Thomas Aquinas

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THOMAS AQUINAS (Tommaso d'Aquino, 12251274), Italian Dominican theologian, doctor of the church, patron of Roman Catholic schools, and Christian saint. One of the most important and influential scholastic theologians, Thomas is seen by the Roman Catholic church as uniquely "her very own" (Pius XI). He has been honored with the scholastic titles Doctor Communis (thirteenth century) and Doctor Angelicus (fifteenth century), among others.

Life and Works

The youngest son of Landolfo d'Aquino, lord of Roccasecca and Montesangiovanni and justiciary of Emperor Frederick II, and his second wife, Teodora of Chieti, Thomas had five sisters, three older brothers, and at least three half brothers. The family castle of Roccasecca, where Thomas was born, midway between Rome and Naples, was on a mountain in the northwest corner of the kingdom of Sicily. Sicily was ruled by the Hohenstaufen emperor Frederic II (11941250), who was in almost continual warfare with the papal armies of Honorius III (12161227), Gregory IX (12271241), and Innocent IV (12431254). Divided political and religious loyalties rendered the position of the d'Aquino family precarious.

Thomas spent his first five years at the family castle under the care of his mother and a nurse. As the youngest son of the family, Thomas was given (oblatus, "offered") to the Benedictine abbey of Monte Cassino by his parents at the age of five or six in the firm hope that he would eventually choose the monastic life and become abbot. His earliest training was in the spiritual life, mainly through the Latin psalter, and in the rudiments of reading, writing, and mathematics. The struggle between the pope and the emperor reached a climax in 1239, when Frederick was excommunicated a second time. The imperial troops occupied the abbey, foreigners were expelled, and the young students were sent to one of the Benedictine houses in Naples to attend the imperial university founded in 1224 as a rival to Bologna. At the university, where Thomas remained until 1244, he studied under Master Martin (grammar and logic) and Peter of Ireland (natural philosophy). It was there that he was introduced to Aristotle's philosophy.

By 1243 Thomas was attracted to the Dominicans living nearby at the priory of San Domenico. This order of mendicant friars, founded by Dominic (11701221) and confirmed by Pope Honorius III in 1216, was devoted to preaching, study, and the common life. Impressed by their apostolic zeal, poverty, and simplicity and free from obligation, Thomas received the habit in April 1244 at the age of nineteen. Under normal circumstances he would have made his novitiate at San Domenico, but because the friars feared that Thomas's family might intervene forcibly to prevent his entrance to the order, he was sent to Rome. At Rome it was decided that he should go to Paris, and so early in May 1244 he left Rome in the company of John of Wildeshausen, third master of the order, and John's companions, who were traveling to Bologna for the general chapter that met annually at Pentecost.

Learning of her son's entry into a begging order, Teodora, now head of the family, hastened to Naples, then to Rome, only to learn that her son had departed for Bologna. She sent orders to her older son Rinaldo, who was with Frederick's army north of Rome, to intercept Thomas and bring him home by force if necessary. Rinaldo and his escort intercepted the travelers near Acquapendente, north of papal territory, and forced Thomas to return on horseback. Stopping for the night at the family castle of Montesangiovanni in papal territory, the soldiers secured the services of a local prostitute to seduce Thomas, but to no avail. The next day the group rode to Roccasecca, where Thomas was restricted to the castle until Frederick II was excommunicated and deposed by the Council of Lyons on July 17, 1245. By then Teodora and her daughters saw that further attempts to change Thomas's resolve were useless and allowed him to rejoin the friars in Naples, from whence he was sent to Paris.

Arriving at the priory of Saint-Jacques by October 1245, Thomas began his studies at the University of Paris under Albertus Magnus, who was then lecturing on the writings of Dionysius the Areopagite. After three years of study in Paris, Thomas and others accompanied Albertus to Cologne, where a new studium generale was to be established, as decreed by the general chapter of Paris in 1248. For the next four years Thomas continued to attend and write down Albert's lectures on Dionysius and his questions on Aristotle's Ethics. As Albert's junior bachelor (12501252), Thomas lectured cursorily on Isaiah, Jeremiah, and Lamentations.

The position of the mendicant friars at the University of Paris came under increasingly severe attack from secular masters, particularly William of Saint-Amour. By 1252 the Dominican master general was eager to send promising young men to the university to prepare for inception as master (full professor). Albert convinced the master general to send Thomas, despite his young age, to study for the university chair for non-Parisians. Thomas began his studies under Elias Brunet de Bergerac in the fall of 1252, lecturing on Peter Lombard's Sentences for four years. His originality and clarity of thought were conspicuous in his teaching and writing, notably in his commentary on the Sentences; On Being and Essence, on the meaning of certain metaphysical terms; and in a short treatise entitled Principles of Nature. In the latter work he unequivocally defended (1) a real distinction between essence and existence (esse ) in all creatures, (2) the pure potentiality of primary matter, (3) absence of matter in spiritual substance (substantia separata ), (4) participation of all created reality, material and immaterial, in God's being (esse ), and (5) the Aristotelian dependence of abstracted universals on individually existing material things.

Under tense circumstances in the spring of 1256, Thomas, though underage, was given license to incept by an order of Pope Alexander IV dated March 3. When finally he was allowed to incept, by an order of the pope dated June 17, he and his audience had to be protected by soldiers of Louis IX because the animosity of the town and some students against the mendicants was so great. William of Saint-Amour's antimendicant book On the Perils of the Last Days, sent to Rome by the king for examination, was condemned by the pope on October 5, and William was permanently exiled from Paris by the king. Thomas's reply to William's charges (Contra impugnantes Dei cultum et religionem ), completed in late September or early October, arrived in Rome after the pope had made his decision and, therefore, did not influence the outcome.

Enjoying a respite from the antimendicant polemic, Thomas lectured from 1256 to 1259 on the Bible, held scholastic disputations (Quaestiones disputatae de veritate ) over three years, preached, and began composing his Summa contra gentiles (12591264), apparently for Dominican missionaries in Spain and North Africa. This systematic summary in four books is an arsenal of sound and persuasive arguments "against the gentiles," that is, nonbelievers and heretics.

Having served the order's interests in Paris, Thomas returned to Italy where he taught, wrote, and preached from 1259 to 1268. After spending two years in his home priory of Naples, he was assigned to teach at Orvieto (12611265), where he lectured to the community on Job and was of great service to Pope Urban IV. At the pope's request, he composed the liturgy for the new Feast of Corpus Christi and expressed his views in Against the Errors of the Greeks on doctrinal points disputed by Greek and Latin Christians. Having thereby discovered the richness of the Greek patristic tradition, he also began compiling a continuous gloss, or exposition, of the Gospels (Catena aurea ), made up almost entirely of excerpts from the writings of the Greek and Latin fathers, dedicating the commentary on Matthew to Urban IV. In June 1265, the provincial chapter of Anagni assigned Thomas to open a school of theology at Santa Sabina in Rome. Soon realizing that Peter Lombard's Sentences, then in common use, was unsatisfactory for young beginners, Thomas projected a three-part survey of Catholic theology (Summa theologiae ) that would be simpler, more orderly, and more inclusive than other works available. The first part was completed and in circulation by 1268. More subtle questions were disputed in the Roman school in a special series on the power of God (De potentia ) and on evil (De malo ). In addition, Thomas lectured on the Bible during this period.

By the end of 1268, Thomas was ordered to return to Paris, as was the Frenchman Peter of Tarentaise (the future Pope Innocent V), to counter a revival of antimendicant sentiment among secular masters. When Thomas and his secretary Reginald of Piperno arrived in Paris early in 1269, Thomas realized that the situation was far more complex and serious than he had assumed. Almost single-handedly he was required to fend off attacks on three fronts: with all mendicants against secular masters opposed to mendicants' being in the university; with a few of his confreres against most of the Dominicans, Franciscans, and secular theologians, opposed to using Aristotle in theology; and with most theologians against young philosophers who tended to promulgate heretical views under the name of Aristotle or his commentator Ibn Rushd (Averroës). Over the next five years Thomas fulfilled his university obligations to lecture on the Bible, to hold disputations, and to preach, while also carrying on a vigorous polemic against the antimendicants, expounding all the major works of Aristotle, writing his Summa theologiae, and replying to numerous requests for his opinions.

Revival of the antimendicant controversy under Gérard d'Abbeville and his colleagues at Paris (encouraged by the exiled William) centered largely on the role of evangelical poverty in the spiritual life and on the practice of admitting young boys into their novitiate. Thomas attacked the views of Gérard in his quodlibetal disputations (12691271), in two polemical treatises on Christian perfection, and in his Summa (2.2.179189). This phase of the controversy ended with the death of its chief protagonists, William of Saint-Amour on September 13, 1272, and Gérard at Paris that same year on November 8.

On December 10, 1270, thirteen philosophical propositions opposed to the Catholic faith were condemned by Étienne Tempier, bishop of Paris. To prevent such views from developing in the classroom, Thomas undertook a detailed literal commentary on all the main texts of Aristotle then in common use at the University of Paris. It is possible that Thomas began his commentary on De anima in Italy, but all the others were written after his return to Paris in 1269, namely, the commentaries on Physics, On Interpretation, Posterior Analytics, Ethics, Metaphysics, Politics, and certain others left unfinished at his death. Because all these works of Aristotle were used as textbooks in the arts faculty and had to be taught by the young masters whose best guide to date had been Ibn Rushd, Thomas therefore felt a particular urgency in writing his own commentaries that remained closer to the original sources and within the context of Christian faith. His unfinished expositions of Aristotle's De caelo, De generatione, and Metheora were among his last writings at Naples.

The extensive second part of the Summa theologiae was entirely written at Paris during the intense years 1269 to 1272. This part, later subdivided into two parts, discusses the ultimate goal of human life, namely, eternal life (2.1.15) 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 (3.159) and the sacraments, and was left incomplete 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 traumatic experience while celebrating mass in the Chapel of Saint Nicholas on December 6, 1273. Although medieval biographers 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 although he did remain physically mobile, he lived as if in a stupor.

Pope Gregory X personally requested that Thomas attend the Second Council of Lyons due to open on May 1, 1274. 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 Annibaldo, 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 Fossanova, 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 remains 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 grasping his originality and profundity, although he had many admirers. 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 generation of largely self-taught Thomists could begin to teach and develop his teachings freely.


Thomas Aquinas was first and foremost a theologian whose teachings have been officially endorsed by the Roman Catholic church. Since 1567 Thomas has been considered one of the doctors of the church and has been numbered among the great teachers of antiquity such as Augustine, 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.


While giving primacy of place and importance to what God has revealed through the Jewish people and through Jesus Christ, Thomas recognized the much larger, though less important, realm of knowledge available to unaided human reason. Unlike many of his contemporaries who merged reason into faith, Thomas emphasized the distinctness 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 contemporaries in the universities, he adapted his own understanding of Aristotelian ideas, terminology, and methodology to the study of "sacred doctrine," especially in his Summa theologiae.

Thomistic "philosophy" is basically Aristotelian, empirical, 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 Posterior Analytics ; moved through natural philosophy, involving all the natural sciences, including psychology; treated moral philosophy, including political science; and concluded with metaphysics, or first philosophy, which today would include 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 importance are the meaning of "scientific" knowledge based on "first principles" and the two ways in which both are acquired: experience (via inventionis ) or education (via disciplinae ).

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 (potentiality), form (actuality), and privation (immediate possibility). 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 activity) or as a passive principle (matter as receptive of outside forces). The aim of natural science is to understand all natural things through their material, efficient, formal, and final causes. In so doing the naturalist discovers an ultimate, intelligent, 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 the 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 immortal.

