The Need to Train Thought

To expatiate upon the importance of thought would be absurd. The traditional definition of man as "the thinking animal" fixes thought as the essential difference between man and the brutes,—surely an important matter. More relevant to our purpose is the question how thought is important, for an answer to this question will throw light upon the kind of training thought requires if it is to subserve its end.

It would be absurd to dwell on the importance of thought. The traditional definition of humans as "the thinking animal" makes thought the essential difference between humans and other animals. That is surely important. More relevant to our purpose is the question of how thought is important. The answer will shed light on the kind of training thought requires if it is to serve its purpose.

I. Thought affords the sole method of escape from purely impulsive or purely routine action. A being without capacity for thought is moved only by instincts and appetites, as these are called forth by outward conditions and by the inner state of the organism. A being thus moved is, as it were, pushed from behind. This is what we mean by the blind nature of brute actions. The agent does not see or foresee the end for which he is acting, nor the results produced by his behaving in one way rather than in another. He does not "know what he is about." Where there is thought, things present act as signs or tokens of things not yet experienced. A thinking being can, accordingly, act on the basis of the absent and the future. Instead of being pushed into a mode of action by the sheer urgency of forces, whether instincts or habits, of which he is not aware, a reflective agent is drawn (to some extent at least) to action by some remoter object of which he is indirectly aware.

I. Thought is the only way to escape purely impulsive or purely routine action. A being without the capacity for thought is moved only by instincts and appetites. These are stirred by outside conditions and by the organism’s internal state. Such a being is, so to speak, pushed from behind. This is what we mean when we say that brute actions are blind. The being does not see or foresee the goal of its action. Nor does it foresee the results of acting one way rather than another. It does not "know what it is about." When thought is present, things we encounter serve as signs of things we have not yet experienced. A thinking being can therefore act on the basis of what is absent and what lies in the future. Instincts or habits can push a being into action through their sheer urgency, without the being being aware of them. Instead, a reflective being is drawn to action, at least to some extent, by a more distant goal of which it is indirectly aware.

An animal without thought may go into its hole when rain threatens, because of some immediate stimulus to its organism. A thinking agent will perceive that certain given facts are probable signs of a future rain, and will take steps in the light of this anticipated future. To plant seeds, to cultivate the soil, to harvest grain, are intentional acts, possible only to a being who has learned to subordinate the immediately felt elements of an experience to those values which these hint at and prophesy. Philosophers have made much of the phrases "book of nature," "language of nature." Well, it is in virtue of the capacity of thought that given things are significant of absent things, and that nature speaks a language which may be interpreted. To a being who thinks, things are records of their past, as fossils tell of the prior history of the earth, and are prophetic of their future, as from the present positions of heavenly bodies remote eclipses are foretold. Shakespeare's "tongues in trees, books in the running brooks," expresses literally enough the power superadded to existences when they appeal to a thinking being. Upon the function of signification depend all foresight, all intelligent planning, deliberation, and calculation.

An animal without thought may go into its hole when rain threatens because of an immediate stimulus to its body. A thinking being will recognize that certain facts are probable signs of coming rain. The thinking being will then act in light of the expected rain. Planting seeds, cultivating soil, and harvesting grain are intentional acts. They are possible only for a being who has learned to put immediate sensations second to the values they suggest and predict. Philosophers have made much of the phrases "book of nature," "language of nature." It is through the capacity for thought that things present can signify things absent. Through thought, nature speaks a language that can be interpreted. To a thinking being, things are records of their past, just as fossils tell of the earth’s earlier history. Things also foretell their future, just as the present positions of heavenly bodies allow us to predict distant eclipses. Shakespeare's "tongues in trees, books in the running brooks," expresses quite literally the added power things gain when they speak to a thinking being. All foresight, intelligent planning, deliberation, and calculation depend on this power to signify.

