In the Taittiriya Upanishad, a seeker successively realises the basis of existence, first in the physical sheath, then in the vital or life sheath, and then in the mental sheath, before exceeding each of these as the progression of his realisation went beyond the mind into the “knowledge” and “bliss” sheaths. A similar progression in fact is taking place in Western science, which first concentrated on Matter as the reality of existence, then moved to Energy and now is starting to recognize consciousness as the ultimate reality. There is a truth to this progression as the Self, the Atman, has its stance in each of these planes of consciousness.
The Self, Atman, or Jivatman, is different from the psychic being or soul-entity in man. The Self stands above and aloof, sanctioning, witnessing and guiding. The psychic being lies in the inner being and from there guides the body, life and mind directly, once it comes forward and takes over the direction of the life and its focus. It is the psychic being that, through its aspiration and devotion, is able to turn the awareness towards the Divine and focus the being on attaining the constant connection.
Sri Aurobindo notes: “The central being — the Jivatman which is not born nor evolves but presides over the individual birth and evolution — puts forward a representative of himself on each plane of the consciousness. On the mental plane it is the true mental being, manomaya purusha, on the vital plane the true vital being, pranamaya purusha, on the physical plane the true physical being, annamaya purusha. Each being, therefore is, so long as the Ignorance lasts, centred round his mental, vital or physical Purusha, according to the plane on which he predominantly lives, and that is to him his central being. But the true representative all the time is concealed behind the mind, vital and physical — it is the psychic, our inmost being.”
“When the inmost knowledge begins to come, we become aware of the psychic being within us and it comes forward and leads the sadhana. We become aware also of the Jivatman, the undivided Self or Spirit above the manifestation of which the psychic is the representative here.”
Sri Aurobindo, Integral Yoga: Sri Aurobindo’s Teaching and Method of Practice, Planes of Consciousness and Parts of the Being, pp. 56-61