Moral philosophy for Aristotle and Thomas presupposes 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 knowable by human reason but open to rejection by the individual. 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 theology), 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 existence 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 (epistemology), natural religion, and public worship.


Thomistic "theology," which Thomas calls sacred doctrine, is distinct from pure philosophy and depends on the divine gift of faith, which involves the whole realm of revelation, divine law, ecclesial worship, the spiritual 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. 11:56). 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 trinitarian 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 transmitted 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 disciplines 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 sacred 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 extracurricular aid for beginners who needed an overview of "sacred 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 Second Part consider the intrinsic means such as virtues, law, and grace, while the Third Part considers Christ and his sacraments as indispensable extrinsic means to salvation. Without 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 contemporary 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 (4.1746). Certainly if Thomas had lived to finish the Summa, many more developed views would have been written 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 mysteries, Thomas considered two as absolutely basic to the Christian religion: the trinity of persons in one God and the incarnation 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 overflow of grace is expressed in good works and in the exercise of all the virtues.

Faith, hope, and love are called "theological" virtues, because 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 Eucharist, and increased by prayer and service to one's neighbor. 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. The terminology, however, is always traditional, largely philosophical, and often Aristotelian. For this reason it is important to understand such technical terms as matter and form, substance and accidents, essence and existence, nature and operations, and soul and faculties, as well as the four Aristotelian causes, if one is to grasp the meaning of Thomas's exceptionally lucid and simple Latin.


Apart from the admiration, love, and respect accorded him by scholars and theologians, Thomas exerted little influence by the time he died in 1274. At Paris his literary and personal efforts could neither stem the tide of heterodoxy among teachers of philosophy nor abate the growing fears of Augustinian theologians against the use of Aristotle or any pagan philosopher in the schools of theology.

From 1278 onward, however, the general chapters of the Dominican order showed an increasing concern that the writings of Thomas be at least respected within the order. By 1309 the chapter required all Dominican lectors to lecture from the works of Thomas, to solve problems according to his doctrine, and to instruct their students in the same. Even before his canonization, Dominicans were obliged to teach according to Thomas's doctrine and the common teaching of the church. In 1279 the Parisian Franciscan William de la Mare compiled a "correctory" (Correctorium ) of Thomas's writings, indicating therein where Thomas differed from Bonaventure and Augustine. In May 1282 this correctory was made mandatory for all Franciscan teachers, but by 1284 there were five defensive replies by young Dominican teachers, three of whom were Oxonians influenced by the brilliant Thomas Sutton, a self-taught Dominican Thomist. The canonization of Thomas on July 18, 1323, and the lifting in 1325 of the Parisian condemnation insofar as it touched or seemed to touch Thomas removed the foremost barriers to the teaching of his ideas universally. But it was not until the sixteenth century that Thomists began to develop his seminal principles in a notable way. An exception was the French Dominican John Capreolus (13801444), "the Prince of Thomists," who in his Defensiones on the Sentences incisively expounded and defended Thomas's views against Henry of Ghent, Duns Scotus, John of Ripa, William of Ockham, and others.

In the sixteenth century four influential teachers substituted Thomas's Summa for the standard Sentences of Peter Lombard: Peter Crokaert in Paris (in 1509); Thomas de Vio Cajetan at Pavia (in 1497), author of an important commentary on the Summa, (15071522); Konrad Koellin at Heidelberg (15001511), author of a commentary on the first two parts of the Summa (1512); and Francisco de Vitoria at Salamanca (in 1526) and his many disciples throughout Spain. These Thomists were concerned not so much with defending Thomism as with replying to issues raised by the reformers, resolving new problems of an expanding civilization, and applying Thomas's principles to developments in international law and the treatment of Indians in the New World. By the time of the Council of Trent (15451563), most of the outstanding Roman Catholic theologians were Thomists. The influence of Thomas is clear throughout the council's decrees, notably on justification, the sacraments, and the mass. The influential Roman Catechism, published by order of Pius V in 1566, was the work of three Dominican Thomists. Pius V declared Thomas a doctor of the church (1567) and ordered that the first Opera omnia (the "Piana") be published with the remarkable index (Tabula aurea ) of Peter of Bergamo at Rome (18 vols., 15701571). Since the Piana edition, there have been ten editions of complete works apart from the current critical edition ordered by Pope Leo XIII in 1879 (the "Leonine").

After the Reformation and throughout the scientific and industrial revolutions, there was little interest in Thomistic philosophy or theology outside the decimated Dominican order and scattered groups in Catholic countries. However, a Thomistic revival in Italy and Spain slowly grew and reached its culmination in the encyclical Aeterni Patris of Leo XIII (August 4, 1879), urging the study of Thomas's works by all students of theology, and in subsequent legislation by Leo and his successors. This revival focused on Thomistic philosophy as a system capable of countering the effects of positivism, materialism, and secularism on Catholic beliefs and practices. This polemical intention was modified by the attitude of dialogue with the modern world that characterized the approach of the Second Vatican Council (19621965). In this spirit Paul VI, in his encyclical on the seventh centenary of Thomas's death (1974), proposed Thomas as a model to theologians, not only with respect to his teachings but with respect to his example of openness to the world and to truth from whatever the source. As a result, there has been increased study and critical reappraisal of Thomas's thought, principles, and methodology. Although Thomism in the restricted sense of a closed system seems no longer tenable, philosophers and theologians of all traditions continue to have recourse to Thomas's thought as a milestone in human thought and to develop his seminal insights in dialogue with modern thought and issues.

See Also

Trent, Council of.


Works by Thomas Aquinas

Of the ninety or more authentic works of Thomas there have been numerous editions of individual works from 1461 to the present day, over 180 incunabula editions alone. Since the Roman edition of Pius V, Opera omnia (15701571), there have been more than ten editions or reprints of older standbys, but the only modern critical edition of the Opera omnia is the Leonine, 48 vols. to date (Vatican City, 1882). Both English translations of the Summa theologiae (22 vols., London, 19161938; bilingual edition, 60 vols., New York, 19641976) are far from satisfactory, except for some volumes. Besides the older translation of the Summa contra gentiles by the English Dominicans, there is a good edited translation by Anton C. Pegis, On the Truth of the Catholic Faith, 4 vols. in 5 (New York, 19551957). The most convenient anthologies are Basic Writings, 2 vols., edited by Anton C. Pegis (New York, 1945); Philosophical Texts, edited and translated by Thomas Gilby (1951; reprint, Durham, N.C., 1982); and Theological Texts, edited and translated by Thomas Gilby (1955; reprint, Durham, N.C., 1982). The best single volume sampling of his writings in philosophy with good introductions by Vernon J. Bourke is The Pocket Aquinas (New York, 1960).

Works on His Life and Writings

The most complete single volume on Thomas and his writings is my own Friar Thomas d'Aquino: His Life, Thought, and Works (1974; reprinted with corrigenda and addenda, Washington, D.C., 1983) with an annotated catalog of authentic writings. Some of the more important biographical documents have been translated and edited by Kenelm Foster in The Life of Saint Thomas Aquinas (Baltimore, 1959). All modern studies of the writings must start with the pioneer work of Pierre Mandonnet, Des écrits authentiques de Saint Thomas d'Aquin (Fribourg, 1910), Martin Grabmann, Die Werke, 3d ed. (Münster, 1949), and some others.

General Works on His Life and Thought

Bourke, Vernon J. Aquinas' Search for Wisdom. Milwaukee, 1965. Excellent alternating biographical and doctrinal chapters that should be read carefully to savor the wisdom of Thomas.

Chenu, M.-D. Toward Understanding Saint Thomas Aquinas. Chicago, 1964. Indispensable for understanding the medieval context and genre of Thomas's writings.

Chesterton, G. K. Saint Thomas Aquinas. London, 1933. A superb appreciation of "the dumb ox" that Gilson and Pegis would have liked to have written, by a natural Thomist.

Copleston, Frederick C. Aquinas. Baltimore, 1967. Most appreciated by historians of philosophy.

Gilson, Étienne. The Christian Philosophy of Saint Thomas Aquinas. Translated from the fifth edition with a catalog of authentic works by I. T. Eschmann. New York, 1956. Gilson's chef d'œuvre, frequently revised over forty years of a distinguished career with all his pet views.

Maritain, Jacques. Saint Thomas, Angel of the Schools. London, 1946. Reflections on the life and significance of Thomas by a distinguished modern Thomist.

McInerny, Ralph. Saint Thomas Aquinas (1977). Reprint, Notre Dame, 1982. The best short introduction to Thomas and his chief sources: Aristotle, Boethius, and Augustine.

Pegis, Anton C. Introduction to Saint Thomas Aquinas. New York, 1948. A handy volume with selections from both summas illustrating principal themes of Thomas's thought.

Pieper, Josef. Guide to Thomas Aquinas. New York, 1962. A thoughtful invitation to explore the world of Thomas for reflective students.

Sertillanges, A. G. Saint Thomas Aquinas and His Work (1933). Reprint, London, 1957. An exciting period piece by a university chaplain in Paris after World War I.

Walz, Angelus M. Saint Thomas Aquinas: A Biographical Study. Westminster, Md., 1951. A much-consulted historian's view of Thomas's life and works; see the improved French adaptation by Paul Novarino.

James A. Weisheipl (1987)

Aquinas, Saint Thomas

views updated May 14 2018

Aquinas, Saint Thomas

(b. Roccasecca, near Monte Cassino, Italy, ca. 1225; d. Fossanuova, near Maenza, Italy, 7 March 1274)

not a scientist in the modern sense, but a philosopher and theologian whose synthesis of Christian revelation with Aristotelian science has influenced all areas of knowledge—including modern science, especially in its early development.

Thomas, the youngest of nine children, was born in the castle of the Aquino family. His father, Landolfo, and his older brothers served the Holy Roman Emperor; Frederick II, then warring against the papacy; his mother, Teodora of Chieti, was a Lombard. The family’s political situation was precarious, and in 1231 Thomas was placed in the abbey of Monte Cassino for his elementary education. When the abbey was occupied by Frederick’s troops in 1239, Thomas was sent to finish his studies at the recently founded University of Naples; his teachers there were Master Martin in grammar and logic and Peter of Ireland in natural science.

Thomas entered the Dominican order at Naples in 1244, against his family’s wishes, and was sent to Paris, and then to Cologne, for further studies (1245–1252). The Dominicans at the time were in the forefront of intellectual life; in natural science, groups of friars were synthesizing the heritage of Greece and Rome, which soon appeared in the encyclopedias of Thomas of Cantimpré and Vincent of Beauvais. Albertus Magnus, earlier recruited into the order by Jordan of Saxony, was himself paraphrasing in Latin all of the works of Aristotle that had just been brought to the West, thus rendering them intelligible to the younger friars. Studying under Albert, possibly at Paris and certainly at Cologne (1248–1252), Thomas was soon abreast of the most advanced scholarship of his time, including the major Greek, Arab, and Latin sources that were to revivify the intellectual life of the Middle Ages.

Sent to Paris “to read the Sentences” at the priory of Saint-Jacques in 1252, Thomas quickly demon-strated his proficiency as a theologian. There was, however, growing jealousy and antipathy toward the friars (both Dominican and Franciscan) among the secular masters at the University of Paris, and in 1256 the intervention of Pope Alexander IV was required before Thomas and the Franciscan Bonaventure were accepted as masters at the university. During or before this, his first Paris professorship (1256–1259), Thomas composed his commentary on the Sentences, some smaller treatises—including the highly original Deente et essentia (“On Being and Essence”)—and the disputed question On Truth; he also began work on the Summa contra gentiles, of special importance for its evaluation of Arab thought.

From 1259 to 1268 he was back in Italy, first at Anagni and at Orvieto, where he was associated with the papal courts of Alexander IV and Urban IV, respectively; then at Rome (1265–1267), where he taught at the Dominican priory of Santa Sabina and began his famous Summa theologiae; and finally at Viterbo, where he served at the court of Clement IV.

