While Aristotle's treatment of emotion has in recent years received considerable attention, Theophrastus' work on the same subject has been mostly ignored. The reason for this neglect is that the relevant material has not been readily accessible, but with the publication of my Quellen zur Ethik Theophrasts that obstacle has been largely removed. Texts whose primary focus is emotional response have been brought together under the heading "Affecte" (L1-L11) and other relevant texts are included elsewhere in the volume. My purpose here is to call attention to this material and to use it to advance our understanding of Peripatetic work on emotion. We shall see that Theophrastus' treatment of emotion is Aristotelian, and yet of special interest, for it involves analyzing closely related emotions in terms of the more and less. We shall look closely at the emotion of fault-finding, observe parallels with Theophrastus' classification of plants, and in the end have a better understanding of why the Greek commentator Aspasius found no definition of pathos among the older Peripatetics.
Fortenbaugh, William W., "Theophrastus on Emotion" (1984). The Society for Ancient Greek Philosophy Newsletter. 188.