CHAPTER THREE: SADHANA ADHYAYA
Section 2: Tadabhavadhikaranam: Topic 2 (Sutras 7-8)

The soul in dreamless sleep.
Tadabhavo nadishu tat sruteh atmani cha III.2.7 (325)
The absence of that (i.e., of dreams, i.e., dreamless sleep) takes place in the nerves (Nadis or psychic currents) and in the self, as it is known from the Sruti or scriptural statement.
Tadabhavah: absence of that (dreaming) i.e., deep sleep; Nadishu: in the nerves (psychic currents); Tat sruteh: as it is known from the Srutis; Atmani: in the self; Cha: and, also. (Tat: about it.)
The state of dreamless deep sleep is now discussed.
The state of dream has been discussed. We are now going to enquire into the state of deep sleep (Sushupti).
Various Sruti texts describe the soul as resting in deep sleep in nerves (Nadis), in Prana, in the heart, in itself, in Brahman or the Absolute.
In different Sruti passages deep sleep is said to take place under different conditions.
"When a man is asleep reposing and at perfect rest so that he sees no dreams, then he has entered into these Nadis (nerves)" (Chh. Up. VIII.6.3). In another place it is said with reference to the Nadis, "Through them he moves forth and rests in the region of the heart" (Bri. Up. II.1.19). In another place it is said "In these the person is when sleeping, he sees no dream. Then he becomes one with the Prana alone" (Kau. Up. IV.19). In another place it is said "That ether which is within the heart in that he reposes" (Bri. Up. IV.4.22). In Chhandogya Upanishad it is said, "Then he becomes united with that which is, he is gone to his self" (Chh. Up. VI.8.1). In Brihadaranyaka Upanishad it is said "Embraced by the highest Self he knows nothing that is without, nothing that is within" (Bri. Up. IV.3.21). "When this being full of consciousness is asleep... lies in the ether, i.e., the real self which is in the heart" (Bri. Up. II.1.17).
Here the doubt arises whether the Nadis, etc., mentioned in the above passages are independent from each other and constitute various places for the soul in the state of deep sleep or if they stand in mutual relation so as to refer to one place only.
The Purvapakshin or the opponent holds the former views on account of the various places mentioned serving one and the same purpose. Things which serve the same purpose, e.g., rice and barley do not depend on each other. As all the words which stand for the places enumerated are in the same case, viz., the locative case in the texts, they are coordinate and therefore alternatives. If mutual relation was meant then different case-endings would be used by the Sruti. Hence we conclude that in the state of deep sleep the soul optionally goes to any one of those places, either the Nadis, or that which is, the Prana, the heart, etc.
The Sutra refutes the view of the Purvapakshin and says that they are to be taken as standing in mutual relation indicating the same place. The view that the soul goes to one or another of these is not correct. The truth is that the soul goes through the nerves to the region of the heart and there rests in Brahman.
There is no alternative here. The assertion made above that we are compelled to allow option because the Nadis, etc., serve one and the same purpose is without foundation. The authority of the Srutis is weakened if we allow option between two statements of the Sruti. If you recognise one alternative, the authority of the other alternative is denied.
Further the same case is used where things serve different purposes and have to be combined. We say, e.g., "he sleeps in the palace, he sleeps on a cot." We have to combine the two locatives into one as "He sleeps on a cot in the palace." Even so the different statements have to be combined into one. "The soul goes through the Nadis to the region of the heart and then rests in Brahman." Just as a man goes along the Ganga to the sea so also the soul goes through the Nadis to Brahman. So he attains Svarupa.
Scripture mentions only three places of deep sleep, viz., the Nadis, the pericardium and Brahman. Among these three again Brahman alone is the lasting place of deep sleep. The Nadis and the pericardium, are mere roads leading to it. The 'Puritat' or pericardium is the covering which surrounds the lotus of the heart.
In deep sleep the individual soul rests in Brahman, but there is a thin veil of ignorance between him and the Supreme Soul. Hence he has no direct knowledge of his identity with the Supreme Soul, as in Nirvikalpa Samadhi or superconscious state. The Sruti declares "He becomes united with the True, he is gone to his own (Self)" (Chh. Up. VI.8).
In the Kaushitaki Upanishad (IV.19) the three places are mentioned together: "In these the person is when sleeping he sees no dreams. Then he becomes one with the Prana (Brahman) alone".
Therefore Brahman is the resting place of the soul in deep sleep.
Atah prabodho'smat III.2.8 (326)
Hence the waking from that (viz., Brahman).
Atah: hence; Prabodhah: waking; Asmat: from this (i.e., Brahman).
The mode of waking from deep sleep is now described.
Therefore waking is coming from that state of union with Brahman or Atman.
Brahman is the place of repose of deep sleep. That is the reason why the Sruti texts which treat of deep sleep invariably teach that in the waking state the individual soul returns to waking consciousness from Brahman. The Sruti declares "In the same manner, my child, all these creatures when they have come back from the True do not know that they have come back from the True" (Chh. Up. VI.10.2). This Sruti passage clearly intimates that the Jiva or the individual soul returns from the True or Brahman to the waking state and that the Jiva rests or merges himself in Brahman and not in the Nadis, Hita, etc., during deep sleep. But he does not realise his identity with Brahman in deep sleep as he is enveloped by the evil of ignorance.
Brihadaranyaka Upanishad also declares "When the time comes for the answer to the question 'whence did he come back'?" (II.1.16); the text says, "As small sparks come forth from fire, thus all Pranas come forth from that Self" (II.1.20).
If there were optional places, to which the soul may resort, in deep sleep, the Sruti would teach us that it awakes sometimes from the Nadis, sometimes from the pericardium (Puritat), sometimes from the Self (Brahman).
For this reason also Brahman is the place of deep sleep. The Nadis are only the gateway to Brahman.