What is Atman?

Sri Ramana Maharshi

(To a question about what Atman is and if it has a finality)

Learn what jiva is. What is the difference between jiva and Atman? Is jiva itself Atman or is there any separate thing as Atman? There is an end for what you observe; that which is created has a destruction or end. That which is not created has no end. That which exists cannot be observed. It is unobservable. We must find out what is it that appears; the destruction of that which appears is the end. That which exists, exists for ever; that which newly appears is later lost.

(Why is Atma vichara necessary?)

If you do not make Atma vichara, then loka vichara creeps in. That which is not, is sought for, but not that which is obvious. When once you have found what you seek, vichara also ceases and you rest in it. As long as one is confusing the body with the Atman, Atman is said to be lost and one is said to seek for it, but the ATMAN itself is never lost. It always exists. A body is said to be Atman, an indriya is said to be Atman, then there is the Jivatman and Paramatman and what not. There are a thousand and one things called Atman. The search for Atman is to know that which is really Atman.