Then, in 1268 or 1269, possibly because of disputes at the University of Paris over the Aristotelianism which he and Albert had introduced, Thomas returned to Paris for a somewhat unusual second professorship (1269–1272). Here he combated both the traditional Augustinian orthodoxy being fostered by such Franciscans as Bonaventure and John Peckham and the heterodox Aristotelianism of Siger of Brabant and his associates, who are usually referred to as Latin Averroists. One of the key issues in the dispute was Thomas’ teaching that the world’s creation in time cannot be demonstrated by reason alone, since there is no philosophical repugnance in a created universe’s having existed from eternity—a thesis with important ramifications for later medieval concepts of infinity.

The condemnation, in 1270, of certain Averroist theses by Étienne Tempier, bishop of Paris, is regarded by some scholars as directed, at least implicitly, against Aquinas’ teaching. Of the later condemnation, in 1277, there can be no doubt that two propositions concern matters taught by Thomas, including his thesis on the unicity of the substantial form in man, which bears on the problem of the presence of elements in compounds. Such controversies drew a series of polemical treatises from Aquinas’ pen, including De aeternitate mundi contra murmurantes (“On the Eternity of the Universe, Against the ‘Murmurers’” [i. e., the traditionalist Augustinians]) and De unitate intellectus contra Averroistas (“On the Unity of the Intellect, Against the Averroists”). The intellectual ferment also stimulated him to further efforts at philosophical and theological synthesis. During these years he elaborated most of his detailed commentaries on Aristotle and worked steadily on the Summa theologiae.

After his second Paris professorship was concluded in 1272, Thomas returned to Italy, this time to Naples, to erect a Dominican studium near the university there. He lectured, directed disputations, and continued writing; but the pace of his work slowed noticeably, partly because of failing health. He suspended all writing activity late in 1273 and died a few months later, while en route to the second Council of Lyons. He was canonized on 18 July 1323 and subsequently was approved by the Roman Catholic Church as its most representative teacher.

Today the name of Thomas is so associated with Catholic orthodoxy that one tends to forget that he was an innovator. In an atmosphere dominated by faith, especially at the University of Paris, he took the leadership in championing the cause of reason. Almost single-handedly he turned the theologians of that university to a study of the pagan Aristotle, to the use of what was then a rigorous scientific method, learned from investigating the world of nature, for probing the mysteries of revelation. Opposing the popular teaching that all knowledge comes by divine illumination, he allowed that man, by sense observation and through the use of unaided reason, could arrive at truth and certitude.

It would be a mistake, of course, to urge that Aquinas’ main concern was with the physical universe. Rather, he was preoccupied with questions about God, the angels, and man; first and foremost he was a metaphysician and a theologian. Yet there can be no doubt that, like Aristotle, his approach to metaphysical problems was through the physical sciences. Like St. Paul, he firmly believed that the invisible things of God are seen through his visible creation, provided it is rightly understood (Romans 1:20). So convinced of this was he that in his later life he turned from his unfinished Summa theologiae to comment on all the physical works of Aristotle. He probably completed his exposition of De caelo et mundo, one of his best works as a commentator, at Naples (1272–1273) and ceased commenting on De generatione et corruptione and the Meteorologica only shortly before his death.

Furthermore, for a man not usually recognized as a scientist, he made noteworthy contributions to medieval science. These can best be indicated by summarizing his more significant teachings relating to the medieval counterparts of physics, astronomy, chemistry, and the life sciences.

In the high scholastic period, foundations were laid for later medieval discussions that adumbrated the distinction in modern mechanics between kinematics and dynamics. The kinematical content of Thomas’ teaching is meager, although he did hold that velocity is a mode of continuous quantity and thus is capable of intensification in the same manner as qualities, thereby allowing for the type of comparison between qualitative change and local motion later made by Nicole Oresme.

In dynamics, he inaugurated some new directions in the study of causality affecting gravitational and projectile motions. Aquinas would probably look askance at the tendency of present-day historians of science to identify Aristotle’s motive powers and resistances with forces and to represent Aristotle’s teaching with precise dynamical equations. His own exegesis of the relevant Aristotelian texts, as opposed to that of Averroës and Avempace, discounts any demonstrative intent on Aristotle’s part and interprets his statements as dialectical efforts to confute his atomist opponents.

Thus, on the disputed question whether motion through a vacuum would take place instantaneously, Thomas did not follow Aristotle literally. He insisted that if, by an impossibility, a vacuum were to exist, motion through it would still take time—that the temporal character of the motion does not arise uniquely from external resistance but, rather, from the proportion of the mover to the moved (which prevents the movements of the heavens from being instantaneous, although they are not impeded by resistance) and also from the continuity of the distance being traversed. The latter reason, particularly, provoked speculation among fourteenth-century thinkers; some, such as Oresme, saw no necessary connection between spatial continuity and velocity limitation and were led on this account to seek some type of resistance internal to the moving body—thereby foreshadowing the modern concept of inertia.

Thomas’ analysis of gravitation is basically Aristotelian, yet it differs in significant respects from that of other commentators. Like all medieval thinkers, he regarded gravitation as the natural motion of a heavy body to its proper place. For Thomas, however, nature was a relational concept, and thus he disagreed with those who defined it as a vis insita or as something absolute; it is a principle of motion, either actively or passively, depending on the particular motion that results.

Aquinas held that the body’s gravity is the proximate cause of its falling, but only in the manner of a “passive principle.” He rejected Averroës’ teaching that the medium through which the body falls plays an essential role in its motion and that there is an active source of such motion within the body, whether this be its gravity or its substantial form. In this respect, Aquinas was also at variance with the later teaching of Walter Burley and the Paris terminists, all of whom saw the cause of falling as some type of active force within the body itself, thereby foreshadowing animist theories of gravitation such as subsequently proposed by William Gilbert. Again, Thomas disagreed with Bonaventure and Roger Bacon, who regarded place as exerting some type of repulsive or attractive influence on the falling body; for Thomas, there was no repulsion involved, and the attractive aspect of place was sufficiently accounted for by its being the end, or final cause, of the body’s movement. Here Thomas implicitly rejected the absolute space and attractive forces later proposed by the Newtonians; his own analysis, it has been remarked, shows more affinity with the ideas behind Einstein’s theory of general relativity, although the two are so remote in thought context as to defy any attempt at detailed comparison.

On the subject of impetus, authors are divided as to Thomas’ teaching. Certainly he has no treatment of the concept to match that found later in Franciscus de Marcia, Jean Buridan, and Oresme, nor does he use it to explain any details of projectile or gravitational motion. In his later writings, particularly the commentaries on the Physics and the De caelo, Thomas clearly defends the original Aristotelian teaching on the proximate cause of projectile motion. In some earlier writings, on the other hand, he speaks of a virtus in the projectile, and, in one text of the Physics commentary, discussing the case of a ball that bounces back from a wall, he mentions that the impetus is given not by the wall but by the thrower. Later Thomists, such as Joannes Capreolus and Domingo de Soto, had no difficulty in assimilating a fully developed impetus theory to Thomas’ teaching, evidently regarding the Aristotelian element in his expositions as reflecting his role as a commentator more than his personal views.

Aquinas took up the problems of the magnet, of tidal variations, and of other “occult” phenomena in a letter entitled De occultis operationibus naturae (“On the Occult Workings of Nature”), whose very title shows his preoccupation with reducing all of these phenomena to natural, as opposed to supramundane, causes. Significantly, Thomas’ analysis of magnetism was known to Gilbert and was praised by him.

Commenting as he did on the De caelo and also, in his theological writings, on the cosmogony detailed in Genesis, Thomas could not help but evaluate the astronomical theories of his contemporaries. He contributed nothing new by way of observational data, nor did he evolve any new theories of the heavens, but his work has an importance nonetheless, if only to show the care with which he assessed the current state of astronomical science. His view of the structure of the universe was basically Aristotelian; he knew of two theories to account for the phenomena of the heavens, both geocentric in the broad sense; that of Eudoxus, Callippus, and Aristotle, and that of Ptolemy. Aquinas generally employed the Eudoxian terminology; he mentions the Ptolemaic system at least eleven times, and five of these are in his late commentary on the De caelo. In most of his references to the Eudoxian or Ptolemaic systems, he refrains from expressing any preference; clearly, he was aware of the hypothetical character of both. At least once, commenting on Ptolemy’s cumbersome theory of eccentrics and epicycles, he voices the expectation that this theory will one day be superseded by a simpler explanation.

The astronomical data reported by Aquinas, according to an extensive analysis by Thomas Litt, were those of a well-informed thirteenth-century writer; he errs in one or two particulars, but on matters of little theoretical consequence. His treatise on comets, included in a work by Lynn Thorndike, is one of the most balanced in the high Middle Ages, rejecting fanciful explanations and pointing out how little is actually known about these occurrences.

In his more philosophical views, however, Thomas was not so fortunate. He believed in the existence of spheres that transport the heavenly bodies and, with his contemporaries, regarded such bodies as incorruptible. He was convinced also of the existence of an empyrean heaven the dwelling place of the blessed and known only through revelation, but nonetheless included in the corporeal universe. He accorded an extensive causality to the heavenly bodies, while excepting from this all actions that are properly human (i.e., that arise from man’s intelligence and deliberate will) and completely fortuitous events, so as to discourage any naïve credence in the astrologers of his day.

Aquinas has no treatment of alchemy to match that of his teacher Albertus Magnus, but he does discuss one topic that had important bearing on later views of the structure of matter, that of the presence of elements in compounds. Earlier thinkers, attempting to puzzle out Aristotle’s cryptic texts, favored one of two explanations of elemental presence offered by Avicenna and Averroës, respectively. Dissatisfied with both, Aquinas formulated a third position, which soon became the most popular among the Schoolmen. He taught that the elements do not remain actually in the compound, but that their qualities give rise to “intermediate qualities” that participate somewhat in each extreme; these intermediate qualities are in turn proper dispositions for a new substantial form, that of the compound, which is generated through the alteration that takes place. Since the elemental qualities remain “in some way” in the compound, one can say also that the substantial forms of the elements are present there, too—not actually, but virtually.

The subsequent influence of Thomas’ teaching has been traced in considerable detail by Anneliese Maier, who characterizes it as inaugurating a modern direction that dominated treatments of the problem in later Scholasticism (Studien III, pp. 89–140). Duns Scotus and his school, particularly, became enamored of the theory and attempted a consistent development of its ramifications. Nominalists such as William of Ockham and Gregory of Rimini took it up, too, as did such Paris terminists as Buridan, Oresme, Albert of Saxony, and Marsilius of Inghen. The basic explanation continued to be taught through the sixteenth century and, coupled with Aristotelian teaching on minima naturalia, became the major alternative to a simplistic atomist view of the structure of matter before the advent of modern chemistry.

In biology and psychology, Aquinas followed Aristotle, Galen, and the medieval Arab tradition; his work is noteworthy more for its philosophical consistency than for its scientific detail. He wrote commentaries on Aristotle’s De anima. De sensu et sensato, and De memoria et reminiscentia, all based on the texts of William of Moerbeke, his fellow Dominican. Also, ca. 1270, he composed a letter to a Master Philippus, who seems to have been a physician and professor at Bologna and Naples on the motion of the heart (De motu cordis), explaining how the principle “Whatever is moved, is moved by another” is saved in this phenomenon. Like his contemporaries, he believed in spontaneous generation and countenanced a qualified type of evolution in the initial formation of creatures. Catholic thinkers, on the basis of his philosophy, have been more open to evolutionary theories than have fundamentalists, who follow a strict, literal interpretation of the text of Genesis.

