The inquiry on mental states is framed within a more general inquiry on the possibility for human beings to realize their telos by the exercise of reason and the acquisition of adequate criteria of knowledge. Epicurus’ need to outline a philosophy of mind arises from the difficulty of combining an atomistic psychology with the idea that human beings are responsible for their mental and moral development. Such difficulty emerged for Epicurus while debating against some rivals who were trying to infer fatalist consequences from atomism. Epicurus’ inquiry develops along two directions: one aiming at the confutation of his rivals, the other at an explicit formulation of a theory of mind able to explain the capacity of self-determination of human beings.
The author shows that in the 25th book, Epicurus endorses an anti-reductionist and anti-deterministic philosophy of mind that is not without theoretical tensions and that the philosopher will later try to solve these tensions by integrating his theory with the doctrine of clinamen.