It is not altogether true that persuasion is one thing and force is another. Many forms of persuasion – even many of which everybody approves – are really a kind of force. Consider what we do to our children. We do not say to them: "Some people think the earth is round, and others think it is flat; when you grow up, you can, if you like, examine the evidence and form your own conclusion." Instead of this we say: "The earth is round."