Adi Shankaracharya taught:

If the universe be true, let it then be perceived in the state of deep sleep also. As it is not at all perceived, it must be unreal and false, like dreams. - Vivekachudamani 234

Why must the universe be unreal because it is not perceived in deep sleep?

If one person is in deep sleep (who doesn't perceive the universe), there may be other persons at the same time who are awake who still perceive the same universe, and may also be interacting with each other. Doesn't that mean the universe is real?

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    "When nobody looks at the moon, it does not exist!!"
    – Second
    Dec 11, 2020 at 17:49
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    Dec 12, 2020 at 4:10
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  • Actually, Kashmiri Shaivism does say that the universe is real. This is the big difference between it and other Shavisms. Dec 12, 2020 at 6:57
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5 Answers 5


Ok, so why must the universe be unreal if it is not perceived in the state of deep sleep?

Start with the advaitic definition of reality - reality is trikAla abhAdita satya - that which is never contradicted in the past, present and future. This is more or less the definition of reality.

Sruti says that in the state of deep sleep everything is contradicted -

Brihadaranyaka upanishad 4.3.22

  1. In this state (of deep sleep) a father is no father, a mother no mother, the worlds no worlds, the gods no gods, the Vedas no Vedas. In this state a thief is no thief, the killer of a noble Brāhmaṇa no killer, a Caṇḍāla no Caṇḍāla, a Pulkasa no Pulkasa, a monk no monk, a hermit no hermit. (This form of his) is untouched by good work and untouched by evil work, for he is then beyond all the woes of his heart (intellect).

So above Sruti statement shows that universe cannot be real, because, as we saw earlier, reality is never contradicted.

However, you raise an interesting point -

If one person is in deep sleep (who doesn't perceive the universe), there may be other persons at the same time who are awake who still perceive the same universe, and may also be interacting with each other. Doesn't that mean the universe is real?

You are correct. If X is sleeping and Y is awake, universe is contradicted only for X and not for Y. Why do we still call the universe unreal?

Let me narrate an analogy here. Two persons X and Y are independently observing a snake. The snake is actually not a real snake. They are actually looking at a rope and imagining it to be a snake. In this situation, the snake appears real for both, but we who are outside the story know that the snake is unreal.

After sometime, X comes to the realization that the snake is actually a rope. But Y is still under illusion of snake. Irrespective of what Y sees, the rope is the reality.

Now let us make the analogy more dramatic. There are 1000 people of whom person # 1 knows that the snake is actually a rope and the rest 999 people are under the illusion that it is a snake. The snake is still unreal, though perceived by 999 people.

Extend this analogy to the universe and deep sleep. Universe = snake. Ideally, rope = brahman, but in deep sleep, there is really no awareness, so let us say rope = negation of universe. Even though people in the waking state are perceiving the universe (snake), the universe is still unreal because it is not perceived by the one who is in deep sleep. Hope that helps.

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It depends on how we interpret/translate the term "universe".

I believe the "universe" in the verses refer to the whole reality experienced by the self through sense organs, or rather, our own personal experience of the perceivable reality which manifests/appears as different forms in our consciousness.

That is, 'universe' in these contexts refer to Naama-Rupatmak Vishva, which refers to the universe perceived by us in the form of representations (mental formations) and concepts (names) that are subjective to our conscious self which arise from our senses (Skandhas) and other functional organs. It does not refer to the absolute/ultimate reality of the universe, which is said to be beyond the reach of words and thoughts (See Characteristics of Brahman).

Regarding the following verse:

If the universe be true, let it then be perceived in the state of deep sleep also. As it is not at all perceived, it must be unreal and false, like dreams.

The way one could interpret it advaitically is that, any form of unconditional and true non-subjective reality should be persistently experienced by our consciousness without having to rely on external senses. But clearly, that is not the case with the perceived form of reality; it is conditioned on the senses. The verse tries to explain that one should not take this limited and conditioned experience as the true form of reality; it's just another state of conscious experience like dreams.

The absolute reality that pervades everything is said to be formless and indescribable (nirguna para-brahman). Hence one must not take the everyday's states of consciousness (like experiences during dreams, waking, and deep sleep) to be the true form of reality.

