study of the whole human person composed of matter
(body) and form (soul). This study also shows that the
human soul has functions, namely, understanding and free
choice, that transcend the limitations of animal nature,
thereby proving the soul to be immaterial, created, and im-
mortal.
Moral philosophy for Aristotle and Thomas presup-
poses psychology and deals with human happiness, which is
the goal of each person in this life, and the optimum (morally
good) means of attaining that goal for the individual, the
family, and the body politic. The foundation of both goal
and correct means is called the natural law, which is know-
able by human reason but open to rejection by the individu-
al. There are four cardinal virtues, or optimum means, for
use in every state of life: prudence, justice, fortitude, and
temperance. The highest of these is prudence, which binds
all virtues together and securely guides humanity to hap-
piness.
Finally metaphysics, or speculative wisdom (natural the-
ology), is about all being-as-such and about the First Cause
as the source of all being. For Thomas the most “sublime
truth” of this wisdom is the realization that all creatures are
composed of a “nature” and a borrowed existence (esse),
while God’s nature alone is “to exist.” God is subsistent exis-
tence itself (ipsum esse subsistens), the Necessary Being that
cannot not be. As the highest science, metaphysics has the
added task of ordering, defending, and safeguarding all other
sciences, speculative and practical. In this role it examines the
roots and foundation of all human knowledge (epistemolo-
gy), natural religion, and public worship.
Theology. Thomistic “theology,” which Thomas calls
sacred doctrine, is distinct from pure philosophy and de-
pends on the divine gift of faith, which involves the whole
realm of revelation, divine law, ecclesial worship, the spiritu-
al life, and human speculation about these. The realm of
faith is in the strict sense “super-natural” in that its truths,
values, and efficacy transcend the realm of “nature.” Faith’s
abilities are freely given by God for human salvation and are
beyond the abilities of pure nature (cf. Rom. 11:5–6). The
content of faith concerns what one must believe (faith) and
do (morals) to gain eternal life as revealed by God. The life
of faith is a personal sharing by grace of the intimate trinitari-
an life of God here and hereafter. The efficacy of the life of
faith is derived from the passion and death of Jesus Christ,
God’s only begotten Son. These beliefs and morals are trans-
mitted in history through the Bible and through the living
church founded by Christ on Peter and his successors.
Thomas did not divide theology into such modern dis-
ciplines as biblical and scholastic, positive and speculative,
dogmatic and moral, spiritual and mystical, kerygmatic and
academic, and so on. In his day, however, each master in sa-
cred theology lectured on the Bible, presided over scholastic
disputations on specific points, and also preached regularly
to the university community. Thomas wrote his Summa
theologiae not as a replacement for the Bible but as an extra-
curricular aid for beginners who needed an overview of “sa-
cred doctrine.” Although the Summa is divided into three
parts, its conceptual unity is the Dionysian circle of the exitus
(“going forth”) of all things from God and the reditus
(“return”) of all things to God. The First Part considers God
and the coming forth of all things from God. The Second
and Third parts consider the final goal of human life and the
actual return of all things to God. The two parts of the Sec-
ond Part consider the intrinsic means such as virtues, law,
and grace, while the Third Part considers Christ and his sac-
raments as indispensable extrinsic means to salvation. With-
out doubt Thomas’s most original contribution to theology
was the large Second Part, on the virtues and vices, inserted
between the original exitus and reditus found in all contem-
porary summae of theology. The “Supplement” to the
Summa fills out what Thomas left unfinished when he
ceased writing on December 6, 1273. It was compiled with
scissors and paste by Reginald and other secretaries from
Thomas’s earlier commentary on Peter Lombard’s Sentences
(4.17–46). Certainly if Thomas had lived to finish the
Summa, many more developed views would have been writ-
ten than are now expressed there.
Because theology concerns mysteries revealed by God,
it can in no way “prove” or “understand” these or any other
mysteries. But it can clarify the terms used, determine what
cannot be said, and defend the truth of revealed mysteries
against attacks from nonbelievers. Of all the revealed myster-
ies, Thomas considered two as absolutely basic to the Chris-
tian religion: the trinity of persons in one God and the incar-
nation of the Son of God as true man born of Mary.
For Thomas the supernatural gifts of sanctifying grace
and the virtues (faith, hope, love, and the moral virtues) are
normally conferred through baptism by water in the name
of Jesus or the Trinity of Father, Son, and Holy Spirit. But
in an adult the beginnings of this supernatural life are stirred
up by God before actual baptism by water. The supernatural
life of grace (gratia) experienced in this life is, for Thomas,
already a foretaste of eternal life (gloria) in heaven. The over-
flow of grace is expressed in good works and in the exercise
of all the virtues.
Faith, hope, and love are called “theological” virtues, be-
cause they alone have God as their direct object. In the life
to come, faith will give way to sight and hope will give way
to the possession of God. Love, alone, which Thomas defines
as friendship with God, will continue essentially unaltered
in heaven in the degree of intensity achieved in this life. This
divine friendship, which is none other than the indwelling
of the Trinity, is initiated by baptism, nourished by the Eu-
charist, and increased by prayer and service to one’s neigh-
bor. For Thomas, one’s place in heaven, or the intensity of
beatitude, is determined by the capacity for love developed
in this life.
The sources of Thomas’s theology are the Vulgate Bible,
the life and practice of the church, and the writings of all the
available Latin and Greek fathers in Latin translation. TheTHOMAS AQUINAS 9163