John of Jandun

John of Jandun

John of Jandun (French Jean de Jandun, Johannes von Jandun, or Johannes de Janduno, circa 1285–1323) was a French philosopher, theologian, and political writer. Jandun is best known for his outspoken defense of Aristotelianism and his influence in the early Latin Averroist movement.


Jandun was born in Reims, in the Champagne region of France, between 1280 and 1289, though the exact date is unknown. It is likely that he grew up in the small town of Jandun (modern day Signy-l'Abbaye).

Jandun is known to have become a member of the arts faculty in Paris by 1310, likely by as early as 1307. While a professor in Paris, Jandun was well informed and involved with theological debates. In 1315 Jandun became an original member of the faculty at the College of Navarre and was in charge of 29 students. In 1316 Pope John XXII awarded Jandun a canonry of Senlis, and it is likely that he spent time there, though he continued to teach in Paris for the next ten years.

Jandun identified closely with Marsilius of Padua, another Latin Averroist who was rector at the university in Paris from 1312-1313. Marsilius presented Jandun with a copy of Pietro d'Abano's commentary on the problems of Aristotle.

On 19 June 1324 Jandun was involved in a business transaction to rent a house for life. Four days later Marsilius finished the Defensor Pacis. When it became known in 1326 that Marsilius had authored the Defensor Pacis, he and Jandun fled together to the court of Louis IV of Bavaria. Pope John XXII began issuing condemnations against Jandun from 6 September 1326 and finally excommunicated Jandun on 23 October 1327 as a heretic.

Jandun accompanied Louis IV to Italy, and was present in Rome on 1 May 1328 when Louis IV was crowned Holy Roman Emperor. Louis appointed Jandun as Bishop of Ferrara. Ten weeks later Jandun was formally accepted as a member of Louis IV's court, and was given indefinite rations for three servants and three horses. Later that summer, around 31 August 1328, Jandun died in Todi, most likely en route to his new bishopric.


Jandun is best known for his work on the agens sensus, the principle of individuation, and the priority of universal knowledge to particular knowledge. He also wrote on the theory of the vacuum, plurality of forms, form and matter, the soul, the intellect, as well as other topics relating to Aristotle.

Jandun's first work, a short quaestio, was published in 1314, though he may have begun writing as early as 1310 or 1307. His writings include: Physics, De anima, Metaphysics, Parva naturalia, and the De caelo.

Because of his closeness to Marsilius of Padua, Jandun is often incorrectly credited with authoring or coauthoring the Defensor pacis. It is now generally accepted that he did not write it, but it is possible that Jandun advised Marsilius on the work.


Jandun's work carried the Latin Averroist tradition from Paris to Bologna, Padua, and Erfurt in the fourteenth century, and Krakow in the fifteenth century. Jandun tended toward the views of Aristotle, but was not afraid to follow an idea to its logical conclusion. Many of