One function of celebrity is to alert the rest of us to hard truths, to teach us the lessons of love and grief. Among these is the cruelest jest of fate: a child's death that precedes his or her parents'. That instructive obscenity slammed home today with the death of Natasha Richardson, a distinguished British actress who was a third-generation star of the noted Redgrave acting clan and the eldest daughter of the great and controversial Vanessa Redgrave. Richardson died two days after a seemingly unremarkable fall while skiing in Quebec. She lost consciousness and within...