Thomas was a mild man, objective and impersonal in his writing, more cautious than most in giving credence to reported facts. He showed neither the irascible temperament of Roger Bacon, nor the subtle questioning of Duns Scotus, nor the pious mysticism of Bonaventure. Calm and methodical in his approach, Proceeding logically, step by step, he offered proof where it could be adduced, appealing to experience, observation, analysis, and (last of all) authority. He appreciated the importance of textual criticism, and possibly was one of the instigators of Moerbeke’s many Latin translations of scientific treatises from the original Greek. He had a penetrating intellect and a strong religious faith, both of which led him to seek a complete integration of all knowledge, divine as well as human. Working with the science of his time, he succeeded admirably in this attempt, thus providing a striking example for all who were to be similarly motivated in the ages to come.


I. Original Works. Standard editions of Aquinas are the Leonine edition, S. Thomae Aquinatis opera omnia, iussu Leonis XIII edita (Rome, 1882- ), a critical edition still in process (American section of the Leonine Commission at Yale University, New Haven, Conn.); Parma edition, S. Thomae opera omnia, 25 vols. (Parma, 1852–1873; photographically reproduced, New York, 1948–1949); Vivès edition, D. Thomae Aquinatis opera omnia, S. E. Fretté P. Maré, eds., 32 vols (Paris, 1871–1880).

English translations of major works include Summa theologiae, trans, and commentary, T. Gilby et al., eds., 60 vols. planned (New York-London, 1964-); Summa theologiae, English Dominicans trans., 22 vols., 2nd ed. (New York-London, 1912–1936); Summa contra gentiles (On the Truth of the Catholic Faith), A. C. Pegis et al., trans., 5 vols. (New York, 1955–1956); (Chicago, 1952–1954).

English translations of scientific writings include Commentary no Aristotle’s PhysiCs, R. J. Blackwell et al., trans. (New Haven, Conn., 1963); Exposition of Aristotle’s Treatise On the Heavens, R. F. Larcher and P. H. Conway, trans. (Columbus, Ohio, 1963–1964), mimeographed, available from College of St. Mary of the Springs, Columbus; Exposition of Aristotle’s Treatise On Generation and Corruption, Bk. I, chs. 1–5, R. F. Larcher and P. H. Conway, trans. (Columbus, Ohio, 1964)—a above; Exposition of Aristotle’s Treatise On Meteorology, Bks. I–II, chs. 1–5 R. F. Larcher and P. H. Conway, trans. (Columbus, Ohio, 1964)—as above. Except on comets in Lynn Thorndike, Latin Treatises on Comets Between 123 and 1368 A. D. (Chicago, 1950), pp. 77–86, Aristotle’s De Anima With the Commentary of St. Thomas Aquinas, K. Foster and S. Humphries, trans. (New Haven, Conn., 1951); Exposition of the Posterior Analytics of Aristotle, P. Conway, trans. (Quebec, 1956)—mimeographed, available from La Librairie Philosophique M. Doyon, Quebec, Canada; The Letter of St. Thomas Aquinas De Occultis Operibus Naturae, with a commentary, J. B. McAllister, trans., The Catholic University of America Philosophical Studies, 42 (Washington, D. C., 1939).

II. Secondary Literature. General works on Aquinas include V. J. Bourke, Aquinas’s Search for Wisdom (Milwaukee, 1965), an excellent biography; M. D. Chenu, Toward Understanding St. Thomas, A. M. Landry and D. Hughes, trans. (Chicago, 1964), a good introduction to Thomas’ intellectual milieu; K. Foster, ed. and trans., The Life of Saint Thomas Aquinas: Biographical Documents (Baltimore, 1959); W. A. Wallace and J. A. Weisheipl, “Thomas Aquinas, St.,” in The New Catholic Encyclopedia (New York, 1967), a compendious survey of his life and works.

Aquinas’ scientific work is discussed in Thomas Litt, Les corps célestes dans l’univers de saint Thomas d’Aquin, Philosophes Médiévaux, VII (Louvain-Paris, 1963), the best on Thomas’ astronomy; Anneliese Maier, Studien zur Naturphilosophie der Spätscholastik, I, Die Vorläufer Galileis im 14, Jahrhundert, Edizioni di storia e letteratura, 22 (Rome, 1949); II, Zwei Grundprobleme der scholastischen Naturphilosophie, Edizioni..., 37 (Rome, 1951); III, an der Grenze von Scholastik und Naturwissenschaft, Edizioni...,41 (Rome, 1952); IV, Metaphysische Hintergründe der spätscholastischen Naturphilosophie, Edizioni..., 52 (Rome, 1955); V. Zwischen Philosophie und Mechanik, Edizioni..., 69 (Rome, 1958). These are the most complete sources; consult the index of each volume under “Thomas von Aquin.” Some of this material is summarized in English in E. J. Dijksterhuis, The Mechanization of the World Picture, C. Dikshoorn, trans. (Oxford, 1961); W. A. Wallace, ed. and trAns., Cosmogony, Vol. X of Aquinas’ Summa theologiae (New York-London, 1967), with notes and appendices on Thomas’ science and its background.

William A. Wallace, O. P.

Aquinas, Thomas

views updated May 23 2018

Aquinas, Thomas



Thomas Aquinas (1225–1274) is by common consent the greatest theologian of the Middle Ages. His work gave a new clarity and comprehensiveness to the systematization of theology, and his philosophical judgment, which was matured in the study of Aristotle, never wavered. These qualities of judgment, organization, and clarity are to be found in his discussions of social and political questions, but it is important to remember the theological context of these questions if his treatment of them is to be understood.

Nearly everything of importance that Aquinas has to say about social and political matters is to be found in the second part of his Summa theologica. This great work, a systematic survey of the whole field of Christian theology, is divided into three parts. The first of these is devoted to God and the creation, the second to man and his nature, and the third to Christ and the sacraments. The second part contains a long series of discussions of the end of man, the law by which he is guided to this end, and the virtues and vices which help or hinder him on his way. This part of the Summa theologica is thus a massive survey of human nature viewed as part of the divine plan of the universe. For convenience it is divided, in turn, into two main sections (referred to as 1, 2 and 2, 2 in what follows), which together comprise 403 questions, each arranged in the form of a series of debates between clearly contrasted positions. The problems we shall discuss occupy no more than about 20 of these questions and are thus only a small fraction of the whole work. The arrangement of the discussions required that Aquinas should summarize earlier arguments and give his judgment on one side or the other. We can only understand what he is saying if we understand both the place of these questions in his work as a whole and the tradition of discussion of which his questions and answers form a part. In what follows we shall, therefore, have to devote a good deal of attention to the background and context of the discussion.

The problems discussed by Aquinas which fall within our field are those concerned with property, trade, the just price, usury, and the political community in general, and we shall speak of them in turn.

Property. The traditional view of private property, which was still accepted in the twelfth century, ascribed its origin to human sin. The ideal community was one in which “no-one called anything his own, but they had all things common” (Acts 4.32). This view was being modified in the late twelfth century by lawyers who drew a distinction between use, which was private except in times of necessity, and ownership (dominium), which ought to be common. Then Aristotle’s Politics, which was translated into Latin about 1250, introduced the medieval West to the view that private property is a necessary instrument of the good life. This view brought with it a radical transformation of the theory of property, and Aquinas was the first who combined a defense of the Aristotelian view of private property with a full discussion and criticism of traditional texts (2, 2, q. 66, art. 2). On all important points Aquinas was decisively on the side of Aristotle. He accepted the view that private property is necessary for the orderly conduct of human society. In answer to the traditional texts he asserted that the ideal of having all things common refers only to times of need; but in this connection he made the important concession that “he who is in great need may take what he needs from another’s goods if he can find no-one to give them to him”: such “stealing” is no sin (2, 2, q. 66, art. 7).

Aquinas’ view, here as everywhere, was expressed with masterly clarity. His powerful arguments were too necessary to the rapidly developing society of the thirteenth century to meet much opposition. The last outpost of conservatism was the Franciscan order, which maintained its formal rejection of private property until 1322, when Pope John xxii revoked the arrangement whereby the Roman church held property in trust on behalf of the Franciscans. At the same time the pope declared heretical the doctrine of the absolute poverty of Christ and his disciples. In this pronouncement we may see the official disappearance of the old view of the inherent sinfulness of private property and the triumph of the view expressed by Aquinas.

Trade. There was no theory of trade in the early Middle Ages. Merchants were necessary to provide luxuries for the rich and adornments for the church, and their activities were protected accordingly. But when merchants grew in numbers, wealth, and organized power, the tide of criticism began to rise. The legal theories of the twelfth century reflected this growing aversion and fear. Gratian’s authoritative collection of canon law contained texts (e.g., Luke 19.45, on the ejection of traders from the Temple) that were held to prove that no Christian ought to be a merchant. The theoretical objection to merchants (as opposed to craftsmen or farmers) arose from the fact that they bought commodities in order to sell them, unchanged, at a higher price. This was the sin of avarice, and it was held to be an almost inescapable sin in trade. The study of Aristotle yielded a further argument to an already existing hostility, since he asserted (Politics 1319a, 1328b) that the life of a trader was incompatible with moral excellence. As a student of Aristotle, Aquinas was much less favorable to trade than to private property. His account of the place of merchants in society (De regno ii, 3) is wholly inspired by Aristotle. Like Aristotle, he greatly preferred a self-sufficient to a commercial state, and he justified this preference by pointing to the risk of the failure of foreign food supplies in time of war, the corruption of manners brought about by the presence of foreigners, and the cupidity, frauds, and unwarlike dispositions induced by trade. Nevertheless, despite these dangers, merchants ought not to be entirely excluded from the state, because no state can be found that does not lack some commodities and have an excess of others. Even the perfect state, therefore, needs some merchants, but the fewer the better.

Aquinas had little more than this to say about trade in general, but (in common with other medieval authors) he presented relatively full discussions of two problems that arise from trade: the problems of the just price and of usury. This emphasis can be easily explained. As a theologian his main interest lay in distinguishing between permissible and reprehensible practices. He was not concerned with building up a theory of trade but a system of morals, and moral problems in trade chiefly arise from the sale of goods, including the sale of money, for profit, or usury. Usury in fact is only a special case of the unjust price.

The just price. The theory of the just price is a distinctively medieval contribution to economic theory, and it influenced economic thought as long as the labor theory of value was a living issue, far into the nineteenth century. But there is an important distinction between medieval theorists and modern economists: medieval theorists were not so much concerned with what does happen as with what ought to happen. Aquinas’ thought on the subject follows the common medieval pattern, although his argument is immensely superior in clarity and refinement to that of most other medieval writers. He accepted the general definition of the just price, which may be stated in the form of an equation: just price equals cost to seller. This equation makes it clear that changes in demand ought to have no place in determining prices. To charge more to someone in dire need is the sin of avarice. But the meaning of the phrase “cost to seller” still remains to be determined, and it is here that Aquinas (2, 2, q. 77) introduced some refinements of considerable interest. For example, he argued that the seller may count the personal damage he receives in parting with a cherished object as part of his cost, although he may not equally count the personal value which the buyer attaches to the same object. Further, while accepting the principle that it is sinful to buy something in order to sell it unchanged at a higher price, he argued that lapse of time between buying and selling may justify a rise in price. Aquinas devoted some attention to the new factors introduced by lapse of time: for example, labor may have been expended, or danger incurred, in moving or keeping the goods; or the goods may have improved in quality (e.g., wines), so that the seller may lose more in parting with them than he gained in acquiring them. These examples illustrate the beginnings of the analysis of the economic concept of cost, and they show how careful attention to detail could gradually turn theories that were primarily ethical in origin into descriptions of the economic process.

