Galen’s work on the soul (psuchē) (including his work on ethics, discussed in §8 below) presents one of the most interesting aspects of his philosophical-medical output, and has attracted considerable scholarly attention in the last 40 years; see especially Manuli and Vegetti 1988; Hankinson 1991b, 1993; Donini 2004, 2008; Gill 2010; Singer 2013 (with further bibliography), 2018; Havrda 2017; Marechal 2019; Vinkesteijn 2019; Devinant 2020. At the same time it is an area beset with interpretive complexities. Galen’s moral psychology, or philosophy of mind, bases itself strongly on Plato, while also attempting to do justice to the contemporary state of knowledge in anatomy and physiology, and also taking on much from both philosophical and medical traditions which tie the psuchē and its pathology closely to a theory of elements or humours, classifying or conceptualizing its pathology in terms of physical imbalances of the body (especially of the brain).