surpassing anything that has been created, no creature, even an angel, is capable of making man happy. Happiness is the reward for works of virtue. Some people do not know what happiness consists in and thus do not desire it.