Thomas Aquinas's Summa theologiae

by Bernard McGinn

  The quiet, prayerful, brilliant young friar began to teach at Paris in 1252 as a “Sentence Bachelor” responsible for teaching and writing on the four Books of Sentences. Thomas’s massive Writing on the Books of Sentences (Scriptum super libros sententiarum) was his first major work (it contains almost a million and a half words). Although positions advanced here were later superseded in the Summa theologiae, the testimony of William of Tocco and others on the impact his novel lecturing and writing had in Paris in the early 1250s is telling:

  When he was made a bachelor and had begun to pour out in his lectures what he had beforehand chosen to hide in silence, God infused such great knowledge into him … that he was seen to surpass even all the masters [of theology], and, by the clarity of his teaching, to move the students to love of knowledge more than others did. In his teaching he argued new articles; he found a new and clear way of deciding questions; he brought in new proofs in scholastic determinations to the extent that no one who heard him teaching new matters and settling doubtful questions with new proofs doubted that God had enlightened him with a new kind of illumination.5

  Although there is doubtless a bit of parti pris in one Dominican writing for the canonization of another, it is hard to doubt that Thomas’s Parisian students were “blown away,” as we say, by his brilliance and originality.

  Thomas remained teaching in Paris from 1252 to 1259. After several years expounding the Sentences, he was promoted by papal letter to the position of magister in sacra pagina (Master of the Bible) in the spring of 1256 and had to prepare an inaugural lecture and dispute several questions over two days. The lecture, discussing Psalm 103:13 (“Watering the mountains from his places on high, the earth will be filled from the fruit of your works”), gives us a sense of how the young friar understood his vocation. Thomas says that all wisdom comes down from God to water the mountains, that is, the teachers of doctrine. Hence these “mountains,” the masters of sacred scripture, are called to be high in the quality of their lives, enlightened in their lecturing, and well-armed to refute errors. In communicating true teaching to make the earth (i.e., their hearers) fruitful, they do not depend on themselves. “God communicates wisdom by his own power,” says Thomas, “and so he is said to water the mountains by himself; teachers can only communicate wisdom in a ministerial role.”6 What is worth noting is not only Thomas’s emphasis on the communication of wisdom, but also the humility with which he approached his calling.

  Thomas and his contemporary, the Franciscan Bonaventure of Bagnorea (1217–74), who had been promoted in 1253, were not accepted into the lists of the masters until 1257, and then only under papal pressure. The reason was the quarrel that had erupted between the friars and the nonmendicant masters at the university in the 1250s, a controversy that had a considerable impact on Thomas’s thought and career. Religious novelty was often suspect in the Middle Ages, and although the mendicants had won papal support, they had many opponents. The favors the mendicants gained from the popes, both in pastoral care and at the university, provoked a group of secular masters led by William of St. Amour to attack them from 1252 on. The Franciscans and Dominicans were accused of setting dangerous precedents and of being religious hypocrites, even of being the false preachers and forerunners of Antichrist who were predicted to arise at the end of the world (Matt. 24:11–12). The peril was real: the supporters of the secular masters threatened the houses of the friars to the extent that King Louis IX had to call out the royal archers to defend them. On the intellectual side, both orders turned to their rising young stars to answer the charges. In 1256 and 1257 Bonaventure and Thomas wrote defenses of the mendicants, upholding their status as true followers of the “apostolic life” of Jesus and the disciples.7 While Thomas’s temperament seems to have been basically irenic, his writings against those who attacked the mendicants, as well as later against the radical Aristotelians, show that in polemical situations he could be roused to expressions of anger and exasperation. Nevertheless, Thomas’s mode of engagement was always to encourage discussion, not invective. In a passage from a later work in defense of the mendicant life, the treatise On Perfection written in 1270, he says,

  If anyone wants to write against what I have said, it would be most welcome. There is no better way to open up the truth and to refute falsity than to answer opponents, as Solomon says, “Iron sharpens iron, and a person sharpens his friend’s face” (Prov. 27:17). God himself, who is blessed forever, will make the judgment between us and them. Amen.8

