Humans are social animals. We need each other to survive. One cannot be entirely
self-reliant, a worthy ideal as it is.
Here's the 17th century poem where the proverb first appeared.
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 any manner 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.
