The man who cannot wonder, who does not habitually wonder, is but a pair of spectacles behind which there is no eye.—Carlyle.

Up to now I have treated exclusively of how to think, but have made no mention of what to think. I have treated of the best methods of dealing with different subjects and questions; I have not considered what subjects or problems are most worth dealing with.

Of course the important thing is that you do think. It is not absolutely essential that the results of your thinking are results which can be directly made use of. Thinking is an end in itself. Most men imagine that “thinking for the sake of thinking” may appeal to philosophers, but means nothing to them, as they like to think only when by so doing they can forward some practical end. These people do themselves an injustice.

Perhaps you, O reader, are among them. If so, let me appeal to your personal experience. Have you ever tried to solve a toy puzzle, tried to take the two wire hooks apart without bending them? Or have you ever stopped to tackle a problem on the family page of your evening or Sunday newspaper? “A grocer buys fifteen dozen eggs, he sells—” you know what I mean. You admit that you have. Exactly. You have been thinking for the mere sake of thinking.

If you protest that you didn’t care about the thinking, that you took no pleasure in the thinking, which was merely incidental, but that what really urged you on and gave you pleasure was the solution of the puzzle, you are again deceiving yourself. The thinking was not incidental. Thinking and problem solving are identical. The fact is that you set yourself to solving a problem, to removing a mental hindrance, for the mere sake of getting the answer, with absolutely no thought of what you were going to do with the answer when you got it.

But if you can derive so much pleasure from thinking which you cannot put to use, how much greater should be your pleasure when your conclusions can be utilized? For when you think of something useful, you have not only the present pleasure of solving your problem, but the ulterior pleasure of applying your solution to action, or to the solution of some further problem. And while I again admit that thinking is an end in itself, this does not prevent it from being at the same time a means to some further end. After all is said there is really no reason why we should be prejudiced against problems or subjects that are useful.

The mere decision that we should think of useful questions is insufficient. Very few questions are without some use. Even the solution of the family page puzzle might some day be useful in solving a similar problem arising in your own business; and even if this never came to pass you might spring the puzzle on your friends, and make yourself socially more interesting. Thought given to a question in a debating book now before me, “Resolved, that Ferocious Wild Beasts are more to be dreaded than Venomous Reptiles,” might result in knowledge which would come handy in selecting equipment if one decided to journey to the wilderness of South America. But there are millions of problems of as much use as these; and it is not within the power of one lone mortal, of years three score and ten, to compass even a corner of them. Our question is not—what problems are of use?, but—of how much use are certain problems?, or stated in another way,—what is the relative utility of problems?

Any adequate con­si­der­a­tion of this question would involve the selection of some criterion for utility, and the testing of individual problems by that criterion. But to treat such a question with anything like justice is beyond the scope of this book; it would require almost a volume in itself. It is almost the same as the problem, What knowledge is of most worth?, and the most masterly treatise on that question which has ever been written can be found in Herbert Spencer’s epoch-making little work, Education. I sincerely hope that the reader study this. But I hope even more earnestly that before he does so he first think the problem out in­de­pen­dently, for it is one of the most important he can put before himself.

But our present question—that of the relative importance of problems—is slightly different from that of the relative importance of knowledge. The first deals with thought and the second with information, or the materials of thought; the first with a process of getting knowledge and the second with knowledge itself.

I believe for example that a knowledge of his own body and of the laws of health is the most valuable a man can have, but there are few problems concerning the body which I would include in the first rank. There are several reasons for this. In the first place, while it may be true that such questions taken as a whole are more important than any other class of questions, taken separately they are relatively minor; there are no one or two questions of all-encompassing importance to which all the others are subsidiary. Moreover, such questions, while they undoubtedly require thought for their solution, depend to a relatively great extent on observation and experiment. No sane medical student would sit down and follow out a lengthy course of reasoning as to where the heart is; he would merely observe or dissect, or consult the book of a man who had dissected, and save mental fatigue. Not least of all, questions of physiology require extensive, highly technical and detailed information—information which requires years of special study to acquire—before any thinking that is at all safe can be put upon them. So in estimating the relative value of problems, there are other con­si­der­a­tions besides the value of knowledge.