II. By thought man also develops and arranges artificial signs to remind him in advance of consequences, and of ways of securing and avoiding them. As the trait just mentioned makes the difference between savage man and brute, so this trait makes the difference between civilized man and savage. A savage who has been shipwrecked in a river may note certain things which serve him as signs of danger in the future. But civilized man deliberately makes such signs; he sets up in advance of wreckage warning buoys, and builds lighthouses where he sees signs that such events may occur. A savage reads weather signs with great expertness; civilized man institutes a weather service by which signs are artificially secured and information is distributed in advance of the appearance of any signs that could be detected without special methods. A savage finds his way skillfully through a wilderness by reading certain obscure indications; civilized man builds a highway which shows the road to all. The savage learns to detect the signs of fire and thereby to invent methods of producing flame; civilized man invents permanent conditions for producing light and heat whenever they are needed. The very essence of civilized culture is that we deliberately erect monuments and memorials, lest we forget; and deliberately institute, in advance of the happening of various contingencies and emergencies of life, devices for detecting their approach and registering their nature, for warding off what is unfavorable, or at least for protecting ourselves from its full impact and for making more secure and extensive what is favorable. All forms of artificial apparatus are intentionally designed modifications of natural things in order that they may serve better than in their natural estate to indicate the hidden, the absent, and the remote.

II. Through thought, people also develop and arrange artificial signs. These signs warn them of consequences and remind them how to bring them about or avoid them. The trait just mentioned makes the difference between a savage and a brute. In the same way, this trait makes the difference between a civilized person and a savage. A savage shipwrecked in a river may notice things that serve as signs of danger in the future. But civilized people deliberately make such signs. They set up warning buoys before wrecks occur. They build lighthouses where they see signs that wrecks may occur. A savage reads weather signs with great skill. Civilized people establish a weather service that gathers signs by artificial means. It distributes information before any signs appear that could be detected without special methods. A savage finds his way skillfully through a wilderness by reading subtle clues. Civilized people build a highway that shows everyone the way. A savage learns to recognize signs of fire and thus invents ways to produce a flame. Civilized people invent lasting arrangements for producing light and heat whenever they are needed. The very essence of civilized culture is that we deliberately build monuments and memorials so that we do not forget. We also deliberately put devices in place before various events and emergencies arise. These devices detect their approach and record their nature. They ward off what is unfavorable, or at least protect us from its full impact. They also make what is favorable more secure and more widespread. All forms of artificial equipment are deliberately designed modifications of natural things. They are meant to indicate what is hidden, absent, and remote better than those things could in their natural state.

III. Finally, thought confers upon physical events and objects a very different status and value from that which they possess to a being that does not reflect. These words are mere scratches, curious variations of light and shade, to one to whom they are not linguistic signs. To him for whom they are signs of other things, each has a definite individuality of its own, according to the meaning that it is used to convey. Exactly the same holds of natural objects. A chair is a different object to a being to whom it consciously suggests an opportunity for sitting down, repose, or sociable converse, from what it is to one to whom it presents itself merely as a thing to be smelled, or gnawed, or jumped over; a stone is different to one who knows something of its past history and its future use from what it is to one who only feels it directly through his senses. It is only by courtesy, indeed, that we can say that an unthinking animal experiences an object at all—so largely is anything that presents itself to us as an object made up by the qualities it possesses as a sign of other things.

III. Finally, thought gives physical events and objects a very different status and value than they have for a being that does not reflect. These words are mere scratches, strange variations of light and shade, to someone who does not see them as linguistic signs. But to someone who sees them as signs of other things, each word has a distinct identity, depending on the meaning it conveys. The same is true of natural objects. A chair is one kind of object to a being that consciously sees it as a chance to sit down, rest, or talk with others. It is a different kind of object to a being that sees it only as something to smell, gnaw, or jump over. A stone is different to someone who knows something of its past and its future use. It is different to someone who experiences it only directly through the senses. Indeed, it is only as a courtesy that we can say an unthinking animal experiences an object at all. For what we experience as an object consists largely of the qualities it has as a sign of other things.

