On the internet, everything can appear equally legitimate. the rantings of a lunatic seem as credible as the findings of a Nobel Prize winner. We have lost, it seems, a shared sense of the basic facts upon which democracy depends. Today around the world, demagogues appeal to our worst instincts. Conspiracy theories once confined to the fringe are going mainstream. What do all these dangerous trends have in common? The greatest propaganda machine in history. Thanks to social media, conspiracies take hold, it’s easier for hate groups to recruit, easier for foreign intelligence agencies to interfere in our elections, and easier for a country like Myanmar to commit genocide against the Rohingya. Voltaire was right, “those who can make you believe absurdities, can make you commit atrocities.” And social media lets authoritarians push absurdities to billions of people.'