But it is not my purpose here to discuss the general principles upon which the selection of worth-while questions should be made. That task I leave to the reader. I have chosen rather the concrete path of suggesting a list of questions which I consider of great import. I believe that no matter how much thought the reader gives to any one of them he will not be losing his time.

I have elsewhere pointed out that the more knowledge a man has the more problems he will have. It is equally true that unless a man has some knowledge on a subject he will not be able to appreciate or even understand some of its most important problems. It is only when we begin to think of subjects that we discover problems and realize their significance. In stating most of the following problems, therefore, I have often thought it necessary to add a few sentences in explanation, and have sometimes stated a question in a variety of forms in order to more clearly convey the thought.

Are specific char­ac­ter­is­tics, acquired during the life­time of an in­di­vi­dual, in­herited by his off­spring? I have re­ferred so often to this problem and its im­por­tance that further ex­pla­na­tion is hardly nec­es­sary. “Char­ac­ter­is­tics” of course refer to in­tel­lec­tual and moral as well as physical char­ac­ter­is­tics.

What is the influence of the individual mind on society and of social environment on the individual?

Does the form of government determine the character of a people, or does the character of a people determine their form of government? Or do government and character react on each other, and how? The same question may be asked of all other social institutions. Does the religion of a people determine their character, or does the character of a people determine their religion? This whole problem is somewhat similar to that immediately preceding, regarding the interaction of the individual and the social mind.

Is society for the benefit of the individual or is the individual for the benefit of society?

Should the jurisdiction of the government be extended or curtailed? Or should it be extended in some directions and curtailed in others? Does the answer to this problem depend on the answer to the previous one? Another form of the same problem is: What is the proper sphere of government?

Should the government grant monopolies? Patents, for example?

What would be the most practicable plan for abolishing or minimizing war? Those who do not wish to beg the previous question may first ask whether it is always desirable to prevent war, whether war is always an evil. What is the effect of war on the physical future of the race? on national and individual character? on government? on national liberty? on personal liberty? What are the ethics of war? for aggression? for territorial conquest? for “national honor”? for defense of a weaker nation? for defense against invasion? What is the ef­fect of pre­pared­ness? of un­i­versal pre­pared­ness? of pre­pared­ness of an in­di­vi­dual nation? In each case what are the principles on which the extent of pre­pared­ness should be de­termined? What are the fun­da­men­tal causes of war? How can they be removed? Is it pos­sible to remove all of them?

Which is the rightful owner of land, the community or the individual? To state the problem in another form: Should private land ownership be abolished?

Who should be entitled to vote? This of course is a question similar to woman suffrage, but it is much broader. It deals not only with the qualification of sex, but of age. Should any one under twenty-one have the vote? The validity of property and educational qualifications should also be considered.

How should the relations of the sexes be regulated? Put in slightly narrower and perhaps less objectionable form: What would be just laws governing marriage and divorce?

What is the effect of attempted State interference with the law of supply and demand? Does the un­re­strict­ed working out of this law forward ultimate justice? Just what is the validity and the meaning of the expression “The law of supply and demand”? The question could be taken up in connection with minimum wage laws, railroad rate regulations, “extra crew” laws, etc.

Which is the best policy: free trade, rev­enue tar­iff, or pro­tec­tive tar­iff? Or under what con­ditions is each best? With what classes of com­mo­dities?

What would be an equitable and sound currency system? This question is somewhat technical, and would have to be considered in the form of a number of subsidiary problems. Ought money to have an intrinsic value? What is the effect of “fiat” paper currency on money of intrinsic value and on prices? The effect of credit? The effect of fluctuations in the supply of gold? Ought there be a double standard or a multiple standard? etc.

Should conduct be judged by the pleasure or happiness it yields? Stated in another form, almost a different problem: Is utility a good moral guide?

