"Among the many debates over the origins and evolution of war is whether humans have been getting more violent or less. Steven Pinker and others who think like him, such as the archaeologist Ian Morris, are on the optimistic side and believe there is a clear trend away from violence. Most countries no longer have public executions; they have laws against cruelty to animals or children; and sports such as bear baiting or dog fighting are normally illegal. The optimists go further and attempt to tot up deaths from war in the past – not in itself an easy task – to argue that homicide rates in the past were far higher than they are today and that deaths in war, as a proportion of humans alive at the time, are fewer in the twentieth and twenty-first centuries, even allowing for the great bloodlettings of the two world wars, than in earlier wars. Others challenge the figures and also point out that war deaths in the twentieth century may amount to 75 per cent of all war deaths in the last 5,000 years. And if you really want to be depressed about the prospects for humanity, studies using mathematical tools at the University of Florence and the University of Colorado claim to show that the trend is for fewer but more deadly wars. Their argument is that the more interconnected societies become the quicker a conflict can spread along the paths of the network – just as computer viruses or forest fires do. A small squabble in the Balkans in the summer of 1914 grew into the Great War because Europe’s powers were so interlinked by treaties, understandings or plans that tensions spread upwards and outwards from the assassination of the Archduke Franz Ferdinand in Sarajevo until a general war exploded. Even if Pinker is right – and the debate goes on – it somehow does not seem very reassuring. Those of us who have enjoyed the Long Peace since 1945 need to reflect that much of the world, including Indochina, Afghanistan, the Great Lakes district in Africa and large parts of the Middle East, has seen and still sees conflict. A long-running project at Uppsala University in Sweden estimates that between 1989 and 2017 over 2 million people died as a result of war. Since 1945 perhaps 52 million have been forced to flee because of conflict."