Once, a few years ago,   I attended a writing conference   on the campus of Brown University.    The summer session was taking place,   so there were lots of students around   (some of whom thanked us for coming,    because the food in the cafeteria improved   when there were conferences on campus).     One day, as I was walking between workshops,   I paused to watch a young man   who was practicing his skills as a tightrope walked.   He had a rope tautly stretch between two large trees,   perhaps two to three feet off the ground.   Enough height to practice,   but not enough to break bones    if balance didn't outwit gravity.     He moved slowly, with determination,   a look of concentration on his face.   One foot. . .   then gingerly, the next foot.   Sometimes his arms shot out to steady him.   And sometimes,   his arms weren't enough   and he'd fall (or self-propel)   from the tightrope.   He'd shake off the mishap   and mount the rope again,   always lookin...