Silence is intellectual property. John Cage's 4'33", a lengthy silent composition from one of his avant-garde performances, constitutes an original work for copyright purposes. This means that other composers who include silent tracks have made a derivative work from Cage's silence. Cage's representatives have served producer Mike Batt with a legal nastygram asserting that he infringed on Cage's copyright with his 60-second silent track on the latest Planets album. "As my mother said when I told her, 'which part of the silence are they claiming you nicked?'" [ Source: Boing Boing Blog]