Why do we care about what happens to others? In 1776, Adam Smith proposed that we hate to see others suffer because our mind makes us suffer with them. In this lecture, Keysers will show how deeply brain science supports his vision. Humans and rats activate neurons and brain regions involved in their own pain while witnessing the pain of others - indeed as if they were in pain themselves. Perturbing this system makes us care less about others. Biology thus wires us to share the joys and distress of others. Yet empathy does not just happen to us: Keysers will also show how easily we can turn off our biologically predisposed empathy – and we should thus learn to use it wisely.