Stoic views on the emotions represent a pivotal transition between the Aristotelian and Kantian accounts of virtue. Of course, Stoic views are complex and by no means embody an homogenous doctrine. There are significant differences articulated in the early Stoa, as well as between it and its later, Roman manifestation. The later Stoics are often criticized for lacking the theoretical rigor and philosophical interest of the earlier Stoa. I, myself, am not particularly sympathetic to this criticism. True, the later Stoics often present their philosophical views in a homey way with an eye to therapy, but their concern to see ethical inquiry as a practical subject matter puts them squarely in the Socratic tradition. In this vein, they follow closely the example of Socrates, who demanded of his interlocutors that they submit for crossexamination not merely entertained beliefs, but those that they sincerely lived by. In extending the project of moral therapy, the later Stoics make an invaluable contribution to ethical inquiry.

Before discussing this contribution, it will be helpful to sketch very schematically the relevant lines of the Stoic transition. For our purposes, what is most important is the Stoic objection to Aristotle's account of the passions and their role in his account of virtue. By isolating reason as the exclusive ground of morality, the Stoics pave the way for Kant's rational grounding of morality. Moreover, their account of nonmoral goods (the so-called preferred indifferents) and the relation of these to the moral good foreshadows Kant's own distinction between the nonmoral and the moral.