“The first principle is that you must not fool yourself and you are the easiest person to fool.” ― Richard P. Feynman 知之为知之,不知为不知。 If you can't explain it simply, you don't understand it well enough.
如果你不能用简单的语言解释它,那么就是你没完全明白。
if you want to undstand something well ... explaint it
类比是解释常用的方法。 费曼经常发出惊世骇俗之语,比如以下两句名言:
"Physics is to math
"Physics is like sex