GILES OF LESSINES

Dominican philosopher and scientist; b. probably Lessines (Hainaut, Belgium), c. 1230–40; d. 1304 or later. He entered the order perhaps at the convent of Valenciennes. His relations with albert the great suggest that he studied under this master, probably at Cologne. His later residence at Paris and the strong Thomistic character of some of his writings make it very likely that he attended the lectures of St. thomas aquinas during Aquinas's second regency at the University of Paris (1269–72). He is known in the early lists of Dominican authors as a bachelor, so he seems not to have been a master in theology. Various treatises are attributed to him. The first is De essentia, motu et significatione cometarum, on the occasion of the comet of 1264, in which the author shows an interest for natural sciences not uncommon in the school of Albert the Great. He made use of the liber de causis and propounded the common doctrine on providence and on the influence of the heavenly bodies. The De concordia temporum, or Summa de temporibus, gives a concordance of historical chronology up to the beginning of the 14th century; its authenticity is not yet entirely demonstrated. A Tractatus de crepusculis, attributed to Giles by P. Mandonnet, is in the same field of scientific investigation. The two last mentioned treatises exist in MS [University of Bologna, 957 (1845)]. There

are no texts for the following works attributed to Giles: De geometria, Quaestiones theologicae, In 1 et 2 sententiarum, Flores casuum, Tractatus de (decem) praeceptis, and De immediata visione divinae essentiae; the last may be a confusion with a similar treatise attributed to william de hothum.

Three other writings are certainly authentic. (1) He wrote a letter to Albert the Great asking his judgment about 15 points of doctrine that were discussed among the masters of Paris. Items one to 13 coincide with points contained in the condemnation promulgated by Bishop É. tempier of Paris on Dec. 10, 1270. (2) The De unitate formae is a strong defense of the doctrine of the unity of the substantial form, one of the most violently attacked Thomist teachings. Its first three chapters expose the opinion of the plurality of forms; the next seven chapters are devoted to the concept of form and its relation to matter; and the final six chapters establish the unity of form and answer the arguments of the pluralists. The treatise was directed especially against robert kilwardby and was most likely written in 1278. henry of ghent tried to refute it, and harvey nedellec made use of it. (3) The De usuris is the most complete study of usury in the Middle Ages. It is against the more backward theories of Henry of Ghent, and thus must have been written between 1278 and 1284 (F. Veraja). It was first attributed to Thomas Aquinas.

Bibliography: m. de wulf, Le Traité "De unitate formae" de Gilles de Lessines (Les Philosophes Belges 1; Louvain 1901). p. mandonnet, "Giles de Lessines et son Tractatus de crepusculis," Revue néo-scolastique 22 (1920) 190–194. m. grabmann, "Einzelgestalten aus der mittelalterlichen Dominikanerund Thomisten-theologie," Mittelalterliches Geistesleben, v.2 (Munich 1936) 512–530. l. thorndike, Latin Treatises on Comets between 1238 and 1368 (Chicago 1950). f. veraja, Le origini della controversia teologica sul contratto di censo nel XIII secolo (Rome 1960) 83–99. p. m. m. duhem, Le Systéme du monde, 5v. (Paris 1913–17), repr. 10 v. (1954–59).

[j. c. vansteenkiste]