Early in his career, Fernand Brunner became one of the few specialists on Ibn Gabirol, a Jewish philosopher and poet in 11th-century Spain, whose treatise, the Fons vitae, is known only in Latin translation. Brunner showed the coherence of this rarely studied version of Platonism and traced its impact on the scholastic philosophy of the succeeding centuries. His work was guided by a systematic interest in Platonic solutions to such problems as the relations of matter and form, and of God to the world. This volume includes a number of previously unpublished papers, several of which also provide broad expositions of a Platonic ontology. The author makes his reader aware that arguments as well as images must be taken seriously in the attempt to approach the Platonic tradition. Des le debut de sa carriere, Fernand Brunner est rapidement devenu l'un des rares specialistes d'Ibn Gabirol, le poete philosophe juif espagnol du 11e siecle - dont le traite, le Fons vitA|, n'est connu qu'en version latine. Guide dans ses recherches par un interAt systematique pour les solutions platoniciennes aux problemes des rapports entre la forme et la matiere, et entre Dieu et le monde, Brunner a demontre la coherence de cette interpretation rarement etudiee du platonisme et en a retrace l'effet sur la philosophie scolastique des siecles suivants. Ce volume comprend plusieurs exposes inedits traitant de l'ontologie platonicienne dont la comprehension, selon Brunner, est essentielle A tout historien de la philosophie. L'auteur fait prendre conscience A ses lecteurs de l'importance des arguments, tout comme des metaphores, dans toute tentative d'approche de la tradition platonique.