The Purpose of Man, according to Thomas Aquinas

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. Aquinas says that 'free-will is the cause of its own movement, because by his free-will man moves himself to act. But it does not of necessity belong to liberty that what is free should be the first cause of itself, as neither for one thing to be cause of another need it be the first cause. From the very fact, therefore, that man is such by virtue of a natural quality which is in the intellectual part, he naturally desires his last end, which is happiness.'

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. Aquinas affirms that 'It is impossible for man's happiness to consist in the goods of the body; and this for two reasons. First, because, if a thing be ordained to another as to its end, its last end cannot consist in the preservation of its being. Secondly, because, granted that the end of man's will and reason be the preservation of man's being, it could not be said that the end of man is some good of the body. For man's being consists in soul and body; and though the being of the body depends on the soul, yet the being of the human soul depends not on the body, and the very body is for the soul, as matter for its form, and the instruments for the man that puts them into motion, that by their means he may do his work. Wherefore all goods of the body are ordained to the goods of the soul, as to their end. Consequently happiness, which is man's last end, cannot consist in goods of the body.

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.

Happiness is the goal of human life, and every human being is on the path toward the complete actualization of his or her potential. Indeed, humans’ actualization and realization of their potential is exactly what constitutes happiness. Humans’ potential, or what humans can be, consists in the contemplation of the Divine Essence. Happiness and the contemplation of the Divine Essence are thus identical and inseparable.

The contemplation of the Divine Essence is not only necessary for happiness, it is uniquely sufficient. Nothing except the contemplation of the Divine Essence can bring happiness. No worldly or material good, such as fame, honor, glory, power, health, or even pleasure itself can bring happiness, as even pleasure is just a component of happiness. A state of happiness can exist only when the will no longer seeks anything. Since the will naturally seeks the Divine Essence, it will continue to seek, and thus to be unhappy, until it finds it.

Aquinas applies Aristotle’s notions of efficient and final cause, whereby human nature, in the form of the will, is the efficient cause and happiness, or contemplation of the Divine Essence, is the final cause. The will thus inescapably propels every individual to seek happiness. The process of becoming leads naturally to God, who is pure being and actuality. The culmination of this process, though, is possible only in the next life and only works of virtue, that is, performance of the will of God, can lead to this culmination. Thus, the will achieves its goal, which is happiness, only when it is at one with the Divine Will.

Aquinas asks whether one can be happy in this life? he answers, 'A certain participation of Happiness can be had in this life: but perfect and true Happiness cannot be had in this life. This may be seen from a twofold consideration. First, from the general notion of happiness. For since happiness is a "perfect and sufficient good," it excludes every evil, and fulfils every desire. But in this life every evil cannot be excluded. For this present life is subject to many unavoidable evils; to ignorance on the part of the intellect; to inordinate affection on the part of the appetite, and to many penalties on the part of the body. Likewise neither can the desire for good be satiated in this life. For man naturally desires the good, which he has, to be abiding. Now the goods of the present life pass away; since life itself passes away, which we naturally desire to have, and would wish to hold abidingly, for man naturally shrinks from death. Wherefore it is impossible to have true Happiness in this life. Secondly, from a consideration of the specific nature of Happiness, viz. the vision of the Divine Essence, which man cannot obtain in this life. Hence it is evident that none can attain true and perfect Happiness in this life.'

This is why the famous passage from St. Augustine's Confessions (Lib 1,1-2,2.5,5: CSEL 33, 1-5) in which Saint Augustine states "You have made us for yourself, O Lord, and our heart is restless until it finds its rest in Thee."

References:

Summa Theologiae of Thomas Aquinas

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