Should conduct be judged by its tendency to produce individual well-being, or should it be judged by its tendency to produce the well-being of all humanity, or of all sentient beings? This problem cannot be lightly dismissed in favor of universal well-being. This becomes apparent when we attempt to give an undogmatic and non-question-begging answer to the query: Why should a man act for the benefit of others?

No science is more provocative of thought than ethics. The question of whether acts should be declared good or bad as they tend to produce pleasure or happiness, either individual or in humanity as a whole, or whether “virtue” or “morality” is an end in itself, is one of the most subtle and elusive we can attempt to solve; no matter which answer we give we are brought into logical and psy­cho­log­i­cal dilemmas from which it seems impossible to escape. This is also true of the problem of whether our knowledge of what constitutes right and wrong comes from experience or from intuition.

The broadest form of the ethical problem, which includes the two preceding italicized problems, is:

What is the proper criterion for determining right and wrong conduct? Or even less dogmatic: Can there be a criterion for determining right and wrong conduct, and what is it?

Somewhat allied with the ethical problem is that problem of problems: how to live? By this is meant how to put the most into life and get the most out of it; what vocation to follow; what hobbies, amusements, avocations to take up; how to plan time by months, by weeks, by days, by hours. How much time and energy do certain activities deserve? How much can we afford to give them? Restated: what activities are of most worth?

Of course every one does think of problems connected with the art of living. But he thinks of them as little unconnected questions. Barely indeed does any one go about the solution of the general problem of living in an orderly, sys­tem­at­ic manner. To insist upon the broad practical bearings of the problem would be unnecessary, absurd. By its very nature it is the most “practical” question we can ask. Any par­tic­u­lar solution or treatment may be impractical, but this does not affect the question itself.

What are the respective influences of environment (education, experience, etc.) and innate tendencies in determining character? Which is the greater determinant?

Does pleasure depend upon the satisfaction of instinctive desires, or do desires for certain activities depend upon the pleasure accompanying the previous performance of such activities? Does an activity or the possession of an object give us pleasure because we have previously desired it, or do we desire an activity or an object because we have previously obtained pleasure from it? Or do pleasure and desire interact, and just how? The solution of this psy­cho­log­i­cal problem is of tremendous importance in ethics.

Does the mind depend entirely on the brain? That is, are all thoughts, emotions, feelings, due to material changes in the brain? The answer we give to this problem may determine our answer to the question of immortality.

What knowledge is of most worth? I have so fully discussed the importance of this question and the method of proceeding with its solution that further explanation is needless.

One sphere of thought where the thinker is compelled to be original; where it is practically impossible for him to fall into beaten tracks, is invention. But there is useless as well as useful invention. A man’s ambition may range all the way from inventing a machine to harness directly the limitless power of the sun, down to devising a tenacious tip for shoelaces. But he should be careful about inventing something already patented. He should be even more careful to avoid inventing something for which there is no demand. One of Edison’s first patents was for a machine to register quickly the votes of legislative assemblies. And it worked. But the legislative assemblies didn’t want it, because they didn’t want their votes quickly registered. That would have ended good old filibuster methods. Another invention of great uselessness which has been several times attempted is a machine to write words just like the human hand writes them. There are really so many useful things which do not exist and for which there is a demand, that it seems quite a pity nine out of ten patents in the files at Washington are for things inutile. If the would-be inventor cannot himself think of something really needed, almost any big patent attorney house will send him an entire book of sug­ges­tions on “What to Invent.”

Invention usually requires highly technical knowledge, not to speak of facilities for experiment and a well-supplied purse. But nothing gives more solid satisfaction to its creator than a successful appliance. While the conscientious philosopher is constantly harassed by doubts as to whether, after all, he has discovered truth; the inventor need not worry. His machine either works or it does not work, and he knows the truth of his thought thereby. On the other hand the philosopher will always have some thoughts. Be they true or not they may at least be interesting and worth recording, whereas the inventor may toil on for years and years with absolutely nothing to show for his exertion at the end....

