"Lu-Tze was eight hundred years old, and that was why he was having a rest. A hero would have leaped up and rushed out into the silent city and then— And there you had it. Then a hero would have had to wonder what to do next. Eight hundred years had taught Lu-Tze that what happens, stays happened. It might stay happened in a different set of dimensions, if you wanted to get technical, but you couldn’t make it unhappen. (p. 253)"