The Italian philosopher and theologian St. Thomas Aquinas (ca. 1224-1274) was one of the foremost minds of medieval scholasticism. He is recognized as the leading theological authority within the Roman Catholic Church.

The central question facing Christian thinkers in the 13th century was the attitude to be taken toward Aristotle and the use to be made of his thought by theologians committed to a Christian view of the nature of God, man, and the universe. By the middle of the century the writings of Aristotle, for the most part unknown in the Latin West until the end of the 12th century, were readily available in Latin translation and were being taught in the arts faculties at universities in England, France, and Italy. In combination with the writings of Averroës, which were used to interpret Aristotle, this new intellectual material provided the early 13th century with the developed, integrated philosophical system for which they had been searching. On the other hand, because of the completeness and self-sufficiency of the Aristotelian system, Christian theology seemed less necessary as an avenue to truth, which because of Aristotle, was now accessible to man by natural reason, without revelation.

For those who were unwilling to relinquish the primacy of Christian revelation and who felt that Aristotle had not made the latter obsolete, there were still particular aspects of the Aristotelian system as they knew it that directly conflicted with Christian truth. For example, the Aristotelian notion of God as a distant and unapproachable prime mover, the idea of the eternity of the world, the notion of necessity and determinism, the idea that there was one intellect shared by men into which souls were absorbed after death, thus denying personal immortality, and the idea that all love is based ultimately on self-interest caused problems for Christian doctrine, which affirmed a personal, transcendent God who created the world freely and in time, who was concerned about particular individuals, and who would ultimately reward with eternal life the person who loved God rather than self.

In the 13th century men believed that all truth was one and that there could be no serious conflict between philosophy and theology or between Aristotle and Christianity. Since for them Christianity could not be wrong and since Aristotle was an established, ancient authority, the natural tendency was to bring Aristotle and Christianity into agreement. It was part of the achievement of St. Thomas Aquinas that he created a theological and philosophical system that remained basically Christian while incorporating significant elements from the Aristotelian world view. Many historians have viewed this system, sometimes referred to as the Thomist synthesis (a synthesis of theology and philosophy, of faith and reason, as well as Aristotelianism and Christianity), as the most important achievement in medieval thought and an archetype of philosophical and theological thinking for the modern period.

Thomas was not alone in this endeavor, nor did his version go unquestioned. He was criticized in his lifetime by such important theologians as Bonaventure, and some of Thomas's solutions were condemned along with a variety of others at Paris in 1277. His reputation, however, remained of major import from the 13th century on, and through the respect accorded him at the Council of Trent in the 16th century and the emergence of a neo-Thomist movement among Catholic philosophers he has had a significant impact on modern thought.

Early Life and Education, 1224-1252

Thomas was born into the Italian lower nobility, the youngest son of Landolfo of Aquino, Lord of Roccasecca and Montesangiovanni and justiciary of Frederick II, Emperor of Germany and King of Naples. Thomas's father lived to see most of his sons, including Thomas, abandon the causes to which he had devoted his life, shifting their allegiance from the Hohenstaufen emperor to the papacy and from the older monastic institutions to the newer mendicant orders.

At the age of 5 or 6, Thomas was placed in the care of the monks of the Benedictine abbey of Monte Cassino with the intention that he should become a monk and, eventually, abbot of this, one of the most prestigious monastic communities in Europe. After 8 years of instruction he was forced by political circumstances to leave Monte Cassino with the other oblates and to complete his education in Naples at a Benedictine house connected with the university there.

Thomas remained in Naples 5 years. During this time he came in contact with several influences that changed the course of his life. First, he was attracted to the opportunities for intellectual growth and service offered by the universities. In particular, he came into contact with Greek and Arabic learning, especially the thought of Aristotle and Averroës, which had been recently translated. Second, he was attracted to the newer mendicant orders, which espoused an apostolic life of service in the world (rather than the cloistered meditation typical of Monte Cassino) and which played an active role in the intellectual life of the university.

By 1243 Thomas had made a momentous decision: turning his back on his family and the plans that had been made for his career, he joined the Dominicans and received the habit in 1244. Foreseeing that his family would oppose his decision and try to intervene, Thomas allowed himself to be taken immediately out of their reach, initially to Rome and then on to Bologna. Before reaching Bologna he was captured by his older brother and returned home. After a year during which Thomas would not change his mind, he returned to the Dominicans at Naples, from where he journeyed northward to begin his theological education.

