“But there is another model for progress – the opposite of the polio model – one in which solutions are not the same as breakthroughs. Progress comes gradually, often painfully, in fits and starts, and only after many people spend their entire careers failing and quarreling and, finally, reconciling. Sooner or later, some ideas fall away as others take hold. And, perhaps only in hindsight, we can see how far we’ve come, and decide on a path forward.”
