Why silence can keep you awake.

Why it works

In a truly quiet room the smallest sound is an event, and so is the smallest thought. Nothing competes with either. That is why some people sleep worse in a silent hotel than beside a road at home. The dark noise on this page is a low, soft floor that takes the edge off the quiet.

A floor of sound deals with the creaks. It does not deal with the thoughts, which have just as much room as before. Something has to be in the room with you. The story layer is meant to be exactly that and no more: a calm presence, saying nothing of consequence.

What you are hearing

• Dark noise. Pink noise low-passed at 320 Hz, with a very slow rise and fall in level that never repeats. Soft, close and a little uneven, like air moving at night.
• The voice. The first four minutes of Aristotle, the Greatest Philosopher, a Lullable story, in a synthesised voice. It only plays if you bring it in.
• The ending. The preview lasts four minutes. Its last ten seconds are a straight fade to silence, so it never stops abruptly.

For a real recording that runs forty minutes, the Lullable iPhone app has rain, waves, a campfire and plain noise, with no voice and no music.