"In a special sense... the three great natural states of waking, dreaming, and deep sleep contain an entire spectrum of spiritual enlightenment."

Next Quote

So you have Sleep Stage One, Two, and then Three/Four. One is a little bit lighter stage of the quiet, non-REM sleep and then Three/Four is really deep, deep sleep. And what you want is, you actually want a number of - you want to go through all of these stages throughout the night.

— Shelby Harris