The Better Angels of Our Nature

Pinker argues that violence of nearly every kind has declined over historical time, and assembles quantitative evidence across homicide rates, war deaths, genocide, torture, capital punishment, slavery, domestic violence and treatment of children and animals. The book runs about eight hundred pages and the statistical apparatus is extensive.

He identifies six trends: the pacification process as states replaced hunter-gatherer societies, the civilising process where European homicide rates fell by a factor of thirty from the medieval period, the humanitarian revolution of the Enlightenment which ended judicial torture and slavery in Europe, the long peace since 1945 among major powers, the new peace since 1989, and the rights revolutions extending protection to minorities, women, children and animals.

His explanations combine five inner demons that produce violence with four better angels that restrain it, and five historical forces: the state's monopoly on violence, commerce which makes others more valuable alive, feminisation, cosmopolitanism through literacy and mobility, and what he calls the escalator of reason.

The criticisms are substantial and technical. Taleb argues that war deaths follow a fat-tailed distribution in which the observed decline since 1945 carries little statistical information about the future risk. Historians dispute the prehistoric violence estimates and the reliability of comparing rates across radically different data regimes. Others argue that measuring per capita rates understates absolute suffering and ignores structural violence. Pinker's causal story attributing the decline to Enlightenment reason is the weakest part, since correlation with the proposed causes is asserted rather than demonstrated. The data compilation is the contribution.