Atman' is the highest self, it remains when everything that is not the self of a man is abolished. Inn English means "soul" or "Self". In Hindu Dharma, the word "Atman" has deeper connotations. It is the imperceptible, timeless, perpetual and essential self, residing within the mortal frame of every Jiva. Lord Krishna, the Divine Incarnation of Lord Vishnu had explained the perplexed Arjuna, the Fundamental Truth of Existence, in the Eternal Book of Life, Bhagavad Gita that the main essence is the Atman. The word 'Atman' is derived from 'an' which means 'to breathe', which is 'the breath of life'. The meaning of the word changed with time and it covered life, soul, self or essential being of the individual. According to Sankara, 'Atman' means 'to derive', 'to eat' or 'pervade all'. It is the principle of man's life. 'Atman' is the Sanskrit word for the soul of a man. Professor Radhakrishnan says in his exposition of the philosophy of the Upanishads, 'Atman' is the 'God's dwelling place'.
The general concept of Atman is that it is the indestructible and eternal soul. It is never born, never dead and after coming into existence never ceases to be. It is always, permanent and very ancient. At the time of death the soul does not die. It just leaves the body and enters into a new one. Adi Shankaracharya observes: "Like the waves in the ocean, the worlds arise, live and dissolve in the Supreme Self; the substance and cause of everything." Atman is that highest self. An individual hears, touches, sees, feels and thinks by the atman. The 'Atman' continues despite the shutting off of consciousness, which is exalted above waking and sleeping. Atman inhabits in the unexplored, deepest recesses, of Jiva. "There the eyes cannot travel, nor speech nor mind. Nor do we know how to explain it. It is other than the known and beyond the unknown".
The 'Atman' is not an object of any sort but is the eternal subject. We hear, touch, see, feel and think by the atman. The 'Atman' continues despite the shutting off of consciousness, which is exalted above waking and sleeping. When a man withdraws from all outward things, by retreating into the ground of soul, in the remotest depth of the soul, we find the infinite. Atman is intrinsically connected to the Pure Consciousness of Brahman, the Cosmic Spirit. Hinduism asserts that Brahman is the Creative Aspect of God. Brahman is the Celestial Source of existence. It is the all-pervading, Divine Core, from which sprouts the inherent life force, driving every individual soul or Atman in Jiva.
Advaita philosophy of Hinduism sees no difference between the Brahman and Atman. Indeed, Mandukya Upanishadreinforces this idea. It is Brahman, which manifests itself as the Jiv atman within the tangible mould of the body, made of Prakriti, the "material-nature" of Ishvara. This ideology claiming every Atman, as Brahman, authenticates that all are its creations and manifestations. Atman is the Universal Soul, the Brahman. Therefore each creature bears as much importance as the other has. The core philosophy of the Upanishad has said that 'Atman' is the 'God's dwelling place'. The real thing in every individual is the self or 'Soul'. According to the Hindu religion, 'Atman' means, the union of the collective human soul with God, which brings about a complete merge in the absolute totality of Brahman.