Fog operates within the depth-psychology corpus across several distinct but interrelated registers. At its most literal, the term designates atmospheric obscuration — mist, haze, cloud — whose Indo-European etymology (IE *h3mit-lh2-) connects it to ancient Greek ὀμίχλη and Armenian meg, tracing a root shared across Balto-Slavic, Sanskrit, and Hellenic languages. In Homeric epic, fog descends upon warriors as a divine intervention, obscuring perception precisely at moments of existential crisis; Ajax’s plea to Zeus — ‘release us from this fog’ — presents atmospheric obscuration as a condition under which purposeful action becomes impossible. The term acquires genuine psychological depth in Welwood and the trauma literature: Ogden and Levine employ fog as technical shorthand for hypoarousal, dissociation, and the depersonalized withdrawal of consciousness that trauma precipitates — a functional ‘fogging out’ in which the ego loses anchorage in present reality. Welwood extends this further, reading the ego’s defensive fog as an intelligent, self-protective maneuver that preserves a cripple identity. The Gnostic tradition, as reported by Hoeller via the Gospel of Truth, understands fog as a literally solidified product of ignorance — anguish crystallizing into obscuring substance. The I Ching commentary tradition treats fog as a metaphor for interpretive obscurity that lifts when inner perspective realigns. Across these registers, fog consistently figures the failure of transparent consciousness.