Why Does the Manas, Which Constantly Scrutinizes and Contemplates, Still Require Sleep?

Sleep is for restoring the physical body's energy and eliminating its fatigue, enabling the six consciousnesses to function better and more effectively. The manas (mind faculty) regards the physical body as its own, considers the six consciousnesses as its own, perceives all five aggregates and eighteen elements as its own, and relies on the eighth consciousness to instantaneously comprehend the state of the physical body. The activities of the six consciousnesses consume energy; to reduce this consumption, the manas decides to cease the activities of the six consciousnesses, actively suspending their discernment of the six sense objects, no longer wishing to perceive the six dusts (sense objects), and relying solely on its own awareness. As energy continuously accumulates and vitality is restored to a certain level, the manas will decide to awaken, re-engage with sensory objects, and resume the activities of the five aggregates.

If the physical body becomes fatigued, sleep is necessary to restore energy. The manas will then decide to sleep, halting the activities of the six consciousnesses. The manas itself wishes to shut off the six dusts and cease perceiving them, causing the five sense consciousnesses and the mental consciousness to gradually fade away. Therefore, it is not the manas that needs sleep, but the physical body that requires rest to replenish energy and restore vitality. This is precisely the result of the manas’ perpetual discerning contemplation. However, sleep does not affect the manas’ perpetual discerning contemplation. The manas can continue its contemplation during sleep and may even manifest dream states, engaging in contemplation within dreams.