WATERLOO, Ontario — Apparently Sgt. James Crowley's arrest of Harvard professor Henry Louis Gates Jr. in Boston on July 17 was "a teachable moment." Here are seven lessons relevant to world affairs.

First, it is possible for intelligent, reasonable, good and honorable people to interpret the same event differently and draw contradictory conclusions.

Second, the reason for this is that we view events through the prism of our respective historical narratives and life experiences. American police officers work in a hostile and life-threatening environment, are correspondingly more heavily armed and operate with a mind set that prioritizes securing compliance from a suspect over other considerations of politeness and nicety.