An English logician (Mr. Venn) has remarked that it may be questioned whether a dog sees a rainbow any more than he apprehends the political constitution of the country in which he lives. The same principle applies to the kennel in which he sleeps and the meat that he eats. When he is sleepy, he goes to the kennel; when he is hungry, he is excited by the smell and color of meat; beyond this, in what sense does he see an object? Certainly he does not see a house—i.e. a thing with all the properties and relations of a permanent residence, unless he is capable of making what is present a uniform sign of what is absent—unless he is capable of thought. Nor does he see what he eats as meat unless it suggests the absent properties by virtue of which it is a certain joint of some animal, and is known to afford nourishment. Just what is left of an object stripped of all such qualities of meaning, we cannot well say; but we can be sure that the object is then a very different sort of thing from the objects that we perceive. There is moreover no particular limit to the possibilities of growth in the fusion of a thing as it is to sense and as it is to thought, or as a sign of other things. The child today soon regards as constituent parts of objects qualities that once it required the intelligence of a Copernicus or a Newton to apprehend.

An English logician, Mr. Venn, once suggested that we may question whether a dog sees a rainbow. A dog may no more see a rainbow than he understands the political constitution of the country where he lives. The same principle applies to the kennel where he sleeps and the meat he eats. When he is sleepy, he goes to the kennel. When he is hungry, the smell and color of meat excite him. Beyond this, in what sense does he see an object? Certainly he does not see a house, i.e. a thing with all the properties and relationships of a permanent residence, unless he can treat what is present as a consistent sign of what is absent. In other words, he must be capable of thought. Nor does he see what he eats as meat unless it suggests its absent properties. These properties make it a particular cut of an animal and make it something known to provide nourishment. We cannot easily say what is left of an object once all such meaningful qualities are removed. But we can be sure that it is then very different from the objects we perceive. Moreover, there is no particular limit to how much our sense of a thing can grow together with our thought of it, or our sense of it as a sign of other things. Today, a child soon regards certain qualities as parts of objects, though grasping those qualities once required the intelligence of a Copernicus or a Newton.

These various values of the power of thought may be summed up in the following quotation from John Stuart Mill. "To draw inferences," he says, "has been said to be the great business of life. Every one has daily, hourly, and momentary need of ascertaining facts which he has not directly observed: not from any general purpose of adding to his stock of knowledge, but because the facts themselves are of importance to his interests or to his occupations. The business of the magistrate, of the military commander, of the navigator, of the physician, of the agriculturist, is merely to judge of evidence and to act accordingly.... As they do this well or ill, so they discharge well or ill the duties of their several callings. It is the only occupation in which the mind never ceases to be engaged."³

These various benefits of the power of thought may be summed up in the following quotation from John Stuart Mill. "Drawing conclusions," he says, "has been called the great business of life. Everyone needs to establish facts they have not directly observed, every day, every hour, and every moment. They do not do this simply to increase their knowledge. They do it because the facts themselves matter to their interests or their work. The work of a judge, a military commander, a navigator, a doctor, or a farmer is simply to judge the evidence and act accordingly.... How well or poorly they do this determines how well or poorly they perform the duties of their professions. It is the only activity in which the mind is always engaged."³

What a person has not only daily and hourly, but momentary need of performing, is not a technical and abstruse matter; nor, on the other hand, is it trivial and negligible. Such a function must be congenial to the mind, and must be performed, in an unspoiled mind, upon every fitting occasion. Just because, however, it is an operation of drawing inferences, of basing conclusions upon evidence, of reaching belief indirectly, it is an operation that may go wrong as well as right, and hence is one that needs safeguarding and training. The greater its importance the greater are the evils when it is ill-exercised.

What a person needs to do not just daily or hourly, but every moment, is not technical or difficult to understand. Nor is it trivial or unimportant. Such an activity must be natural to the mind. An unspoiled mind must engage in it whenever the occasion calls for it. But the activity involves drawing inferences, basing conclusions on evidence, and reaching beliefs indirectly. For that very reason, it can go wrong as well as right. So it needs safeguards and training. The more important the activity, the greater the harm when it is done poorly.

