Balance pairs of opposites

What I had been calling good and evil were simply the qualities of kindness and cruelty, generosity and selfishness, tenderness and aggression that we had evolved to survive in different environments and under different circumstances. And as Jane had said, we will do whatever it takes to survive in the world. If we live in a society with a reasonable standard of living and some degree of social justice, the generous and peaceful aspects of our nature are likely to prevail; while in a society of racial discrimination and economic injustice, violence will thrive.

- The Book of Hope, Jane Goodall