The ZEITGEIST adventure path is motivated by antagonists with strong philosophical views on what the nature of a perfect world is. You at several points get a chance to advance your view, and the various factions of the setting each have their own philosophies.
The most prominent one is eschatology, which frames life in relation to how things end, and encourages people to seek good endings in their affairs, ranging from how to end a job or book or relationship, to how to die and how when the world ought to end.
Naturally, some people take this too literally and start working to ensure the world has a good ending by trying to be the ones to end it. But they're not the main villains.