 One day, Zhuangza and a friend were walking by the river. Look at the fish swimming about, said Zhuangza. They are really enjoying themselves. You're not a fish, replied his friend. There's no way that you could truly know that they're enjoying themselves. You are not me, replied Zhuangza. So how could you know that I do not know that the fish are enjoying themselves? I am not you, to be sure, replied his friend. So of course I don't know about you, but you are obviously not a fish. So the case is complete. You do not know that the fish are happy. Zhuangza smiled. Let's go back to the beginning. You said, how do you know the fish are happy? But in asking me this, you already knew that I know it. I know it right here, above this river. This parable comes to us from a book of Zhuangza, one of the two foundational texts of Taoism that contains stories that exemplify the carefree nature of the ideal Taoist sage. While the exact point or lesson isn't always clear, it's thought that the tale is a discussion about the nature of knowledge. Everyone we meet in the world may have a different view of life, having different subjective knowledge and experience. However, if knowledge comes through experience and learning, is there such a thing as true or objective understanding? The point seems to be that knowing a thing is simply a state of mind, and that it isn't really possible to determine if that knowing has any objective validity by looking at it outside of ourselves, as all understanding is ultimately experiential. Zhuangza often beautifully concludes this tale by saying, I know the joy of fishes in the river through my own joy, as I go walking along the same river. After all, even modern science today is simply a collection of atoms trying to understand themselves through direct experience. As some scholars of Taoist texts have pointed out, this tale is a great example of Zhuangza's wisdom and written mastery, as he has said to use reason to make an anti-rationalist point.