In pursuit of Atman, with the desire to transcend this transient world, the seekers raise a question.
Q: One Atman is whom we all worship.The Other is in each life form who sees through the eyes, hears through ears, smells through nose and who analyses voices and acquires knowledge of what is tasteful and what is not.
Of these two Atman (Brahma and Soul), which is the one acclaimed by the scriptures?
A: What is heart is also called as mind. Consciousness, Perception, Discernment, Discrimination, Intellect, Vision, Determination, Contemplation, Prudence, Suffering, Memory, Resolve, Perseverance, Life Force, Desires and Attachments all are different aspects of Intelligence.
Soul, the source of Intelligence is Brahma itself. This is Indra and this is the Creator and this also pervades in the fundamental elements of earth, fire, air, water and space along with the light to be.
The whole perceivable world including worms with their source, birds, humans, insects and all kind of flora and fauna and mountains are carried by senses( eye), exist in conscious Intelligence and dissolve therein itself.
This Conscious Intelligence is Brahma or Atman.
The sages, having realized this Truth transcended the world that is perceived by senses and having all their desires fulfilled in that heaven, became immortal.
(Thus concludes Aitareya Upanishada from Rigveda)