Those people you saw—the realborn—are born without a plan. They're born because biology tells humans to make more humans; but it doesn't consider what to do with them after that. Realborn go for years without the slightest clue what they're going to do with themselves. From what I understand, some of them never actually figure it out. They just walk through life in a daze and then fall into their graves at the end of it. Sad. And inefficient.

Chapter 5 (p. 86) - The Ghost Brigades (2006)