“Thought like that showed me the needless ambiguity of words like space-time. The average person heard a word like that and figured he'd never understand it. But it was so simple. Every place you ever saw was linked to a specific time ... the school you visited twenty years after you graduated, the football field you played on, the track you ran -- none of them was the same. If they were, you would collide with the generations that had run on them before and after you. The lover you kissed was not the same person he or she was sixty seconds before. In that minute, a million skin cells had died and been replaced by new ones. The smallest slices of space-time separated thought from action Life from death.”