To avoid the various foolish opinions to which mankind are prone, no superhuman genius is required. A few simple rules will keep you, not from all error, but from silly error.
If the matter is one that can be settled by observation, make the observation yourself. Aristotle could have avoided the mistake of thinking that women have fewer teeth than men, by the simple device of asking Mrs. Aristotle to keep her mouth open while he counted. He did not do so because he thought he knew. Thinking that you know when in fact you don't is a fatal mistake, to which we are all prone. I believe myself that hedgehogs eat black beetles, because I have been told that they do; but if I were writing a book on the habits of hedgehogs, I should not commit myself until I had seen one enjoying this unappetizing diet. Aristotle, however, was less cautious. Ancient and medieval authors knew all about unicorns and salamanders; not one of them thought it necessary to avoid dogmatic statements about them because he had never seen one of them.
Many matters, however, are less easily brought to the test of experience. If, like most of mankind, you have passionate convictions on many such matters, there are ways in which you can make yourself aware of your own bias. If an opinion contrary to your own makes you angry, that is a sign that you are subconsciously aware of having no good reason for thinking as you do. If some one maintains that two and two are five, or that Iceland is on the equator, you feel pity rather than anger, unless you know so little of arithmetic or geography that his opinion shakes your own contrary conviction. The most savage controversies are those about matters as to which there is no good evidence either way. Persecution is used in theology, not in arithmetic, because in arithmetic there is knowledge, but in theology there is only opinion. So whenever you find yourself getting angry about a difference of opinion, be on your guard; you will probably find, on examination, that your belief is going beyond what the evidence warrants.
A good way of ridding yourself of certain kinds of dogmatism is to become aware of opinions held in social circles different from your own. When I was young, I lived much outside my own country in France, Germany, Italy, and the United States. I found this very profitable in diminishing the intensity of insular prejudice. If you cannot travel, seek out people with whom you disagree, and read a newspaper belonging to a party that is not yours. If the people and the newspaper seem mad, perverse, and wicked, remind yourself that you seem so to them. In this opinion both parties may be right, but they cannot both be wrong. This reflection should generate a certain caution.
Becoming aware of foreign customs, however, does not always have a beneficial effect. In the seventeenth century, when the Manchus conquered China, it was the custom among the Chinese for the women to have small feet, and among the Manchus for the men to wear-pigtails. Instead of each dropping their own foolish custom, they each adopted the foolish custom of the other, and the Chinese continued to wear pigtails until they shook off the dominion of the Manchus in the revolution of 1911.
For those who have enough psychological imagination, it is a good plan to imagine an argument with a person having a different bias. This has one advantage, and only one, as compared with actual conversation with opponents; this one advantage is that the method is not subject to the same limitations of time or space. Mahatma Gandhi deplores railways and steamboats and machinery; he would like to undo the whole of the industrial revolution. You may never have an opportunity of actually meeting any one who holds this opinion, because in Western countries most people take the advantage of modern technique for granted. But if you want to make sure that you are right in agreeing with the prevailing opinion, you will find it a good plan to test the arguments that occur to you by considering what Gandhi might say in refutation of them. I have sometimes been led actually to change my mind as a result of this kind of imaginary dialogue, and, short of this, I have frequently found myself growing less dogmatic and cocksure through realizing the possible reasonableness of a hypothetical opponent.
Be very wary of opinions that flatter your self-esteem. Both men and women, nine times out of ten, are firmly convinced of the superior excellence of their own sex. There is abundant evidence on both sides. If you are a man, you can point out that most poets and men of science are male; if you are a woman, you can retort that so are most criminals. The question is inherently insoluble, but self esteem conceals this from most people. We are all, whatever part of the world we come from, persuaded that our own nation is superior to all others.
Seeing that each nation has its characteristic merits and demerits, we adjust our standard of values so as to make out that the merits possessed by our nation are the really important ones, while its demerits are comparatively trivial. Here, again, the rational man will admit that the question is one to which there is no demonstrably right answer. It is more difficult to deal with the self esteem of man as man, because we cannot argue out the matter with some non-human mind. The only way I know of dealing with this general human conceit is to remind ourselves that man is a brief episode in the life of a small planet in a little corner of the universe, and that, for aught we know, other parts of the cosmos may contain beings as superior to ourselves as we are to jellyfish.
