去伪存真 (qù wěi cún zhēn), remove the falsehood and keep the truth. The first time I heard of this was long ago from my father. I don't think I understood it at that time. Not until much later after I heard it again from my mother did I gain a better understanding of its meaning.
The year 1967 saw the birth of a small secret group of Red Guards in Beijing, which was said to distribute leaflets against Premier Zhou Enlai. This group was later labeled 5.16 Anti-revolutionary Conspiracy Clique.
In 1970 the central government issued an official order to capture and eradicate all the 5.16 anti-revolutionaries. It was an era when people were overzealous in answering the call from the above against the anti-revolutionary. There was an over surplus of self-righteous revolutionary fervor burning around, witnessing the young and the stupid of the highest level.
As the result, throughout the country, thousands of thousands of people were thus labeled, arrested, loss of freedom, undergoing persecution, interrogations in isolation, supervised labor and public humiliation. Plenty of them didn't survive the process.
My father worked in Tianjin Mayoral government at that time. Thousands of people were rounded up for interrogation in Tianjin. From the beginning, my father insisted on seeking truth when going through each person. In the end, all were quickly sent home because of my father.
Today I think of my father's words every time I see someone appears to be 装逼 (zhuāng bī), meaning: pretending. The two words are not coherently connected. It doesn't matter as long as I make the connection in my head.