Jean Buridan

Jean Buridan was an especially gifted instructor in Aristotelian logic, and scholars place the two Latin-language texts he authored in a historical timeline that bridges strict Christian theology and the revolution that came with the foundational writings in the hard sciences that began in the early 1500s. Through his writings, Buridan also inadvertently lent his name to the thought experiment known as the Paradox of Buridan's Donkey—better known in shortened form as the dilemma of Buridan's Ass. Based on one of his suppositions and promulgated long after his death, this premise invites students to consider a lowly beast of burden that is thirsty and hungry. If presented with a pile of hay and a trough of water, each an equal distance away, the creature would be unable to decide between the two and remain in a state of stasis before dying of dehydration or starvation.

There are scant details about the life of Buridan, save for few reliable facts in the historical records of the University of Paris. He was born in the late 1290s and self-identified as hailing from Picardy, the larger region that included those who spoke a Flemish (Dutch)-inflected version of French. Historians posit that he was a native of the town of Béthune in the Pas-de-Calais region, about 45 miles inland from the English Channel. Pas-de-Calais was part of the larger Arras region, which bordered that of neighboring Flanders, a major center of textile production and commerce hundreds of years before Buridan was born. A millennium-old center of Christianity dating back to the emergence of the Franks as the dominant local force after 500 CE, this part of northeastern Europe was prosperous and dotted by Gothic- and Romanesque-style churches. During Buridan's lifetime, these churches were among the largest human-built structures existing in Europe.

Although Buridan was likely of humble origins, he likely demonstrated above-average intellectual capabilities early in life. For this reason, he was selected for study at the elite Collège du Cardinal Lemoine, founded in Paris in 1302 by the bishop of Arras. From there he went on to the University of Paris and at some point took vows as a priest, although he never formally joined a religious order. Evidence that he held the status of cleric and had several wealthy, influential patrons in Arras survives in the fact that his name is attached to a benefice, a form of income granted to a church official. In Buridan's case, the income was attached to the Collegiate Church of St. Pol-sur-Ternoise in Arras.

Around 1320, Buridan likely completed his Master of Arts degree at the University of Paris, a supposition based on subsequent references to his status as a member of its faculty. The famous university was nearly 200 years old by then and benefited from its long association with the Paris landmark the Notre Dame cathedral. As both a student in the Master of Arts program and then one of its faculty members, Buridan would have been fluent in Latin, the language of scholarship for hundreds of years. The core curriculum, however, was rooted in the teachings of fourth-century BC scholar Aristotle, the Greek master at the renowned Academy of Athens. In Buridan's time, students who entered the university arts program studied three primary fields. These began with grammar, progressed to logic (also called dialectic), and finished with courses in a philosophy of the natural world based on Aristotelian tenets.

At the University of Paris and similar institutions of higher learning, a Master of Arts degree was merely a prelude to more rigorous training in one of three fields: medicine, law, or theology. Buridan did not pursue a theology degree, which marked him as one of the rare philosophers of late-medieval Christian Europe who did not hold a doctorate in his subject. Nor did he enter a religious order, as other philosopher-theologians of this era had done. The student body at the University of Paris was composed of men who were technically priests of the Roman Church, which enabled them to pursue higher education in the first place and then ensured they had protected status while enrolled.

Evidence of the high esteem in which Buridan was held by students and colleagues at the University of Paris turns up in references to his status as a rector, an elected position that gave him supervisory status for all teaching for the term. The first time he was voted rector, records show, was in late 1327, for a term that lasted from December of 1327 until March of the following year; he held it for a second term in 1340.

