From 《
韩非子·
外储说左上》: a man from Zheng wanted to buy shoes. He measured his feet at home but forgot the slip of paper. At the market he returned home to fetch it, and found the shop shut when he came back. Asked why he did not just try the shoes on his own feet, he said, 'I trust the measurement, not my own feet.' Han Feizi's classic barb against blind rule-following.