One of the signal pleasures of a nostalgic soap opera like AMC's Mad Men-—or, more recently, ABC's Pan Am—is the consistent appeal of discovering that our predecessors' morality is roundly inferior to our own. We watch as Betty lights a cigarette at the dinner table, as Roger offhandedly waxes patrician, as a boor pats a woman's bottom, and get a little thrill from both the transgression and our own superiority to it.

Steven Pinker's scientized history The Better Angels of Our Nature: Why Violence Has Declined (Viking, $40) is a self-congratulatory opus of much greater dimension. Pinker amasses an impressive array of facts and graphs showing that worldwide per capita violence has indeed declined precipitously since Europe's enlightened 1700s, that racism has waned, spankings been spanked and major wars made less frequent. Against the notion that humanity has degenerated from nobly peaceful hunter-gatherers to mechanized killers, he employs relentless statistical proof. We really don't off each other like we used to. Even the gruesomely bloody 20th century—with its 70 million dead in two world wars—is, when those mind-boggling numbers are considered relative to the world's expanding population, less violent on average than the preceding centuries.

When Pinker moves toward explaining why this shift away from violence has happened, however, he mostly leaves science at the doorstep. Much of the book is taken up, in chatty tones, explaining just how awful we all used to be, and how awful we all aren't now. In the past, we are told, inquisitors stretched alleged crypto-heathens on racks, Genghis' officers cut off ears as trophies of kills, goats of all kinds were mercilessly scaped, men were culled and women raped as spoils of war, etc. 

The slow de-moding of such practices is, for Pinker, part of something he terms the "civilizing process," which he seems to see as history's inevitable forward path. As society has adopted Enlightenment ideals and notions of the sanctity of the individual, and as states have supplanted the old vengeful codes of honor with impersonal justice, we have grown peaceful and prosperous.

This model holds up beautifully well when only Europe is considered, but elsewhere Pinker's optimism seems hapless and hopelessly selective in its descriptions. America's idiosyncratically violent nature is left to be mostly a mystery, while present-day Haitian necklacings, Salvadoran guerrilla massacres and coked-up African child soldiers—essentially the byproducts of U.S./European prosperity—go largely unmentioned. Pinker blames the violent spike of the 1960s on the "de-civilizing" influences of a dangerous counterculture, calls American blacks violent and "stateless," and attributes our current drop in violent crime largely to the positive effects of mass incarceration.

That said, Pinker's heartening narrative of progress toward a more blameless present and an even better future is a story I do hope is true. However, I am left to suspect that as much violence is likely to result from our pacific Enlightenment as has ever been tamped down by it, and that the future has an unsettling habit of slipping any noose we prepare for it.

GO: Steven Pinker reads at the Bagdad Theater, 3702 SE Hawthorne Blvd., 855-227-8499. 7 pm Wednesday, Oct. 26. $9.99.