brahma satyam jagan mithya jivo brahmaiva napara Brahman is the Reality, the universe is an illusion, The living being is Brahman alone, none else. This statement, though it presents the core teaching in all the Upanishads, has evoked much criticism. Most people are naturally unable to accept as illusion the world in which they live and the things they directly perceive and experience throughout their lives. So also are those with a predominantly materialistic culture. Doubts from other quarters are probably caused by a superficial or incomplete understanding of the significance of the words, "Reality" and "illusion," used in this statement. What follows is an attempt to clarify the meaning intended by the revered Acharya. Let us consider the following examples:

2. Examples
a. The primitive people could see that the earth they lived in had a very extensive, more or less flat surface; and that the sky was like a huge curved roof, touching the earth’s circular boundary line far away. For them, this perception was "real." We know that the earth is spherical in shape and the appearance of the sky touching the earth at the horizon is illusory.
b. We all see the sun rising in the East every morning, travelling across the sky during the day and setting in the West every evening. We also experience the light and warmth when the sun shines, and the darkness in its absence. However, ever since the physical sciences convincingly proved the facts, we know that the sun is neither rising, nor travelling, nor setting, but the earth is rotating and revolving around the sun, following certain laws of nature.
c. I stand facing a vertical mirror, and I see myself — a second "I" — standing in the mirror. That sight also enables me to have my morning shave. But I know that the second "I" vanishes when the mirror is removed and that it was a reflection with no substance.
Note: The above examples convey an important message. All that we perceive with our senses do not have to be real always. At times, they may be mere appearances, i.e., illusions.
d. In a cinema hall, we sit and watch so many things happening before our eyes, some funny, some exciting, some tragic, making us either laugh or cry. In the end, when the projector is switched off, everything disappears, and the plain white screen alone remains.
e. And now, the very familiar story of the "rope and snake" in Vedanta:
A traveller on a village footpath at dusk sees a snake lying across his path. Shocked, he screams for help. Another person comes along and casts the light from a flaming torch on the "snake." The traveller sees that it is only a rope, and continues on his journey, in peace.
Note: These last two examples convey a second important message, viz., some unreal perceptions are actually operational, in as much as they cause certain effects, good or bad, until their unreality is discovered and the reality dawns.
All the examples above relate to our "waking-state" perceptions and experiences only. But daily, we go through two other states of consciousness, viz., the "dream state" and the "deep-sleep" state. Let us also consider what happens in those states.
3. Dream and Deep-sleep States
a. The dream state: We often dream while asleep. For example, I dream that I am in an aircraft, returning to India. Control of the aircraft is wrested by a hijacker and the plane is diverted to Karachi. All passengers are gripped by fear and tension. Just then, a saintly passenger sitting next to me, unperturbed, tells me: "Don’t be afraid. This is an illusion."
I react: "What? Don’t you see that hijacker pointing the gun at the pilot?"
I hear a noise… I wake up, safe on my bed. What the dream-saint said was proved true.
Note: While still in the dream state, I take as reality what I see and experience; they cannot be an illusion to me. But the moment I wake up from the dream state, the whole of the dream experience becomes an illusion.
b. The deep-sleep state (sushupti): Here, we all know that there is neither perception of any world, nor action, feelings or thoughts. The body, senses, mind, intellect and the whole world are all negated; the jiva alone exists, but steeped in ignorance of everything. From this state, we wake up in time to the familiar "waking state," which now becomes the reality to us.
Keeping the above examples in mind, let us now turn to Sri Shankaracharya’s statement.
4. Sri Shankaracharya’s Statement
a. brahma satyam ("Brahman is the Reality"): In Vedanta, the word "Satyam" (Reality) is very clearly defined and it has a specific significance. It means, "that which exists in all the three periods of time (past, present and future) without undergoing any change; and also in all the three states of consciousness (waking state, dream state and deep-sleep state)." This is therefore the absolute Reality — birthless, deathless and changeless — referred to in the Upanishads as "Brahman."
b. jagan mithya ("the world is an illusion"): The world appears "real" only in the "waking state;" but it is negated (it disappears) in the dream and deep-sleep states. Hence, it is not real, according to the definition above. Therefore, the world is said to be mithya by the Acharya.
However, many people seem allergic to the word, "mithya," when it is used to refer to the perceptible world. For this reason, perhaps, the Acharya, in his later works, like Brahmasutra Bhashya, calls it "vyavaharika satta" (relative reality) or "pratibhasika satta" (apparent reality), as if to accommodate them.
c. jiva brahmaiva napara ("the jiva is Brahman alone, none else"): "Jiva" refers to the sentient principle in all living beings, including human beings. In the deep-sleep state, the body, senses, mind and intellect are all negated (rendered totally ineffective or insentient). Hence, the jiva is one with the sentient, inner life-principle, which revives the body, senses, mind and intellect after sleep. This life-principle is the pure consciousness that is the same in all beings. The all-pervading Brahman of the Upanishads is that pure consciousness present in all jivas as their antaryami (inner spirit).
5. Conclusion
No one has any hesitation, obviously, in taking the dream world as an illusion; for, when they wake up to this familiar world, the dream world disappears. But all of us find it hard to believe that this familiar world, which we all actually perceive and experience, is an illusion. If I jump down from an upper floor, I will certainly be fatally injured. This difficulty is because we are all part of this world and are attached to it in some way.
But a spiritual aspirant may ask, "Is there a higher state to which I can wake up, so that this waking world will disappear, just like the dream world?"
The answer is a resounding "yes." What that higher state is no one can precisely describe. But Sri Shankaracharya was an intellectual and spiritual prodigy. He could experience that sublime, transcendental state (turiya, wherein the jiva is in a state of complete identification with Brahman), just like the Upanishadic seers. Thus, the great Acharya could confirm and authoritatively summarise the vision of the ancient seers of Sanatana Dharma — the truth of Advaita. Before he left his mortal coil, he firmly established this philosophy by his masterly commentaries on the prasthanatraya (the three basic texts on Vedanta, viz., Upanishads, Bhagavad Gita and the Brahma Sutras).(amratapuri.org)