An earlier writer than Mill, John Locke (1632-1704), brings out the importance of thought for life and the need of training so that its best and not its worst possibilities will be realized, in the following words: "No man ever sets himself about anything but upon some view or other, which serves him for a reason for what he does; and whatsoever faculties he employs, the understanding with such light as it has, well or ill informed, constantly leads; and by that light, true or false, all his operative powers are directed.... Temples have their sacred images, and we see what influence they have always had over a great part of mankind. But in truth the ideas and images in men's minds are the invisible powers that constantly govern them, and to these they all, universally, pay a ready submission. It is therefore of the highest concernment that great care should be taken of the understanding, to conduct it aright in the search of knowledge and in the judgments it makes."⁴ If upon thought hang all deliberate activities and the uses we make of all our other powers, Locke's assertion that it is of the highest concernment that care should be taken of its conduct is a moderate statement. While the power of thought frees us from servile subjection to instinct, appetite, and routine, it also brings with it the occasion and possibility of error and mistake. In elevating us above the brute, it opens to us the possibility of failures to which the animal, limited to instinct, cannot sink.

John Locke (1632-1704), who wrote before Mill, explains why thought matters in life. He also explains why we need training to realize its best possibilities rather than its worst. He writes: "No one ever sets out to do anything without some idea that serves as a reason for acting. Whatever abilities a person uses, the understanding always leads, with whatever light it has, whether well or poorly informed. By that light, true or false, all the person's powers of action are directed.... Temples have their sacred images, and we see what influence these images have always had over a great part of humanity. But in truth, the ideas and images in people's minds are the invisible powers that constantly govern them. Everyone readily submits to these powers. It is therefore of the highest importance to take great care of the understanding, so as to guide it properly in its search for knowledge and in the judgments it makes."⁴ If all deliberate activities and all uses of our other powers depend on thought, Locke's claim is a modest one. He says that it is of the highest importance to take care in how we conduct our thinking. The power of thought frees us from slavish submission to instinct, appetite, and routine. But it also brings opportunities and possibilities for error and mistakes. Thought raises us above animals, but it also exposes us to failures that an animal, limited by instinct, cannot suffer.

Up to a certain point, the ordinary conditions of life, natural and social, provide the conditions requisite for regulating the operations of inference. The necessities of life enforce a fundamental and persistent discipline for which the most cunningly devised artifices would be ineffective substitutes. The burnt child dreads the fire; the painful consequence emphasizes the need of correct inference much more than would learned discourse on the properties of heat. Social conditions also put a premium on correct inferring in matters where action based on valid thought is socially important. These sanctions of proper thinking may affect life itself, or at least a life reasonably free from perpetual discomfort. The signs of enemies, of shelter, of food, of the main social conditions, have to be correctly apprehended.

Up to a point, ordinary natural and social conditions help us draw sound conclusions. The necessities of life impose a basic, constant discipline that even the cleverest inventions could not replace. A child who has been burned fears the fire. The painful result shows the need to draw correct conclusions far more clearly than a learned lecture on heat would. Social conditions also reward correct reasoning when acting on sound thought matters to society. These rewards and penalties for proper thinking may affect life itself, or at least the chance of living reasonably free from constant discomfort. We have to recognize signs of enemies, shelter, food, and the main social conditions.

But this disciplinary training, efficacious as it is within certain limits, does not carry us beyond a restricted boundary. Logical attainment in one direction is no bar to extravagant conclusions in another. A savage expert in judging signs of the movements and location of animals that he hunts, will accept and gravely narrate the most preposterous yarns concerning the origin of their habits and structures. When there is no directly appreciable reaction of the inference upon the security and prosperity of life, there are no natural checks to the acceptance of wrong beliefs. Conclusions may be generated by a modicum of fact merely because the suggestions are vivid and interesting; a large accumulation of data may fail to suggest a proper conclusion because existing customs are averse to entertaining it. Independent of training, there is a "primitive credulity" which tends to make no distinction between what a trained mind calls fancy and that which it calls a reasonable conclusion. The face in the clouds is believed in as some sort of fact, merely because it is forcibly suggested. Natural intelligence is no barrier to the propagation of error, nor large but untrained experience to the accumulation of fixed false beliefs. Errors may support one another mutually and weave an ever larger and firmer fabric of misconception. Dreams, the positions of stars, the lines of the hand, may be regarded as valuable signs, and the fall of cards as an inevitable omen, while natural events of the most crucial significance go disregarded. Beliefs in portents of various kinds, now mere nook and cranny superstitions, were once universal. A long discipline in exact science was required for their conquest.

