Source: The Quotable Feynman, Sep 2015
I finally figured out a way to test whether you have taught an idea or you have only taught a definition. Test it this way: You say, “Without using the new word which you have just learned, try to rephrase what you have just learned in your own language”.
National Science Teachers Association Fourteenth Convention lecture, “What is Science?” April 1966
To know when you know, and when you don’t know, and what it is you know and what it is you don’t know, you gotta be very careful not to confuse yourself.
Yorkshire Television Interview, “Take the World from Another Point of View”, 1972
Study hard what interests you in the most in the most undisciplined, irreverent and original manner possible.
Letter to J.M. Szabados, Nov 1965
Work as hard and as much as you want on the things you like to do the best. Try to keep the other grades from going to zero if you can.
Letter to V.A. Van Der Hyde, July 1986
It is wonderful if you can find something you love to do in your youth which is big enough to sustain your interest through all your adult life. Because, whatever it is, if you do it well enough (and you will if you truly love it), people will pay you to do what you want to do anyway.
Letter to Eric W. Leuliette, September 1984
Work hard to find something that fascinates you. When you find it, you will know your lifework.
Letter to student Mike Flasar, November 1966
Tell your son to stop trying to fill your head with science – for to fill your heart with love is enough.