The Third Eye enters the depth-psychological corpus along several distinct but convergent axes. In its most literal dimension, Strassman grounds the term in comparative neurobiology, identifying the pineal gland of evolutionarily older vertebrates as a structure possessing lens, cornea, and retina — a ‘third eye’ in the strict anatomical sense — and tracing its progressive internalization through evolutionary history as a suggestive analogue for the inward movement of spirit. A second, properly psychological axis runs through Edinger and von Franz, who develop the motif as an archetypal image of the Eye of God: the transcendent, knowing subject within the unconscious that perceives the ego as object. Von Franz situates this inner eye within a lineage from Plato through Paracelsus and the Christian mystics, designating it the eye of the soul, of intelligence, and of faith. Edinger reads the same figure through Egyptian religion and Jungian Self-psychology, arguing that to be seen by this eye is to have unconscious contents exposed to a light they cannot endure. Jung himself, in both Psychology and Alchemy and The Archetypes and the Collective Unconscious, treats the single luminous eye as a mandala prototype, linking it to Böhme’s ‘Eye of Eternity’ and Matthew’s logion on the single eye. Campbell and Govinda contribute the chakric register, wherein the ājñā centre — the brow lotus — functions as the organ of transcendent inner vision superseding duality. Across these positions the Third Eye names a capacity for reflexive, non-dualistic perception that ordinary ego-consciousness cannot supply.