There are a number of problems that are not of great “practical” importance, but whose theoretic value is so transcendent as to compel attention. Among these are certain problems in psychology, but more especially in metaphysics, philosophy and even religion, insofar as religion can be said to have problems.

Is there a God and is it possible for man to learn anything of His nature? Some readers may object to the first part of this question. But I state it because I am anxious to avoid dogmatism.

Is the soul immortal? What do we mean by the soul? Does science disprove the life after death?

What is the test of truth? How shall we know truth when we have it? What after all is “truth”?

Are our wills free, or are our actions pre­de­ter­mined? Some may object to this way of stating the question. Much confusion exists as to the meaning of the problem. A different way of stating it would lead to different treatment. What is the “will”? What do we mean by “free”? What do we mean by “pre­de­ter­mined”?

The problem of existence. How did the universe come into being? This is the last problem in which interest can be stimulated from without. No matter in how many different ways he phrases it, a writer cannot convey this sense of mystery to another. It must arise from within. Most of the time we accept, we take for granted, the universe and the existent order of things, and it requires the greatest effort to keep alive our mystification and doubt for even short periods.

The list of questions foregoing is of course merely suggestive. It is impossible to select, say twenty-five questions, and pronounce them the twenty-five most important that can be asked. I fully realize there are questions of greater importance than some I have propounded. But I have not gone so far as to advise that every one of these should be thought over. The list has been given merely for thought stimulation, and to indicate what is meant by “worth while” questions.

Unfortunately I have not been able to explain why most of these are so important. To have done so would have required too much time for each individual problem. It would have drawn us too far out of our subject. The reader must find out or sense the importance for himself.

Practically all of the problems given in the list come under one of the sciences, especially if we count metaphysics or philosophy as a science, which it is in so far as it is organized knowledge. This may seem somewhat narrow. Now I admit there are important problems which are not included in any science. But there are very few. As soon as deep thought is given to a problem its treatment becomes sys­tem­at­ic. It either falls into one of the sciences or a new science evolves about it. John Stuart Mill once started a journal in which he promised himself to put one thought a day, but he did not permit himself to record there any thought on a problem falling within one of the special sciences. None of the thoughts he put in the journal is of any great value. It came to an abrupt end in about two months.

It may be objected that though the questions selected are most important in themselves, there are other things more worth thinking about, because of the mental discipline they yield. Now putting aside the fact that questions important in themselves should be dealt with ultimately—that mental discipline would be useless unless applied to important problems—I must voice my suspicion that the most useful questions are also the best for training the mind. It may be true that punching the bag will help a prizefighter in boxing. But other things equal, a man who has spent one week in actual boxing is better prepared to enter the prize ring than one who has devoted a month to bag punching. The best practice for boxing is boxing. The best practice for solving important questions is solving important questions.

Nor do I admit the contention is valid that one problem rather than another should be thought of because it is “deeper.” We cannot truthfully say that psychology is a “deeper” science than ethics, or that metaphysics is deeper than psychology, or vice versa. Most subjects and most problems are just as deep as we care to make them. Their depth depends entirely on how deep we go into them. This applies especially to the so-called philosophical sciences. We may give them shallow treatment or we may give them profound treatment. But we shall usually find that the deepest questions are the most important questions. For the most important questions have generally attracted the greatest minds; consequently they have been given the deepest treatment; and when a man reads the attempted solutions of these great minds his thoughts tend toward this deeper plane. Of course certain problems, especially in mathematics, can be dealt with by only one method. In this case we may properly speak of some problems being objectively deeper or at least more difficult than others.

Some objections may be offered to several of the questions in my list, on the ground that they are invalid. Such problems as the immortality of the soul and the problem of existence may be declared inscrutable, unsolvable. Such a problem as “Is society for the benefit of the individual or is the individual for the benefit of society?” may be said to imply that society is something which has been voluntarily formed like the State. It may be declared that this is not the case; it may be objected that this question is meaningless. All these objections may be justified. But their truth cannot be determined until we actually attempt a solution. The determination of the validity of a problem is part of the problem.

