The eternal self or soul

Atman

Atman is a word used in Hinduism meaning ‘soul’ or ‘spirit’. Some Hindus find it helpful to think of it as the ‘real person’ trapped inside the physical body. The idea of atman describes the life in every living creature but is not something that can be sensed or touched.

Never was there a time when I did not exist, nor you, nor all these kings; nor in the future shall any of us cease to be. (Bhagavad Gita 2.12)

Atman comes from Brahman, the Ultimate Reality. Hindus believe that atman is eternal and will live on after the body dies, unlike the human mind. Atman can be reincarnated into the body of any living thing, including an animal, a bird or a human, perhaps thousands of times.

quote
That which pervades the entire body, know it to be indestructible. No one can cause the destruction of the imperishable soul.Bhagavad Gita 2.12

Atman as indestructible

Like salt in water, atman cannot be seen but still exists

In one of the Hindu scriptures, the Upanishads, the concept of atman is explained using the analogy of putting salt in water: The father said to the son: ‘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, do you 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 that is what you are.’ (Chandogya Upanishad 6.12)

This analogy teaches that just like the dissolved salt remains unseen in the water, the atman (or the true self) is invisible but real. Even when the salty water is spilled on the ground, the salt (like atman) goes on existing.

Question

How do Hindus believe atman is different from the human mind?

Hindus believe atman is different from the human mind in the sense that it is eternal, and because it is in every living creature, not just humans.