Within Hindu thought, the terms ātmān and Brahman name two poles of a single spiritual inquiry: the nature of the self and the nature of ultimate reality. Ātmān is spoken of as the innermost Self, the true essence of a being that lies beyond body, mind, and personality. It is pure consciousness, not the shifting stream of thoughts and emotions, and is described as eternal, unborn, and undying. This Self is distinct from the ego and the temporary aspects of identity, and is said to endure through the cycles of birth, death, and rebirth. To discern ātmān is to look past what changes and recognize what remains constant at the core of experience.

Brahman, by contrast, is the name given to the ultimate reality that underlies all existence. It is the infinite, formless, and all-pervading ground of being, beyond all names, forms, and attributes, yet the source of everything. Hindu texts describe Brahman as sat–cit–ānanda: existence, consciousness, and bliss. It is the unified essence of the entire universe, the absolute that transcends all limitations while silently sustaining every appearance. To contemplate Brahman is to turn attention from the many to the One that makes the many possible.

A central teaching in many Upaniṣadic and Vedāntic traditions is that ātmān and Brahman are not two separate realities but ultimately one. Pithy mahāvākyas such as “tat tvam asi” (“That thou art”) and “ayam ātmā brahma” (“This Self is Brahman”) express this identity in strikingly direct language. From this standpoint, the sense of separation between the individual self and the universal ground is attributed to ignorance (avidyā), a fundamental misperception about who and what one truly is. When this ignorance is dispelled through insight, meditation, and disciplined living, the individual recognizes that the deepest Self is none other than the ultimate reality itself.

The realization of the true nature of ātmān and its unity with Brahman is described as moksha, liberation from the cycle of rebirth and from the bondage of ignorance. This liberation is not the acquisition of something new, but the uncovering of what has always been the case: the identity of the inner Self with the universal ground. In this light, spiritual practice becomes a process of remembering rather than attaining, a gradual clearing of the veils that obscure what is already present. The journey of the seeker is thus framed as a movement from mistaken identification with the transient toward abiding recognition of the eternal Self that is, at once, the heart of the individual and the essence of all that exists.