Literally, this term means to reverse the state of one being hung upside down. It originated from Zhuangzi. The author Zhuangzi (369?-286 BC) found that people tend to look at other people or things from their own positions, and they thus develop biased views about others and the world. Their mind is consequently in a state of tension. To Zhuangzi, this state of mind of clinging to one’s prejudice is like one being bound and hung upside down. So, breaking free from subjective bias is like freeing one from this state of tension.

When time called, Laozi was born; when time was due, he passed away. When one follows the law of nature, he will not be disturbed by grief or joy. This was known in ancient times as a natural way of freeing the mind from bias or distorted perception, like freeing one from a state of being hung upside down. Zhuangzi