Reading a book should be a conversation between you and the author. Presumably he knows more about the subject than you do; if not, you probably should not be bothering with his book. But understanding is a two-way operation; the learner has to question himself and question the teacher, once he understands what the teacher is saying. Marking a book is literally an expression of your differences or your agreements with the author. It is the highest respect you can pay him.

I wonder if most people ever ask themselves why love is connected with reproduction. And if they do ask themselves about this, I wonder what answer they give.

True freedom is impossible without a mind made free by discipline.

Television, radio, and all the sources of amusement and information that surround us in our daily lives are also artificial props. They can give us the impression that our minds are active, because we are required to react to stimuli from the outside. But the power of those external stimuli to keep us going is limited. They are like drugs. We grow used to them, and we continuously need more and more of them. Eventually, they have little or no effect. Then, if we lack resources within ourselves, we cease to grow intellectually, morally, and spiritually. And we we cease to grow, we begin to die.

There are genuine mysteries in the world that mark the limits of human knowing and thinking. Wisdom is fortified, not destroyed, by understanding its limitations. Ignorance does not make a fool as surely as self-deception.

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.

We are selfish when we are exclusively or predominantly concerned with the good for ourselves. We are altruistic when we are exclusively or predominantly concerned with the good of others.