Non-dual Hindus, by contrast, believe that individual atmans are Brahman; as a result, all atmans are essentially identical and equal.
The first known mention of atman is in the Rigveda, a set of hymns, liturgy, commentary, and ritual written in Sanskrit.
Sections of the Rigveda are among the oldest texts known; they were likely written in India between 17 BC.
They are discussed and named as distinct from one another, but they are not always thought of as distinct; in some schools of Hindu thought, atman is Brahman.
Atman is similar to the Western idea of the soul, but it is not identical.
It may be that Hinduism should more properly referred to as Vedanta, and that Indian philosophy should be more properly referred to as Vedic philosophy because of these roots in the Vedas.
A certain difficulty for people brought up in monotheistic faith based cultures, in relation to Hinduism and Vedic-Hindu doctrine, lies in the view that Vedic philosophy speaks of Mystical Union as being with "The Atman which is Brahman".The soul is thought to come into existence when an individual human being is born, and it is not reborn through reincarnation.The atman, by contrast, is (according to most schools of Hinduism) thought to be: Brahman is similar in many ways to the Western concept of God: infinite, eternal, unchanging, and incomprehensible to human minds. In some interpretations, Brahman is a sort of abstract force which underlies all things.The final stage of moksha (liberation) is the understanding that one's atman is, in fact, Brahman.The concept of the atman is central to all six major schools of Hinduism, and it is one of the major differences between Hinduism and Buddhism.In other interpretations, Brahman is manifested through gods and goddesses such as Vishnu and Shiva.According to Hindu theology, the atman is reincarnated over and over again.Much like the Advaita Vedanta school, members of the Samkhya School see atman as the essence of a person and ego as the cause of personal suffering.Unlike Advaita Vedanta, however, Samkhya holds that there are an infinite number of unique, individual atmans—one for every being in the universe.The Yoga school has some philosophical similarities to the Samkhya school: in Yoga there are many individual atmans rather than a single universal atman.Yoga, however, also includes a set of techniques for "knowing atman" or achieving self-knowledge.