Posting these quotes by Paul Halmos (1916 -2006) was inspired by seeing the the film I want to Be a Mathematician and reading a few of Paul Halmos's essays. Most of these quotes were taken from an essay "The Problem of Learning to Teach," which is a transcript of a lecture that Halmos delivered in 1974 at an AMS-MAA meeting.
Teaching is an ephemeral subject. It is like playing the violin. The piece is over, and it's gone. The student is taught, and the teaching is done.The best way to learn is to do; the worst way to teach is to talk.The best way to read a book..., with, to be sure, pencil and paper on the side, is to keep the pencil busy on the paper and throw the book away.What mathematics is really all about is solving concrete problems.The way a bad lecturer can be a good teacher, in the sense of producing good students, is the way a grain of sand can produce pearl-manufacturing oysters.The best way to learn is to do - to ask, and to do.Don't preach facts - stimulate acts.