Within the depth-psychology library, ‘Pupil’ operates across two distinct but occasionally overlapping registers. The first is physiological: Allan Schore’s neurobiological work treats pupillary dilation as a measurable index of sympathetic arousal, linking the mother’s affectively charged gaze to hypothalamically regulated dilation in the infant — a somatic bridge between intersubjective attunement and brain activation. The second register is pedagogical and therapeutic: Martha Nussbaum’s extensive treatment of Hellenistic therapeutic philosophy situates the pupil as the primary subject of philosophical medicine, a figure whose beliefs, desires, and emotional repertoire are simultaneously the disease, the diagnostic material, and the instrument of cure. Here the pupil-teacher relation is fraught with epistemological tension — the pupil’s self-report is unreliable precisely because the ‘diseased’ faculties generate it, yet the therapeutic process cannot bypass the pupil’s own rational autonomy without degenerating into manipulation. Eric Havelock adds a third valence, tracing how Platonic mimesis positions the young student as psychologically vulnerable to poetic identification, the guardian-in-formation whose character is shaped — or dispersed — by imitative encounter. Across these traditions the pupil figures as a site of formation, risk, and transformation, making the concept central to any depth account of education, therapeutic relationship, and developmental selfhood.