What is it which makes a man and a woman know that they, of all other men and women in the world, belong to each other? Is it no more than chance and meeting? no more than being alive together in the world at the same time? Is it only a curve of the throat, a line of the chin, the way the eyes are set, a way of speaking? Or is it something deeper and stranger, something beyond meeting, something beyond chance and fortune? Are there others, in other times of the world, whom we should have loved, who would have loved us? Is there, perhaps, one soul among all others--among all who have lived, the endless generations, from world's end to world's end--who must love us or die? And whom we must love, in turn--whom we must seek all our lives long--headlong and homesick--until the end?