Patanjali Yoga Sutra ||1.10||— abhāva — pratyayālambanā vṛttirnidrā|| अभाव — प्रत्ययालम्बना वृत्तिर्निद्रा||

Sleep is a state of mind where there is unintentional thoughtlessness or emptiness or vacuum.

Samādhi is a state of thoughtlessness achieved by a sādhaka with his sheer yogic efforts. Once he experiences Samādhi, a state of Superconsciousness, he comes out as an enlightened or realized soul. In this superconscious state, he is one with the Supreme Soul — Paramātma — state of perfect Yoga (Unity). What one gets with Samādhi? It is said, through samādhi, one possesses what one always possessed, and loses what one can never lose at all. To experience this kind of thoughtlessness, Sādhaka needs saintly efforts. However, in sleep, though a person experiences thoughtlessness, he is the same old person when wakes up, except that he got good, rejuvenating rest both bodily and mentally; because it is driven by tamoguṇa. thus, deep sleep (suṣupti) is the absence of experience, whereas Samādhi is the experience of absence. Dronāchārya says, lesser the difference between wakeful state and sleep state, better it is for a yoga sadhāka.

According to māṇḍūkya Upaniṣad, citta has three states:

Having any one of these three experiences at any given point of time, we identify ourselves to these three states, like: I am waking, I am dreaming, I enjoyed deep sleep. Let us analyze the attributes of each of these three states:

1. Jāgr̥ta: This is the waking state, where our Jñānendriyas are functional, antaḥkaraṇas are functional, karmendriyas are also functional. There is free will in our transactions with the external world. Śaṅkarācārya calls this state as ‘Laukika’ as the man is aware of the vastu prapañca.

2. Svapna: (REM — Rapid Eye Movement phase in sleep): This being our dreaming state the Jñānendriyas are functional, antaḥkaraṇas are functional, karmendriyas are also functional. However, influenced by the transactions of the Jāgr̥t state, the mind recreates and projects like a projector projecting the film on a screen. That is nothing but our dream. But the free will in our dealings is absent; I cannot decide the nature of the dream I want to witness. Śaṅkarācārya calls this state as ‘śuddha Laukika’, as the man experiences the vastu prapañca even in its absence.

3. Suṣupti: (NREM — Non-Rapid Eye Movement phase in sleep): This is a deep sleep state where there is the absence of experience, as the jñānendriyas and antaḥkaraṇas are not functional (Karmendriyas are functional). Śaṅkarācārya calls this state as ‘Lokottara’, as the man experiences nothing related to vastu prapañcha.

Why Jāgr̥ta and Svapna are not true? It is easily understandable that only in Jāgr̥ta state, Svapna and Suṣupti are understandable. However, from the Upaniṣadic perspective, even Jāgr̥ta is also not our waking state; like the other two states, this is also the outcome of our ignorance. This can be recognized only by a realized sādhaka, say the Upaniṣads (SwāmiĀdidevānanda, 2004). Svapna jagat is experienced only in svapna; neither before nor after, similarly Jāgr̥ta jagat is experienced only in Jāgr̥ta, neither before nor after. That which has a beginning and an end is not absolute. Further, the experiences of svapnāvastha are not true for Jāgr̥atāvastha; similarly, the experiences of Jāgr̥tāvastha are not true in svapnāvastha. Hence, Jāgr̥ta and Svapna are not existence absolute.

Brahma Sūtras clearly differentiate jāgṛta with svapna. The phenomenal world is the creation of the Lord whereas the dream world is illusory and is the creation of Jīva.

Bhagavān says, sleep itself is not yogasādhana, though thoughtlessness similar to Dhyāna is experienced in deep sleep (suṣupti). However, sleep is only an untold essential occurrence for a yogi, but to be done in moderation, in right sprits and in appropriate or suitable (yukta) ways.

युक्ताहारविहारस्य युक्तचेष्टस्य कर्मसु।

युक्तस्वप्नावबोधस्य योगो भवति दुःखहा॥६.१७॥

yuktāhāravihārasya yuktaceṣṭasya karmasu.

yuktasvapnāvabodhasya yogo bhavati duḥkhahā॥6.17॥

Yoga is for the one who appropriately eats and amuses. It is for the one who is duly devoted to his duties, suitably sleeps (Svapna) and wakes up rightfully. Yoga of such a sādhaka brings forth liberation from all kinds of miseries.