Ignorance: A global history

Throughout history, every age has thought of itself as more knowledgeable than the last. Renaissance humanists viewed the Middle Ages as an era of darkness, Enlightenment thinkers tried to sweep superstition away with reason, the modern welfare state sought to slay the "giant" of ignorance, and in today's hyperconnected world seemingly limitless information is available on demand. But what about the knowledge lost over the centuries? Are we really any less ignorant than our ancestors? In th...