When I was a child I often had a toothache,” wrote C. S. Lewis in his classic book Mere Christianity. He continued, “and I knew that if I went to my mother she would give me something that would deaden the pain for that night and let me get to sleep. But I did not go to my mother—at least not till the pain became very bad. . . . I knew she would take me to the dentist the next morning. . . .  I wanted immediate relief from pain, but I could not get it without having my teeth set permanently right.”