It’s called ‘revelation’ when a thought, a dream, an idea gets planted in a person’s head and takes over his or her life in such a way that it gets accredited as a calling from the gods. Richard Dawkins called such ideas as could influence other people to copy and adopt them, ‘memes’. Susan Blackmore recognized that compatible ideas could be combined and organized into groups to which she offered the name, ‘memeplex’. That such ideas are most often unverifiable despite their ability to gather followers earn such criticism as Mr. Clemens expressed.
Samuel Clemens: http://en.wikipedia.org/wiki/Mark_Twain