We come now to the question of what is most worth reading. The simplest answer is that that is most worth reading which is most worth thinking about, and therefore we should read those books which deal with such problems as I have indicated. But this counsel needs to be supplemented.

A conservative estimate places the number of books in the world at 4,500,000. (This estimate was made before the war broke out, and the war-books by now have doubtless brought the number to 5,000,000.) This does not mean books as collections of printed sheets of paper bound together—books as physical objects—for if it did the number would be immensely greater. It means 4,500,000 (or more) separate and distinct treatises. If you were to read one book every two weeks, you would read about twenty-five a year, and if you read for fifty years you would cover 1,250. One book in every three thousand six hundred! (3,600!)

From this it is apparent that even the most omnivorous reader, even the reader who can cover a book swiftly by efficient skipping, will at least have to ask himself before beginning a volume, “Is this a book in a thousand? Can I afford to read this at the cost of missing nine hundred and ninety-nine others?” And most men who ask this question will have to substitute the number five thousand, or even ten thousand.

Nine-tenths of our reading is on mere chance recommendation, passing whim or by sheer accident. We catch sight of a book on a library table. Having nothing better to do we pick it up; we start perusing it. Every book read in this way means a sinful waste of time. To be sure, a book read in this chance manner might (accidentally) be very good—even better than some you would have planned for; but this will happen seldom, and is never a justification of the practice. By going a round about way to a place a man might stumble across a lost pocketbook, but this would not justify taking round about ways.

The first thing needed, then, is that we should plan our reading. Perhaps the best way to do this would be to make out a list of the books we intend to read for the coming year, or say a list of from a dozen to twenty-five volumes, and then read them in the order listed. Another good plan is to jot down the title of every book we intend to read, and keep the list about with us. Then when we meet with a book which we think would be good to read, or which we feel we simply must read, we can before starting it glance at our list. The formidable array we find there will probably induce us either to give up entirely our intention to read the book before us, or at least to put it somewhere on the list which will allow more important books to be read first.

Some people cannot endure planning their reading in this manner. It grates on them to think they are tied down to any sort of program; it seems to deprive them of the advantages of spontaneous interest. Well, if you cannot plan your reading prospectively, at least plan it retro­spec­tive­ly. If you cannot keep a list of books you intend to read, at least keep a list of books you have read. Refer to this from time to time. See whether you have been reading uniformly good literature. See whether you have been reading too much on one topic and not enough on another, and what topics you have been long neglecting. But at best this method is a poor substitute for planning your reading prospectively.

We should plan not only with regard to topics and subjects, but with regard to authors. Obviously if two men of equal ability both study the same subject, one will get more out of his study than the other if he reads authors who treat the subject on a deeper plane—provided of course he understands them.

Whether consciously or not, we tend to imitate the authors we read. If we read shallow books we are forced, while reading them, to do shallow thinking. Our plane of thought tends toward the plane of thought of the authors we study; we acquire either habits of careful critical thinking, or of dogmatic lack of thinking.

This emphasizes the importance of reading the best books, and only the best books. Our plane of thinking is determined not alone by the good books we read, but by all the books we read; it tends toward the average. Most men imagine that when they read a good book they get a certain amount of good out of it, and that this good will stay with them undiminished. Provided they read a certain number of serious books, they see no reason why they should not read any number of superficial or useless books, or any amount of ephemeral magazine or newspaper literature. They expect the serious reading to benefit them. They do not expect the shallow reading to harm them. This is just as if they were to buy and eat unnutritious and indigestible food, and excuse themselves on the ground that they ate nourishing and digestible food along with it.

The analogy may be carried further. As it is the average of the physical food you digest which ultimately determines the constitution of your body, so it is the average of the mental food you absorb which determines the constitution of your mind. One good meal will not offset a week of bad ones; one good book will never offset any number of poor books. Further, as no one has a perfect memory, you do not retain all you read any more than you retain all you eat. Therefore if you do not want your mind to retrogress, you should not rest satisfied with books already read, but should continue to read books at least as good as any previous. As at any given time your bodily health—so far as it depends on food—is mainly determined by the meals of the last few days or weeks, so is your mental health dependent on the last few books you have read.

