The Taittiriya Upanishad describes a series of planes or sheathes that are ever more subtle, with the outermost sheath being the physical being, and then the vital sheath and the mental sheath, which makes up our ordinary human existence. Each of these sheaths are connected to a plane of universal nature that has its own characteristic action, and each one has its own being that is separate from the ego-personality of the individual and which acts as the central organizing awareness for that being behind the external existence. The Brahmanandavalli chapter of this Upanishad describes these sheaths, and the being that presides over each sheath in some detail. There are additional ever-more-subtle sheaths and beings that represent higher causative principles as well, specifically the knowledge sheath and the bliss sheath.
Sri Aurobindo carries this understanding forward with his description of the inner being of the physical, vital and mental planes that act within the individual. When the seeker takes up the yogic practice and begins to separate himself from the thrall of the external being, he can enter into and become intimately aware of the status of each of these inner levels. Behind all of them lies the psychic being, or soul, which is the constituting being of the specific individual who has taken birth, and which gathers the fruit of the experience of the lifetime as it grows and evolves through time and birth and death. While the self of mind, self of life and self of the physical are ultimately independent of the individual soul and its evolutionary status, and are connected to the higher self of the spiritual existence, the realisation of these levels is part of the process of the seeker disassociating himself from total identification with the external being. This is the process of liberation from the ego-personality which can aid the seeker in discovery of the deeper significance of his existence.
Sri Aurobindo writes: “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 purusa, on the vital plane the true vital being, pranamaya purusa, on the physical plane the true physical being, annamaya purusa. 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.”
“The true inner being — the true mental, the true vital, the true physical represent each on its plane and answer to the central being, but the whole of the nature and especially the outer nature does not, nor the ordinary mental, vital or physical personality. The psychic being is the central being for the purposes of the evolution — it grows and develops; but there is a central being above of which the mind is not aware, which presides unseen over the existence and of which the psychic being is the representative in the manifested nature. It is what is called the Jivatman.”
Sri Aurobindo and the Mother, Our Many Selves: Practical Yogic Psychology, Chapter 2, Planes and Parts of the Being, pp. 81-82
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.