Aquinas’s Early View of Intellective Memory in the Commentary on the Sentences :

Medieval thinkers debate how we retain and recall what we have previously learned, especially our intellectual knowledge about essences like treeness. Thomas Aquinas argues that intellect retains its abstracted forms or species “habitually” while not using them “actually.” But it has rarely been noticed that in his earliest major writing, the Sentences commentary, Aquinas had originally endorsed a different view, positing a separate mental faculty of intellective memory to retain abstracted forms. The goal of this study is to show that Aquinas takes a different position in this early work, compare it philosophically with his mature view, and identify the conceptual pressures that drive him into the mature view. As I will show, that Aquinas initially attempts to combine two historically venerable models of intellective memory: an Augustinian “storage” model and an Aristotelian “habituation” model. This approach fails under pressure, resulting in the alternative, rather cryptic, distinction between “habitual” and “actual” species that will characterize his mature view of intellective memory. In light of this historical development, we can demystify this distinction and explain exactly what a habitual species is.