Cause-and-effect assumes history marches forward, but history is not an army. It is a crab scuttling sideways, a drip of soft water wearing away stone, an earthquake breaking centuries of tension. Sometimes one person inspires a movement, or her words do decades later; sometimes a few passionate people change the world; sometimes they start a mass movement and millions do; sometimes those millions are stirred by the same outrage or the same ideal, and change comes upon us like a change of weather. All that these transformations have in common is that they begin in the imagination, in hope. To hope is to gamble. It's to bet on the future, on your desires, on the possibility that an open heart and uncertainty is better than gloom and safety. To hope is dangerous, and yet it is the opposite of fear, for to live is to risk.