"The correct procedure I am sure it is to learn by doing, not by being told what to do. The notion that one can learn by attending a course of lectures is as absurd as the notion that the way to learn to ride a bicycle would be to hire someone to ride it for you, and to sit hour after hour watching him. The only reason for attending a lecture is to acquire hints as to the right method of tackling some particular problem or other. And this would be almost unnecessary in a properly designed and graded system of examples."