It’s tough to speculate that silence, absolute silence, might not exist if in “the quietest place on earth” as certified by the Guinness organization I hear my own auditory system. Or some damn thing. Everyone’s auditory system, apparently, makes noise, but the question remains, is it always audible to oneself? If so—if the auditory faculty comes down to a version of Heisenberg’s uncertainty principle, whereby the act of hearing in itself changes what can be heard—then my search is over. Silence cannot be because within the instruments through which I must measure it, a total absence of sound cannot exist.

George Michelsen Foy, Zero Decibels, loc. 526