Across the depth-psychology corpus, ‘emotion’ occupies a contested theoretical frontier where neuroscience, phenomenology, evolutionary biology, and cultural theory converge without reaching consensus. Damasio anchors emotion in somatic signaling, distinguishing background, primary, and social emotions while insisting on the insula and anterior cingulate as their neural substrates — a position that rehabilitates feeling after its twentieth-century exile from the laboratory. Barrett’s theory of constructed emotion challenges this somatic essentialism directly: emotions are not biological fingerprints but goal-based concepts assembled from cultural inheritance, interoceptive prediction, and language. Simondon offers the most radical departure, treating emotion not as a private interior state but as the signal of an ontogenetic process — the calling-into-question of the individual in the presence of a pre-individual charge that demands collective resolution. Lench and the functionalist tradition position emotions as discrete coping strategies shaped by natural selection, each serving motivational ends legible in appraisal, physiology, behavior, and phenomenology. The Stoics, via Graver, define emotion as irrational judgment — sufficient but not necessary for psychophysical disturbance. Konstan demonstrates that the very category ‘emotion’ is a modern Western folk taxonomy, inadequate to ancient Greek pathos or the cross-cultural diversity documented by Lutz. These tensions — universal versus constructed, somatic versus cognitive, individual versus collective — define the living problem of emotion in contemporary depth psychology.