one of the most basic concepts in Hindu philosophy, describing that eternal core of the personality that survives after death and that transmigrates to a new life or is released from the bonds of existence. While in the early Vedic texts it occurred mostly as a reflexive pronoun (oneself), in the later Upanishads (Upanishad) it comes more and more to the fore as a philosophic topic: atman is that which makes the other organs and faculties function and for which indeed they function; atman underlies all the activities of a person, as Brahman (brahma) (the absolute) underlies the workings of the universe; to know it brings bliss; it is part of the universal Brahman, with which it can commune or even fuse. So fundamental was the atman deemed to be that certain circles identified it with Brahman. Of the various systems (darshans) of Hindu philosophy, the schools of Sāṃkhya and Yoga (which use the term purusha to convey the idea of atman) and the orthodox school of Vedānta particularly concern themselves with the atman, though the interpretation varies in accordance with each system's general worldviews.