From 1245 until 1252 Thomas studied at the Dominican houses at Paris and Cologne under the leading Dominican theologian on the Continent in that period, Albertus Magnus. When Albertus organized the house of studies at Cologne in 1248, Thomas accompanied him as his student and assistant, lecturing on sections of the Scriptures and being ordained to the priesthood. In 1252 Albert recommended Thomas to be one of the two Dominican lecturers on the Sentences of Peter Lombard at Paris and thus to become a candidate for the degree of master of theology, in spite of the fact that Thomas was 3 or 4 years too young for that stage in his career.

Teaching Career in Paris, 1252-1259

Thomas remained in Paris for 7 years, living at the Dominican house of studies and lecturing, debating, and writing. His first important work was his commentary on the Sentences, polished during 1254-1256, which for over 200 years remained one of the major sources for the thought of Thomas. After his 4 years of study Thomas was granted the license to teach, and for 3 additional years he was one of the two regent masters of theology for the Dominicans at Paris. During this period he wrote several important philosophical treatises, the most remarkable being De ente et essentia and De veritate, which revealed even at this early stage his Aristotelian approach to philosophical questions.

Thomas faced strong opposition from the secular masters at Paris. In the mid-13th century in Paris animosity toward the mendicants had been growing among the secular masters of theology and arts, an animosity that was founded on the belief that some mendicants were theologically unorthodox, that in any case they had no right to belong to the university, and that, as semimonastic persons, they should not be copying the functions of secular priests. This animosity toward both Dominicans and Franciscans delayed Thomas's recognition by his colleagues, and the debate over the place of the mendicants within the structure of the university occupied much of Thomas's time.

Teaching Career in Italy, 1259-1268

Upon his return to Italy, probably at the request of the general chapter, or governing body, of the Dominicans, Thomas lectured at the Dominican convents in central Italy that were connected with the residence of the papal court: Anagni, Orvieto, Rome, and Viterbo. Here he came in contact with the improved translations of Aristotle directly from the Greek that were being compiled by a Dominican, William of Moerbeke. On the basis of this new source material and his growing desire to provide an acceptable interpretation of Aristotle's thought, Thomas began a series of commentaries on the works of Aristotle that rank among the most significant ever written.

A similar product of Thomas's ability as an expositor and commentator that dates from this period is the Catena aurea, or Golden Chain, a commentary on the four Gospels. Unlike his commentaries on Aristotle, however, this work is not Thomas's own interpretation but gathers passages from other writers to enlighten the meaning of Scripture.

Italy provided Thomas with the opportunity and incentive to expand the types of philosophical and theological problems with which he dealt in his writings. He wrote De regimine principum, an important political treatise that discussed the principles governing society and the political activity of rulers, basing his work in part on Aristotle's Politics. Moreover, he became more aware of the conflicting issues within Islamic theology--particularly, concerning the problem of expressing the freedom and power of God without, on the one hand, making God's freedom so extensive that it can become arbitrary and irrational in its operation or, on the other hand, limiting God's activity within the bounds of a deterministic system.

In part as a result of this awareness of the importance of the problem of the freedom and power of God and the importance of Islamic theology for the Western theologian, Thomas composed two works: De potentia, which dealt with the question of God's omnipotence and of His creative power; and a theological manual, the Summa contra Gentiles, written to provide the Christian missionary with a clear, precise statement of the Christian faith along with a defense of its basic doctrines. The latter work, probably begun while Thomas was still in Paris, and at the suggestion of the Dominican missionary Raymond of Peñafort, was primarily intended to be of use in attempting to convert the Mohammedans. Similarly, it could be helpful in converting the Jews.

Return to Paris, 1268-1272

Late in 1268 or early in 1269 the Dominican order sent Thomas back to Paris for a second period of teaching. The crisis which he found there and which may have occasioned his being summoned back was quite different from the earlier controversy between the seculars and mendicants, although that animosity was still in evidence. The type of Christian Aristotelianism that Thomas and Albertus Magnus had been intent on creating was being threatened from two sides. On the one hand, the anti-Aristotelian forces within theology had increased and were reaffirming a strong Augustinian approach that rejected Aristotle on a number of points and limited his use as an authority in theological argumentation. On the other hand, there was an attempt to teach an unchristened Aristotelianism in the arts faculty by a group known as the Latin Averroists, led by such figures as Siger of Brabant and Boethius of Dacia.

