Atman literally means the Self with a capital S, as different from the ego-self, which changes as the field of nature changes. The true Self or the Atman, is regarded as the Immutable (unchanging) Reality, the Truth behind the ever-changing appearances. This is common to all schools of mysticism: that there is indeed One Self, Atman, behind all the countless variations and differences of name, form and appearances that we find in nature.
The question that arises out of this is whether there is a truth of our individuality or not. It is here that we find differences in different schools of philosophy. There is an extreme school of Advaita that rejects the idea of individual soul, an immortal spark of the Divine in the individual. On the other hand, there is the other extreme that insists on the duality, Dwaita, that admits the individual soul, the immortal element that undergoes transmigration and the pure Atman as two connected but distinct aspects of the One Truth, as the waves and the sea. This idea of the individual soul, antaratma, is prominently presented in the Sankhya school and accepted by both Sri Krishna and Sri Aurobindo.
However, the exact role of the individual soul remained unclear before Sri Aurobindo. The individual soul, antaratma, is generally spoken of as somehow caught in a web of ignorance. It has no specific role except to find ways and means of escaping from Ignorance in which it has somehow landed in.
Now Sri Aurobindo reveals the full secret. The individual soul, antaratma, has entered wilfully into the field of ignorance so that it can grow into its full divine possibility. That is the real purpose of the journey in ignorance. The fully developed individual soul is called as the psychic being, chaitya satta.
To summarise, Atman or Self is the universal Self, the single Self behind Nature.
Soul or antaratma is the immortal individual spark of the Divine within us.
Psychic Being is the fully developed individual soul as it goes through the cycle of rebirth.
Affectionately,
Alok Da