A more important post—and one of longer duration—that Buridan held as late as 1358 was as the chosen representative of the Picardians at the University of Paris. As a famous school of higher learning, the university attracted students from across Europe, and in the 1200s it adopted a Four-Nation arrangement to deal with administrative matters. An English-German contingent included students from the Scandinavian region; second among the four equals were scholars from the vast lands of the kingdom of Normandy. The third section comprised students from lands south of Paris—the south of France, plus Spain and Italy—and the fourth comprised the Picardians, whose members incorporated students from Ghent, Bruges, and the other Flemish wool-merchant and textile-exporting cities. Representatives of each of the four nations met to resolve disputes over exams and other administrative matters, and Buridan's name can be found in multiple instances recorded as the head of the Picardians.

Exams at the University of Paris were based on lectures and readings from laboriously hand-copied texts. Talented professors also compiled their course notes and that sometimes evolved into respected texts. In Buridan's case, he left behind two important works written in standard 14th-century Latin. Like other works of non-theological scholarship, these manuscripts drew from the Aristotelian School and its precepts of grammar, logic, and natural philosophy. The first is Tractatus de Consequetiis, or Treatise on Consequences. The exact date of its completion is unknown, but one passage mentions a white-cloaked cardinal as leader of the Roman Church. Interpreted by scholars as a reference to one of the Avignon popes, who ruled from the south of France during a time of great turmoil and internecine debate in Western European Christianity, this reference dates Buridan's Treatise to sometime after December of 1334, when a monk of the white-cassock-wearing Cistercian order became Pope Benedict XII.

Treatise on Consequences did not appear in print in full English translation until the mid-1970s, along with Buridan's other magnum opus, Summulae de Dialectica, or Compendium of Dialectic. This latter work, nearly 1,000 pages in length, delves deep into the Aristotelian syllogia, or system of reasoning. Copies of Buridan's Summulae could be found in major university collections during the pre-Gutenberg era. His work influenced generations of scholars and fueled the waves of radical thought emanating from France and northern Italy during both the 1400s and the early 16th century.

Buridan's position in Western European scholarship—as a transitional figure between the so-called Dark Ages and the humanistic Renaissance—derives from his commentary on inertia in Aristotle's Physics. In this text, which was standard reading for students immersed in the third main course in the Master of Arts program, the Athenian philosopher ponders the properties of objects in motion. “Contrary to Aristotle, it was clear to Buridan that nothing, especially not the air, pushes a thrown ball after it leaves the hand that threw it,” explained James Hannam in his book God's Philosophers: How the Medieval World Laid the Foundations of Modern Science. “It was equally clear that the ball moves as a direct result of the movement of the hand. Buridan suggested that the hand gives the ball a quality, which he called impetus.”

The laws of motion, inertia, and other physical properties of the known world may seem obvious to the contemporary reader, but in France during the 14th century those who ventured theories about such dilemmas risked official censure from the Roman Church. The idea that the natural world might operate according to its own rules—ones that were separate from Christian dogma about God and the creation of the universe—veered toward a heretical statement. In the most extreme scenarios, university masters even as widely known and respected as Buridan could be excommunicated and even put to death.

Fortunately, “Buridan answered the now familiar question—whether local motion is a thing distinct from the moved object and the places it successively occupies—by reference to theological doctrine,” explained David C. Lindberg in The Beginnings of Western Science: The European Scientific Tradition in Philosophical, Religious, and Institutional Context, 600 B.C. to A.D. 1450. “The theological starting point of Buridan's argument was the assumption that God, by his absolute power, could have endowed the cosmos as a whole with a rotational motion had he so wished. Buridan knew this by virtue of the principle that God can do anything that involves no self-contradiction.”

Those of Buridan's students at the University of Paris who went on to complete doctorates in theology and influence subsequent scholars are thought to include Albert of Saxony, who was elevated to the rank of bishop and helped found the University of Vienna, and Marsilius of Inghen, an important teacher at the newly created University of Heidelberg during the 1380s. Little else is known about Buridan's life, and even the date of his death is uncertain. A reference to a new recipient of the benefice from the Collegiate Church of St. Pol-sur-Ternoise gives a hint that Buridan may have died in 1360 or 1361.