Usury. The problem of usury was the biggest single problem in medieval social theory. There was no area in which practice and theory were in such conspicuous conflict. Usury, whether open or concealed, was ubiquitous and necessary, but all the arguments, whether Biblical or philosophical, were against it. The arguments found in Aristotle served only to reinforce those used by Biblical commentators. The problem could not be solved, but it could be mitigated by refining the notion of usury, and Aquinas contributed several such refinements. In the first place he gave a subtle explanation of the nature of the evil of usury: it is unjust per se because it exacts the return of something that does not exist. He explained this by drawing a distinction (2, 2, q. 78, art. 1) between things that are consumed as they are used (e.g., food) and things that may be used without being consumed (e.g., a house). Only in the second case can use be separated from ownership. Money belongs to the first class. Therefore, he who sells money must sell it outright. He who exacts a price in the form of an annual payment and then demands a return of his capital is guilty of being paid twice for the same thing. No seller is entitled to receive more than an exact equivalent of what he has given up. This brings us back to the problem of the just price and to the question, “What exactly has the seller of money given up?” With his usual scrupulous regard for the facts, Aquinas agreed that the seller of money may receive damage through loss of enjoyment greater than the sum of money immediately involved. For this damage compensation is due, and this is not usury. Also, like most writers from the early thirteenth century onward, Aquinas agreed that a man who invests in a business and assumes a share of the risk is entitled to a share in the profit while retaining his rights in his capital. He fitted this into his general theory of usury by saying that, unlike the usurer, the risk sharer retains the ownership of his capital by membership in the firm. He did not seem to see that this makes a serious break in his general argument that money is a commodity which can be used only by being consumed. It was not until 1546 that this objection was developed by Charles Dumoulin in his refutation of the scholastic theory of usury.

The political community. In his general attitude to politics Aquinas displayed the same basic Aristotelianism that we find elsewhere in his social thought. The abandonment of Augustinian pessimism with regard to political society is characteristic of several writers of the twelfth and thirteenth centuries, but Aquinas gave fuller and more coherent expression to this tendency than any previous medieval writer. He accepted the argument of Aristotle’s Politics that the state exists for the good life (1, 2, q. 92, art. 1) and that the common good is in some sense different in kind and superior to the good of the individual (1, 2, q. 90, art. 2). He saw the political community as a natural institution based on reason, which would have existed among men even if man had never sinned (1, q. 96, art. 4); and he argued that the natural end of man in political society can, in large measure at least, be achieved under a pagan ruler (2, 2, q. 10, art. 10). He went very far in accepting statements of Aristotle that have seemed to others barely consistent with a Christian view, for example, that “the perfect community is the state (civitas)” and that “the individual is to the perfect community as the imperfect to the perfect” (1, 2, q. 90, art. 2). But in interpreting such statements it is necessary, here as elsewhere, to remember their context. The state did not mean to Aquinas what it meant to Aristotle, still less of course what it means to us. The political community was a vaguer concept in the thirteenth century than it was in fourth-century Athens, and the “perfect community” had none of the sinister totalitarian implication of post-Hegelian theory. Nevertheless, it is undeniable that Aquinas attached less importance to individuality than he did to the good of the community. What interested him most in politics was law, and most of his discussions of political topics occur in those sections of the Summa theologica concerned with the relations between divine and human law and between natural and positive law. His definition of law as “an ordinance of reason, for the common good, promulgated by one who has the care of the community” (1, 2, q. 90, art. 4) is the basis of all his political thinking. For him, the political community was at once corporate and authoritarian, rational and natural, but certainly not utilitarian or “liberal” in the modern sense.

Aquinas’ great contribution to social and political thought lies in his emphasis on the importance of reason and nature in the universe. In his hands Aristotle became the main instrument for bringing the idea of natural order to its fullest development in medieval thought. A veneration for nature runs through all the work of Aquinas and explains his careful (however brief) attention to the details of social and economic life. His lucidity in exposition and moderation in argument complete his qualifications for being regarded as the Christian Aristotle.

R. W. Southern

[For the historical context of Aquinas’ work, seeEconomic thought, article onancient and medieval thought, and the biography ofAristotle.]


Summa theologica. 22 vols. Translated by the Fathers of the English Dominican Province. London: Oates & Washbourne, 1912–1925.

Opera omnia. 25 vols. New York: Misurgia, 1948–1950.

On Kingship: To the King of Cyprus. Translated by Gerald B. Phelan. Revised with an introduction and notes by I. Th. Eschmann. Toronto: Pontifical Institute of Mediaeval Studies, 1949.

The Political Ideas of St. Thomas Aquinas: Representative Selections. Edited with an introduction by Dino Bigongiari. New York: Hafner, 1953.

Selected Political Writings. Edited with an introduction by A. P. d’Entrèves. New York: Macmillan, 1959.


Baldwin, John W. 1959 The Medieval Theories of the Just Price: Romanists, Canonists, and Theologians in the Twelfth and the Thirteenth Centuries. American Philosophical Society, Transactions, Vol. 49, part 4. Philadelphia: The Society.

Gilby, Thomas 1958 The Political Thought of Thomas Aquinas. Univ. of Chicago Press.

Nelson, Benjamin N. 1949 The Idea of Usury: From Tribal Brotherhood to Universal Otherhood. Princeton Univ. Press.

Noonan, John T. JR. 1957 The Scholastic Analysis of Usury. Cambridge, Mass.: Harvard Univ. Press.

Tooke, Joan D. 1965 The Just War in Aquinas and Grotius. London: Society for Promoting Christian Knowledge.

Thomas Aquinas

views updated May 11 2018

Thomas Aquinas

Born c. 1225

Died 1274

Italian philosopher and theologian

T he writings of Thomas Aquinas represented the pinnacle of the medieval school of thought known as Scholasticism. The latter, which had its roots in the work of Abelard (see entry) and others, attempted to bring together Christian faith, classical learning, and knowledge of the world. Thomas Aquinas wrote his Summa theologica to address new ideas that seemed to threaten the stability of Christian faith. As an inheritor of the Scholastic tradition, Thomas and his work can be seen on the one hand as the culmination of many centuries of thinking. Yet other ways of looking at the world were also emerging in Thomas's time and afterward, and thus his adherence to the Scholastic line can also be viewed as a defense of an old way of life against change.

The influence of Frederick II

Born of nobility in the Italian town of Aquino—hence his name, Aquinas (uh-KWYN-us)—Thomas was the youngest son of a count who descended from the Normans. His father had once fought in the armies of Emperor Frederick II (see Holy Roman Emperors entry), who like many another Holy Roman emperor was in conflict with the reigning pope. Hoping to ensure their good standing with the church, his parents placed the five-year-old Thomas in the Benedictine monastery at Monte Cassino, founded by St. Benedict (see box in Innocent III entry).

Things did not quite work out as planned: the emperor's conflict with the pope led to the latter excommunicating Frederick, or expelling him from the church, in 1239, when Thomas was fourteen. As a result, Frederick threatened Monte Cassino, and Thomas had to change schools. He moved to Naples in southern Italy, where he enrolled in what was to become that city's university.

The university system of Europe was in its earliest days at that time, and a number of new ideas were in the air. Most of these "new" concepts were actually old ones, inherited from the ancient Greeks and translated by Arab thinkers such as Averroës (see entry). The latter's writings had a great impact on the school at Naples, not only because it was relatively close to the Arab world, but also because Frederick (who had founded the school in 1224) encouraged the introduction of Islamic as well as Christian ideas there.

Albertus Magnus and the bellowing ox

Though he had been trained as a Benedictine, Thomas found himself drawn by the order founded by St. Dominic (see box in St. Francis of Assisi entry). In 1244, he joined the Dominicans against the protests of his mother, now a widow, and his brothers. The following year found him studying with the Dominicans at the University of Paris, where he came under the influence of Albertus Magnus (c. 1200–1280).

The latter, whose name means "Albert the Great," was considered the greatest scholar of his time, though he has been overshadowed by Thomas, his more famous pupil. Albert made a prophecy about Thomas, who had received the nickname "the dumb ox" from his classmates. Obviously it was an uncomplimentary expression; however, it referred not to Thomas's intellect—which was clearly superior to that of most—but to his physical body, which was tall, fat, and slow. Albert, however, remarked that the bellow of this ox would be heard around the world.

Begins his life's work

Thomas studied with Albert at the latter's home in Cologne, now a city in western Germany, from 1248 to 1252; then he returned to Paris to earn his degree in theology, or the study of questions relating to God and religion. Like graduate students now, Thomas served as a teacher of undergraduates while earning his own graduate degree; then in 1256, he obtained his license to teach theology as a full-time instructor at the university.

As an undergraduate, Thomas had written a commentary of a kind typical among the works of university students at that time. Next he produced the Summa contra gentiles (c. 1258–64), a book designed to aid Dominican missionaries in Spain and North Africa who got into religious arguments with Jews and Muslims, or with Christians who had adopted heretical ideas (ideas contrary to church teachings).

In 1261, Thomas moved to Rome to serve as a lecturer at the papal court, and while there, he began writing his most important work, Summa theologica (c. 1265–73). Part one, completed during this time, concerned the existence and attributes, or characteristics, of God. He then returned to Paris, just in time to become involved in a brewing controversy.

Caught in a controversy

The influence of Averroës had become widespread among scholars and students at the University of Paris. The Arab philosopher held the viewpoint that one can use both reason and faith without the two contradicting one another. This could also be interpreted to mean that reason sometimes takes greater importance than religious faith—an idea the church considered dangerous.

Thomas argued against one of the leading promoters of Averroës's ideas, but Thomas too came under suspicion because in his writing he reflected the influence of the ancient Greek philosopher Aristotle. (At that time, church authorities were still skeptical of philosophical ideas that came from the ancient Greeks, since they were pagans and not Christians.) Thomas did indeed maintain that reason can aid the believer in discovering certain truths about God, an idea he put to use in several proofs of God's existence; but at all times Thomas saw reason as secondary to faith.

Some Notable Thinkers and Scholars of the Middle Ages

The pages of medieval history are filled with a number of scholars and thinkers who are noteworthy, even if not well known. An example is Dionysius Exiguus (dy-oh-NISH-us ek-SIJ-yoo-uhs; c. 500–c. 560), a Byzantine monk and scholar from what is now Russia. Though his name is not exactly a household word, perhaps it should be: Dionysius originated the system of dating events from the birth of Christ. Because he miscalculated the date of Christ's birth in relation to the founding of Rome, his system resulted in error, illustrated by the fact that Christ himself was probably born in 6 b.c.. Also, Dionysius lacked the concept of zero, meaning that in his system, the next year after 1 b.c.. was a.d..1. For this reason, as a number of commentators noted in 1999 and years following, the third millennium began not on January 1, 2000, but on January 1, 2001.

Another fascinating figure was Isidore of Seville (c. 560–636), a Spanish priest who wrote a number of encyclopedic works. Isidore was considered one of the most learned men of his time, and the fact that his writings are filled with myths and superstitions says a great deal about the poor quality of learning in the early Middle Ages.

Soon after Isidore's time, Spain was overrun by Muslims, and this ironically made it a center for Jewish culture and scholarship. Among the important Jewish intellectual figures produced by Muslim Spain was Hisdai ibn Shaprut (kis-DY ib'n shahp-RÜT; c. 915–c. 975), court physician to Caliph Abd ar-Rahman III, whose support of scholarship helped initiate a golden age of Hebrew learning in Spain. One of the beneficiaries of his efforts was Samuel ha-Nagid (hah-NAH-geed; 993–c. 1055), who also held an important position in the Muslim government. Samuel produced a commentary on the Talmud, or Jewish scriptures, that continued to be influential for many years. Shlomo Yitzhaqi (sh'loh-MOH yits-HAHK-y; 1040–1105) also wrote commentaries on the Talmud. Better known by the nickname Rashi (RAH-shee), this French rabbi was one of the few no-table Jewish figures in Christian Europe.

