This ancient debate flowered into various dual and non-dual theories in Hinduism. Some teach that Brahman (highest reality universal principle being-consciousness-bliss) is identical with Ātman, while others teach that Ātman is part of Brahman but not identical to it.

The Upanishads express two distinct, somewhat divergent themes on the relation between Atman and Brahman. Cosmology and psychology are indistinguishable, and these texts state that the core of every person's Self is not the body, nor the mind, nor the ego, but Ātman. The Upanishads say that Atman denotes 'the ultimate essence of the universe' as well as 'the vital breath in human beings', which is 'imperishable Divine within' that is neither born nor does it die. Ātman is a central topic in all of the Upanishads, and 'know your Ātman' is one of their thematic foci. Yāska, the ancient Indian grammarian, commenting on this Rigvedic verse, accepts the following meanings of Ātman: the pervading principle, the organism in which other elements are united and the ultimate sentient principle. The earliest use of the word Ātman in Indian texts is found in the Rig Veda (RV X.97.11). As Puchalski states, 'the ultimate goal of Hindu religious life is to transcend individuality, to realize one's own true nature', the inner essence of oneself, which is divine and pure. Atman is the unchanging, eternal, innermost radiant Self that is unaffected by personality, unaffected by ego Atman is that which is ever-free, never-bound, the realized purpose, meaning, liberation in life. something beyond which permeates all these'. In Hinduism, these are all included in embodied reality, the counterpart of Atman.Ītman, in Hinduism, is considered as eternal, imperishable, beyond time, 'not the same as body or mind or consciousness, but. It is 'pure, undifferentiated, self-shining consciousness.' Īs such, it is different from non-Hindu notions of soul, which includes consciousness but also the mental abilities of a living being, such as reason, character, feeling, consciousness, memory, perception and thinking. Embodied personality and Ahamkara shift, evolve or change with time, while Atman doesn't. It is distinct from the ever-evolving embodied individual being ( jivanatman) embedded in material reality, exemplified by the prakriti of Samkhya, and characterized by Ahamkara (ego, non-spiritual psychological I-ness Me-ness), mind ( citta, manas), and all the defiling kleshas (habits, prejudices, desires, impulses, delusions, fads, behaviors, pleasures, sufferings and fears). In Hinduism, Atman refers to the self-existent essence of human beings, the observing pure consciousness or witness-consciousness as exemplified by the Purusha of Samkhya. Ātman, sometimes spelled without a diacritic as atman in scholarly literature, means 'real Self' of the individual, 'innermost essence.' While often translated as 'soul', it is better translated as 'self.' Meaning Ātman ( Atma, आत्मा, आत्मन्) is a Sanskrit word that refers to 'essence, breath.' It is derived from the Proto-Indo-European word *h₁eh₁tmṓ (a root meaning 'breath' with Germanic cognates: Dutch adem, Old High German atum 'breath,' Modern German atmen 'to breathe' and Atem 'respiration, breath', Old English eþian).

This is a major point of difference with the Buddhist doctrine of Anatta, which holds that in essence there is no unchanging essence or Self to be found in the empirical constituents of a living being, staying silent on what it is that is liberated. The six orthodox schools of Hinduism believe that there is Ātman in every living being ( jiva), which is distinct from the body-mind complex.

In order to attain moksha (liberation), a human being must acquire self-knowledge ( Atma Gyaan or Brahmajnana).Ītman is a central concept in the various schools of Indian philosophy, which have different views on the relation between Atman, individual Self ( Jīvātman), supreme Self ( Paramātmā) and, the Ultimate Reality ( Brahman), stating that they are: completely identical ( Advaita, Non-Dualist), completely different ( Dvaita, Dualist), or simultaneously non-different and different ( Bhedabheda, Non-Dualist + Dualist). The term is often translated as soul, but is better translated as 'Self', as it solely refers to pure consciousness or witness-consciousness, beyond identification with phenomena.

Ātman ( / ˈ ɑː t m ə n/ Sanskrit: आत्मन्) is a Sanskrit word for the true or eternal Self or the self-existent essence of each individual, as distinct from ego ( Ahamkara), mind ( Citta) and embodied existence ( Prakṛti).

Absolute soul