This paper examines the theories of the soul proposed by Girolamo Cardano in his De immortalitate animorum (1545) and his De subtilitate (1550-4), Julius Caesar Scaliger's comprehensive critique of these views in the Exercitationes exotericae de subtilitate of 1557, and Cardano's reply to this critique in his Actio in calumniatorem of 1559. Cardano argues that the passive intellect is individuated and mortal, and that the agent intellect is immortal but subject to constant reincarnation in different human beings. His theory of cognition leads him to claim that at its highest level, the intellect is converted into the object of its perception. In his refutation of the various elements of Cardano's theories, Scaliger uses his knowledge of the Greek text of Aristotle to stress the reflexive faculty of the soul, its ability to conceive of objects greater than itself, and its status as the individuating principle of the hylemorphic human being. In spite of Cardano's pretention to novelty and Scaliger's humanist credentials, both thinkers are shown to conduct their discussions in an inherited scholastic matrix of thought.