Peter Lombard

c. 1100-1160

Peter Lombard's birthplace, the Piedmontese town of Novara, lies at a strategic crossroads between Turin, Milan, Genoa, and Switzerland. When Peter found himself at the crossroads of competing approaches to theology, he again chose the middle ground.

The intellectual climate of the early twelfth century was stormy. Peter Abelard (1079-1142), author of Sic et Non (Yes and No), questioned everything—and readily flouted church authority—in a quest for theological truth. Ecclesiastical authorities struggled just as vigorously to maintain the primacy of church fathers such as Augustine, Jerome, and Gregory the Great.

Peter Lombard responded to this clash by writing a textbook characterized by its rigorous approach to the whole spectrum of theological knowledge. This text, called Sentences, would become the template for formal theological discourse well into the Modern period.

"We have studied to encircle the Tower of David with shields … and open things withdrawn from theological inquiry and display the knowledge of the church's sacraments as far as our poor understandings might reach." So begins Peter's prologue to the four books in which he attempts to navigate a path between reckless speculation and authoritarianism.

The first book, on the unity of God and the nature of the Trinity, is followed by books devoted to created beings and their corporeal and spiritual natures, the Incarnation and Christ's rescue of humanity, and the sacraments and the four last things (death, judgment, hell, and heaven).

Peter consistently looks to both tradition and reason. While exploring questions about the Trinity, for example, he quotes Augustine: "Against the garrulous reasoners, more elated than capable, one must use catholic reasons and congruous similitudes … so that satisfying their questions we may more fully instruct the meek." Then he tirelessly combs through Scriptures in search of precedent for the puzzling doctrine of "the plurality of persons and the unity of divine essence."

Eventually his reasoning takes him to Augustine's idea that the nature of the Trinity can be discovered in the three-fold operations of the human mind. From there Peter proceeds, using the same careful analysis, to the relation of the three persons to one another, and to creation.

Peter's analysis is slightly stodgy, but it invites sophisticated philosophical analysis. The great theological minds of the later Middle Ages, including Aquinas, Scotus, Bonaventure, and William of Ockham, defined the foundations of their philosophical theology by writing detailed commentaries on the Sentences. Some of these commentaries have become well known, but Sentences, unfortunately, remains largely untranslated and unavailable.


John Duns Scotus

c. 1266-1308

Perhaps no great medieval thinker is as little understood as John Duns Scotus. Scholars cannot agree when or where he was born, students try to avoid reading his dense work, and some theologians wonder if he strayed into heresy. The most common reference to his name, sadly, is the derogatory epithet "dunce," used to describe someone who cannot give a simple answer.

Scotus, known as the "Subtle Doctor," was likely born in the town of Duns in the Scots lowlands. He joined the Franciscans and studied in Oxford until 1301. Francis's emphases on loving Christ in the Eucharist and respecting church authorities influ- enced Scotus throughout his career.

In 1304 he was named Franciscan Regent Master at the University of Paris, where he conducted theological disputations and became known as the greatest theologian of his generation. In assigning Scotus to the university post, Master Gonsalvus Hispanus called him "Friar John Scotus, of whose laudable life, excellent knowledge, and most subtle ability as well as his other remarkable qualities I am fully informed, partly from long experience, partly from report which has spread everywhere."

While he was in Paris, conflict arose between King Philip IV of France (who wanted to raise funds for a military campaign by taxing French clergy) and Pope Boniface VIII (who believed that church properties—as well as all spiritual and much temporal authority—belonged to the papacy). Scotus's support for the pope got him kicked out of the country, but he soon returned. He died on November 8, 1308, after traveling to Cologne to serve as rector at the Franciscan college there.

Scotus's thought is difficult to characterize. He did not write clearly or systematically. Because he died young, he was unable to finish or synthesize many of his writings. His work at times reads like a series of sharp, unrelated arguments. Further muddling matters, he frequently wove his own position into his assessment of other philosophers' ideas. Nevertheless, his Aristotelianism is manifest to any reader familiar with disputes of the day, as is his use of the Muslim thinker Avicenna.

Though Scotus's positive view of the human will conflicted with both Aquinas and Augustine, Scotus's arguments for the Immaculate Conception of Mary raised more of a ruckus in his day.

Early church fathers who had promoted Mary's special status had already raised the idea of her sinlessness, but Scotus was the first to suggest that she was free from inherited sin because Christ's grace was applied to her, preventatively, at her own conception.

Because Albert the Great, Bona-venture, and Aquinas had all opposed this theory, their Dominican and secular heirs launched an attack. Jean de Pouilly went so far as to call the idea heretical and declared, ominously, that anyone who supported it should be countered "not with arguments but otherwise." Nonetheless, Scotus's thesis gained ground, and the Immaculate Conception was made dogma in 1854.

