Comment by pklausler
6 hours ago
I think that Feynman was talking about preparing a freshman-level lecture for Caltech-standard freshmen, but maybe you have somebody else in mind.
6 hours ago
I think that Feynman was talking about preparing a freshman-level lecture for Caltech-standard freshmen, but maybe you have somebody else in mind.
I would say: You either don't understand your subject, or don't understand your audience, if you can't explain your subject to your audience, at the highest level they can understand, coherently.
The average person can understand anything ... at some level. Being able to match that level is positive evidence (but not proof) of competence.
I think if you understand something really well (anything: the law of gravity, the Curry-Howard isomorphism, electrolytic dissociation, general relativity,...), you can find a bunch of comparisons, or metaphors, or other ways to explain it so that an interested five-years-old will get a rough idea. A very rough idea indeed, but one that could allow them to ask qualitatively reasonable questions, and that forms an intuition which helps during a real study.