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IN 1879, exactly 20 years after Charles Darwin published On the Origin of Species, Pope Leo XIII delivered an encyclical arguing that Catholics should dialogue with the scientific world without sacrificing tradition:

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We exhort you . . . to restore the golden wisdom of St. Thomas [Aquinas], and to spread it far and wide for the defense and beauty of the Catholic faith, for the good of society, and for the advantage of all the sciences. Let . . . teachers endeavor to implant the doctrine of Thomas Aquinas in the minds of students, and set forth clearly his solidity and excellence over others . . . and use it for the refutation of prevailing errors.

What was it about this controversial thirteenth-century preacher that led a pope six centuries later to declare his wisdom still indispensable? Why does Thomas’s Summa Theologiae (loosely translated as A Compilation of Theology) endure as the arguable gold standard of theological works? 

On the path to greatness?

Thomas was the youngest of eight children born to Landulf of Aquino, a minor lord in the Kingdom of Sicily, and his aristocratic wife, Theodora. The date of his birth is uncertain—probably around 1225—but the place is well known, the family castle in Roccasecca, near the famed monastery of Monte Cassino. The monastery was not only the center of Benedictine monasticism, but also the epicenter of conflicts between Emperor Frederick II and the pope. 

At the tender age of five, Thomas was sent to Monte Cassino to be raised by his paternal uncle, the abbot of the monastery. According to church regulations, the boy was still too young to become an oblate (a young person educated at and sharing in the life of the monastery, possibly with the intention of becoming a monk), but that was undoubtedly the path on which his family was placing him. Unfortunately for their plans, imperial soldiers stormed and occupied Monte Cassino in 1239 when Thomas was about 14. Landulf and Abbot Sinibald decided that the monastery was no longer safe for young Thomas, so, fatefully, they sent him south to study at the new university in Naples. 

Naples was not only independent from the church, but it had antipapal leanings making it a surprising choice for a lad being primed for Benedictine leadership. Scholasticism—an approach to study that emphasized rigorous logic, carefully reasoned debate, and judicious use of earlier (often pagan) philosophy—dominated all thirteenth-century universities. But at Naples Thomas was first exposed to teachings regarded as controversial to clergy of other universities (such as Paris, where he would eventually end up). 

The prime example was philosophy derived from the work of the great Greek philosopher Aristotle, studied in the form of translations and commentaries written by Muslim intellectuals. Aristotelians taught that everything is subject to reason and all knowledge is obtained by sense impressions. These studies would have a significant impact on Thomas’s later writings. 

A traveling preacher 

Just as fatefully, in Naples lived a small contingent of monks from a new group called the Order of Preachers, or as they would become known, the Dominicans. The Dominicans were mendicant (begging) preachers, who relied solely on charity for their sustenance. The order was founded to combat heresy, and Dominicans were known for their intellect, breadth of knowledge, and ability to present arguments. All of these qualities made the group attractive to the young scholar from Aquino. In short order the 19-year-old Thomas made the monumental decision not to return to prestigious Monte Cassino to take Benedictine vows, but rather to take the black cloak of a Dominican preacher.

His family was furious. Theodora was not about to allow her dream to die; her youngest child was destined to be the abbot of St. Benedict’s monastery, not a beggar in an order despised by clergy and traditional monks alike. To protect their new protégé from his family’s wrath, the Dominicans sent Thomas to study at the University of Paris, far away from parental influence. 

Theodora, though, caught wind of the impending transfer. She instructed her older son to capture Thomas and return him to the family. Before Thomas even made it as far as Rome, his brother nabbed him and spirited him off to a family castle at Monte San Giovanni, where he was told he would remain under house arrest until he renounced his foolish dream of being a Dominican.

In the year Thomas’s family held him captive, it is hard to know where fact stops and legend begins. He was not cut off from his family; indeed, he spent much time tutoring his sisters. He was also permitted to correspond with Dominican colleagues, which is somewhat perplexing since these contacts further solidified his commitment to join the ranks of the Black Friars.

But this limited freedom did not mean that Thomas’s family had given up the fight. They were so adamant that Thomas should never join the Dominicans that, according to one legend, his brothers sent a prostitute to tempt him. The pious young man drove the woman off to maintain his chastity and was thereafter protected by holy angels.

After a year of no progress, Theodora finally gave up. She made arrangements for her son to “escape” through an open window in the castle. He went straight back to his Dominican mentors in Naples and thereafter to Paris, where he began the scholarly life that would help to define Catholicism for centuries. 

Thomas the theologian

Like all theologians of this period, Thomas studied Scripture and the early church fathers, especially Augustine. His theological works show clear mastery of Neoplatonic thought (a famous system of pagan philosophy). But had he focused on these, Thomas would have been just one more medieval scholar repeating long-held doctrines and aphorisms.

