The Manas Perpetually Examines and Reflects: Why Is Sleep Necessary?

Since the manas considers the physical body as its own, considers the six consciousnesses as its own, and considers the five aggregates and eighteen elements as its own, it relies on the eighth consciousness to instantaneously perceive the state of the physical body. When the physical body becomes fatigued and requires sleep to restore energy, the manas feels the need to sleep and does not wish the six consciousnesses to remain active. The manas itself decides to shut off the six sense objects, ceasing awareness of them, causing the five sense consciousnesses and the mental consciousness to gradually cease. Therefore, it is not the manas that requires sleep, but the physical body that needs rest to replenish energy and restore vitality. This is precisely the result of the manas's constant mental deliberation.

The activities of the six consciousnesses consume energy. To reduce this energy consumption, the manas decides to prevent the six consciousnesses from further activity, actively shutting down their discrimination of the six sense objects and no longer wishing to perceive them, relying instead solely on its own awareness. As energy continuously accumulates and vitality is restored to a certain level, the manas decides to awaken, re-engage with sensory objects, and resume the activities of the five aggregates.