How insupportable would be the days, if the night with its dews and darkness did not come to restore the drooping world. As the shades begin to gather around us, our primeval instincts are aroused, and we steal forth from our lairs, like the inhabitants of the jungle, in search of those silent and brooding thoughts which are the natural prey of the intellect.

The Writings of Henry David Thoreau (ed. 1803)