(ii) Svarūpa-j.āna, knowledge of one’s true nature. What is the nature of this
Atman? Unfortunately we are aware of only the existence of the Atman but, owing to the covering of kāraṇa-aj.āna, we are not aware of its true nature, svarūpa. According to Shankara, the true nature of the Atman can be known only from Vedantic scriptures. The Upanishads state that the true nature of Atman is Brahman. This kind of knowledge is at first only a conceptual knowledge produced by mental vṛttis, modifications. But this vṛtti-j.āna is the starting point. According to Shankara, once this knowledge is gained, all that remains to be done is to stop identifying oneself with one’s body, mind, and so on.
This non-identification, practised with the help of the ‘neti, neti ’ process,begins as dṛg-dṛśya-viveka—discrimination between the seer and the seen—andculminates in a higher type of inner absorption, known as nididhyāsana.
Sureshwaracharya equates nididhyāsana with savikalpa samādhi. Beyond this lies nirvikalpa samādhi, in which akhaṇdākāra-vṛtti, a unitary mental mode, removes themūlāvidyā, causal ignorance. When the mūlāvidyā is completely removed, the Atman is realized as Brahman. When this happens, astitva-j.āna is replaced by svarūpa-j.āna.
The popular notion that in Advaitic experience the Atman ‘merges’ into Brahman is not quite true.
The Atman remains as self-existence. Owing to the coverings of aj.āna and its products, the Atman is at first experienced as ‘I exist’. But as the coverings are removed, the Atman’s self-existence expands until it becomes infinite. The same Atman that was at the beginning remains at the end also, only its coverings are gone; we then call it Brahman.
From: Four Basic Principles of Advaita Vedanta
by Swami Bhajanananda, Ramakrishna Mission
Source: Prabuddha Bharata — Jan/Feb 2010