Atma (आत्मन्, ātman) is the term used across the Upanishads, the Gita, and the darshanas for the innermost reality of a being. It is not the body, not the breath, not the mind, not the intellect, not even the changing stream of consciousness. It is the sakshi, the witness behind all these, whose very nature is being (sat), consciousness (chit), and bliss (ananda).
The Upanishadic Discovery
The Upanishads describe a careful inward search. The Taittiriya Upanishad peels away five sheaths (panchakosha) — food, breath, mind, intellect, and bliss — to point beyond them. The Brihadaranyaka asks again and again kaḥ ayam ātmā? — "what is this self?" The famous answer is neti neti — "not this, not this" — by which everything finite is set aside until only the witness remains.
and
Sanatan thought often distinguishes the individual self (jivatma, जीवात्मा) from the supreme Self (paramatma, परमात्मा). Whether these are ultimately one, qualifiedly one, or eternally distinct is precisely the question that divides Advaita, Vishishtadvaita, and Dvaita Vedanta. All schools agree, however, that the is real, conscious, and not produced.
Distinction from
Buddhist thought famously denies a substantial atman and teaches anatman — no permanent self. Sanatan schools respond by sharpening their account. The they affirm is not the empirical ego (ahamkara) but the unchanging awareness that lights up the ego's coming and going. The ego is conceded to be a process; the is the prior fact that any process is known at all.
The Witness Argument
A frequent Upanishadic move is to ask: what knows the mind itself? Thoughts arise and pass; moods rise and fall; even sleep comes and goes. Something is continuously present that registers all these changes without itself being one of them. That, the tradition says, is the . It cannot be objectified, because it is the very subject of every objectification.
and Moksha
Bondage is described as forgetting one's true nature and identifying instead with body, role, and history. Liberation is the steady recognition that aham brahmāsmi — "I am brahman", or in Vishishtadvaitic terms, the realisation that one is an eternal soul of the Lord. Either way, knowing the is the central spiritual event.
Practical Bearing
To remember the is to loosen the grip of small selfhood without rejecting daily life. One acts, but the actor is held lightly. One feels, but the feelings are not all that one is. This double-sightedness is the freedom that Sanatan teachings keep pointing toward.