Semantics and Ontology in Robert Kilwardby’s Commentaries on the Logica Vetus

The chapter analyzes the notions of Being, substance and accident, universal and individual, and individuation and matter, as they are found in Kilwardby’s commentaries on the Logica vetus. I argue that Kilwardby’s world, as evidenced by these commentaries, is neither a purely Aristotelian world nor a purely Augustinian one, but contains elements of both. The young Parisian master applies to logic principles and modes of analysis drawn from Aristotle’s physics and metaphysics, at the same time addressing tensions that such applications cause when injected into the Patristic tradition. For example, Kilwardby thinks that universals can be considered as they exist in individuals, or in our minds. But he also accepts the Augustinian notion that the likeness of the universal exists in the divine mind even when all the instantiating individuals have perished. His thought in these works shows other Augustinian influences too, for example, in accepting a plurality of substantial forms in composite substances, the presence of seminal reasons in matter, and individuation by matter and form. In the commentary on the Isagoge he holds that there is some kind of materiality in angelic intelligences, thus adopting the doctrine of universal hylomorphism, which he will later defend in his Epistulae. He attributes active powers to matter, and he holds that there must be a plurality of substantial forms in a composite substance.