Atman is a Hindu word that means ‘soul or spirit’. Essentially, it refers to the real person inside an individual. It is made of part of the spirit of Brahman, who Hindus believe is the one true ultimate God. Therefore, it is not something that can be seen or touched, but it is eternal and everlasting.
This is different from the physical body, or matter, which can be seen and touched. A key Hindu belief is the idea that when a person dies the atman will move on into the body of another being. This process is called samara. Hindus believe that the atman is about accumulating knowledge. When the atman moves on to another life, it is as if it is letting go of the ego and gaining true knowledge.
Hindus believe that the physical and material worlds are different. Whereas the physical self exists in this world, the spiritual self exists in the spiritual world.
In one of the Hindu scriptures, the Upanishads, there is a story that is used by Hindus to explain the idea of the atman. The story explains that, just like salt in water, you know it is there but cannot see it. The atman, or part of Brahman, is there even though you cannot see it.
‘Be it so, my child’, the father replied; and he said, ‘Place this salt in water, and come to me tomorrow morning.’ The son did as he was told. Next morning the father said, ‘Bring me the salt you put in the water.’ The son looked for it, but could not find it, for the salt, of course, had dissolved. The father said, ‘Taste some of the water from the surface of the vessel. How is it?’ ‘Salty.’ ‘Taste some from the middle. How is it?’ ‘Salty.’ ‘Taste some from the bottom. How is it?’ ‘Salty.’ The father said, ‘Throw the water away and then come back to me again.’ The son did so; but the salt was not lost, for the salt existed forever. Then the father said, ‘Here likewise in this body of yours, my son, you do not perceive the True; but there, in fact, it is. In that which is the subtle essence, all that exists has its self (atman). That is the True, that is the atman, and thou, Svetaketu, art that.’Chandogya Upanishad 6.12