Nearly everyone I talk politics to says the world is in a mess. But I live in a student town – Lund in Sweden – and most of them have nothing to measure their opinions against. They know not much about the Cold War, the Cuban missile crisis, Watergate or the great famines in Africa and India. In many ways most of us live in the best of times, on better incomes than our parents, with longevity increasing all over the world, not least in the poorer countries and helped by inventions that our parents never dreamt were possible. As for war, as each year goes by less people are killed, UN peacekeeping is more advanced and sophisticated than before, Russia and the West, although at loggerheads over Ukraine, worked together to get Iran to give up its nuclear plans and are talking now about how to cooperate against ISIS....