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.

The tragedy of being both rational and animal seems to consist in having to choose between duty and desire rather than in making any particular choice

Ultimately there can be no disagreement between history, science, philosophy, and theology. Where there is disagreement, there is either ignorance or error.

Philosophy is everybody's business.

Is it too much to expect from the schools that they train their students not only to interpret but to criticize; that is, to discriminate what is sound from error and falsehood, to suspend judgement if they are not convinced, or to judge with reason if they agree or disagree?

If you are reading in order to become a better reader, you cannot read just any book or article. You will not improve as a reader if all you read are books that are well within your capacity. You must tackle books that are beyond you, or, as we have said, books that are over your head. Only books of that sort will make you stretch your mind. And unless you stretch, you will not learn.

More consequences for thought and action follow the affirmation or denial of God than from answering any other basic question.