  During the period 1256 to 1259 Thomas taught at Paris as one of the two Regent Masters of the Dominicans, disputing and composing his questions On Truth, perhaps the most significant of his disputations,9 as well as works like a Commentary on Boethius’s “De Trinitate,” important for its view on the relation of philosophy and theology. We should remember that Thomas, as a member of the Order of Preachers, also preached. Even though he was an academic and not assigned to a parish, he was required to preach Latin sermons to the university community during the year, and, when in southern Italy, he preached to broader audiences in the vernacular. Only about twenty of Thomas’s academic sermons survive, but we have Latin collections of sermons on important religious texts, such as the “Our Father,” the “Hail Mary,” the “Apostles’ Creed,” as well as homilies on the ten commandments (probably originally given in Italian). These sermons show Thomas was a strictly doctrinal preacher, but clear, concrete, and easy to follow. He avoided the lively exemplary stories and rhetorical flourishes found in much medieval preaching.10

  Sometime in late 1259 or early 1260 Thomas returned to the Roman province of the Dominicans, probably first going to his home convent in Naples. In 1261 he was ordered to the convent at Orvieto north of Rome, which was also the location of the papal court. Thomas was the “Reader of Theology” at this house between September 1261 and September 1265. It was during this time that he brought to conclusion a project he had begun in Paris, what is called in the manuscripts both the Summa against the Pagans (Summa contra Gentiles) and The Truth of the Catholic Faith against the Errors of Unbelievers. In four books (some surviving in his own hand), this work was intended to show that theology could make good use of philosophy in its investigation and defense of revealed truths, both those that have been studied by the philosophers, though often erroneously (books 1–3), and those, like the Trinity and Incarnation, that cannot be attained by reason (book 4). By consensus, this work is Thomas’s other great synthesis, along with the Summa theologiae. In the second chapter of the first book of the work Thomas expresses his intention with a rare personal tone: “Taking up by divine kindness the task of pursuing the office of a wise person with confidence, although it is beyond my powers, my intention is to make known the truth that the Catholic faith professes to the best of my ability by eliminating the errors against it.”

  Friar Thomas’s intellectual efforts during these four years extended widely. He completed a long Commentary on Job, one of his most important biblical works, and at the behest of Pope Urban IV wrote a treatise Against the Errors of the Greeks (1263 or 1264), in which he appealed to the Greek Fathers to correct what he considered the errors of contemporary Greeks. It was also at the pope’s request that Thomas began one of his most popular works, The Golden Chain (Catena Aurea), a running commentary on the four Gospels culled from the Greek and Latin Fathers, showing a deep knowledge, unusual for the time, of many Greek writers. Finally, and again at the request of Urban IV, Thomas composed the Mass and Office for Corpus Christi, which was proclaimed as a universal feast on August 11, 1264. Despite some doubts about its authenticity, this collection of readings, prayers, and hymns to the Eucharist (the famous “Pange lingua,” or “Sing My Tongue”) reveals Thomas’s sacramental piety and considerable skill as a poet. On September 8, 1265, the provincial authorities again sent orders to Thomas, commanding him to repair to nearby Rome and the convent at Santa Sabina on the Aventine. It was at Santa Sabina that he began the writing of the Summa theologiae.
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  During the 1260s Thomas made contact with the new and improved translations of many of Aristotle’s works by a fellow Dominican, William of Moerbeke, who had spent time in Greece and learned the language well. Older claims about Moerbeke’s influence on Thomas are now considered exaggerated, but there is no question that during this decade Thomas deepened his knowledge of Aristotle by beginning to write a series of commentaries on the Greek philosopher. Thomas was to write no fewer than a dozen commentaries on Aristotle in a relatively brief time (ca. 1267–73). In the nineteenth and early twentieth centuries, when Thomas was seen as an “Aristotelian” in outlook, these works were carefully mined to extract an “Aristotelico-Thomistic” philosophy. That view is now disputed, and some have questioned whether we should speak of Thomas as an “Aristotelian” at all (a term he never used). Nevertheless, Thomas knew Aristotle well, cited him extensively throughout his works, and generally followed Aristotle’s philosophical views. But we still can ask why Thomas expended so much energy in writing his commentaries, some quite long, on Aristotle’s writings.

