What is the idiom of not believing in rumors?

Ear food theory: believe in rumors. Refers to what is heard without conclusive evidence.

Source: Sima Qian of the Western Han Dynasty, Preface to Chronology of Historical Records and Six Kingdoms: "Scholars heard that Qin was shallower than the throne and did not look at its end. He laughed at it and dared not tell the truth. This is no different from eating with your ears. "