 Theophrastus is reported to have written a treatise with the title On the Soul, which was a commentary on Aristotle’s On the Soul and comprised at least two books. Nearly all we know about this Theophrastean work comes from Themistius’ paraphrase of Aristotle’s On the Soul, which was used heavily in Arabic philosophical writings, as well as from Priscian of Lydia’s paraphrase of Theophrastus’ work. In this treatise, just like in his Metaphysics, Theophrastus pointed out difficulties in Aristotle’s text, suggested conceptual distinctions and clarified the implications of obscure Aristotelian doctrines like, for instance, the definition of perception as assimilation of the sensible form of an object without its matter (see Laks 2002, 2019; Caston 2019). It is debatable, however, whether Theophrastus also offered clear and unambiguous solutions to the problems he raised.