But this training, effective as it is within certain limits, can take us only so far. Logical skill in one area does not prevent wild conclusions in another. A hunter in a society considered primitive may be an expert at reading signs of animals' movements and locations. Yet the hunter may accept and seriously tell the most absurd stories about the origins of their habits and bodies. When a conclusion has no directly noticeable effect on the security and prosperity of life, nothing naturally checks the acceptance of mistaken beliefs. People may draw conclusions from a few facts simply because the ideas those facts suggest are vivid and interesting. A large collection of facts may fail to suggest the right conclusion because existing customs discourage people from considering it. Without training, there is a "primitive credulity" that tends not to distinguish fantasy from what a trained mind calls a reasonable conclusion. A face in the clouds is believed to be a fact of some kind, simply because the image comes so forcefully to mind. Natural intelligence does not prevent the spread of error. Nor does extensive experience without training prevent the accumulation of firmly held false beliefs. Errors may support one another, weaving an ever larger and stronger fabric of misconception. Dreams, the positions of stars, and the lines of the hand may be regarded as valuable signs. The fall of cards may be seen as an unavoidable omen. Meanwhile, natural events of the greatest importance may go unnoticed. Beliefs in various omens were once universal, though they now survive only as superstitions in isolated corners. A long discipline in exact science was required to overcome them.

In the mere function of suggestion, there is no difference between the power of a column of mercury to portend rain, and that of the entrails of an animal or the flight of birds to foretell the fortunes of war. For all anybody can tell in advance, the spilling of salt is as likely to import bad luck as the bite of a mosquito to import malaria. Only systematic regulation of the conditions under which observations are made and severe discipline of the habits of entertaining suggestions can secure a decision that one type of belief is vicious and the other sound. The substitution of scientific for superstitious habits of inference has not been brought about by any improvement in the acuteness of the senses or in the natural workings of the function of suggestion. It is the result of regulation of the conditions under which observation and inference take place.

As mere suggestions, a column of mercury predicting rain is no different from animal entrails or the flight of birds predicting the fortunes of war. For all anyone can tell in advance, spilled salt is as likely to mean bad luck as a mosquito bite is to bring malaria. We can decide that one kind of belief is unsound and the other sound only through systematic control of the conditions of observation. We must also rigorously discipline our habits of considering suggestions. Scientific habits of drawing conclusions have replaced superstitious ones. This change has not come about because our senses have become sharper or our natural ability to form suggestions has improved. It is the result of controlling the conditions under which observation and inference take place.

It is instructive to note some of the attempts that have been made to classify the main sources of error in reaching beliefs. Francis Bacon, for example, at the beginnings of modern scientific inquiry, enumerated four such classes, under the somewhat fantastic title of "idols" (Gr. ειδωλα, images), spectral forms that allure the mind into false paths. These he called the idols, or phantoms, of the (a) tribe, (b) the marketplace, (c) the cave or den, and (d) the theater; or, less metaphorically, (a) standing erroneous methods (or at least temptations to error) that have their roots in human nature generally; (b) those that come from intercourse and language; (c) those that are due to causes peculiar to a specific individual; and finally, (d) those that have their sources in the fashion or general current of a period. Classifying these causes of fallacious belief somewhat differently, we may say that two are intrinsic and two are extrinsic. Of the intrinsic, one is common to all men alike (such as the universal tendency to notice instances that corroborate a favorite belief more readily than those that contradict it), while the other resides in the specific temperament and habits of the given individual. Of the extrinsic, one proceeds from generic social conditions—like the tendency to suppose that there is a fact wherever there is a word, and no fact where there is no linguistic term—while the other proceeds from local and temporary social currents.

