Do not be scared by the word authority. Believing things on authority only means believing them because you have told them by someone you think is trustworthy. Ninety-nine per cent of the things you believe are believed on authority. I believe there is such a place as New York. I have not seen it myself. I could not prove by abstract reasoning that there must be such a place. I believe it because reliable people have told me so. The ordinary man believes in the Solar System, atoms, evolution, and the circulation of the blood on authority — because the scientists say so. Every historical statement in the world is believed on authority. None of us has seen the Norman Conquest or the defeat of the Armada. None of us could prove them by pure logic as you prove a thing in mathematics. We believe them simply because people who did see them have left writings that tell us about them: in fact, on authority. A man who jibbed at authority in other things as some people do in religion would have to be content to know nothing all his life.