Nobel-Prizewinning physicist Richard Feynman was a master teacher as well as brilliant thinker. After his death, these words were found at the top of the blackboard he used to lecture from at the California Institute Of Technology:
“What I cannot create, I do not understand”
—Dick Feynman
They encapsulate his belief that if he was unable to explain a concept in physics in simpler terms then he either didn’t understand it himself, there was no everyday analogy that could be applied to explain the idea, or no one at all in the world of physics really understood it.
This excellent article by Jason Kottke explains this rule-of-thumb and its history in Feynman’s life nicely. It includes this excerpt from a 1996 book:
Feynman was a truly great teacher. He prided himself on being able to devise ways to explain even the most profound ideas to beginning students. Once, I said to him, “Dick, explain to me, so that I can understand it, why spin one-half particles obey Fermi-Dirac statistics.” Sizing up his audience perfectly, Feynman said, “I’ll prepare a freshman lecture on it.” But he came back a few days later to say, “I couldn’t do it. I couldn’t reduce it to the freshman level. That means we don’t really understand it.”
I can say from my own experience of teaching scientific concepts that there is real truth in this heuristic. Its converse is also true: Very often, you believe that a concept you have studied and even been successfully examined on is something you have a good understanding of. But it’s only when you try to explain it to other people who have never been exposed to it that you realise how incomplete or inaccurate your knowledge of it is.
Photo by Roberto Sorin on Unsplash
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