Is modern social change a reflection of women’s new power? It remains a mystery what drives the ongoing ferment in Western societies. What explains the disorienting shift, in the last decade or so, toward policies and attitudes that—whether one likes them or not—would have been virtually unthinkable half a century ago? And how can we account for the wildfire contagion of the past year’s Great Awokening, with its strange scenes of penitence and violence? It is easy to make a list of plausible factors. Television, the Internet, and, more recently, Internet-based social media, have all accelerated social change. These technical...