No man is an island, entire of itself

 every man is a piece of the continent, a part of the main

 if a clod be washed away by the sea,  Europe is the less,

 as well as if a promontory were,  as well as if a manor of thy friends or of thine own were 

any man's death diminishes me, because I am involved in mankind 

and therefore never send to know for whom the bell tolls it tolls for thee.    -- John Donne