Sophrosyne — rendered variously as temperance, self-restraint, moderation, or ‘the virtue of the happy medium’ — occupies a peculiar position in the depth-psychology corpus: it arrives not as a merely private moral achievement but as the structural precondition of both psychic and political order. Vernant treats it as the civic counterpart of geometrical equality, the virtue that prevents pleonexia from dissolving the polis into dysnomia. Plotinus elevates it to a cosmic principle, locating sophrosyne’s archetype within the Intellectual-Principle itself as self-concentration — the Soul’s inward-turning away from dispersal. Plato’s Charmides stages the most sustained and aporetic inquiry: successive definitions — modesty, doing-one’s-own-business, self-knowledge — each collapse under Socratic examination, suggesting that sophrosyne is easier to embody than to theorize. Nussbaum reads the Phaedrus as positioning sophrosyne against eros and mania, so that its acquisition marks the extinction of passion in the ex-lover. Snell notes that sophrosyne, with its interest in ‘health, harmony, and the concordance of opposites,’ ultimately fails to satisfy the Socratic demand for teleological knowledge of the good. Hobbs tracks its systematic pairing with andreia in the Politicus, where the two virtues constitute rival temperamental poles requiring statesmanlike weaving. Taken together, these readings position sophrosyne as simultaneously psychology, politics, and cosmology — a term whose depth far exceeds its conventional translation.