Saint Thomas Aquinas

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Aquinas, Saint Thomas, sometimes called the Angelic Doctor and the Prince of Scholastics (1225-74), Italian philosopher and theologian, whose works have made him the most important figure in Scholastic philosophy and one of the leading Roman Catholic theologians. Aquinas was born of a noble family in Roccasecca, near Aquino, and was educated at the Benedictine monastery of Monte Cassino and at the University of Naples. He joined the Dominican order while still an undergraduate in 1243, the year of his father's death. His mother, opposed to Thomas's affiliation with a mendicant order, confined him to the family castle for more than a year in a vain attempt to make him abandon his chosen course. She released him in 1245, and Aquinas then journeyed to Paris to continue his studies. He studied under the German Scholastic philosopher Albertus Magnus, following him to Cologne in 1248. Because Aquinas was heavyset and taciturn, his fellow novices called him Dumb Ox, but Albertus Magnus is said to have predicted that “this ox will one day fill the world with his bellowing.”

Early Years

Aquinas was ordained a priest about 1250, and he began to teach at the University of Paris in 1252. His first writings, primarily summaries and amplifications of his lectures, appeared two years later. His first major work was Scripta Super Libros Sententiarum (Writings on the Books of the Sentences, 1256?), which consisted of commentaries on an influential work concerning the sacraments of the church, known as the Sententiarum Libri Quatuor (Four Books of Sentences), by the Italian theologian Peter Lombard. In 1256 Aquinas was awarded a doctorate in theology and appointed professor of philosophy at the University of Paris. Pope Alexander IV (reigned 1254-61) summoned him to Rome in 1259, where he acted as adviser and lecturer to the papal court. Returning to Paris in 1268, Aquinas immediately became involved in a controversy with the French philosopher Siger de Brabant and other followers of the Islamic philosopher Averroës.

Study of Aristotle and the Averroists

To understand the crucial importance of this controversy for Western thought, it is necessary to consider the context in which it occurred. Before the time of Aquinas, Western thought had been dominated by the philosophy of St. Augustine, the Western church's great Father and Doctor of the 4th and 5th centuries, who taught that in the search for truth people must depend upon sense experience. Early in the 13th century the major works of Aristotle were made available in a Latin translation, accompanied by the commentaries of Averroës and other Islamic scholars. The vigor, clarity, and authority of Aristotle's teachings restored confidence in empirical knowledge and gave rise to a school of philosophers known as Averroists. Under the leadership of Siger de Brabant, the Averroists asserted that philosophy was independent of revelation. Averroism threatened the integrity and supremacy of Roman Catholic doctrine and filled orthodox thinkers with alarm. To ignore Aristotle, as interpreted by the Averroists, was impossible; to condemn his teachings was ineffectual. He had to be reckoned with. Albertus Magnus and other scholars had attempted to deal with Averroism, but with little success. Aquinas succeeded brilliantly.

Reconciling the Augustinian emphasis upon the human spiritual principle with the Averroist claim of autonomy for knowledge derived from the senses, Aquinas insisted that the truths of faith and those of sense experience, as presented by Aristotle, are fully compatible and complementary. Some truths, such as that of the mystery of the incarnation, can be known only through revelation, and others, such as that of the composition of material things, only through experience; still others, such as that of the existence of God, are known through both equally. All knowledge, Aquinas held, originates in sensation, but sense data can be made intelligible only by the action of the intellect, which elevates thought toward the apprehension of such immaterial realities as the human soul, the angels, and God. To reach understanding of the highest truths, those with which religion is concerned, the aid of revelation is needed. Aquinas's moderate realism placed the universals firmly in the mind, in opposition to extreme realism, which posited their independence of human thought. He admitted a foundation for universals in existing things, however, in opposition to nominalism and conceptualism.

Later Years

Aquinas first suggested his mature position in the treatise De Unitate Intellectus Contra Averroistas (1270; trans. The Trinity and the Unicity of the Intellect, 1946). This work turned the tide against his opponents, who were condemned by the church.

Aquinas left Paris in 1272 and proceeded to Naples, where he organized a new Dominican school. In March 1274, while traveling to the Council of Lyon, to which he had been commissioned by Pope Gregory X, Aquinas fell ill. He died on March 7 at the Cistercian monastery of Fossanova. Aquinas was canonized by Pope John XXII in 1323 and proclaimed a Doctor of the Church by Pope Pius V in 1567.


More successfully than any other theologian or philosopher, Aquinas organized the knowledge of his time in the service of his faith. In his effort to reconcile faith with intellect, he created a philosophical synthesis of the works and teachings of Aristotle and other classic sages; of Augustine and other church fathers; of Averroës, Avicenna, and other Islamic scholars; of Jewish thinkers such as Maimonides and Solomon ben Yehuda ibn Gabirol; and of his predecessors in the Scholastic tradition. This synthesis he brought into line with the Bible and Roman Catholic doctrine.

Aquinas's accomplishment was immense; his work marks one of the few great culminations in the history of philosophy. After Aquinas, Western philosophers could choose only between humbly following him and striking off in some altogether different direction. In the centuries immediately following his death, the dominant tendency, even among Roman Catholic thinkers, was to adopt the second alternative. Interest in Thomist philosophy began to revive, however, toward the end of the 19th century. In the encyclical Aeterni Patris (Of the Eternal Father, 1879), Pope Leo XIII recommended that St. Thomas's philosophy be made the basis of instruction in all Roman Catholic schools. Pope Pius XII, in the encyclical Humani Generis (Of the Human Race, 1950), affirmed that the Thomist philosophy is the surest guide to Roman Catholic doctrine and discouraged all departures from it. Thomism remains a leading school of contemporary thought. Among the thinkers, Roman Catholic and non-Roman Catholic alike, who have operated within the Thomist framework have been the French philosophers Jacques Maritain and Étienne Gilson.

St. Thomas was an extremely prolific author, and about 80 works are ascribed to him. The two most important are Summa Contra Gentiles (1261-64; trans. On the Truth of the Catholic Faith, 1956), a closely reasoned treatise intended to persuade intellectual Muslims of the truth of Christianity; and Summa Theologica (Summary Treatise of Theology, 1265-73), in three parts (on God, the moral life of man, and Christ), of which the last was left unfinished. Summa Theologica has been republished frequently in Latin and vernacular editions.

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