One of the first things we should look to in selecting books is their comp­re­hen­sive­ness. To quote Arnold Bennett: “Unless and until a man has formed a scheme of knowledge, be it but a mere skeleton, his reading must necessarily be un­phi­lo­soph­i­cal. He must have attained to some notion of the inter­re­la­tions of the various branches of knowledge before he can properly comprehend the branch of knowledge in which he specializes.”23 As an aid in forming this scheme of knowledge, Mr. Bennett suggests Herbert Spencer’s First Principles. I heartily endorse his choice. I would add to it the essay on The Clas­si­fi­ca­tion of the Sciences by the same author.

These works are classics, and one of the most regrettable of difficulties is that of getting people to read the classics. Mention to a man Darwin’s Origin of Species or Descent of Man, and he will reply, “Oh, yes, that’s the theory that says men descended from monkeys.” Satisfied that he knows all there is to know about it, he never reads any of Darwin’s works. Now passing over the fact that the theory does not assert that man descended from monkeys and never intended to assert it;—what a compliment to Darwin’s thought and brevity to assume that all his books can be summed up in a phrase! But Darwin is not the only sufferer. If we come across the title of a classic often enough, and hear a lot of talk “about it and about” and a few quotations from it, we gradually come to believe we know all the contents worth knowing. This is why Shakespeare, and in fact most of the classics, are so seldom actually read, and why we go for our serious reading to a book on “How to Read Character from Handwriting” or to a sensational volume on prostitution by one of our modern “sociologists.” The only way we can keep ourselves from such stuff is to lay out some definite end, some big objective, to be attained; and before reading a book we should ask how that helps us to attain it.

I have not given a formal list of books worth reading, nor do I intend to; one of the reasons being that the work has been done so well by others. Ever since Sir John Lubbock published his list of one hundred best books, the number of selections has been legion. Charles Eliot’s selection for his Five Foot Shelf is to be commended, and a little volume by Frank Parsons The World’s Best Books. Of course our purpose is special:—to find the best books for making thinkers; but the remarks already made should aid the reader sufficiently in making his own selection from these lists. As previously pointed out, if the reader is studying a specialty he can usually find a fairly well selected bibliography at the end of the article on that specialty in any standard encyclopedia.

The reader probably sees clearly by now that it is impossible to do his own thinking in every case; that if he is to have sound knowledge on important questions he must have the courage to be ignorant of many things. How much trouble to go to in any par­tic­u­lar case it is difficult to say.

We can lay it down as a general principle that questions of the highest importance, such as those of which I have given a suggestive list—questions which deal with facts known or easily ascertainable, and which depend for their right solution more on thinking than on anything else—a man should solve for himself, and should take the greatest caution in so doing. On the other hand, questions of the highest importance which depend for their solution mainly on full and detailed knowledge of highly technical facts which lie outside of one’s specialty, should be dealt with by consulting authorities and taking their word for it.

There still remains the great mass of questions which are relatively unimportant, but continually coming up in our daily life, the answers to which greatly influence our conduct. Time forbids us not only from thinking these out for ourselves, but even from consulting an authority—for the selection of an authority often involves almost as much in­tel­lec­tual responsibility as self-thinking. The only thing we can do is to accept the verdict of popular opinion.

Custom, convention and popular belief, no matter how many times they have been overthrown, have fairly reliable foundations. Popular ideas, to be sure, are products of mere unorganized experience. They are empirical; seldom if ever scientific. But though they are founded on experience which is unorganized, they are founded on so much of it that they are worthy of respect. Society could not long exist if it persisted in acting on beliefs altogether wrong, though it is safe to say that popular ideas are never more than approximately right. But unless and until you have either thoroughly thought over a question for yourself or have consulted an acknowledged and trustworthy authority, it is best tentatively to accept and act on common belief. To think and act differently, merely for the sake of being different, is unprofitable and dangerous, all questions of ethics aside.