… is from page 192 of 1987 Nobel-laureate economist Robert Solow’s October 13th, 1988, lecture, “My Evolution as an Economist,” in Lives of the Laureates, William Breit and Roger W. Spencer, eds. (3rd ed., 1995):
We often say among ourselves that the best way to learn a subject is to teach it. There is some truth in that, but one wants to be clear about what the kernel of truth is. You don’t have to teach a subject to master its mechanical and technical details. Books will do quite nicely for that. The experience of teaching does, if you take it seriously, require you to figure out how to explain the subject at hand clearly; and that is already a higher level of understanding than the first.
DBx: Pictured above is one of the greatest economics professors of all time, Ken Elzinga, teaching his famed Principles of Microeconomics course at the University of Virginia.