The extensive second part of the Summa theologiae was
entirely written at Paris during the intense years 1269 to
- This part, later subdivided into two parts, discusses the
ultimate goal of human life, namely, eternal life (2.1.1–5)
and the means of attaining it, namely, human acts, reason
(law), grace, and all the virtues considered in general (2.1)
and in particular (2.2) as practiced in various states of life.
The third part, begun at Paris, considers the incarnation and
life of Christ (3.1–59) and the sacraments, and was left in-
complete on the subject of penance when Thomas died.
Shortly after Easter 1272, Thomas left Paris with Friar
Reginald for the chapter at Florence, which commissioned
him to establish a theological studium anywhere he liked in
the Roman province. He chose his home priory of Naples,
where he subsequently taught, wrote, and preached. After
five years of intense activity, however, Thomas had a trau-
matic experience while celebrating mass in the Chapel of
Saint Nicholas on December 6, 1273. Although medieval bi-
ographers were uncertain about the nature of this experience,
it seems that Thomas suffered a breakdown of some sort. In
any case, his productive life had come to an end, and al-
though he did remain physically mobile, he lived as if in a
stupor.
Pope Gregory X personally requested that Thomas at-
tend the Second Council of Lyons due to open on May 1,
- He also asked him to bring a copy of his treatise
Against the Errors of the Greeks, composed for Urban IV.
Leaving Naples with Reginald and others early in February,
Thomas had a serious accident near Maenza in which he hit
his head against an overhanging branch and was knocked
down. Growing weaker, Thomas asked to stop at the castle
of Maenza, home of his niece Francesca, the wife of Annibal-
do, count of Ceccano. Lent had already begun on February
14, and Thomas’s condition became so serious that he asked
to be transported to the nearby Cistercian monastery of Fos-
sanova, where the old abbot Theobald was a member of the
Ceccano family. There he received the last rites and died
early Wednesday morning March 7, 1274. Thomas’s re-
mains stayed at Fossanova until they were transferred by
order of Urban V to the Dominican priory in Toulouse on
Saturday, January 28, 1369, where they are today. Since the
anniversary of Thomas’s death always falls in Lent, the Latin
church celebrates his feast on January 28.
Thomas had no immediate successors capable of grasp-
ing his originality and profundity, although he had many ad-
mirers. His labors in Paris were effectively dissipated by the
condemnation of 219 various propositions at Paris on March
7, 1277, and of 30 different propositions at Oxford on
March 18 that same year. Sixteen propositions of the Paris
list reflected the thought of Thomas; three of the Oxford list
directly concerned unicity of substantial form in material
composites, a pivotal Thomistic thesis. It was not until
Thomas’s canonization on July 18, 1323, that a new genera-
tion of largely self-taught Thomists could begin to teach and
develop his teachings freely.
THOUGHT. Thomas Aquinas was first and foremost a theolo-
gian whose teachings have been officially endorsed by the
Roman Catholic church. Since 1567 Thomas has been con-
sidered one of the doctors of the church and has been num-
bered among the great teachers of antiquity such as Augus-
tine, Jerome, Ambrose, and Gregory I. Moreover, the Latin
church has regarded Thomas as the model for all theologians,
requiring that his philosophy and his theology be taught in
all seminaries and Catholic colleges.
Philosophy. While giving primacy of place and impor-
tance to what God has revealed through the Jewish people
and through Jesus Christ, Thomas recognized the much larg-
er, though less important, realm of knowledge available to
unaided human reason. Unlike many of his contemporaries
who merged reason into faith, Thomas emphasized the dis-
tinctness and importance of Aristotelian philosophy and the
sciences, even for theology. His own strictly philosophical
thought is found in his numerous commentaries on Aristotle
and in independent treatises. In the manner of his contem-
poraries in the universities, he adapted his own understand-
ing of Aristotelian ideas, terminology, and methodology to
the study of “sacred doctrine,” especially in his Summa
theologiae.
Thomistic “philosophy” is basically Aristotelian, empir-
ical, and realist, or what G. K. Chesterton called “organized
common sense.” Thomas preferred an order of study that
presupposed the liberal arts and mathematics and began with
Aristotelian logic, principally On Interpretation and the Pos-
terior Analytics; moved through natural philosophy, involv-
ing all the natural sciences, including psychology; treated
moral philosophy, including political science; and concluded
with metaphysics, or first philosophy, which today would in-
clude epistemology and natural theology.
In logic the Aristotelian categories, syllogisms, and rules
of correct reasoning for “demonstration” as distinct from
“dialectics” and “sophisms” are considered essential for an
accurate understanding of all other disciplines. Of special im-
portance are the meaning of “scientific” knowledge based on
“first principles” and the two ways in which both are ac-
quired: experience (via inventionis) or education (via disci-
plinae).
In natural philosophy the existence of a physical world
and its substantial mutability are taken as self-evident in
order to establish the first principles of change: matter (po-
tentiality), form (actuality), and privation (immediate possi-
bility). Natural science is about natural things (not artificial
or incidental), things that have within themselves “nature”
either as an actual principle (form as a dynamic source of ac-
tivity) or as a passive principle (matter as receptive of outside
forces). The aim of natural science is to understand all natu-
ral things through their material, efficient, formal, and final
causes. In so doing the naturalist discovers an ultimate, intel-
ligent, efficient, and final cause that is not physical (i.e., not
material and not mutable) and is the “first cause” and “agent”
of all that is natural. The noblest part of this science is the9162 THOMAS AQUINAS