Truth is a small word liable to sanctimonious overuse and philosophical dispute, but in its humblest sense of accurate and verifiable information we like to think we know it when we see it. In Alan Rusbridger’s view, journalism should be among its leading providers: societies depend on good journalism to distinguish fact from fiction, to form a realistic view of their problems and futures. And here, he writes, a little hopefully, Donald Trump may have done journalism a favour. In his cavalier disregard for truth, Trump has reminded the rest of us why we need it. That’s the good news. The bad news is that digital technology and the web have created “the most prodigious capability for spreading lies the world has ever seen”, while the economics that support truth-seeking journalism have never looked feebler. To adapt the dictum of one of Rusbridger’s predecessors: bad facts are free and good ones expensive.