The present looks less sinister, the past less innocent. The mind always focuses on current threats, and takes for granted the violent events that don’t happen but could easily have happened a few decades ago. A sniper in Norway kills dozens of innocent people—and the population does not riot or lynch the perpetrator and his extended family, but holds candlelight vigils. The Egyptian government falls—but the new one does not vow to push the Israelis into the sea. North Korea sinks a South Korean ship, killing 45 sailors—but instead of escalating to war, the Koreans go back to life as usual. Every day I notice the dogs that don’t bark.