When reading a book you will often come across a statement, perhaps an entire chapter, with which you disagree. This disagreement should be recorded in the form of a question; as for instance, “Is such and such the case?” You may doubt whether an author’s explanation really explains. You may have a vague inarticulate suspicion that he is sliding over facts, or that his solution is too superficial. This suspicion should also be recorded in the form of a question. Often again, while reading, a problem connected with the subject will occur to you which the author has not even considered. This too should be recorded. All these questions should unfailingly be written, either in the margin or on a piece of paper or notebook kept always at hand. You should then set aside a definite time for thinking and attempt to solve the questions for yourself. And in thinking for yourself you should not make the author’s remarks the basis of your thinking. You should deal with a problem almost as if it had never occurred to any one else but you. Simply because somebody else has been satisfied with a certain solution, that is no reason why you should be. You should deal directly with the facts, data and phenomena under consideration; not with the opinions of others about those facts, data and phenomena. You should not ask yourself whether the pragmatists are right, or whether the nominalists are right, or the socialists, or the evolutionists, or the Democrats, or the Presbyterians, or the hedonists, or what not. You should not ask yourself which “school” of thinking you ought to belong to. You should think a problem out _for yourself_, in every way that phrase implies. At the end you may, incidentally, find yourself agreeing in the main with some school of thought. However, this will be only accidental, and your thought will be much more likely to be true. But you should never agree with a school of thought any more than independent thinking leads you to. Of problems dealt with in this manner, some will take ten minutes, others a week. If you encounter a particularly obstinate problem it may be best to leave it for a while, say a week or two or even longer, and go on with other problems. When problems are thus recurrently treated it may take months, even years, before a satisfactory solution is reached. In such cases you should be willing to give months and even years to their solution. If a problem is not important enough to devote so much time to you may be forced to abandon it; but you should constantly keep in mind the fact that you have not solved it, and you should be willing to admit to others that you have not solved it. Never allow mere intellectual laziness to stifle your doubts and make you think you have solved a problem, when you know in your heart of hearts that you have worked yourself into the state of belief merely to save yourself mental discomfort.