It is instructive to look at some attempts to classify the main sources of error in forming beliefs. For example, Francis Bacon listed four such classes at the beginning of modern scientific inquiry. He gave them the somewhat fanciful title of "idols" (Gr. ειδωλα, images). These idols were ghostly forms that lure the mind down false paths. He called them the idols, or phantoms, of the (a) tribe, (b) marketplace, (c) cave or den, and (d) theater. In less metaphorical terms, these are: (a) persistent errors in reasoning, or at least temptations to error, rooted in human nature generally; (b) errors arising from communication and language; (c) errors caused by things peculiar to an individual; and (d) errors originating in the fashion or general current of a period. We can classify these causes of mistaken beliefs somewhat differently. Two are intrinsic, and two are extrinsic. Of the intrinsic causes, one is common to all people alike. An example is the universal tendency to notice instances that support a favorite belief more readily than those that contradict it. The other intrinsic cause lies in the particular temperament and habits of an individual. Of the extrinsic causes, one comes from general social conditions. An example is the tendency to suppose that wherever there is a word, there is a corresponding fact, and that where there is no word, there is no corresponding fact. The other extrinsic cause comes from local and temporary social currents.

Locke's method of dealing with typical forms of wrong belief is less formal and may be more enlightening. We can hardly do better than quote his forcible and quaint language, when, enumerating different classes of men, he shows different ways in which thought goes wrong:

Locke's approach to common forms of mistaken belief is less formal and may be more enlightening. We can hardly do better than quote his forceful and quaint words. In describing different groups of men, he shows the different ways thinking goes wrong:

1. "The first is of those who seldom reason at all, but do and think according to the example of others, whether parents, neighbors, ministers, or who else they are pleased to make choice of to have an implicit faith in, for the saving of themselves the pains and troubles of thinking and examining for themselves."

1. "The first group consists of people who seldom reason at all. Instead, they act and think by following others' examples. They may follow their parents, neighbors, ministers, or anyone else they choose to trust unquestioningly. This saves them the pain and trouble of thinking and examining things for themselves."

2. "This kind is of those who put passion in the place of reason, and being resolved that shall govern their actions and arguments, neither use their own, nor hearken to other people's reason, any farther than it suits their humor, interest, or party."⁵

2. "This group consists of people who put passion in place of reason. They are determined to let passion govern their actions and arguments. They use their own reason or listen to other people's reason only when it suits their mood, interests, or party."⁵

3. "The third sort is of those who readily and sincerely follow reason, but for want of having that which one may call large, sound, roundabout sense, have not a full view of all that relates to the question.... They converse but with one sort of men, they read but one sort of books, they will not come in the hearing but of one sort of notions.... They have a pretty traffic with known correspondents in some little creek ... but will not venture out into the great ocean of knowledge." Men of originally equal natural parts may finally arrive at very different stores of knowledge and truth, "when all the odds between them has been the different scope that has been given to their understandings to range in, for the gathering up of information and furnishing their heads with ideas and notions and observations, whereon to employ their mind."⁶

3. "The third group consists of people who readily and sincerely follow reason. But they lack what might be called broad, sound, well-rounded judgment. So they do not see everything relevant to the question.... They talk with only one kind of person, and read only one kind of book. They will listen to only one kind of idea.... They do a fair amount of trading with familiar contacts in some little creek ... but will not venture out into the great ocean of knowledge." People who begin with equal natural abilities may eventually gain very different stores of knowledge and truth. The only difference between them may have been "how much freedom they gave their minds to range. This freedom let them gather information and fill their heads with ideas, notions, and observations to think about."⁶

In another portion of his writings,⁷ Locke states the same ideas in slightly different form.

In another part of his writings,⁷ Locke expresses the same ideas in a slightly different way.

