Why does one gesture matter more than another? Why this Facebook post, this girl with a drum?
Even to try to answer this you’d have to say that the butterfly is born aloft by a particular breeze that was shaped by the flap of the wing of, say, a sparrow, and so behind causes are causes, behind small agents are other small agents, inspirations, and role models, as well as outrages to react against. The point is not that causation is unpredictable and erratic. The point is that butterflies and sparrows and young women in veils and an unknown 20-year-old rapping in Arabic and you yourself, if you wanted it, sometimes have tremendous power, enough to bring down a dictator, enough to change the world.