6 hours of sleep allow our brains to process information with a great degree of accuracy and reliability.
It’s sort of like cleaning up and defraging your hard drive: you want the best performance out of your computer and while you’re optimizing & defraging it you want to shut down as many open programs as you can.
When that screen goes blank, it doesn’t mean the computer has shut down - just like someone sleeping. To “wake” the computer, all you have to do to is slowly and gently wrap your hand completely around the mouse and quickly and firmly move it back and forth while caressing the scroll wheel - trust me, you’ll soon realize that the computer was far from off. . .I guess I’m carrying this analogy too far so I’ll stop.
Yet to be reconciled with the reality of the dark for a moment, I go on wandering from dream to dream.
Just a guess but perhaps some time in our evolutionary past it was found beneficial to become less active when it was darker/colder and food was harder to find, thus conserving energy. Organisms developed which partially shut down at theses times. Later developments then took advantage of this down-time to do those pesky but necessary housekeeping activities, freeing the wide awake organism for more productive stuff. Once started down this road you would be locked into the wake/sleep cycle otherwise the housekeeping stuff would never get done.
