“There is a thing that happens with children: If no one is watching them, nothing is really happening to them. It is not some philosophical conundrum like the one about the tree falling in the forest and no one hearing it: that is a puzzler for college freshman. No. If you are very small, you actually understand that there is no point in jumping into the swimming pool unless they see you do it. The child crying, ‘‘Watch me, watch me,’’ is not begging for attention; he is pleading for existence itself.”