To understand the Atma is a difficult proposition. Scriptures refer to the real nature of the Atma as immortal and as the essence of consciousness and bliss and it should be a matter of great pride to us to realise that we live and are engaged in worldly activities because of this Atma which is yoked with the physical body. But the presence of the Atma is not recognised when “I am the doer” complex, (where the identity of the “I” coupled with one's ability) shifts to the body-mind-complex alone.
Only when the individual's cognition is able to distinguish the physical and the subtle components distinctly and is clear about the agency, can there be any spiritual progress, said Sri K. Srinivasan in a lecture.
The Taitiriya Upanishad teaches us to recognise the subtle Atma in a very practical manner. The material body of the individual is the earthly abode for the Atma.
The unique immutability of the Atma is established by analysing all the physically-related aspects of the individual as temporary and hence shown to be the non-Self (Anatma). Turning our study inwards, is it possible to presume that the body is the Atma? The physical body is seen as composed of the five sheaths (Koshas) — Annamaya, Pranamaya, Manomaya, Vijnanamaya and Ananadamaya.
All these are systematically examined and their ephemeral and gross quality established in contrast to the unique and subtle nature of the Atma.
The first outer sheath (Annamaya Kosha) is born and grows by consuming food. It lives for some time and then dies.
The knower is Atma and what is known is the body. The Self is thus different from the body. The wakeful/dream/deep sleep states that an individual experiences is also used to illustrate the presence of the Atma in the body. In the dream state, the mind is active but the body is at rest; in deep sleep there is no consciousness of the body.
The Atma is unaffected and remains unattached when the body perishes, even as the ether in a pot suffers no change when the pot is broken. So meditation on the Atma is advised.