The phrase "No man is an island", was originated by the English divine John Donne
. He wrote in Meditation XVII:No man is an island, entire of itself; every man is a piece of the continent, a part of the main.
Donne is asserting that people need each other – we cannot exist independently from others or interactions.
Simon & Garfunkel's "I Am A Rock
," with its lyric "I am an island," was likely derived from the piece as well.