• If you ask a living teacher a question, he will probably answer you. If you are puzzled by what he says, you can save yourself the trouble of thinking by asking him what he means. If, however, you ask a book a question, you must answer it yourself. In this respect a book is like nature or the world. When you question it, it answers you only to the extent that you do the work of thinking an analysis yourself.

    Mortimer J. Adler, Charles Van Doren (2014). “How to Read a Book: The Classic Guide to Intelligent Reading”, p.14, Simon and Schuster