Q: What is the relationship between Atman and Brahman?
A: As with many parts of Hindu belief, there is broad variety in the way this point has been construed. However, it may be generally said that the relationship of Atman to Brahman is most significant in the Hinduism of the Upanishads (c. 500 BC). This is perhaps the most mystical form of Hinduism and that which has been commonly popularized in the West.
Before the significance of their relationship can be understood, the concepts themselves must be illuminated. Neither directly corresponds to a word in common Western speech, but rather to a mystical element, peculiar to Eastern cosmology. “Brahman,” is the broader concept. It might sometimes be translated, “God” or “World Soul” or “The Spirit of the Cosmos.” When we say that in pantheism, “everything is God,” that sense of “God” is Brahman. “Atman” is the narrower concept. It is the “true self.” It could be translated, “the self soul,” but that can be confusing, because Western thought typically equates the soul with consciousness and awareness and Atman transcends those. It is the self which lies behind thought, emotion, and false spirituality, for all those things are just as much illusion as the rest of the world.
What then do the Upanishads teach about Atman and Brahman? That they are the same. “Atman is Brahman.” In other words, the true self is the World Soul or (more roughly) “Thou art God.” It is important that this be understood as identity, for it is not simply that the self is a part of collection of spiritual “stuff,” called “Brahman,” nor that the self contains Brahman or vice versa. The self, it is maintained, is the same as the spiritual truth which transcends “Maya,” the illusory reality which we call “the world.”
It is equally important that the equation of Atman with Brahman not be confused with the infamous New Age declaration, “I am God!”-- for the sense of “God” in the Upanishads is rather more mystical and transcendent. Brahman is beyond personality and interaction with the world; Brahman is that which is, to the contrary, true because it is not part of the world. This then becomes the key to salvation in this vein of Hinduism: the realization that your true self is not the physical, emotional, mental being with which you are most familiar but rather your true self is found in the spiritual reality which lies behind the illusion we call the world. In other words, the individual is bound to free themselves by realizing that he is already free.
While there may be a certain appeal to a belief that one has already found salvation, it must be appreciated that this is not a, “so relax and don’t worry about anything,” proposition. Quite the opposite: it puts the onus on the individual believer to grapple with the concept that he is not who he thinks he is and that even by entertaining the question he is still locked down by his illusory mind. Strict adherents to this form of Hinduism took it upon themselves to retreat into the wilderness to live a life of placid, ascetic contemplation. For the ordinary man, this goal of detachment from self becomes an unattainable position, and hence the Hinduism of the Upanishads fairly quickly gave way among the general populace to Bhakti Hinduism, in which one strives for salvation through devotion to a particular god or avatar.