  The answer lies in Thomas’s conception of the vocation of the theologian. As he began the writing of the Summa theologiae in 1266, Thomas seems to have become more and more convinced that a careful study of the philosophical resources found in Aristotle could help him deepen his thinking on important theological issues, such as the nature of the soul. He may also have been aware of the growing disputes over the use of Aristotle, the “Aristotelian crisis” that began to disturb the University of Paris in the 1260s. Thomas thought that in the midst of debates over the legitimacy of employing Aristotle in theology, it was necessary to correct misinterpretations and to give students a clear and correct understanding of how the “Philosopher” (as he was named in the medieval schools) could be used in theology, as well as the limits of that use.

  In 1268 Thomas was called back to Paris to assume one of the two Dominican chairs of theology. This was an unusual privilege, but the Order seems to have become convinced that Thomas’s presence at Paris was important in the midst of the conflict over the use of Aristotle and the deeper issue of the role of philosophy in theology. Although the teaching of Aristotle’s natural philosophy had been banned at Paris in 1210 and 1215, it proved impossible for both the masters of the arts faculty and the theologians to refrain from employing such a useful intellectual tool, not only in logic, but also more broadly in philosophy. By the 1230s Aristotle was creeping back in, and in the 1240s Albert the Great and others were teaching and commenting on Aristotle and using Aristotelian elements in their theology. Like most medieval textbooks, Aristotle’s writings were used within a “commentarial envelope,” that is, along with the extensive explanations of the Islamic philosopher Ibn Rushd (1126–98), or Averroes. Aristotle’s philosophy, however, especially as filtered through Averroes, conflicted with Christian belief at key points, such as its claim for the eternity of the universe and its denial of personal immortality because of the teaching that there was only one universal Intellect in which all humans participate (monopsychism). Some teachers of Aristotle in the arts faculty, often called “Averroists” (Thomas was the first to use the term) or “radical Aristotelians,” presented Aristotle’s teachings on these controversial points as necessary conclusions of reason, much to the annoyance of conservative theologians who used such claims to attack any use of Aristotle in theology beyond his logic. These theologians, of whom Bonaventure can be considered the founding father, are often called Neo-Augustinians, because they insisted that Augustine’s authority extended equally to both theology and philosophy.

  The Dominicans, led by Albert and Thomas, defended a broad use of Aristotle’s philosophy as helpful for constructing a reasonable and coherent account of Christian faith, though, of course, they stood ready to convict Averroes, and even Aristotle, of error when their teachings conflicted with revelation. In this heated atmosphere, with Dominican theology under suspicion by the Neo-Augustinians who stressed the dangers of Aristotle, as well as the presence of Radical Aristotelian philosophers who argued that from the point of view of reason some important Christian doctrines could not be sustained, the Preachers summoned their premier theological mind back to Paris. Another factor in Thomas’s recall was a new flare-up in the attacks on the friars by the secular masters, one that prompted Thomas to write several more defenses of the mendicant life after his return to Paris.