As Europe emerged from the Dark Ages into the gradual rebirth of learning that attended the eleventh century, it produced a number of figures who contributed to literature, philosophy, and the arts. One of these was a woman, Hrotsvitha von Gandersheim (raws-VEE-tah; GAHN-durs-hym; c. 935–1000). Regarded as the first woman to write poetry in German, she helped revive the art of drama, which had been dormant for many years due to its association with pagan Rome. She wrote six comedies based on the work of the ancient Roman playwright Terence, but embodying Christian ideas.

Another notable scholar was a pope, Sylvester II (945–1003; ruled 999–1003), born in France with the name Gerbert. Formerly a teacher, he studied mathematics and the natural sciences, and wrote a number of works, including textbooks and two books on mathematics. He also influenced young Otto III (see Holy Roman Emperors entry) in his dreams of a unified empire.

Among the areas that Gerbert promoted was music, which would be heavily affected by the work of Guido of Arezzo (GWEE-doh; ar-RED-zoh; c. 991–1050). Guido developed the rudiments of the system of musical notation in use today, particularly the four-line staff.

This list of notable scholars began with a Byzantine writer, and ends with one: Michael Psellus (SEL-us; 1018–c. 1078). An important official in the empire's government, he also served as professor of philosophy in Constantinople. Michael was widely known for his encyclopedic knowledge and his promotion of classical studies, particularly those involving the ancient philosopher Plato. His most well known work was the Chronographia, a history of the Byzantine Empire from 976 to 1078.

Completion of the Summa theologica

By 1271 or 1272, Thomas had completed the second portion of his Summa theologica, concerning questions of happiness, sin, law, and grace. Though he may have moved slowly, he was a man of boundless energy who, it was said, employed as many as four secretaries at a time so that he could dictate to them. The completed Summa theologica, the greatest of his books, though only one of several, ran to about two million words—the equivalent of about 8,000 double-spaced, typewritten sheets.

Having returned to Naples in 1272 to set up a Dominican study house attached to the university there, Thomas went to work on the third part of the Summa, this one concerning the identity of Christ and the meaning of his work. On December 6, 1273, his own work suddenly stopped, and he explained to others that everything he had done seemed meaningless. Whether he suffered a physical breakdown, experienced a spiritual insight, or simply ran out of ideas is not known.

His health failing, Thomas in 1274 set out to attend a church council in France. He was struck on the head by a branch falling from a tree over the road, and may have suffered a concussion. He stopped at a castle belonging to his niece to recover, and soon afterward was taken to a monastery, where he died on March 7, 1274.

Doctor of the Church

It is ironic that Thomas would later be regarded as a symbol of Catholic rigidity. At the time of his death, his work was under question by the church, which took issue with his attempts to reconcile reason and faith. Four decades later, however, inquiries were under way to canonize him, or declare him a saint. He was canonized in 1323, and in 1567 named a Doctor of the Church, or one of the leading church fathers.

As for the viewpoint that Thomas represented an attempt to hold on the past, this idea fails to take into account the actual conditions of his time. Though forces were at work that would ultimately challenge the absolute power of the church—forces that included the rise of nation-states, international trade, and a growing attitude of scientific curiosity—the church was still very much in control, and it still tended to regard new ideas as heresy. Thus Thomas was very much on the cutting edge when he asserted that it was possible to use reason and still remain firm in dedication to God. Throughout his career, he walked a fine line, and he managed to do so without losing his integrity either as a man of faith or as a thinker.

For More Information


Brehaut, Ernest. An Encyclopedist of the Dark Ages, Isidore of Seville. New York: Benjamin Franklin, 1964.

Daughters of St. Paul. Pillar in the Twilight: The Life of St. Thomas Aquinas. Illustrated by the Daughters of St. Paul. Boston: St. Paul Editions, 1967.

Harvey, O. L. Time Shaper, Day Counter: Dionysius and Scaliger. Silver Spring, MD: Harvey, 1976.

Pittenger, W. Norman. Saint Thomas Aquinas: The Angelic Doctor. New York: Franklin Watts, 1969.

Web Sites

Aquinas Page. [Online] Available (last accessed July 26, 2000).

"Stephen Loughlin's Home Page—St. Thomas Aquinas." [Online] Available (last accessed July 26,2000).

"Thomas.htm." [Online] Available (last accessed July 26, 2000).

"Tips on Reading Thomas Aquinas." [Online] Available (last accessed July 26,2000).

"The 21st Century and the Third Millennium." [Online] Available (last accessed July 26, 2000).

Thomas Aquinas

views updated May 23 2018

Thomas Aquinas

Thomas Aquinas held that revelation was essential for grasping truth of faith but he relied on reason to understand the world that God created. Mindful of this division, Thomas warned against dogmatic interpretations in areas of faith that might have to be abandoned if subsequent natural evidence falsified them. Convinced that Aristotle's (384322 b.c.e.) natural philosophy provided the most accurate interpretation of cosmic operations, Thomas refused to Christianize natural philosophy and, to the greatest extent possible, he applied reason to both science and theology.

Life and works

Thomas Aquinas was born near Monte Cassino, Italy, around 1225. He was the youngest of nine children. After elementary education in the abbey of Monte Cassino, Thomas was sent to Naples in 1239, where he studied at the University of Naples. In 1244, while still at Naples, Thomas entered the Dominican order, contrary to the wishes of his family. From 1245 to 1252, Thomas studied at Paris and then Cologne. At Cologne, and perhaps at Paris, Thomas's teacher was Albert the Great (Albertus Magnus) (c. 12061280), one of the great scientists and natural philosophers of the Middle Ages and a thorough student of Aristotle's writings. After training as a theologian, Thomas became a professor of theology at the University of Paris (12561259). He spent the years between 1259 and 1268 in Italy serving different popes at their papal courts. During 1269 to 1272, Thomas returned to another professorship at the University of Paris, after which he returned to Naples, where his health began to fail. Thomas died in 1274 while on his way to the second Council of Lyons.

Thomas was a prolific author who left approximately fifty works that have been thus far identified. He wrote on numerous topics, the most significant of which are his theological treatises, especially his famous Summa of Theology (Summa theologiae), commentaries on books of the Bible, and commentaries on various works of Aristotle, especially those on natural philosophy, which include Aristotle's Physics, On the Heavens, On Generation and Corruption, Meteorology, and On the Soul. In addition, Thomas composed sermons, letters, and replies to queries.

Thomas on the relationship of faith and reason

Issues of science and religion in the Middle Ages involve the relationship between natural philosophy and religion. By the time Thomas began writing, Aristotle's works on logic and natural philosophy had been adopted as the basic curriculum in faculties of arts of medieval universities. Because Aristotle's natural philosophy raised issues that were directly relevant to theology and the Catholic faith, it was inevitable that Thomas, who was both a theologian and a natural philosopher, would have to confront those issues in his works on theology and natural philosophy.

When Thomas dealt with issues of science and religion, he was guided by his overall view of the relationship between faith and reason. Thomas emphasized the importance and power of reason, but insisted that it was inadequate to gain knowledge of unseen things, such as God, for which faith and divine revelation are essential. For knowledge of the physical cosmos and its regular operations, however, reasonembodied in the works of Aristotlewas Thomas's instrument for understanding those operations. But reason was also an instrument for the study of theology. In the very first question of his Summa of Theology, Thomas asked whether theology is a science and replied affirmatively. He is usually regarded as the scholar who gave credence to the claim that theology is a science, a claim that was widely assumed in the late Middle Ages.

Two principles derived from the early Christian leader Augustine of Hippo (354430 c.e.) and expressed in the Summa of Theology, guided Thomas in his explanations of natural phenomena. He insisted: (1) that the truths of Scripture must be held inviolate, but that (2) no passage in Scripture should be interpreted rigidly and dogmatically because it might later be proved false by convincing arguments, thus leading to a loss of credibility that would inhibit nonbelievers from adopting the faith.

Thomas and Aristotle

Although Aristotle's natural philosophy formed the basic curriculum in the arts faculties of medieval universities, those aspects of his work that conflicted with basic Christian beliefs evoked opposition through most of the thirteenth century. In the 1260s, and 1270s, when Thomas was writing, the opposition was led by the Franciscan theologian Bonaventure (12211271), whose neoconservative Augustinian colleagues eventually prevailed upon the bishop of Paris to condemn certain of Aristotle's articles deemed offensive to the faith; thirteen articles were condemned in 1270 and 219 articles were condemned in 1277, three years after the death of Thomas. Since Thomas was a supporter of Aristotle's philosophy, as were many Dominicans, some of the hostility was plainly directed against him and his colleagues. It was not until 1325, two years after the canonization of Thomas Aquinas, that the bishop of Paris, Stephen Bourret, revoked the condemnation of all articles condemned in 1277 that were directed against the teachings of Thomas.

The most significant idea condemned in 1277 was Aristotle's claim for the eternity of the world, which was denounced at least twenty-seven times in a variety of contexts. In a treatise he titled On the Eternity of the World, Thomas neither rejected nor accepted the eternity of the world. By absolute power, God could have created a world that was coeternal with God. For as Thomas argued, "The statement that something was made by God and nevertheless was never without existence . . . does not involve any logical contradiction." If God wishes, God can choose not to precede any effect God decides to produce, and thus God can make the world eternal. Although God could make the world coeternal with God, an eternal world would still be a created effect, because it is wholly dependent on an immutable God, thus guaranteeing that the world cannot be coequal with God. Of the articles condemned in 1277, Article 99 was probably directed against Thomas's interpretation of the eternity of the world. Thomas's approach to the question of the world's duration proved popular and found supporters up through the Renaissance. Bonaventure and others were convinced that Aristotle had denied the personal immortality of the soul, but Thomas thought Aristotle had believed it.

Since Aristotle firmly believed that every material thing is derived from previous matter, he would have been opposed to the Christian doctrine of creation from nothing. Article 185 condemned the view that something could not be made from nothing. Indeed, the Fourth Lateran Council of 1215 had declared belief in creation from nothing to be an article of faith. On this issue, Thomas, and all Christians, were compelled to reject Aristotle's interpretation.

Thomas's conception of the physical world and its operations was basically the same as that held by Aristotle, from whom he derived it. In his commentaries on Aristotle's natural philosophy, Thomas considered the numerous problems Aristotle presented, accepting most of Aristotle's solutions, but disagreeing on some important issues. Although Thomas believed with Aristotle that the existence of void spaces was impossible, he disagreed with the absurd consequence Aristotle deduced from the assumption of motion in a vacuum, namely that because of an absence of material resistance, a body would move instantaneously in a vacuum and, as a consequence, no ratio could obtain between motions in a hypothetical void and motions in a space filled with matter. Thomas rejected these conclusions. A body falling or moving in a void space would have a definite speed and take a definite time to move successively between two distant points. This is so, argued Thomas, because any distance in a three-dimensional void has prior and posterior parts that a body must traverse to get from one point to another, which requires time. Hence there could indeed be a ratio between motions in a vacuum and motions in a plenum.

In a letter to a soldier, Thomas explained how bodies could perform actions that do not follow from the nature of their constituent elements, as, for example, the attraction of a magnet for iron. Thomas regarded such actions as occult, explaining the causes of such phenomena by the behavior of two kinds of superior agents: (1) celestial bodies, or (2) separate spiritual substances, which included celestial intelligences, angels, and even demons. A superior agent can either communicate the power to perform the action directly to an inferior body, as is the case with the magnet; or the superior agent can, by its own motion, cause the body in question to move, as, for example, the moon causes the ebb and flow of the tides.

