Most of the time he asked questions. His questions were very good, and if you tried to answer them intelligently, you found yourself saying excellent things that you did not know you knew, and that you had not, in fact, known before. He had "educed" them from you by his question. His classes were literally "education" - they brought things out of you, they made your mind produce its own explicit ideas.

Thomas Merton, about professor Mark Van Doren