“One of the things that you see in many movements is that there is sort of a simplistic assumption that we must avoid, which is that progress moves forward in straight lines. And boy, does it ever not go in straight lines. It twists back, it doubles over itself. And it crosses many categories, such as economics, gender and race. That’s something that we may forget, and perhaps it goes against Dr. Martin Luther King’s precept that the arc of justice always bends forward”