Whatever disagreements Thomas had with Aristotle, whether doctrinal or otherwise, it is obvious that Thomas was an Aristotelian in natural philosophy. As an Aristotelian natural philosopher and a professional theologian, one may appropriately inquire how Thomas related natural philosophy and theology, the medieval equivalent of the relations between science and religion. Thomas followed in the path of his teacher, Albert the Great, and generally refrained from introducing theological ideas into his treatises on natural philosophy, whereas he did not hesitate to introduce natural philosophy to elucidate his theological discussions. As a theologian doing natural philosophy, Thomas could easily have resorted to theological appeals and arguments in his natural philosophy, but he did not think it appropriate to do so. As he explained in a reply to one of forty-three questions sent to him by the master general of the Dominican order, "I don't see what one's interpretation of the text of Aristotle has to do with the teaching of the faith." Thomas refused to Christianize Aristotle's natural philosophy and to confuse natural philosophy with theology. In this, Thomas followed the practice of most medieval theologians and natural philosophers.

See also Aristotle; Augustine; Christianity, Roman Catholic, Issues in Science and Religion; Creatio ex Nihilo; Creation; God


copleston, frederick c. aquinas. harmondsworth, uk: penguin books, 1955.

thomas aquinas. summa theologiae, vol. 10: cosmogony, trans. and ed. william a. wallace. london: blackfriars, 1967.

dijksterhuis, e. j. the mechanization of the world picture, trans. c. dikshoorn. oxford: clarendon press, 1961.

gilson, etienne. history of christian philosophy in the middle ages. london: sheed and ward, 1955.

pegis, anton c., ed. introduction to saint thomas aquinas. new york: modern library, 1948.

wallace, william a. "aquinas on creation: science, theology, and matters of fact." thomist 38 (1974): 485-523.

wallace, william a. "aquinas, saint thomas." in dictionary of scientific biography, vol. 1, ed. charles c. gillispie. new york: scribner, 1970.

weisheipl, james a. friar thomas d'aquino: his life, thought, and work. garden city, n.y.: doubleday, 1974.

weisheipl, james a. "motion in a void: aquinas and averroes." in st. thomas aquinas 1274-1974, commemorative studies, ed. a. a. mauer. toronto: pontifical institute of medieval studies, 1974.

edward grant

Thomas Aquinas

views updated May 23 2018


Thomas of Aquino (ca. 1225–1274), a philosopher and theologian, was born into an aristocratic family at Roccasecca, near Naples, Italy. He joined the Dominican order in 1245, taking a licentia docendi at Paris in 1256. He later taught at Paris, Rome, Orvieto, and Naples. Thomas died at the Cistercian abbey of Fossa Nuova on March 7 and was canonized in 1323 by Pope John XXII. The Summa contra Gentiles was completed about 1264. His longest and most influential work, the Summa Theologiae, was unfinished at the time of his death.

Ethics and Politics

Thomas was the foremost contributor to the thirteenth-century recovery of Aristotle. His achievement in ethics lies chiefly in the application of a Christianized version of Aristotle to politics and law. In most respects he departs from the Augustinian orientation of previous generations that found the present world sin-laden and disordered and its politics harsh and coercive.

Thomas accepted the rational, humane, ordered world depicted by Aristotle. There is no tension between the acquisition of present goods on earth and the achievement of eternal ones in heaven so long as the former are directed toward and subordinated to the latter. Human beings have a final ethical end—eternal blessedness—that transcends all earthly ends, but earthly happiness is also possible and desirable. God has equipped human beings with the rational capacity to pursue earthly as well as heavenly goods, and although sin has impaired the will, it has not obliterated reason. Thomas believes, as Augustine (354–430) did not, that humans are capable, under proper governance, of cooperating with one another to achieve a common good.

For Thomas human beings are by nature political animals; government is not merely a consequence of sin. Even if the Fall of Adam had not occurred, no individual would be able to acquire all the necessities of life unaided; only cooperation can secure the benefits of divisions of labor. However, there are many ways to achieve human ends, and so a community must be guided toward the common good by just and wise rule. The best government is a "mixed" constitution of the kind that Aristotle called politeia. Kingship may be the most efficient form of rule, but it is also the most likely to deteriorate into tyranny. It therefore must be tempered by elements of democracy and aristocracy. A king should choose the best people as his counselors, and what he does should be ratified by the people. Thomas follows Aristotle in supposing that a government in which as many people as possible participate will be the most stable because it will commend itself to all sections of the community.

Law and Ethics

In the Summa Theologiae Thomas develops a typology of law as eternal, natural, human, and divine. This theory has a Platonic starting point insofar as law is defined as a rational pattern or form. In the political realm law thus serves as a "rule and measure" for citizens' conduct. When citizens obey the law, they "participate" in that order in the way a table "participates" in the rational pattern or form of a table.

Because God is the supreme governor of everything, the rational pattern or form of the universe that exists in God's mind is law in the most comprehensive sense: the law that makes the universe orderly and predictable. This rational pattern is what Thomas called eternal law, and to it everything in the universe is subject. The eternal law is similar in content to what science now calls the laws of nature.

Inasmuch as humankind is part of the eternal order there must be a portion of the eternal law that relates specifically to human conduct. This is the lex naturalis, the "law of [human] nature": an idea present in Aristotle to which Thomas gave extensive elaboration. In developing his natural law theory Thomas restored human reason to a central place in moral philosophy. For Thomas, as for Aristotle, human beings are preeminently reason-using creatures. The law or order to which people are subject by their nature is not a mere instinct to survive and breed. It is a moral law ordering people to do good and avoid evil, have families, live at peace with their neighbors, and pursue knowledge. It is natural in that humans are creatures to whom its prescriptions are rationally obvious. To all humans, pagans included, these precepts simply "stand to reason" by virtue of a faculty of moral insight or conscience that Thomas called synderesis.

However, humans act on the principles of natural law with the assistance of more particular and coercive provisions of what Thomas called human law. The natural law is too general to provide specific guidance. Part of this specific guidance can come from the moral virtues that equip people to achieve practical ends: prudence, justice, temperance, and fortitude. However, these personal guidelines are developed and reinforced by human or positive laws that that help cultivate such good habits. These particular, positive rules of behavior include civil and criminal laws of the state as formulated by practical reason, or what Aristotle called phronesis, in the light of the general principles of natural law and have a morally educative function. Human laws that are not based on natural law—laws that oppress people or fail to secure their good—have more the character of force than that of law. Obedience may be called for if disobedience would cause greater harm, but people are not obliged to obey unjust laws. Individuals may exercise independent moral judgment; they are not simply subjects but rational citizens.

The fourth kind of law—divine law—is part of the eternal law but, unlike human law, is not derived from rational reflection on more general principles and historical circumstances. It is a law of revelation, disclosed through Scripture and the Church and directed toward people's eternal end. Human law is concerned with external aspects of conduct, but salvation requires that people be inwardly virtuous as well as outwardly compliant. The divine law governs people's inner lives: It punishes people insofar as they are sinful rather than merely criminal.

Applying Thomism

The strongest implications of Thomas's thought for ethics, science, and technology are found in the doctrine of natural law and the underlying idea of human equality. For instance, Pope Leo XIII in his encyclical Rerum Novarum (1891) drew on law theory to criticize the conditions of labor under industrial capitalism. Insofar as it requires people to do good, avoid evil, pursue knowledge, and live at peace with their neighbors, the natural law suggests that governments should support scientific and technological research intended to have beneficial outcomes. By the same token, it supports the principle that governments should not sponsor such research when it involves the development of weapons of mass destruction or the exploitation of some human beings by others.

Natural law doctrine implies as well that governments should not harm, but seek to preserve, the physical environment of humankind: the natural world that God created and over which humans properly exercise dominion. In regard to biological and medical science, the idea of human nature as a repository of value implies a distinction between laudable biomedical research, which is a work of charity beneficial to the human race, and unacceptable research involving the manipulation or distortion of human nature. In this connection Thomas often is cited in support of the Catholic Church's prohibition of artificial (as distinct from natural) methods of contraception.

Finally, it may be noted that Thomas's insistence on citizen participation in government speaks against any suggestion that political decisions should be made by technocratic elites of scientists and engineers rather than by those who will be affected by those decisions. Thomas presided over a thorough revaluation of the capacity of human beings for autonomous moral action and hence for responsible political participation. In effect, he reinvented the Aristotelian ideal of citizenship after its long medieval eclipse, and that reinvention would apply today to scientific and technological decision making.


SEE ALSO Aristotle and Aristotelianism;Christian Perspectives;Just War;Natural Law;Virtue Ethics.


Chesterton, G. K. (1974). Saint Thomas Aquinas: The Dumb Ox. New York: Image. A popular and uncritical biography, but useful for purposes of orientation.

Dyson, R. W., ed. Political Writings/Thomas Aquinas. Cambridge, UK, and New York: Cambridge University Press. A comprehensive selection of passages in translation, with detailed notes and introduction.

Finnis, John. (1998). Aquinas: Moral, Political and Legal Theory. Oxford, UK: Oxford University Press. A comprehensive and recent scholarly treatment of Thomas's thought on ethics, politics and law.

McInerny, Ralph M. (1982). Ethica Thomistica: The Moral Philosophy of Thomas Aquinas Washington DC: Catholic University of America. A clear exposition and summary of Thomas's moral philosophy; still regarded as a standard textbook on the subject.

O'Connor, D. J. (1967). Aquinas and Natural Law. London: Macmillan.

Thomas Aquinas

views updated May 23 2018

Thomas Aquinas

CIRCA 1225–1274
Philosopher and theologian


The Synthesis of Philosophy and Theology. The two defining influences on the great medieval philosopher-theologian Thomas Aquinas were Scholasticism and Aristotelianism. At the time of Thomas’s birth, the dominant approach to theology was that of the university Schoolmen (or Scholastics), who considered reason a necessary complement of faith and emphasized the use of logic and the importance of rational inquiry. One of the greatest aids to their task of systematizing Christian doctrine along philosophical lines was the rediscovery, in the late twelfth century, of certain major writings of Aristotle. Thomas was, therefore, born at a time when Scholasticism was reaching its height and the intellectual weight of Aristotelianism was just beginning to be felt. His great contribution to theology was his effort to synthesize Christianity and Aristotelianism, which resulted in one of the most comprehensive philosophical systems in history and the crowning achievement of Scholasticism.

Education. Thomas was born at Roccasecca, a family castle near Naples, Italy, to the noble house of Aquilo. He received his early schooling at the Benedictine monastery of Monte Cassino, where he demonstrated a precocious intelligence and piety. In 1240 he went to Naples to continue his studies at the recently established university, where he was probably introduced to Aristotle, whose Physics and Metaphysics had recently reached western Europe through Latin translations of Arabic texts preserved by the Muslim world and its philosophers. At Naples, Thomas also came into contact with the Dominicans, a relatively new monastic order with a mission of preaching and instruction and an emphasis on the education of its members. In 1244 Thomas took Dominican vows against the wishes of his family, which even abducted Thomas and held him at various family strongholds during 1244–1245. When Thomas was released the Dominicans sent him to the University of Paris, where he studied under Albertus Magnus, one of the pre-eminent Scholastics and an admirer of Aristotle. When Albertus was sent to Cologne, Thomas went with his teacher and continued to study with him for the next four years, absorbing much of his mentor’s Aristotelianism.

