They say that laughter is a purely human phenomenon, so exclusively ours that we brook no intruders except, of course, for the laughing hyena, the laughing jackass (officially known as the kookaburra bird of Australia), laughing matters, laughing gas, or the perennial laughing stock. But what is humor, that funny thing so varied in its colors and tones, so encompassing in its themes, so different from time to time and place to place? And when we poke fun, at whom are we really laughing? At W...