I think he was. I understood this way too late after my studies.
Now when I am learning something I always try to explain it in my mind (or write it down) to imaginary 'student'. It's so effective it's amazing. It lets me catch many knowledge 'holes' in my new studied topic. Whereas I used to just read the material (multiple times) and imagine that I know it. If somebody does not know what I am talking about just try to explain some topic you recently.
P.S. AFAIK, teaching is the best way to study/learn new topics.
Don't (just) read books. Put down the highlighter. Explain them. Get in front of a whiteboard and explain it to an imaginary audience. Imagine the questions you get back. Try to answer them. Sometimes you can do that nearly sentence by sentence, other times you have to do it section by section.
I was lucky enough to have a Feynman level (in terms of teaching) EE professor. I banged my head against modelling electron behavior in NPN junctions until I recognized that his teaching style was exactly how I needed to approach the material. From there on out everything became much easier.
Michael L. Jones discusses the teaching out loud technique in, The Overnight Student (1990)[1]. He says that in high school he was a B and C student, and in college his first semester GPA was 1.9. The next semester he failed every class. He was expelled. When allowed to re-enroll he again got all F's. A few years later he tried again with success. He credits teaching out loud as the technique that made him an A student.
I find sometimes that people around me think I'm strange or crazy for getting excitable or long-winded while explaining or going through a story I've recently read that gave me some insight into something new and cool, to me.
I'm just realizing now that it's possible that those people don't have that same inner spark that I have. That same passion and drive to learn and understand. I really still feel like a kid in so many ways in life but even when I feel that twinge of embarrassment for geeking out on a topic too hard I will now and forever feel content in the fact that I'm always trying to teach that inner kid in me.
That second quote is very powerful. Often enough we proceed to higher usage of previous knowledge without understanding its foundations. Often enough, you really don't need to understand previous steps to make a leap to the next. That's simply progress. Taking the next logical step.
However, some have argued that with deriving foundational knowledge you attain a discipline and through this process the decisions you make about taking the next step are done completely differently. You sincerely evaluate whether to take that next step.
