Robert Fuller: No species other than ours holds the fate of the Earth in its hands. The question, then, is what is it about humans that has brought us such power?
Paul Rogat Loeb: None of us can predict when the causes we support will capture the popular imagination or enlist someone who goes on to do powerful work for justice. “Before water turns to ice,” writes psychologist Joanna Macy, “it looks just the same as before. Then a few crystals form, and suddenly the whole system undergoes cataclysmic change.”