"Quiet is the absence of sound; silence is the presence of silence." - Robert Fripp
According to science (science!), darkness is the absence of light, and cold is the absence of heat. Is silence truly the absence of sound, though? Within music it’s definitely more, and it’s super interesting.
Even before American music theorist John Cage’s landmark work 4’33” – composed in 1952, able to be played by any number of musicians with any combination of instruments, and instructing said musician/s not to play their instrument/s for the entirety of the score – musicians have treated silence as a component just as important to their craft as sound. While 4’33” is commonly perceived as comprising four minutes and thirty-three seconds of total silence, it's truly about the environmental sounds which the audience would hear within whichever space the piece was being performed.
Some artists prefer not to 'over-produce' their records, instead including the ‘flaws’ of ambient studio sound or indirect instrumental sound – like the hammer’s movement within the piano (a soft wooden thud) or the sound your finger makes when it moves across a guitar string (that tight ‘schick’ sound) which give a track warmth.
The length of the silence in a song is super important – think of the pause before the drop in a giant dance track – as is its quality. What about white noise? IRL we use white noise to create a kind of pseudo-silence, wherein the bursts of noise that would otherwise disturb you (colleague singing the Yakult ad theme, dog snorting in his sleep) are swept over by the constant drone of a sound you are so used to that it functions as silence in your mind. In electronica, white noise is used to synthesise percussive instruments which have a lot of crazy frequencies going on (or "high noise content in their frequency domain", if that means anything to you). Then there's brown noise, blue noise and a whole bunch of others on the colour noise spectrum.
If you’re as weirdly interested in the antimatter of music as I am, I recommend you check out podcast Stuff To Blow Your Mind’s episode on silence, which is here.