Michael Shermer, Publisher of Skeptic magazine, columnist for Scientific American

War is not inevitable, and in fact, has been in decline for millennia. Prehistoric peoples were far more murderous than states in percentages of the population killed in combat. For example, on average, nonstate societies kill around 15 percent of their people in wars, whereas today’s states kill a few hundredths of a percent. Even in the murderous 20th century, about 40 million people died in war out of the approximately six billion people who lived, or 0.7 percent. Even if we include war-related deaths of citizens from disease, famines and genocides, that brings the death toll up to 180 million deaths, or about 3 percent. Over the past five centuries the European Great Powers have been at war with one another almost continuously up to 1945. Since then there have been 0 Great Power wars. Can you imagine France invading England today? Or Germany invading France? What was once commonplace is now unthinkable! The data are overwhelmingly in support of the hypothesis that war is in decline, and no amount of anecdotal examples your guests will trot out to paint their doomsday scenario can trump the long term data trend.