Teaching and Writing. In 1252 Thomas returned to Paris and began his career as a teacher, lecturing on the Libri Quatuor Sententiarum (Four Books of Sentences, written 1148–1151) of Peter Lombard. About four years later he received the title master of theology. In 1259 he left Paris for Italy, where he taught at Rome and several other cities for a decade before returning to Paris. There he disputed the extreme Aristotelianism of Siger of Brabant and other young scholars. Although Thomas’s own thought relied heavily on Aristotle’s teachings, he remained loyal to the Christian doctrine of revelation, departing from Artistotle whenever his teachings disagreed with those of the Church. He attested to this loyalty again on his deathbed, when concerning his writings he pronounced, “I submit all to the judgement and correction of the Holy Roman Church, in whose obedience I now pass from this life.” Thomas moved a final time in 1272, to establish a Dominican school at Naples. He died two years later, on 7 March 1274, on his way to attend the Council of Lyons.

The Summa Theologiae. The number of Thomas’s writings is remarkable given the relatively brief span of his life. In fewer than fifty years he wrote scores of commentaries, tracts, and treatises covering a broad range of spiritual and philosophical topics; some of his early biographers mentioned that he had several scribes working for him at once. Among his most influential works are his commentaries on Aristotle and on the Bible, and his Summa de Veritate Catholcae Fidei contra Gentiles (Comprehensive Truth of the Catholic Faith against the Gentiles, written 1259–1262). His greatest work is his Summa Theologiae (Comprehensive Theology, written 1265–1273), a systematic and thorough treatment of all the major (and many minor) questions of Christian theology. The work is presented in the form of a series of articles, each posing a specific question. Among the more than three thousand questions answered are whether it can be demonstrated that God exists, whether the human soul is incorruptible, whether God is the cause of evil, and whether created goods can bring man happiness. Thomas addressed each question in the Scholastic form prevalent in the lecture halls of his day, first listing every reasonable objection to his proposed answer, then citing an authority to support him, explaining his solution, and finally replying to each of the objections initially raised.

“The Angelic Doctor.” The Summa Theologiae was left unfinished when Aquinas gave up writing in 1273, not long before his death. According to his medieval biographers, Thomas was often given to mystical ecstasies, and after an especially profound experience at a mass on 6 December he had abandoned his work on the Summa Theologiae. When a companion urged him to finish it, Thomas replied, “I cannot… in comparison with what I have seen in prayer all that I have written seems to me as if it were straw.” His fellow Dominicans seem to have held a loftier view of his written work; in 1278, just four years after his death, his works were made the official doctrinal basis of the order. Despite initial resistance by the Franciscans, the influence of Thomas’s works and teaching spread, eventually becoming a cornerstone of Roman Catholic theology. Even theologians who disagreed with Thomas were forced to take some account of his work. Thomas Aquinas was canonized by Pope John XXII in 1323, and in 1567 he was declared a Doctor of the Church.


G. K. Chesterton, St. Thomas Aquinas: The Dumb Ox (London: Hodder& Stoughton, 1933).

Frederick C. Copleston, Aquinas (Harmondsworth, U.K.: Penguin, 1955).

Arthur Cushman McGiffert, “Thomas Aquinas,” in A History of Christian Thought, 2 volumes (New York & London: Scribners, 1933), II: 257–1955).

James A. Weisheipl, Friar Thomas Aquinas (Garden City, N.Y.: Double-day, 1974).

Thomas Aquinas

views updated Jun 11 2018

Thomas Aquinas

c. 1224–1274

Dominican friar

A Life in the Church.

Thomas Aquinas, called the "Common Doctor" or (some centuries later) the "Angelic Doctor," was born in the family castle of Roccasecca in the county of Aquino (hence his name), which was located in the Kingdom of Naples. The youngest son in a noble family of thirteen children, Thomas was undoubtedly destined by his father for service in the Church. Hence it was that he was packed off at the age of five to the nearby monastery of Monte Cassino as an oblate (a lay member of the religious community), possibly one day to be its abbot, a post befitting his aristocratic status. Thomas's career path took a different turn, however, after his superior transferred him to nearby Naples to continue his studies at the newly founded university, the establishment of the emperor, Frederick II. There Thomas was exposed, full bore, to the newly translated works of Aristotle. It was also there that he first encountered the religious order of begging preachers, founded by St. Dominic. Attracted to the mendicant way of life, young Thomas took the habit, much to the consternation of his mother. Sending his older brothers, both knights, to seize her youngest son, she had Thomas placed under "house arrest" in the family castle.

A Master of Theology.

A year's captivity was not able to shake his resolve, however, and Thomas was allowed to continue his interrupted journey to Paris, where he came under the tutelage of Albert of Swabia, who was already being called Albertus Magnus, or "Albert the Great." The teacher recognized the genius of his pupil; one time, on overhearing the nickname with which his fellow students had dubbed him, "the dumb ox," he predicted that one day the bellowing of this dumb ox would fill the world. Following a period in Cologne, where he witnessed the laying of the cornerstone of the great cathedral, Thomas was sent back to Paris to study for the terminal degree in theology, the "master of the sacred page" (referring to Scripture). Owing to university politics, however, the degree was withheld, and it took a letter from the pope to the chancellor before Thomas and his fellow student Bonaventure (the future Minister General of the Franciscan Order) were admitted to the "university" of masters.

The Beginnings of the Summa.

For three years Thomas held the chair assigned to the Dominicans at Paris, then was transferred to his native Italy for the next ten years. While teaching in the house of studies in Rome, Thomas conceived the idea of what was to become his masterpiece, the Summa theologiae, the "Summary of Theology," which was written, as he said in the Prologue, for beginners in the discipline. In 1268 Thomas was transferred again to Paris, this time to do battle against the movement that had arisen in his absence, Latin Averroism. One detects in his writings from this period a dramatic change from his usual placid and tranquil demeanor, and Thomas used rather harsh language in challenging the professors who he was convinced were misinterpreting Aristotle and threatening his own project, which was to build a new synthesis of Christian theology on the foundations of Aristotle's natural philosophy.

A Remarkable Output.

Thomas left Paris after four years of incredibly intense activity, when in addition to his lectures on Scripture and his continuing work on the Summa, he had begun his own commentaries on the works of Aristotle. Although these commentaries were extracurricular for Thomas—that is, they did not constitute part of his duties as a master of theology—they were written by him precisely to defend his use of Aristotle in theology in the face of the "Augustinians" who had accused him of Averroism. Back in Naples, exhausted by his Herculean efforts (he wrote or dictated fifty works in his forty-nine years), he suddenly stopped writing altogether, leaving the Summa incomplete. When questioned by his secretary, Reginald of Piperno, Thomas would only reply that after what had been revealed to him, he realized that he had not come close. The following spring, on his way north to attend the Council of Lyons to which he had been summoned, he fell from his horse and was taken to a nearby monastery, where some days later he died. He was officially recognized as a saint almost fifty years later, after several of his teachings which had been condemned in 1277 were subjected to a re-examination and found to be orthodox.


Albert and Thomas. Selected Writings. Trans. and ed. Simon Tugwell (New York: Paulist Press, 1988).

Jean-Pierre Torrell, Saint Thomas Aquinas. Vol. 1. Trans. Robert Royal (Washington D.C.: Catholic University of America Press, 1996).

James A. Weisheipl, Friar Thomas d'Aquino; His Life, Thought, and Works (Washington, D.C.: Catholic University of America, 1983).

Thomas Aquinas (ca. 1225-1274)

views updated May 23 2018

Thomas Aquinas (ca. 1225-1274)

One of the most profound scholars and subtlest logicians of his day. Aquinas was born around 1225 in Roccasecca, Italy. He was educated under the Benedictine Monks of Monte Cassino and in the University of Naples, and entered the Society of Preaching Friars, or Dominicans, at 17 years of age. His mother, indignant that he should take the vow of poverty and thus remove himself from the world for life, employed every means in her power to induce him to change his mind. In order to remove Aquinas from her influence, the friars relocated him from Naples to Terracina, from Terracina to Anagnia, and from Anagnia to Rome.

His mother followed him in all these changes of residence but was not permitted to see him. At length she induced his two elder brothers to seize him by force. They kidnapped him while he was traveling to Paris, where he had been sent to complete his course of instruction, and they carried him off to the castle of Aquino, where he had been born. Here Aquinas was confined for two years, but he found a way to correspond with the superiors of his order, and he finally escaped from a window in the castle.

Aquinas exceeded most men in the severity and strictness of his metaphysical disquisitions and thus acquired the name of "Seraphic Doctor." He was canonized by Pope John XXII in 1323.

Because of his association with Albertus Magnus, he shared many legends of magical powers. For example, it was said that because his study was placed in a great thoroughfare where the grooms exercised their horses, Aquinas found it necessary to apply a magical remedy to this nuisance. He made by the laws of magic a small brass horse, which he buried two or three feet underground in the middle of this highway so that horses would no longer pass along the road. The grooms were compelled to choose another place for their daily exercises.

Another legend claimed that Aquinas was offended by the perpetual chattering of an artificial man made of brass, constructed by his tutor Albertus Magnus, and he dashed the automaton to pieces. Aquinas was also supposed to have written some tracts on alchemy.

However, his credulity regarding demonology and witchcraft had an unfortunate influence on witchhunters, and he was later cited as an authority by such writers as Heinrich Kramer and Jakob Sprenger, authors of the infamous Malleus Maleficarum. Although Aquinas did not accept the concept of a pact with the Devil, he endorsed the belief of diabolical association, and the incubus and succubus. He echoed Albertus Magnus in claiming that when Satan tempted Christ on the mountain-top, he carried Christ on his shoulders, and this belief was used by later witchhunters to endorse the theory of transvection, or magical transport of witches through the air. Aquinas also believed in the power of the evil eye used by old women who had an association with the Devil. His argument that heretics should be burned was later used to justify the burning of witches.

It should be stressed that Aquinas's credulity was characteristic of his time, and his theses concerning the Devil reflected the conclusions of theological dogmas of his day. Nevertheless, his discussions were used by later and lesser individuals to justify the witchcraft delusion.

The major works of Aquinas include the Summa Theologica and the Summa contra Gentiles. His great intellectual and theological achievements have somewhat overshadowed the mystical side of his character, and it should be remembered that he ended his life as a contemplative mystic.

He died March 7, 1274, in Fossanova, Italy.


St. Thomas Aquinas and His Legacy. Washington, D.C.: Catholic University of America, 1994.

Stockhammer, Thomas. Thomas Aquinas Dictionary. New York: Philosophical Library, 1965.

Aquinas, Thomas, St

views updated May 23 2018

Aquinas, Thomas, St (c.1225–74). Dominican philosopher and theologian, recognized as one of the greatest thinkers of the Catholic Church. He was canonized in 1323 and declared a Doctor of the Church in 1567. Feast day, 28 Jan. Aquinas's major works include commentaries on Aristotle and the Bible, general treatises (Summae) on Christian doctrine, and discussions of particular topics such as Truth and Evil. Central to his outlook is the notion of God as Creator ex nihilo (out of nothing). On Aquinas's account, God is the cause of there being anything apart from himself. In the light of this view, Aquinas further argued that God is not one of a class of spiritual beings; he is sui generis, not an individual, omniscient, omnipotent, changeless (meaning ‘timeless’), perfect, incomprehensible, and the cause of all that comes to pass, including the choices of his creatures. Aquinas rejected determinism and believed in free will, but he also insisted that the free actions of creatures are directly caused by God as Creator of everything.

In the areas of ethics and psychology Aquinas resembles Aristotle. He rejected a sharp mind-body dualism, and he held that criteria of human goodness are discovered by a study of human nature which is essentially bodily and social. But according to Aquinas, human beings can be transformed by grace to a level not anticipated by philosophy. He also held that by faith one can have access to truths about God not themselves demonstrable philosophically. These truths include doctrines like the Trinity and the Incarnation, which Aquinas believed to be revealed by God. See also THOMISM; QUINQUE VIAE.

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Saint Thomas Aquinas