Until well into the Modern period, the "Subtle Doctor" was widely known and respected as the zenith of scholastic thought. His work embodies an analytic precision, systematic complexity, and theological depth that continues to awe his readers, few though they may be.


Albert the Great


While teaching at Cologne in 1245, Albert noticed the remarkable mind of his shy pupil Thomas. Albert famously scolded students who derided Thomas's apparently plodding behavior, saying, "Call this young man a dumb ox, but his bellowing in doctrine will one day resound throughout the world!" If his student had not risen to prominence, though, Albert likely would be remembered as the greatest Dominican philosopher in the thirteenth century.

Born to a noble family in Swabia in 1206, Albert joined the Dominican order and studied theology in Padua. His mastery of the range of natural sciences, from astronomy and physics to zoology and botany, earned him the sobriquet "Universal Doctor." He combined that scientific knowledge with formal scholastic reasoning and an experimental approach to learning.

While his contemporaries were largely content to accept Aristotle's science as the final word on the natural world, Albert insisted that experiments alone would advance scientific understanding. "The aim of natural science," he said, "is not simply to accept the stories of others, but to investigate the causes at work in nature."

Albert and his Franciscan contemporary Roger Bacon both dedicated their lives to proving that the scientific study of the physical world could benefit the church, while turning a blind eye to nature's complexities would only detract from God's glory. Bacon's approach was occasionally iconoclastic and abrasive, but Albert's was guided by a respect for authority and a sensitivity to nuance that ensured his writings a wide and appreciative audience for centuries to come.

Albert had scant patience for the occult, and he viewed alchemy, the mystic attempt to unlock nature's secrets through weak metaphysics and superstition, as unalloyed nonsense. Unlike these silly speculations, his own careful reasoning pointed the way to later discoveries. He used mathematics to demonstrate that the earth is round, which had not been done since classical antiquity, and he wrote of the probable existence of continents yet undiscovered by Europeans.

Albert's scientific reputation spawned wild stories of magical pursuits. One tale holds that he created a thinking, speaking robot. Thomas supposedly destroyed the creature, fearing that it was the work of the devil. Such stories are likely the product of early Modern scientists eager to denigrate the work of their medieval predecessors.

Sadly, Albert outlived his brilliant pupil, but he never forgot him. When a campaign arose to condemn Thomas's writings, he expended his last energies to return to Paris to defend his student's work. He died soon afterward.



c. 1217-1274

Giovanni Fidanza, later known as Bonaventure, joined the Franciscans when he was 17. After Francis of Assisi, Bonaventure was the person most responsible for the organization and growth of the Franciscan order. He was also one of its greatest theologians.

Bonaventure began a friendship with Thomas Aquinas at the University of Paris, where they received their doctorates together in 1267. He wrote voluminously, establishing himself as the Franciscans' answer to the Dominican Aquinas.

In each of Bonaventure's theological works, he reveals his devotion for the beauty of creation and the realization of God's love in each creature. Perhaps the best example of his unique approach is "The Mind's Road to God," which leads the reader in a series of six meditations from contemplation of God's reflection in nature, in the natural faculties of the human soul, and ultimately through grace to the perfect Being of the divine.

The purely intellectual theorizing that was creeping into scholastic discourse repelled Bonaventure. He was determined to keep love, compassion, and an awareness of nature's abundance as integral parts of daily spiritual development.

"The beauty of things," he wrote, "in the variety of light, shape and color, in simple, mixed and even organic bodies—such as heavenly bodies—and minerals like stones and metals, and plants and animals clearly proclaims the divine power that produces all things from nothing, the divine wisdom that clearly distinguishes all things, and the divine goodness that lavishly adorns all things."

Bonaventure had gained a reputation for an even-handed, judicious temperament while studying in Paris, and the Franciscans desperately needed that influence. The order had been split by violent disagreement about Francis's ideal of apostolic purity. One group, the Spirituals, denounced all property ownership as a compromise with the curse of Original Sin. The other group, the Conventuals, saw the Franciscan mission as including an embrace of the world and its trappings.

Bonaventure's willingness to listen carefully and lovingly to all sides of a dispute allowed him to rescue the order from chaos by instituting a code of laws that struck a balance between the two factions. His biography of Francis, approved by the order in 1263, helped define that compromise. He even explained the rule of poverty in a way that made sense to a world entranced with material success.

As his reputation within the church grew, he earned the position of Cardinal-Bishop of Albano in 1273. Bonaventure was not eager to become a prince of the church, though. When papal envoys came bearing the cardinal's wide-brimmed hat, the story goes, they found Bonaventure washing dishes outside a Florence convent. Rather then interrupt himself from his task, he told the envoys to hang the hat on a nearby tree until he had time to free his hands.

He died while trying to mend the Roman church's schism with the Greek church a year later. He might have been poisoned.

Stephen E. Lahey is assistant professor of philosophy at LeMoyne College in Syracuse, New York.