It was Francis Bacon who said that knowledge is power. By knowledge I take him to mean the possession of, or the ability to access, information. In Bacon's time, I expect that the amount of information readily available to most people was limited. Some Bible stories, a few pictures and an endless supply of gossip and hearsay would probably be your lot. Even the top dogs at court would possess no more than a handful of books on hunting,hawking and the arts of war. As always, no doubt, the real power lay in knowing what the people in charge were up to. It might save your life if you got the right piece of information at the right time.
Today it's different. Those in power still guard their knowledge carefully, but we live in a sea of information, whose accuracy no one can really determine for sure. We know that the average television-age human cannot concentrate for more than three minutes, or assimilate any argument not presented in easy soundbites. We know too that fatty foods are bad for the heart, that almost any food additive causes cancer, that Darwin's theory describes a process known as 'the survival of the fittest', and that eating beef will kill you. These things are common knowledge, received wisdom.
A few years after Bacon finished writing the works of Shakespeare, Alexander Pope observed that a little knowledge is a dangerous thing. Ours is a time of random and untried information, when a significant number of people readily accept that UFOs roam the skies on a nightly basis, pausing only to abduct innocent bystanders, or mark out a few crop circles. I can't say that they don't, but I've seen no reliable evidence. We have so much information to hand, and the media to propagate it, that most of us think we know more than we do. Maybe we should remember Socrates, who was the wisest man in Athens because he was the only man who knew that he knew nothing.