In this crisis, toward which the intellectual currents of the century had been building, Thomas tried to establish a middle position. He believed that Aristotle could be shown to agree with Christian truth in the majority of instances and therefore could be used as a source in argumentation, although not in theology on the level with Scripture or the Fathers.

One of the most crucial issues was the question of the eternity of the world. Thomas's position, against Bonaventure and others, was that although the world was created in time, as revelation teaches, this doctrine could not be demonstrated by reason alone which, in this matter, can provide no final solution.

This conclusion is typical of the way in which Thomas approached the relation of faith and reason, Aristotle and Christian truth. Faith completes rather than contradicts reason. Although some things can be known only through reason because revelation is not concerned with those things, and although some things can be known through both reason and revelation, such as the existence and unity of God, there are many truths necessary for salvation which are inaccessible to man apart from revelation, such as the doctrine of creation in time or the mystery of the Trinity. Aristotle, because he lived before Christ, could go only so far, and his thought must be completed by Christian revelation.

Thomas therefore accepts the idea of God as prime mover but goes on to identify Aristotle's God with the personal God of revelation, who has knowledge and concern for individuals. Thomas rejected the Averroistic notion of one active intellect for all mankind, and he argued that there was only one substantial form in man, the rational soul, which, with its individual intellect, provides the psychological foundation for personal immortality. Similarly, Thomas accepted the Aristotelian idea that man is naturally a political animal who finds his fulfillment in a quest for happiness within human society. But for Thomas that is only one end of man which, although important, is secondary to the primary end of man, the love of God, an end that is learned only through revelation.

Many of these conclusions are found in Thomas's most important work, the Summa theologiae, or Summa theologica, written in this period, although it was begun earlier in Italy, probably at Rome, and completed by a disciple after Thomas's death. Most of his reputation is based on this work. It is a systematic analysis and defense of the Christian faith, arranged topically, beginning with the nature of God and moving through creation and salvation to the last things and the beatific vision. Within each topic Thomas, in proper scholastic style, presented the most important questions and arranged his argument by initially presenting the pro and con arguments, then his analysis of the issue, and then his rebuttal to the initial objections.

Last Years, 1272-1274

At the request of the general chapter in Florence in June 1272, which he attended, Thomas went to Naples to establish a program of theological studies at the Dominican house, near the university. His writings from this period, although numerous and of high quality in comparison to those of his contemporaries, did not maintain the level of the works written in previous periods in his life. In December 1273, on the feast of St. Nicholas, his writing career came to an end. As an early biographer described it, the change resulted from a vision or mystical experience. When his secretary asked him why he had ceased to write, Thomas answered, "All that I have written seems to me like so much straw compared to what I have seen and what has been revealed to me."

Thomas set out early in 1274 to attend the second Council of Lyons. He soon became ill and broke his journey at the Cistercian monastery of Fossanova, where he died in March.

Further Reading

• The best biography of St. Thomas Aquinas in English is Vernon Joseph Bourke, Aquinas' Search for Wisdom (1965). Other useful biographies are Martin C. D'Arcy, St. Thomas Aquinas (1930; rev. ed. 1953), and Jacques Maritain, St. Thomas Aquinas (trans. 1931; rev. ed. 1958). The best work on the background of Thomas's writings is Marie Dominique Chenu, Towards Understanding Saint Thomas (1950; trans. 1964).
• For a survey of Thomas's thought the following works are all of high quality, although each takes a somewhat different approach: Réginald Garrigou-Lagrange, Reality: A Synthesis of Thomistic Thought (trans. 1950); Frederick Copleston, Aquinas (1955); and Étienne Henry Gilson, The Christian Philosophy of St. Thomas Aquinas (trans. 1956). Among the works on Thomistic metaphysics, the following are especially helpful: Herman Reith, The Metaphysics of St. Thomas Aquinas (1958); George Peter Klubertanz, St. Thomas Aquinas on Analogy: A Textual Analysis and Systematic Synthesis (1960); and Joseph Owens, An Elementary Christian Metaphysics (1963). One of the few works in English treating the political views of Thomas is Thomas Gilby, The Political Thought of Thomas Aquinas (1958). Jacques Maritain, Art and Scholasticism, with Other Essays (trans. 1930), is a recommended study of Thomas's esthetic theory.