There once was a man from the state of Zheng who wanted to buy a pair of shoes. He measured his foot and put the measurement on a chair. However, setting out for the market, he forgot to bring it along. It only occurred to him when he found the pair he wanted.
"I forgot the measurement," he said.
He then went home to get it. When he returned, the market had closed, and he did not get his shoes after all.
Someone asked, "Why didn't you try on the shoes with your feet?"
He said, "I'd rather trust the measurement than place confidence in my own feet."
Later, people use this phrase to ridicule those who completely depend on dogma, regardless of the actual conditions.
zhèng rén măi lǚ
xŭ xŭ rú shēng
lifelike; lively; vivid