Doctor keltner says we should also be talking about survival of the kindest. As humanis the only way that we survive is by being able to respond to the cries of our infants. And then we react to other human beings in distress in general. It's at the same levelits as basic to us as our need to breathe and our need to digest food, is our pre conscious response to other beings suffering. Who we are is also competitive and sometimes cruel, like these. These two things sit side by side in human nature. But this compassionate aspect, it is real. And its foundation, you could say, is sadness.