Abstract

In the late medieval period, the issue of the composed nature of human beings and its relation to medieval faculty psychology became central. There is ample scholarship on this topic, focusing primarily on authors such as the Dominicans Albert the Great and Thomas Aquinas, and the Franciscans Alexander of Hales, Hugh of St. Cher, John of La Rochelle, and Peter John Olivi. In this paper, we want to examine the view of one of Olivi’s disciples, the Franciscan theologian Peter of Trabibus (fl. 1290s), on the unity of the human soul and the nature of its powers, especially the powers of the intellect and the will. We are particularly interested in his application of the principle of plurality of substantial forms to explain the nature of the relation between the powers of the soul and its essence.