There's an old belief that truth will always overcome error. Alas, history tells us something different. Without someone to fight for it, to put error on the defensive, truth may languish. It may even be lost, at least for some time. No one understood this better than the renowned Italian scientist Galileo Galilei.

My father, a neurologist, once had a patient who was tormented, in the most visceral sense, by a poem. Philip was 12 years old and a student at a prestigious boarding school in Princeton, New Jersey. One of his assignments was to recite Edgar Allan Poe's The Raven. By the day of the presentation, he had rehearsed the poem dozens of times and could recall it with ease. But this time, as he stood before his classmates, something strange happened.