There is a story, widely told among information researchers, about a policeman who happens upon a thoroughly inebriated man late one night under a streetlight. The man is searching, diligently but thus far ineffectively, along the sidewalk and gutter for his house key, which he has dropped. The policeman, wanting to speed the unfortunate fellow along home, drops to his hands and knees and joins the search. He too is unsuccessful. After several questions aimed at determining the type of key, the kind of key case, and so forth, the policeman finally asks exactly where the unlucky man dropped the key. "Down the street about half a block," is the reply. Then, in response to the policeman's exasperated, "Why in heaven's name are you looking here instead of where you dropped it?" the man patiently explains, "the light is so much better up here."