Dullaert of Ghent, Jean

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Dullaert of Ghent, Jean

(b. Ghent, Belgium, ca. 1470; d. Paris, France, 19 September 1513)

logic, natural philosophy.

Dullaert is sometimes confused with John of Jandun, owing to the Latin form of his name, Joannes de Gandavo. At the age of fourteen Dullaert was sent to Paris to study. He was a pupil of, and later taught with, John Major at the Collège de Montaigu; in 1510 he became a master at the College de Beauvais. Among his students at Montaigu were the Spaniards Juan de Celaya and Juan Martinez Siliceo, both important for their contributions to the rise of mathematical physics, and the humanist Juan Luis Vives.

At Paris, Dullaert published his questions on the Physics and the De caelo of Aristotle (1506), which appeared in at least two subsequent editions (1511; Lyons, 1512); a commentary on the De interpretatione of Aristotle (1509; Salamanca, 1517, edited by Siliceo); and an exposition of Aristotle’s Meteorology (1512). The last title was reissued posthumously, “with Dullaert’s questions,” in 1514 by Vives, who prefaced a brief biography wherein he states that Dullaert had left unfinished a commentary on the Prior Analytics; this apparently was prepared for publication in 1520/1521 by Jean Drabbe, also of Ghent. At the time of his death Dullaert was also working on a general edition of the works of Albertus Magnus that was based on previously unedited manuscripts which he himself had discovered. Earlier he had edited and revised for publication Jean Buridan’s questions on Aristotle’s Physics (1509) and Paul of Venice’s De compositione mundi (ca. 1512) and Summa philosophiae naturalis (1513).

Like Paul of Venice, Dullaert was an Augustinian friar, and he showed a predilection for the realist views of this confrere while being strongly attracted also to the nominalist teaching then current at Paris. Perhaps for this reason his questions on the Physics are eclectic and, in many passages, inconclusive. At the same time they summarize in great detail (and usually with hopelessly involved logical argument) the teachings of Oxford “calculatores” such as Thomas Bradwardine, William Heytesbury, and Richard Swineshead; of Paris “terminists” such as Jean Buridan, Albert of Saxony, and Nicole Oresme; and of Italian authors such as James of Forli, Simon of Lendenaria, and Peter of Mantua—while not neglecting the more realist positions of Walter Burley and Paul of Venice. The logical subtlety of Dullaert’s endless dialectics provoked considerable adverse criticism from Vives and other humanists, but otherwise his teachings were appreciated and frequently cited during the early sixteenth century.

The structure of Dullaert’s treatment of motion, which covers sixty-nine of the 175 folios constituting the questions on the Physics and De caelo, shows the strong influence of Heytesbury’s Tractatus de tribus praedicamentis, with some accommodation along lines suggested by Albert of Saxony’s Tractatus proportionum. Dullaert treats successively the entitative status of local motion, the velocity of local motion (both rectilinear and curvilinear), the velocity of augmentation, and the velocity of alteration, digressing in the latter tract to take up the intension and remission of forms. He is ambiguous in discussing the reality of local motion but holds for the impetus theory of Jean Buridan, regarding impetus as a kind of accidental gravity in the projectile that is corrupted by the projectile’s own natural tendencies. He raises the question whether the impetus acquired by a falling body is proportional to the weight of the body but declines an answer. Following John Major, he teaches that God has the power to produce an actual (as opposed to a potential) infinity, and he sees no difficulty in the existence of a void. His views were generally taken over and clarified by Juan de Celaya, Luis Coronel, and others at Paris and in Spanish universities.


None of Dullaert’s works is available in English. A copy of the Quaestiones super octo libros Aristotelis physicorum necnon super libros de caelo et mundo (Lyons, 1512) is in Houghton Library of Harvard University. Pierre Duhem, Études sur Léonard de Vinci, III (Paris, 1913), gives numerous brief excerpts from this in French translation.

On Dullaert or his work, see Hubert Élie, “Quelques maîtres de l’université de Paris vers l’an 1500,” in Archives d’histoire doctrinale et littéraire du moyen âge. 18 (1950– 1951), 193–243, esp. 222–223; R. G. Villoslada, La universidad de Paris durante los estudios de Francisco de Vitoria, O.P., (1507–1522), Analecta Gregoriana XIV (Rome, 1938); and William A. Wallace, “The Concept of Motion in the Sixteenth Century,” in Proceedings of the American Catholic Philosophical Association, 41 (1967), 184–195; and “The Enigma of Domingo de Soto: Uniformiter difformis and Falling Bodies in Late Medieval Physics,” in Isis, 59 (1968), 384–401.

William A. Wallace, O.P.