Do I believe in ghosts, I am often asked, and I answer that I do. Not in the sense that I believe in Winston Churchill, but rather as I believe in David Copperfield. There are few major authors who do not include ghosts in their work. Homer has them, though in his case they are often referred to as shades of the dead. Shakespeare has two most celebrated ghosts: Hamlet’s father’s and Banquo’s, “with twenty trenched gashes in his head”. The nineteenth century is where the whole thing really took off. Dickens has Jacob Marley’s ghost, clanking his chains, and…