How can we stay happy in an age gone mad? It often feels as though all is unstable at the moment. Uncertainty dominates the economy. Our politics and planet are a mess. Scientific experts and government workers have been cast aside. Many more fear their jobs could be wiped out by artificial intelligence. Little surprise then that historic levels of Americans report being depressed, anxious and lonely. Fewer say they are very satisfied with their lives than at any point since Gallup began asking the question a quarter-century ago. But there may be a practical way to keep ourselves on...