Earlier quoted context omitted.
I would note that 4 minutes and 33 seconds of silence is copyrighted by John Cage as " 4'33" ", and a single chord sustained for 20 minutes, followed by 20 minutes of silence, is copyrighted by Yves Klein as "The Monotone-Silence Symphony".
Cage's case is more complicated and less a violation than it may sound at first. It's not 4'33" of "mathematically true silence", that is, you don't violate it per se just by having the right number of zeros in your .wav file. It's 4'33" of performed silence, where the performance is actually the incidental noise of the auditorium it is in. Having a copyright on this particular piece specifically in a performance con…
That's an incorrect way to view it actually. 4'33" copyrightable essence is actually represented by the active production of its scoring. I.e. nothing. The background sound is not what makes it copyrightable. You can go ahead and sit at a piano for the length of the composition all you want, wherever you want, and you'll still be publically performing 4'33".
The rather humorous outcome, if one asks me, is that anyone who writes in 4 beats of silemce into a score should be violating copyright if we're going to be consistent.