‘abhava pratyaya alambana vrittih nidra’
abhava – absence, non-existence
pratyaya – the cause
alambana – support, depending on
vrittih – fluctuations
nidra – deep sleep
This yoga sutra 10, chapter 1, elaborates upon the fourth modification of the mind; nidra or sleep. Modifications of the mind are the possible states the mind can stay into. Mind is not the brain. Patanjali considers these states of minds as the fluctuations or vrittis of the mind which need to be overcome.
Sleep as a modification of the mind is a bit unique from among the other four modifications; sleep is the only modification which lacks the object, cause, or any content (thoughts) in which the mind remains engrossed.
Nature of Sleep – Modification of the Mind
Sleep is a state (fluctuation) of the mind which lacks any anchor to which the mind is tied upon, or dwells upon like the other modifications have. Sleep is actually a state of dullness the mind slips into as the blood supply to the brain gets reduced leading to tiredness as toxic substances begin to accumulate within the brain. Thus, the cause for the state of mind called as sleep is absent, and no real thoughts exist as is the case in the wakeful state of the mind.
For the entire duration the individual remains in this state of mind it is like remaining in a void, or a blank state. Sleep lacks clarity of thought though certain unconnected thoughts may exist in this state of the mind. Dreams, as a state of mind, though occur during sleep, are not put under sleep as a modification of mind, it is put under viparyaya, or wrong knowledge.
During sleep the senses remain disconnected from the mind, or they are not feeding the corresponding information to the mind for the respective knowledge to emerge. In the case of all the other four modifications of the mind – right knowledge, wrong knowledge, imagination, and memory – the mind remains in the wakeful state and the senses remain actively connected to the it where the thoughts of the corresponding modification arise.
Difference between Sleep and Samadhi
As per Vedanta view, as during deep sleep, also known as susupti, the Citta gets disengaged from the external world on account of the closing down of the senses, it returns to the state of joy, which is very close to the state of samadhi, or meditation.
Yoga refutes this claim; it claims that the Citta always remains embroiled in the kleshas and avidya and it cannot be cleansed of these two that easily. Though the Citta appears thoughtless (no fluctuations of the mind) during sleep the thoughts remain dormant and well up again the moment the mind attains the wakeful state.
It is very similar to putting a vehicle with a running engine out of gear, where the engine is running (thoughts persist), it only that it has been disconnected from the wheels (body) by putting it out of gear (sleep). The moment the engine (thoughts) and the wheels (body) are connected back again by putting the car in gear (wakeful state of mind) it resumes its impact on the wheels.
Moreover, since the states of the mind are the result of the presence of the dominant guna, from among the three gunas of which the mind is made up of like all the matter which evolves from Prakriti, sleep is the result of the dominance of tamasic guna over the mind.
herein, the calmness experienced as a result of inertia (tamasic) is not similar to the calmness which comes from concentration from Samadhi state of mind. Due to the tamasic influence on sleep it is not considered good for the yogis. In order to overcome the modification of sleep the individual must learn to always remain in a relaxed state of mind. Yogis are known not to sleep for many days because their body always remains in a relaxed state.
Why to Overcome Modification of Sleep?
When one sleeps, one gets overpowered by tamas. The sattva of Citta which is its true nature gets overpowered by tamas. Due to its tamasic nature it is considered worst thing that can happen to a yogi. The absence of the normal state of wakefulness is also considered as sleep. Dreaming is also considered more like imagination. Dreamless state is the most highly recommended state of sleep in the Indian Thinking.
Conclusion: Sleep is one of the modifications of the mind one must strive to overcome on the path of yoga. When one in the state of sleep one is not engaging one’s senses, and thus no thoughts are being generated within the mind as is the case in the wakeful state. Therefore, sleep is known as a state of void or blank in the mind. This state lacks the cause (pratyaya) due to which the thoughts can be generated, or the mind gets activated.
Since sleep is a modification of the mind it can be overcome by training the mind and the boy to constantly remain in a state of relaxation. The state of sleep and samadhi may appear to be similar but differ in the presence of the dominant guna within the two: tamas in case of sleep, sattva in case of samadhi.