Other passions besides self-esteem are common sources of error; of these perhaps the most important is fear. Fear sometimes operates directly, by inventing rumors of disaster in war-time, or by imagining objects of terror, such as ghosts; sometimes it operates indirectly, by creating belief in something comforting, such as the elixir of life, or heaven for ourselves and hell for our enemies. Fear has many forms-fear of death, fear of the dark, fear of the unknown, fear of the herd, and that vague generalized fear that comes to those who conceal from themselves their more specific terrors. Until you have admitted your own fears to yourself, and have guarded yourself by a difficult effort of will against their mythmaking power, you cannot hope to think truly about many matters of great importance, especially those with which religious beliefs are concerned. Fear is the main source of superstition and one of the main sources of cruelty. To conquer fear is the beginning of wisdom, in the pursuit of truth as in the endeavor after a worthy manner of life.
There are two ways of avoiding fear: one is by persuading ourselves that we are immune from disaster, and the other is by the practice of sheer courage. The latter is difficult, and to everybody becomes impossible at a certain point. The former has therefore always been more popular. Primitive magic has the purpose of securing safety, either by injuring enemies, or by protecting oneself by talismans, spells, or incantations. Without any essential change, belief in such ways of avoiding danger survived throughout the many centuries of Babylonian civilization, spread from Babylon throughout the empire of Alexander, and was acquired by the Romans in the course of their absorption of Hellenistic culture. From the Romans it descended to medieval Christendom and Islam. Science has now lessened the belief in magic, but many people place more faith in mascots than they are willing to avow, and sorcery, while condemned by the Church, is still officially a possible sin.
Magic, however, was a crude way of avoiding terrors, and, moreover, not a very effective way, for wicked magicians might always prove stronger than good ones. In the fifteenth, sixteenth, and seventeenth centuries, dread of witches and sorcerers led to the burning of hundreds of thousands convicted of these crimes. But newer beliefs, particularly as to the future life, sought more effective ways of combating fear. Socrates on the day of his death (if Plato is to be believed) expressed the conviction that in the next world he would live in the company of the gods and heroes, and surrounded by just spirits who would never object to his endless argumentation. Plato, in his "Republic," laid it down that cheerful views of the next world must be enforced by the State, not because they were true, but to make soldiers more willing to die in battle. He would have none of the traditional myths about Hades, because they represented the spirits of the dead as unhappy.
Orthodox Christianity, in the Ages of Faith, laid down very definite rules for salvation. First, you must be baptized; then, you must avoid all theological error; last, you must, before dying, repent of your sins and receive absolution. All this would not save you from purgatory, but it would insure your ultimate arrival in heaven. It was not necessary to know theology. An eminent cardinal stated authoritatively that the requirements of orthodoxy would be satisfied if you murmured on your death-bed: "I believe all that the Church believes; the Church believes all that I believe." These very definite directions ought to have made Catholics sure of finding the way to heaven. Nevertheless, the dread of hell persisted, and has caused, in recent times, a great softening of the dogmas as to who will be damned. The doctrine, professed by many modern Christians, that everybody will go to heaven, ought to do away with the fear of death, but in fact this fear is too instinctive to be easily vanquished. F. W. H. Myers, whom spiritualism had converted to belief in a future life, questioned a woman who had lately lost her daughter as to what she supposed had become of her soul. The mother replied: "Oh, well, I suppose she is enjoying eternal bliss, but I wish you wouldn't talk about such unpleasant subjects." In spite of all that theology can do, heaven remains, to most people, an "unpleasant subject."
The most refined religions, such as those of Marcus Aurelius and Spinoza, are still concerned with the conquest of fear. The Stoic doctrine was simple: it maintained that the only true good is virtue, of which no enemy can deprive me; consequently, there is no need to fear enemies. The difficulty was that no one could really believe virtue to be the only good, not even Marcus Aurelius, who, as emperor, sought not only to make his subjects virtuous, but to protect them against barbarians, pestilences, and famines. Spinoza taught a somewhat similar doctrine. According to him, our true good consists in indifference to our mundane fortunes. Both these men sought to escape from fear by pretending that such things as physical suffering are not really evil. This is a noble way of escaping from fear, but is still based upon false belief. And if genuinely accepted, it would have the bad effect of making men indifferent, not only to their own sufferings, but also to those of others.
