[finite_jest]

I think that is probably a "folk quote", the attribution to Feynman is also inaccurate AFAIK. He said something similar though:

> 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.”

– Feynman’s Lost Lecture by David and Judith Goodstein

[skrebbel]

I like the subtle hidden arrogance that "we don't really understand it" if Feynman can't explain it at freshman level.

[kragen]

It's probably true that if he didn't understand it well enough to explain it at freshman level then nobody did.