From None — surrounding passage

“We must think of human progress, not as of something going on in the race in general, but as something going on in a small minority, perpetually beleaguered in a few walled towns. Now and then the horde of barbarians outside breaks through, and we have an armed effort to halt the process. That is, we have a Reformation, a French Revolution, a war for democracy, a Great Awakening. The minority is decimated and driven to cover. But a few survive - and a few are enough to carry on.”