The Teacher and His Time
Thomas Aquinas was born around 1225 into a noble family in southern Italy. Against his family’s wishes, he joined the Dominican order, a new preaching order devoted to study and teaching. He studied at Naples, Paris and Cologne, where he learned from the scholar Albert the Great, and he later taught at the University of Paris and in Italy. He died in 1274 while traveling to a church council, and he was declared a saint in 1323.
He was a very productive writer, though he dictated and wrote at great speed and left much unfinished. Besides his large theological syntheses, he wrote commentaries on scripture, commentaries on Aristotle, and short works on specific questions.
His Main Works
- Commentary on the Sentences: an early work from his student years, following the standard textbook by Peter Lombard.
- Summa contra Gentiles: a work arranged to explain Christian belief to readers who might not share it, using reasoned arguments where possible.
- Disputed Questions: records of formal debates he led at the university, each on a single topic such as truth or the power of God.
- Commentaries on Aristotle: careful, line-by-line studies of works such as the Ethics and the Physics.
- Summa Theologiae: his best-known and most influential work, started in the mid-1260s and left incomplete.
Reading Aristotle
Aquinas lived at a moment when Aristotle’s writings on nature, ethics and the soul had recently become available in Latin. Some church authorities were uneasy about them, and teachers disagreed over how to handle the new learning. Aquinas worked with improved translations, including those made by a fellow Dominican from Greek, and he wrote commentaries to explain what Aristotle meant before deciding what to accept.
He did not simply adopt Aristotle wholesale. Where the philosopher’s ideas clashed with Christian teaching, such as the question of whether the world had a beginning, Aquinas argued that reason alone could not settle the matter and that faith supplied what philosophy could not. He also drew on Augustine and other Christian sources, and was aware of Islamic and Jewish writers like Ibn Sina and Moses Maimonides, whom he cited on some topics.
His approach rested on a few steady convictions. Human reason is a real and good capacity. Grace does not destroy nature but completes it. And truths known by reason and truths known by revelation cannot finally contradict one another. Some of his teachings drew criticism, and the 1277 condemnations in Paris touched ideas close to his, though historians debate how directly. He gained wide authority only gradually after his death.
The Summa Theologiae
The Summa Theologiae was meant as a textbook for students of theology, a reliable outline, not a quick summary. It is divided into three parts, with the second part split into two.
- First Part: God and the divine nature, the Trinity, creation, angels and human nature.
- First Part of the Second Part: the human goal of happiness, human action, passions, habits, law and grace.
- Second Part of the Second Part: the virtues in detail, including faith, hope, charity and the cardinal virtues.
- Third Part: Christ and the sacraments. Aquinas stopped writing in late 1273, and this part breaks off before the sacraments are fully covered. A supplement was later added by others, drawn from his earlier writings.
Each section is divided into questions and articles that follow the pattern of objection, reply and answer used throughout the scholastic method, which makes it look repetitive but easy to navigate.
Famous Arguments
The Summa’s First Part includes the “five ways,” short arguments from features of the world, such as motion and order, toward the existence of God. They are brief outlines, not full treatises, and philosophers still discuss how they should be read. He also wrote at length about natural law, the idea that humans can grasp basic moral principles by reason, and about how divine providence relates to human freedom.
His treatment of the virtues proved influential too. By fitting Aristotle’s account of moral habits together with Christian theology, he gave later preachers and teachers a framework that they used in many forms.
Legacy
Over the following centuries, his writings became a standard reference, especially in the Dominican order. A Thomist tradition grew up, with rivals such as the followers of Duns Scotus disagreeing on points like the will and individuality. In 1879 the Catholic Church gave his thought special prominence, and he remains widely studied by both believers and historians of philosophy.
For a reader new to him, the best starting point is a short selection from the Summa, read slowly. Its patient style rewards that kind of attention.