What set Thomas’s thinking apart was his reliance on Aristotle, or as Thomas always called him, “The Philosopher.” It did not seem to bother Thomas that he was drawing on a “pagan” author, because he believed that philosophy is not intrinsically incompatible with Christian teaching. 

The human intellect is a mark of the image of God, he thought: thus, intelligent, virtuous non-Christians such as Aristotle have the ability to discern some truth through natural reason. Intellect illumines Christian truth, and Christian faith completes the salvation that natural intellect alone cannot achieve.

Thomas was a prolific writer. As a young scholar, he was charged with teaching his students Peter Lombard’s Sentences, the basic textbook of the day for budding theologians. In preparation for his lectures, Thomas wrote a commentary on the Sentences, showing the makings of a scholar who studied even the most revered Catholic texts with a critical, analytical eye.

Thomas also wrote commentaries on Isaiah, Jeremiah, and Lamentations that focused on the literal meaning of the passages. While this may not sound unusual today, medieval commentaries often fixated on interpretations that were allegorical (seeing Old Testament events as prefiguring Christ) and anagogical (seeking the eternal significance of Old Testament passages). 

All this was enough to establish Thomas as a first-rate thinker. But the crowning achievements of Thomas’s scholarly career, written near the end of his life, would be his apologetic works, the Summa contra Gentiles and his related theological manual, the Summa Theologiae.  

Not fitting into the curriculum

Despite his unmistakable theological prowess, the theologians at the University of Paris never accepted Thomas. It was bad enough that he was a member of an order of “begging” preachers that they despised; these clerics were equally offended by the introduction of new ideas and methods into their established curriculum. Consequently Thomas left Paris for the Dominican centers of Santa Sabina and Naples to write his magnum opus, the Summa Theologiae.

The Summa is not a systematic theology in the modern sense, laying out doctrines of revelation, Christology, ecclesiology, and other “ologies,” each building on the other. Its massive three volumes do discuss the nature of God and creation, the virtues, and the work of Christ. But within each section, Thomas introduced basic doctrinal questions (“Is the Eucharist a sacrament?”), reviewed opinions different from his, and then presented the logic behind his answers to the questions with careful precision.

It is difficult to overstate the long-term impact these volumes had on the theology and practice of the church through their systematic presentation of doctrine and repeated insistence on seeking reasonable compromise positions on disputed questions. 

Catholic sacramental theology holds that the seven sacraments (not two, as in most Protestant traditions) actually bring about change in the believer. Its mature formulation relies heavily on the Summa. In the Eucharist the bread and wine are changed, so that the whole substance of Christ is present in the elements; Aquinas described this presence as so objective that even those without faith receive. The Summa’s teachings on natural law are also enshrined in the Catechism of the Catholic Church: the law of God is inscribed in the human heart, universally perceivable through human reason and sufficient to establish ethical standards that make all humans accountable to God.

Perhaps the Summa is best known for its five proofs of the existence of God. Using logic drawn from Aristotle, Thomas argued that motion in the universe requires an initial mover; that effects require a first cause; that there must be something in the universe whose existence is not contingent on something else; that varying degrees of goodness in the universe only have meaning when measured against something of absolute goodness; and that nonintelligent things can only reach their end when guided by an infinitely intelligent being. While these arguments have been frequently criticized, they nevertheless serve as staples in theology classes (and on apologetics websites) and are echoed by other writers in this issue. 

The end and beyond

On the Feast of St. Nicholas, December 6, 1273, Thomas was celebrating Mass in Naples when he had a profoundly life-altering experience. His contemporaries insist Thomas levitated before the altar and received a vision; later scholars have wondered if he experienced a mental or physical collapse. Whatever it was, after coming down from the altar, Thomas declared that his life’s work was nothing but straw. He never wrote again; the Summa Theologiae remains unfinished to this day. In about three months, the great scholar was dead at the age of 49.

In the years immediately following his death, Thomas continued to generate controversy in clerical circles. In 1277 the bishop of Paris delivered a lengthy condemnation of theologically suspect doctrines, some clearly Thomistic teachings based on Aristotelian thought. 

But as the centuries rolled on, Thomas’s immense contributions to the church were recognized and celebrated. He was canonized in 1323 by Pope John XXII, and in 1567 the Holy See declared him a doctor of the church, to be venerated at the same level as Augustine and Ambrose. We can only suppose that, had Landulf and Theodora been permitted to look down the centuries to witness Pope Leo XIII declare their son the bedrock of Catholic theology, they finally would have had the faith and reason to realize that Thomas knew what he was doing all along. CH

This article is from Christian History magazine #116 Twenty-Five Writings that Changed the Church and the World. Read it in context here!

By Garry J. Crites

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