The Brihadaranyaka Upanishad has an instructive anecdote to illustrate why Prana is considered different from the experiencing subject. Ajatashatru, king of Kashi, is approached by the proud orator Balaki, who wishes to instruct him on scriptural truths. Balaki considers Prana, the cosmic Energy (termed conditioned Brahman in the Upanishads) as the Self and starts instructing the king about this. But the king was already familiar with all the different aspects of this cosmic Energy (from that associated with the sun to that residing in the heart and intellect) that Balaki wishes to explain.
Balaki is soon reduced to being Ajatashatru’s student. The king then leads him to a sleeping man whom he hails with the well-known epithets of Prana. Nothing happens. Ajatashatru then pushes the man repeatedly till he awakens and gets up. Ajatashatru has made his point without a word of explanation.
The inability of Prana to respond to his call despite being active and the lack of response from the physical frame to an isolated touch were pointers to consciousness being a distinct entity. Sri Adi Shankaracharya, in his commentary on this mantra, observes: ‘Therefore it is proved that that which awoke through pushing — blazing forth, as it were, flashing, as it were, and come from somewhere, as it were, rendering the body different from what it was, endowing it with consciousness, activity, a different look, etc.—is an entity other than the body.’
The king then raises that famous question: ‘When this being full of consciousness was thus asleep, where was it then and whence did it thus come back?’ and proceeds to explain.
The Atman — that is the Vedantic term for self — has two aspects: conditioned and unconditioned. In its unconditioned state it is Brahman, absolute and non-dual. The conditioned state involves complete identification with the body, mind, senses, and life, making it empirical, as it were. This is termed maya. And this is how the Atman appears to be well or ill, asleep or awake, and so on. Just as sunlight passing through different colored glasses appears differently colored, so does the Atman appear affected by its conditionings. Thus the experiencer, the conditioned Atman, appears to be handicapped when in a body with a defective brain. Again, it is only the subtle conditionings of the self that are responsible for its transmigration. In reality, the Atman neither comes nor goes, for it transcends the limitations of body and mind. In reality we are not identical with our bodies; but at the same time our bodies are deeply involved in the process of self-awareness. We are custodians of the limitless within the limited.
Source – excerpts from article titled ‘the Self and the Atman’ by Swami Satyamayananda in Prabuddha Bharata Magazine November 2006 issue.