THE NATURE OF TRUE SELF orATMAN
That "essence" which is described in the Upanishads is Brahman, Atman or the Absolute. It is the source of all knowledge of the scriptures. It is the origin or the womb of everything. It is Existence Absolute, Knowledge Absolute and Bliss Absolute. It is indivisible, all-pervading, independent, eternal and immortal. It is beyond time, space and causality. It has no beginning or end. It is the indweller of all beings. It is the witness of the activities of all minds.
Atman is Satchidananda (Existence-Consciousness-Bliss).
Atman is Sat (eternal Existence). That which exists in the past, present and future, which has no beginning, middle and end, which is unchanging, which is not conditioned in time, space and causation, which exists during Jagrat, Svapna and Sushupti, which is of the nature of one homogeneous essence (Sada Ekarasa, Sada Ekarupa) is Sat. This is found in Atman. Srutis emphatically declare: Sat only was prior to the evolution of this universe.
Atman is Chit (Consciousness). Atman is Chit for it shines by itself unaided by any other light and illumines the whole universe by its own light.
Atman is Ananda. Ananda is that bliss which is eternal, uncaused and unexcelled. It is the real nature of Atman. We experience the bliss of Atman every day in deep sleep. It is not mere absence of pain that we experience there. It is undoubtedly positive happiness, for we remember on waking up that we slept happily. This indicates the fact of the existence of bliss to Atman in that state.
Sat, Chit and Ananda are not three distinct entities
Satchidananda (Existence-Consciousness-Bliss) is only a provisional definition of Atman. Sat, Chit and Ananda are one. Atman is partless and homogeneous. The three characteristics Sat-Existence, Chit-Consciousness and Ananda-Bliss are not distinct from one another. They are coeval and coexistent with Atman. Just as water, Jal, Pani signify one and the same thing, so also Sat-Chit-Ananda signify the one Atman. Sat is Chit. Sat is Ananda. Chit is Sat. Chit is Ananda. Ananda is Sat. Ananda is Chit. You cannot split up Sat-Chit-Ananda into three separate entities, just as you cannot separate light, heat and luminosity from fire.
Atman is distinct from the five Koshas or sheaths. The five sheaths are Annamaya Kosha (food-sheath), Pranamaya Kosha (vital sheath), Manomaya Kosha (mental sheath), Vijnanamaya Kosha (intellect-sheath) and Anandamaya Kosha (blissful sheath).
The Annamaya Kosha forms the gross body. The Pranamaya, Manomaya, Vijnanamaya Koshas go to constitute the subtle or astral body or Linga Sarira. The Anandamaya Kosha forms the causal body or Karana Sarira. The five Karma Indriyas are contained in the Pranamaya Kosha. The five Jnana Indriyas are contained in the Manomaya Kosha.
Atman or consciousness is beyond the body, mind, senses, prana or energy, emotions and thoughts. Consciousness is unattached, self-existent, self-luminous, ever present, ever free and blissful. (Atman Nityananda)
He who has realised this Sat-Chit-Ananda Atman is a liberated sage. He has nothing more to learn, has nothing more to do, has nothing more to gain. All his desires are gratified. He has obtained all worlds. He is freed from the jaws of death. He attains immortality.