And there are two reasons why this thinking should not be put off until after you have finished a book. The first and more important is that after you have finished reading, most of the ideas will have unrecallably dropped out of mind. The second is that when you are undecided about the solution of a problem, you will often find later arguments depending upon that solution. Unless its truth or falsity is decided in your own mind you will not know how to deal with these later arguments. I have spoken of feeling that an argument is fallacious, and of being unable to point out just where it is so. To cease reading for a while, and to endeavor to make these inarticulate objections articulate, is excellent practice for training analytic powers and developing clearness of thought. Another way of reading a book is what I may call the anticipating method. Whenever a writer has started to explain something, or whenever you see that he is about to, stop reading and try to think out the explanation for yourself. Sometimes such thinking will anticipate only a paragraph, at other times an entire chapter. School and college text-books, and in fact formal text-books generally, often contain lists of questions at the end of the chapters. Where you find these, read them before you read the chapter, and where possible try to answer them by your own thinking. This practice will make you understand an explanation much more easily. If your thinking agrees with the author’s explanation it will give you self-confidence. It will make you realize whether or not you understand an explanation. If you were not able to think the thing out for yourself you will appreciate the author’s explanation. If your thinking disagrees with that of the author you will have an opportunity to correct him—or be corrected. In either case your opinion will rest on firmer grounds. Not least of all you will be getting practice in self-thinking. After reading and criticising a book, it is a good practice to study one taking a different viewpoint, or written even in direct opposition. You will doubtless find that it points out many fallacies and controverts many statements in the first book, which you allowed to pass unchallenged. Ask yourself what the trouble was. Was your attitude too receptive? Did you swallow words without substituting clear mental images? Did you fail to trace out the consequences of a statement? All these questions will help you do better the next time. Because of your ignorance of the facts, your failure to refute a conclusion will sometimes not be your fault. But even here, though you cannot contradict an author’s statement of facts, you can criticise conclusions drawn from those facts.