As the twentieth century dawned, philosophers and social scientists were trumpeting the arrival of the Modern Age, a breathless optimism that the thundering stampede of new technology would radically improve the quality of life for people the world over. Overlooked was that human nature had not evolved along with its machines. Humanity’s worst instincts—for conquest, domination, aggression, jealousy, and barbaric cruelty—would become plainly evident. The killing machines had improved as well.
