St. Thomas on Human Nature: Essence, Existence & God

Conception of Man in St. Thomas's Thought

IV. Conception of Man

1. The Structure of Created Reality

The contingency of all being, the finite radical destitution of all finite beings, requires a being that is the foundation of self and all reality: God. All creatures have a metaphysical composition of essence and existence contrasted with the single necessary and infinite God, who is the cause of their existence. From God, St. Thomas offers us a vision of reality created in a hierarchical fashion. To refer to the creatures he uses Aristotelian concepts: action and power, substance and accident, matter and form, adding the distinction essence/existence. The hierarchy of beings is given by their degree of simplicity and their greater proximity to the pure existence of God.

At the apex of creation are the angels (composed of essence and existence), then humans (with a soul which is its substantial form, attached to a subject). The substances of the corporeal world are composed of matter and form. In man the "form" is the soul and can exist independently of the body, whereas sentient beings such as animals, or purely vegetative beings such as plants, are perishable and dependent forms of matter. The forms of beings and the inert forms of the first elements are the most imperfect.

2. The Human Image of God

Man is composed of body and a spiritual soul: the body is linked to the sensible world and the soul to the spiritual world. The human being is most perfect in the sensible order and less perfect in the order of intellectual substances. St. Thomas defines the soul as the principle of life and as the form of a physical body which has life potentially. It is what separates the living from the nonliving.

He also describes the active powers of the soul with which it performs vital operations. These include both corporeal and incorporeal faculties. The intellect is divided into the theoretical and the practical. The human soul has three principal faculties:

• Will (the rational appetite)
• Powers of sensation (sensory faculties)
• Sensuality (sensual desire)

St. Thomas defends anthropological dualism, but his position is more moderate than Plato's: the term "man" signifies the unity of body and soul, not the soul alone as in Plato's view.

3. Man's Relation to God

Man is elevated to the supernatural by divine grace, through which he reaches a state of perfection that cannot be achieved by himself. Nevertheless, many areas of human activity can be understood without constant explicit reference to man's final end in God.

God as the Ultimate Object of Knowledge

The intellectual vocation of man to God implies that theology is the supreme science and the highest perfection of our intelligence, because knowledge is ordered to truth and God is the supreme truth. All truth is connected with God: He is the creator and sustainer and is that which gives intelligibility to all reality. We know God in all we know because the world is a form of natural revelation from God. The ultimate goal of man is the vision of God in the afterlife, that is, a purely intellectual knowledge of Him and to live⁴.