Real knowledge is to know the extent of one’s ignorance.
Confucius
The meaning of the quote
On January 6, 1995, McArthur Wheeler and a partner robbed 2 banks near Pittsburgh without masks. They had rubbed lemon juice on their faces instead.
Lemon juice works as invisible ink, and Wheeler’s partner convinced him it would hide their faces from security cameras too. Wheeler even tested it with a Polaroid camera, and his face didn’t show up in the photo. In April the bank footage aired on the local news, and police arrested him less than an hour later. When they showed him the pictures, he couldn’t believe it.
“But I wore the lemon juice. I wore the lemon juice.”
McArthur Wheeler
Wheeler knew a true fact about lemon juice on paper and assumed it worked on cameras too. He never checked where his knowledge stopped.
To Confucius, real knowledge means seeing which of your beliefs you could prove and which ones you’re only assuming.
After reading about Wheeler, a pair of psychologists tested students on grammar, logic and humor, then asked them to guess how well they’d done. The students with the lowest scores thought they had beaten most of the class. The psychologists concluded that the skills you need to get something right are the same skills you need to notice you got it wrong, a pattern now called the Dunning-Kruger effect.
The quote comes from the book The Analects, a collection of Confucius’s sayings that his students put together after his death. He said it to Zilu, one of his first students. Zilu was a former warrior known for rushing in before thinking.
“Yu, shall I teach you what knowledge is? When you know a thing, to hold that you know it; and when you do not know a thing, to allow that you do not know it; this is knowledge.”
Confucius, The Analects
Action steps
Use Confucius’s rule for Zilu the next time you feel sure of yourself.
- Split what you know from what you guess.
Before a big decision, write what you could prove in one list and what you’re assuming in another. Check the assumptions first. - Say “I don’t know” out loud.
Then add “but I’ll find out,” and go and find out. - Explain it to a 12-year-old.
Pick a topic you’re sure you understand and explain it in plain words the way physicist Richard Feynman did. Wherever you stumble is where your knowledge ends, and that’s where to start learning.
Wheeler only found out what he didn’t know when his face was on the evening news. A sheet of paper can show you yours before it costs you anything.
About the author
Confucius was 3 years old when his father died, leaving him and his mother poor in the state of Lu, in eastern China. As a young man he kept the books at a granary and looked after livestock, studying whenever he could.
He worked his way up to a government post in Lu, then offended powerful families there and was forced out. For years after that he traveled from state to state looking for a ruler who would put his ideas to use, and none of them did.
A story in the Records of the Grand Historian, an early Chinese history, tells how he lost his students on one of those trips. A local man told his student Zigong he had seen a tall, odd-looking old man by the city’s east gate, as worn out as a stray dog. When Zigong passed this on, Confucius laughed and said the stray-dog part was exactly right.
When Confucius entered the Grand Temple in Lu, The Analects says, he asked about everything. Someone sneered that a supposed expert on ritual shouldn’t need to ask, and Confucius answered that asking was the proper ritual.
Late in life he returned to Lu and taught until his death in 479 BC, believing his work had failed. His students wrote down his conversations, and Chinese students and officials studied that collection for more than 2,000 years.
Nearly 2,500 years before McArthur Wheeler trusted his lemon juice, Confucius had already warned Zilu about that kind of certainty. You can find their conversation in Book 2 of The Analects, along with hundreds of his other short lessons.
Resources
- The Analects (Book)
- Who was Confucius? (YouTube)
- Why incompetent people think they’re amazing (YouTube)
- Think Again (Book)
- Dunning-Kruger effect (Wikipedia)
- Confucius (Article)
- The Feynman Technique (Article)
- Information only becomes knowledge (Article)
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