Atman is a person’s true self, which is infused with or is entirely coterminous with the universal spirit of Brahman, thus lying beyond the phenomenal, changing reality we perceive. It is vaguely similar to the Western concept of the soul, as each person “possesses” or partakes of the atman, but it differs from a soul in that the atman is not entirely unique to an individual; some Hindus believe that all individual atman are joined to the separate and superior Brahman (the dualistic view), and others believe that each individual atman is Brahman itself (the non-dual view). Either way, the individual atman is not entirely individual, as it is infused with the same Absolute Reality of Brahman as every other atman.
Atman is an important term in Hindu thought and is perhaps most notable as the concept that divides not just different branches of Hinduism, but also theologically divides Hinduism from Buddhism. Hinduism maintains that the atman is the true self beyond temporal existence, our attachment to which is illusory; Buddhism holds that there is no atman because there is no self as the self is just another illusion. Within Hinduism, the idea of the atman divides non-dualistic Hindus—who equate the atman with Brahman, making all beings connected as one and the same—from dualistic Hindus—who hold that there is at least some measure of separate identity between individual atman and the Supreme Atman of Brahman, the latter of which is usually identified in terms of a god.