Spirit figures among the most contested and consequential terms in the depth-psychology corpus, bearing philosophical, theological, alchemical, and psychological valences that resist easy synthesis. Jung anchors the term’s modern problematic: spirit, like God, designates an object of psychic experience that cannot be verified externally and cannot be grasped through pure reason — it is, precisely, that autonomous, overruling complex which ego-consciousness cannot subsume and without which life becomes ‘dull’ and truncated. His insistence that spirit sets limits on life even as life sets limits on spirit articulates the central dialectical tension. Ficino, recovered through Thomas Moore, offers an alternative Neoplatonic framework in which spirit is a subtle mediating vapor — almost body, almost soul — inhabiting the threshold between matter and mind and animating the senses. The Philokalia authors locate spirit as the eschatological gift of the Holy Spirit whose warmth, joy, and transformative energy exceed natural love and carry the practitioner toward deification. Von Franz, reading the alchemical Aurora Consurgens, renders the Holy Spirit as an anima mundi immanent in matter, a fire that sublimes the cold earth and corresponds psychologically to the guiding function of the unconscious. Derrida’s Hegelian register treats spirit tripartitely — subjective, objective, absolute — as the self-developing structure of thought itself. Across all these registers, spirit emerges as the third term that refuses reduction to either matter or pure intellect, constituting instead the dynamic field in which psyche, cosmos, and the sacred interpenetrate.