In Divergent, society is organized by faction. Just about everything about this society comes down to what faction people belong to: their jobs (Erudite teach, while Amity counsel), where they live, who they marry, what they wear, what they do for fun (Dauntless go zip lining, while Abnegation like to knit). Divergent never quite explains how this division of society actually took place, but from what we see in this book, it doesn't seem like it's going all that well. By the end of the novel, two of the five factions are a wreck, and they're about to bring the fight to a third. But what will follow the five-faction society? Peace? Chaos? A rump state? No seriously, that's a thing.