The aim of Yoga, of union, is to unite the thinking mind with its source in pure awareness. In modern terms, “pure awareness” means quantum space, the silent, empty void that is the womb of all matter and energy.
Pure awareness exists in the gap between thoughts; it is the unchanging background against which all mental activity takes place. We would not ordinarily suspect that such a state exists because our minds are so preoccupied with the stream of thoughts, wishes, dreams, fantasies, and sensations that fill waking consciousness. That is why the ancient Indian sages had to devise the specific technique of meditation, in order to show the mind its own origins in the quantum depths.
Sitting in meditation with the eyes closed induces the nervous system to enter a state of “restful alertness” ~ i.e., the mind remains awake while the body goes into a deeply relaxed state.
Sleep is a hypometabolic state in which oxygen consumption decreases, heartbeat slows, and consciousness blanks out. The waking state, on the other hand, is marked by higher oxygen consumption, a faster heartbeat, and an alert mind.
These opposites are united in meditation. While remaining alert enough to feel the experience of pure awareness, people go into a state of rest twice as deep as sleep. Moreover, they do so very quickly, usually within ten minutes after shutting their eyes, compared to the four to six hours it takes us to reach our deepest relaxation in sleep.