Abstract
The paper examines Aquinas’s understanding of purely mental objects, i.e. things that have no existence outside the mind but only therein. According to the traditional story, Aquinas’s treatment of purely mental objects is mainly driven by semantic concerns and in particular by the need to explain the reference of terms denoting inexistent objects. The paper tries to counterbalance the traditional picture by showing how inexistent objects can be accommodated within Aquinas’s ontology. More particularly, Aquinas distinguishes different kinds of inexistent objects on the basis of their different extra-mental ground: privations and negations, possible objects and impossible ones