These findings have enormous implications. They tell us that our impulse to respond to other beings sadness sits in the same location as our need to breathe, digest food, reproduce, and protect our babies; in the same place as our desire to be rewarded and to enjoy lifes pleasures. They tell us, as Keltner explained to me, that caring is right at the heart of human existence. Sadness is about caring. And the mother of sadness is compassion.

Bittersweet by Susan Cain