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?" Each morning, her answer was the same. "No," she said, "I haven't." The guru would then strike her over the head with his cane.
This scenario repeated itself for months. One day the guru entered the cave, asked the same question, heard the same answer, and raised his cane to hit her in the same way, but the woman grabbed the cane from the guru, stopping his assault in midair.
Relieved to end the daily batterings but fearing reprisal, the woman looked up at the guru. To her surprised, the guru smiled. "Congratulations," he said, "you have graduated. You now know everything you need to know."
"How's that?" the woman asked.
"You have learned that you will never learn everything there is to know," he replied. "And you have learned how to stop the pain."