Under the influence of great fear, almost everybody becomes superstitious. The sailors who threw Jonah overboard imagined his presence to be the cause of the storm which threatened to wreck their ship. In a similar spirit the Japanese, at the time of the Tokyo earthquake took to massacring Koreans and Liberals. When the Romans won victories in the Punic wars, the Carthaginians became persuaded that their misfortunes were due to a certain laxity which had crept into the worship of Moloch. Moloch liked having children sacrificed to him, and preferred them aristocratic; but the noble families of Carthage had adopted the practice of surreptitiously substituting plebeian children for their own offspring. This, it was thought, had displeased the god, and at the worst moments even the most aristocratic children were duly consumed in the fire. Strange to say, the Romans were victorious in spite of this democratic reform on the part of their enemies.
Collective fear stimulates herd instinct, and tends to produce ferocity toward those who are not regarded as members of the herd. So it was in the French Revolution, when dread of foreign armies produced the reign of terror. And it is to be feared that the Nazis, as defeat draws nearer, will increase the intensity of their campaign for exterminating Jews. Fear generates impulses of cruelty, and therefore promotes such superstitious beliefs as seem to justify cruelty. Neither a man nor a crowd nor a nation can be trusted to act humanely or to think sanely under the influence of a great fear. And for this reason poltroons are more prone to cruelty than brave men, and are also more prone to superstition. When I say this, I am thinking of men who are brave in all respects, not only in facing death. Many a man will have the courage to die gallantly, but will not have the courage to say, or even to think, that the cause for which he is asked to die is an unworthy one. Obloquy is, to most men, more painful than death; that is one reason why, in times of collective excitement, so few men venture to dissent from the prevailing opinion. No Carthaginian denied Moloch, because to do so would have required more courage than was required- to face death in battle.
But we have been getting too solemn. Superstitions are not al-ways dark and cruel; often they add to the gaiety of life. I received once a communication from the god Osiris, giving me his telephone number; he lived, at that time, in a suburb of Boston. Although I did not enroll myself among his worshipers, his letter gave me pleasure. I have frequently received letters from men announcing themselves as the Messiah, and urging me not to omit to mention this important fact in my lectures. During prohibition, there was a sect which maintained that the communion service ought to be celebrated in whiskey, not in wine; this tenet gave them a legal right to a supply of hard liquor, and the sect grew rapidly. There is in England a sect which maintains that the English are the lost ten tribes; there is a stricter sect, which maintains that they are only the tribes of Ephraim and Manasseh. Whenever I encounter a member of either of these sects, I profess myself an adherent of the other, and much pleasant argumentation results. I like also the men who study the Great Pyramid, with a view to deciphering its mystical lore. Many great books have been written on this subject, some of which have been presented to me by their authors. It is a singular fact that the Great Pyramid always predicts the history of the world accurately up to the date of publication of the book in question, but after that date it becomes less reliable. Generally the author expects, very soon, wars in Egypt, followed by Armageddon and the coming of Antichrist, but by this time so many people have been recognized as Antichrist that the reader is reluctantly driven to skepticism.
I admire especially a certain prophetess who lived beside a lake in Northern New York State about the year 1820. She announced to her numerous followers that she possessed the power of walking on water, and that she proposed to do so at 11 o'clock on a certain morning. At the stated time, the faithful assembled in their thousands beside the lake. She spoke to them, saying: "Are you all entirely persuaded that I can walk on water?" With one voice they replied: "We are." "In that case," she announced, "there is not need for me to do so." And they all went home much edified.
Perhaps the world would lose some of its interest and variety if such beliefs were wholly replaced by cold science. Perhaps we may allow ourselves to be glad of the Abecedarians, who were so-called because, having rejected all profane learning, they thought it wicked to learn the ABC. And we may enjoy the perplexity of the South American Jesuit who wondered how the sloth could have traveled, since the Flood, all the way from Mount Ararat to Peru-a journey which its extreme tardiness of locomotion rendered almost incredible. A wise man will enjoy the goods of which there is a plentiful supply, and of intellectual rubbish he will find an abundant diet, in our own age as in every other.