The soul is a portion of the Divine specifically detailed to each individual being that is created as part of the universal manifestation. The soul develops the inmost being, the psychic being, through lifetimes of experience. This psychic being grows, matures and transitions through birth and death as the aspect of the soul that accumulates the essence of experience as a basis for continued evolution of consciousness over time.
The soul inhabits the entire being including its subtle, inner sheaths. The soul, over time, builds up the psychic being as the soul-center of the being. Undeveloped souls may exist that do not have a fully formed psychic being. Upon death, the physical body disintegrates, and then it is followed by the disintegration of the vital and mental levels of the being. What is left is the soul’s repository of experience, the psychic being, which can then go on and acquire new experience in new forms after undergoing the process of rebirth. The Tibetan Book of the Dead outlines clearly this process of the after-death stages of dissolution of the outer being, body, life and mind, and the further process of taking a new birth. Note that this is not intended to validate the transmigration of any specific person or personality, which are related to the external being, but rather the most inward being, which Sri Aurobindo calls the soul or the evolved psychic being. Thus, it is not “John Smith” reborn as a future version of “John Smith”.
Sri Aurobindo observes: “A distinction has to be made between the soul in its essence and the psychic being. Behind each and all there is the soul which is the spark of the Divine — none could exist without that. But it is quite possible to have a vital and physical being without a clearly evolved psychic being behind it….”
“The inner being is composed of the inner mental, inner vital, inner physical, — but that is not the psychic being. The psychic is the inmost being and quite distinct from these. The word ‘psychic’ is indeed used in English to indicate anything that is other or deeper than the external mind, life and body, anything occult or supraphysical, but that is a use which brings confusion and error and we entirely discard it….”
“The psychic being is veiled by the surface movements and expresses itself as best it can through these outer instruments which are more governed by the outer forces than by the inner influences of the psychic. But that does not mean that they are entirely isolated from the soul. The soul is in the body in the same was as the mind or vital — but the body it occupies is not this gross physical frame only, but the subtle body also. When the gross sheath falls away, the vital and mental sheaths of the body still remain as the soul’s vehicle till these too dissolve.”
Sri Aurobindo and the Mother, Our Many Selves: Practical Yogic Psychology, Chapter 2, Planes and Parts of the Being, pp. 89-90
Santosh has been studying Sri Aurobindo's writings since 1971 and has a daily blog at http://sriaurobindostudies.wordpress.com and podcast at https://anchor.fm/santosh-krinsky He is author of 17 books and is editor-in-chief at Lotus Press. He is president of Institute for Wholistic Education, a non-profit focused on integrating spirituality into daily life.