This can also be helpful: Dreaming in Advaita Vedānta (Also see: Turiya)

I believe it is pointless to compare this philosophy with modern science, as people have done in the comments. Science only deals with things & concepts at the materialistic boundaries of reality, and does not deal with any forms of such abstract philosophical proposals. There is no way one can scientifically prove or disprove if there is anything more than the materialistic reality, as science only deals with what is knowable and measurable in a consistent manner (which in-turn is materialistic).


According to Adi Shankara, universe as perceived objectively with all its variegated differentiations is unreal as exposited in the following verse (& also in subsequent verses) from the same text,

अतः पृथङ्नास्ति जगत्परात्मनः पृथक्प्रतीतिस्तु मृषा गुणादिवत् । आरोपितस्यास्ति किमर्थवत्ताद् धिष्ठानमाभाति तथा भ्रमेण ॥ २३५ ॥

ataḥ pṛthaṅnāsti jagatparātmanaḥ pṛthakpratītistu mṛṣā guṇādivat | āropitasyāsti kimarthavattād dhiṣṭhānamābhāti tathā bhrameṇa || 235 ||

  1. Therefore the universe does not exist apart from the Supreme Self; and the perception of its separateness is false like the qualities (of blueness etc., in the sky). Has a superimposed attribute any meaning apart from its substratum ? It is the substratum which appears like that through delusion.

And the fact that this objectively perceived dualistic universe is absent in deep sleep, so it implies that the dualistic world isn't real as there is an instance (deep sleep) where it is absent.

In simple words, universe is differentiation according to the Acharya, since the differentiation ceases to exist in deep sleep, it's unreal because according to him reality has to be ever-existing.

  • Becomes absent in deep sleep? Also does that mean when we die we can’t perceive it?
    – Adiyarkku
    Jan 22, 2021 at 5:02
  • @Archit Death is still a waking state as perceived by subtle jeevatman. Jan 22, 2021 at 5:34
  • So, is moksha equivalent to deep sleep? And also if we can’t perceive anything including ourselves or even Parabrahman, then can we doubt their existence? But yes universe = Parabrahma. I didn’t understand the sleep part.
    – Adiyarkku
    Jan 22, 2021 at 5:38
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    @Archit Have a look into Mandukya Upanishad. Moksha is not in deep sleep; it's in Turiya. Means are of various kind, not only direct perception. I haven't visited America yet I believe in its existence on virtue of verbal testimony. Jan 22, 2021 at 5:41
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    Okay till then +1 :) I’ll try to understand how it is not perceived in deep sleep
    – Adiyarkku
    Jan 22, 2021 at 6:26

Here is the answer from Ramana Maharshi For same Question

D:Neither do I deny the world’s existence while I am asleep. It has been existing all the while. If during my sleep I did not see it, others who are not sleeping saw it.

M:To say you existed while asleep, was it necessary to call in the evidence of others so as to prove it to you? Why do you seek their evidence now?. Those‘others’ can tell you of having seen the world (during your sleep) only when you yourself are awake. With regard to your own existence it is different. On waking up you say you had a sound sleep, so that, to that extent you are aware of yourself in the deepest sleep, whereas you have not the slightest notion of the world’s existence then. Even now, while you are awake, is it the world that says “I am real”, or is it you?

D:Of course I say it, but I say it of the world.

M:Well then, that world, which you say is real, is really mocking at you for seeking to prove its reality while of your own Reality you are ignorant.You want somehow or other to maintain that the world is real. What is the standard of Reality?. That alone is Real which exists by itself, which reveals itself by itself and which is eternal and unchanging.Does the world exist by itself?. Was it ever seen without the aid of the mind? In sleep there is neither mind nor world. When awake there is the mind and there is the world. What does this invariable concomitance mean?. You are familiar with the principles of inductive logic, which are considered the very basis of scientific investigation. Why do you not decide this question of the reality of the world in the light of those accepted principles of logic?. Of yourself you can say ‘I exist’. That is, yours is not mere existence, it is Existence of which you are conscious. Really, it is Existence identical with Consciousness

Maharshi's Gospel


Deep sleep is merely the absence of mental objects, and that in itself says nothing about the "universe". Our experience of the universe in the waking state isn't "unreal", it is transient and dependent upon Brahman.


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