Once upon a time, a woman moved to a cave in the mountains to study with a guru. She wanted, she said, to learn everything there was to know. The guru supplied her with stacks of books and left her alone so she could study. Every morning , the guru returned to the cave to monitor the woman's progress. In his hand, he carried a heavy wooden cane. Each morning, he asked her the same question. "Have you learned everything there is to know yet?