The past: Contrary to popular opinion, violence at all scales have been in decline over the course of history.

The present: Human nature comprises faculties that encourage violence, such as dominance and revenge, but also faculties that inhibit it, such as self-control, empathy, and reason. The level of violence in a given society depends on how its norms and institutions affect the balance between them.

The future: Professor Pinker speculates on which of the historical changes that reduced violence in the past will continue into the future.