The moment when mortality, ephemerality, uncertainty, suffering, or the possibility of change arrives can split a life in two. Facts and ideas we might have heard a thousand times assume a vivid, urgent, felt reality. We knew them then, but they matter now. They are like guests that suddenly speak up and make demands upon us; sometimes they appear as guides, sometimes they just wreck what came before or shove us out the door. We answer them, when we answer, with how we lead our lives. Sometimes what begins as bad news prompts the true path of a life, a disruptive visitor that might be thanked only later. Most of us don't change until we have to, and crisis is often what obliges us to do so. Crises are often resolved only through anew identity and new purpose, whether it's that of a nation or a single human being.