The real fascination of this book is how we got from being a species that enjoyed the spectacle of roasting each other alive to one that believes child-killers have the same rights as everyone else. As Pinker shows, it is both a long story and a relatively recent one. The first thing that had to happen was the move from a nomadic, hunter-gatherer existence (where your chances of meeting a violent end could be as high as 50:50) to settled communities. The trouble was that early governments showed themselves at least as capable of cruelty as anyone else: most of the truly horrific instruments of torture Pinker describes were designed and employed by servants of the state. As the 17th-century philosopher John Locke remarked of the escape from the state of nature to so-called civilisation: why run away from polecats only to be devoured by lions?
So the next thing that had to happen was the state had to be properly civilised. This took place over the course of what we have come to call the enlightenment, thanks in part to philosophers such as Locke. In both private and public life – covering everything from table manners to bills of rights – the means were found to restrain our worst instincts. Slowly, painfully, but ultimately successfully torture was outlawed, slavery was abolished, democracy became established and people discovered that they could rely on the state to protect them.
Yet the enlightenment has acquired something of a bad name. Why? The answer is simply put: the 20th century, surely the most appallingly violent of them all, scarred by total war, genocide and other mass killings on an almost unimaginable scale. All those table manners and bills of rights didn't prevent the Holocaust, did they? At the heart of this book is Pinker's careful, compelling account of why the 20th century does not invalidate his thesis that violence is in a long decline.