This story, like The Wren and the Cicada, is taken from the Chuang Tzu (in Three Ways of Thought in Ancient China, Arthur Waley, 1939).
There was a frog who lived in an abandoned well. When the giant turtle from the Eastern Sea came, the Frog said “How you must envy my life. When I feel like it, I can hop to the top railing and be in the sun. When I tired, I can crawl into the side of the wall where a tile is missing and take a nap. And when I feel like a swim, I just hop down to the bottom. There may be a few tadpoles down there, but it is my pond. To have the use of the entire water, to have the use of a disused well, this is certainly the most that life has to offer. Please come down and see it for yourself.”
The giant turtle from the Eastern Sea attempted to get into the well, but before his left foot was in, its right foot had become wedged in. He wiggled free, crawled out and said to the frog: “As you have been kind enough to tell me of your well, let me tell you about the sea. Imagine a distance of a thousand leagues, and you will still have no idea of its size. Imagine a height of thousand man’s stature, and you will have no idea of its depth. In the time of the great Yu, in ten years, there were nine floods; but the sea became no deeper. In the time of T’ang the Victorious, there were seven years of drought in eight years, but the sea did not retreat from its shores. Not to be harried by the moments that flash by, nor changed by the ages that pass; to receive much, yet not increase, to receive little, yet not diminish , this is the Great Joy of the Easter Sea.
Will the frog leave the contentment of his well and experience the vastness of the world. The question is asked, but only the frog can respond.
With this question, His current experience and knowledge no longer is sufficient standard to set the boundaries between false and true. But, the well is comfortable.