  The details of the Aristotelian quarrel cannot delay us here. Suffice it to say that the positions of the Radical Aristotelians, like Siger of Brabant and Boethius of Dacia, were condemned by Stephen Tempier, the Bishop of Paris, in December 1270, while the opposed theological camps of those who were suspicious of Aristotle (mostly Franciscans) and those in favor of using philosophy, including Aristotle despite his problems (mostly Dominicans), were left to fight it out. Many issues were under contention. Two key differences between Thomas and his opponents, such as the Franciscans Bonaventure and John Pecham, involved Aristotle directly or indirectly. The Philosopher had argued for an eternal universe; Christian revelation taught that the universe was created in time (in principio: Gen. 1:1). The Franciscans contended that reason alone could prove Aristotle wrong, while Thomas, against most of his contemporaries, argued that the duration of the universe, that is, whether it was eternal or temporal, could not be demonstrated by reason—creation in time is a truth of revelation. A second major issue concerned the unicity of the substantial form of the human person. Thomas held that the soul was the single substantial form of the body; his opponents believed that a number of different forms or souls (vegetative, sensitive, rational), including a “form of corporeity,” constituted the human person, something like the layers of an onion. Though there had been differing views about this issue, even in the recent past, by Thomas’s time most masters held to a plurality of forms, often citing Augustine (incorrectly) in their favor. The dispute seems arcane to us, but it had implications regarding personal immortality and the status of Christ’s body after death that were important to the scholastics.11 These quarrels, among others, disturbed Thomas’s second Paris period and continued to dog his reputation after death.

  The dozen years 1261–73 in Italy and France saw Thomas at the height of his powers. A number of incidents recounted by the hagiographers provide us with a sense of what he was like. These tales seem to come in part from the witness of Reginald of Piperno, the friar who was assigned to be Thomas’s special companion (socius) from as early as 1259 until his death, functioning as the master’s helper, secretary, confessor, and (in the case of the absent-minded Thomas) what we might call his “minder.” One such story, meant to indicate Thomas’s indifference to worldly matters, rings especially true. It seems one day Thomas and some students walked out to St. Denis in the Paris suburbs to reverence the church’s relics.12 On their return, as they sat down looking out at Paris, one of the brethren said, “Master, see what a beautiful city Paris is. Wouldn’t you like to be Lord of the city?” “Why,” answered Thomas, “what would I do with it?” The student said that he could sell it to the king to build houses for the friars. “I would rather have the homilies of Chrysostom on Matthew’s Gospel,” responded Thomas. William of Tocco gives some moralizing remarks he ascribes to Thomas about not wanting to be put in a position where his contemplation would be impeded, but the original exchange reveals Thomas’s academic obsessions.13

  In early 1269 Thomas had less than five years of teaching and writing left. They were to be years of almost incredible productivity, because he was not only continuing work on the massive Summa theologiae, but also teaching, disputing, and writing commentaries on Aristotle and the Bible at an astonishing rate, not to mention various treatises, short and long. Thomas lived in a tearing hurry—he probably thought he never had enough time. Few great thinkers have produced so much material of such quality in so short a time—quite probably to the detriment of his health. Most of the Aristotelian commentaries come from these years. With regard to the Bible, Tho
mas wrote long commentaries on the Gospels of Matthew and John, the latter possibly his greatest exegetical work. He also composed two important polemic treatises against his opponents. In 1270 his On the Unity of the Intellect Against the Averroists attacked the claim of the radical Aristotelian Siger of Brabant that there is only one Intellect in which all humans participate. In the same year he rebutted John Pecham’s argument that reason alone can prove that the world must have had a beginning in On the Eternity of the World Against the Murmurers. These polemical writings did not preclude Thomas’s obligations of teaching the Bible and conducting public disputations, later put into written form in the Disputed Questions on the Virtues and a number of his Quodlibetal Disputations.

  Thomas returned to Italy in the spring of 1272. On June 12 the Roman province assigned him the task of setting up a new studium generale. Thomas chose his home convent for this house of studies. Thus, his life as a Dominican, begun in Naples thirty years before, was to see its last chapter there. In the First Canonization Inquiry of 1319 we are given a picture of Thomas’s daily routine by a layman Nicholas Fricia, who used to hear Mass daily in the Dominican church and attend Thomas’s lectures:

  Very early in the morning Thomas would say his Mass in the chapel of St. Nicholas, after which … he heard another Mass, and then, taking off his vestments, at once began his teaching. This done, he would set himself to write or dictate to his secretaries until the time for dinner [midday]. After dinner he went to his cell and attended to spiritual things until siesta, after which he resumed his writing. And so the whole of his life was directed to God. It was the common view … that he had wasted scarcely a moment in his lifetime.14