An expert is a person who has made all the mistakes that can be made in a very narrow field.
Niels Bohr
The meaning of the quote
In 1978, James Dyson pulled the clogged bag out of his Hoover and fixed a cardboard cone in its place. He had watched a sawmill spin sawdust out of the air with a giant cyclone and wanted to know if the same trick could work inside a vacuum cleaner.
It took him 5,127 prototypes and about 5 years to get his answer. By his own count, 5,126 of them were failures.
Niels Bohr measures an expert by exactly that kind of pile. Every one of Dyson’s failed machines sat inside a single narrow problem, how to stop a vacuum from losing suction, and each one crossed a wrong answer off the list.
Without the narrow field, Bohr’s expert couldn’t exist. Nobody can make every mistake in “music” or “business” because the list never ends. Shrink the field to bagless vacuums or to a single tricky bar of a piano piece, and the possible mistakes get few enough to work through one by one.
The quote is also a dry joke. By Bohr’s definition, the expert in the room is the person who has been wrong the most times. The beginner who is scared of looking silly simply hasn’t been wrong enough yet.
The physicist Edward Teller liked to repeat this line, and a 1954 LIFE magazine profile of Teller printed Bohr’s fuller version. In it, the expert learns those mistakes through their own painful experience. Watching someone else fall off a bike teaches you far less than falling off one yourself.
In the book The Talent Code, Daniel Coyle calls this process deep practice. You reach just past what you can do, miss, notice the miss and try again, and Coyle counts progress in those reaches rather than in hours. The quote post Deep practice is not measured covers how that works.
Action steps
Dyson needed a shed full of vacuums, but the quote works at a much smaller scale too, as long as your field is narrow enough for your mistakes to start repeating.
- Shrink your field.
Swap “cooking” for frying plantain, or “public speaking” for the first 30 seconds of a talk. Pick something small enough that you could list its common mistakes within a week. - Keep a mistake list.
Each time something goes wrong, add a line to a note on your phone. When the same mistake shows up a 3rd time, you know what to practice next.
When new mistakes stop showing up, Bohr would call you an expert.
About the author
In September 1911, a 26-year-old Danish physicist named Niels Bohr arrived at Cambridge to work with J.J. Thomson, the man who discovered the electron. At their first meeting, Bohr pointed out errors he had found in Thomson’s work.
Thomson was not charmed. He avoided theory talks with the young Dane, and months later he still hadn’t read Bohr’s thesis. Bohr later joked about how naive he had been.
In March 1912, Bohr left for Manchester to work with Ernest Rutherford, who had just discovered the atomic nucleus. There he started sketching a new model of the atom and finished it back in Copenhagen in 1913. The model explained the pattern of light given off by hydrogen, and in 1922 that work won him the Nobel Prize in Physics.
As a young man, Bohr also played in goal for the Copenhagen football club Akademisk Boldklub. In one match the ball stayed at the other end for so long that he leaned on a post and got lost in a maths problem. When a long shot suddenly came his way, he was busy writing calculations on the goalpost.
Bohr kept making mistakes in his narrow field long after that first meeting with Thomson. His 1913 atom model turned out to be not quite correct and gave way to quantum mechanics in the 1920s, a field Bohr helped build at his institute in Copenhagen.
The young man who walked into Cambridge pointing out another expert’s errors spent the next 50 years finding his own, and by his definition, that is exactly what made him an expert.
Resources
- Quote Origin: An Expert Is a Person Who Has Made All the Mistakes (Article)
- Niels Bohr biographical (Website)
- Field theory: The soccer careers of the Bohr brothers (Article)
- Invention: A Life (Book)
- The Talent Code (Book)
- Deep practice is not measured (Article)
- Learning through mistakes: From Einstein to Edison (Article)
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