The other day in Hannover, Germany: I am walking down a city street and see a man riding a bicycle in my direction. He turns his head away to look at something, and in that instant he crashes head-on into a pole. He flies from his bike, lands on his head with a sickening thud. For the next ten minutes he lies motionless in the gutter with a pool of blood growing larger and larger from under his head. I suspect that he is dead.

A group of people gather around him, each trying in some way to make him comfortable, trying to revive him. Others have gone for help. Soon the emergency medical technicians arrive, put him on the gurney, and speed him away to the hospital.

All day long this horrific scene replays in my mind. The sights—the fall to the pavement, the blood, the motionless body—cannot be resisted. Then as time passes, I see another picture. I see myself, many years ago, crashing violently in a different but just as real way. And I remember the people who crowded about me ...