This world
Reality is on the other side of the river, yet all we can see from this side is the upside down reflection of the other bank.
Thus, the mind of the sage cannot be appreciated by those absorbed int he world. They can only see the appearance of his mind, which is always upside down. This is why it says in onee of the Buddhist scriptures: "The virtuous one's mind is turned upside down, and does not accord with the Buddha wisdom."