Basic facts
There is life. Life is conditional and self-preserving. An organism can continue or cease to be, depending on conditions and its actions.
The greatest threat to life is major trauma. It can end life instantly. If survived, it can leave great damage and impairment of function. The greatest support of life is profound rest. It is longer than daily rest, with perfected conditions. With it, life restores itself from wear and trauma.
Consciousness is the ability to know and respond to the facts of reality. All organisms possess it to some degree. The faculty of consciousness is the psyche. Psychology studies the psyche, particularly reason, the volitional consciousness of man.
The psyche is an organic system. It can both suffer trauma and heal itself.
Rest that is profound enough for healing from major trauma, psychic and physical, occurs in total extended darkness. This healing is a function of physiology, environment, attitude, behavior, and support.