1. "That which is inconsistent with our principles is so far from passing for probable with us that it will not be allowed possible. The reverence borne to these principles is so great, and their authority so paramount to all other, that the testimony, not only of other men, but the evidence of our own senses are often rejected, when they offer to vouch anything contrary to these established rules.... There is nothing more ordinary than children's receiving into their minds propositions ... from their parents, nurses, or those about them; which being insinuated in their unwary as well as unbiased understandings, and fastened by degrees, are at last (and this whether true or false) riveted there by long custom and education, beyond all possibility of being pulled out again. For men, when they are grown up, reflecting upon their opinions and finding those of this sort to be as ancient in their minds as their very memories, not having observed their early insinuation, nor by what means they got them, they are apt to reverence them as sacred things, and not to suffer them to be profaned, touched, or questioned." They take them as standards "to be the great and unerring deciders of truth and falsehood, and the judges to which they are to appeal in all manner of controversies."

1. "When something contradicts our principles, we do not merely think it improbable. We will not even admit that it is possible. We respect these principles so deeply and give them authority over everything else. As a result, we often reject other people's testimony and even the evidence of our own senses. We reject them when they offer support for anything contrary to these established rules.... Nothing is more common than children accepting ideas ... from their parents, nurses, or others around them. These ideas are planted in minds that are unsuspecting and free from bias. They take hold gradually, and long habit and education finally fix them there beyond any possibility of removal. This happens whether the ideas are true or false. When people grow up, they reflect on their opinions. They find that these ideas have been in their minds for as long as they can remember. They did not notice how the ideas were planted early on or how they acquired them. So they tend to revere them as sacred and will not allow anyone to profane, touch, or question them." They take these ideas as standards "that decide truth and falsehood without error and judge all kinds of disputes."

2. "Secondly, next to these are men whose understandings are cast into a mold, and fashioned just to the size of a received hypothesis." Such men, Locke goes on to say, while not denying the existence of facts and evidence, cannot be convinced by the evidence that would decide them if their minds were not so closed by adherence to fixed belief.

2. "Second, next come men whose minds have been shaped to fit an accepted hypothesis." Locke goes on to say that these men do not deny that facts and evidence exist. Yet their fixed beliefs close their minds. As a result, evidence that would otherwise convince them cannot do so.

3. "Predominant Passions. Thirdly, probabilities which cross men's appetites and prevailing passions run the same fate. Let ever so much probability hang on one side of a covetous man's reasoning, and money on the other, it is easy to foresee which will outweigh. Earthly minds, like mud walls, resist the strongest batteries.

3. "Dominant Passions. Third, evidence that goes against people's desires and dominant passions meets the same fate. No matter how much evidence favors one side of a greedy person's reasoning, money favors the other. It is easy to predict which will outweigh the other. Earthly minds, like mud walls, resist the strongest attacks.

4. "Authority. The fourth and last wrong measure of probability I shall take notice of, and which keeps in ignorance or error more people than all the others together, is the giving up our assent to the common received opinions, either of our friends or party, neighborhood or country."

4. "Authority. The fourth and last false measure of probability I will mention is accepting commonly held opinions without question. These may be the opinions of our friends, our party, our neighborhood, or our country. This false measure keeps more people in ignorance or error than all the others combined."

Both Bacon and Locke make it evident that over and above the sources of misbelief that reside in the natural tendencies of the individual (like those toward hasty and too far-reaching conclusions), social conditions tend to instigate and confirm wrong habits of thinking by authority, by conscious instruction, and by the even more insidious half-conscious influences of language, imitation, sympathy, and suggestion. Education has accordingly not only to safeguard an individual against the besetting erroneous tendencies of his own mind—its rashness, presumption, and preference of what chimes with self-interest to objective evidence—but also to undermine and destroy the accumulated and self-perpetuating prejudices of long ages. When social life in general has become more reasonable, more imbued with rational conviction, and less moved by stiff authority and blind passion, educational agencies may be more positive and constructive than at present, for they will work in harmony with the educative influence exercised willy-nilly by other social surroundings upon an individual's habits of thought and belief. At present, the work of teaching must not only transform natural tendencies into trained habits of thought, but must also fortify the mind against irrational tendencies current in the social environment, and help displace erroneous habits already produced.

Both Bacon and Locke make it clear that false beliefs arise partly from natural tendencies in individuals. These include the tendency to jump to conclusions that go too far. But social conditions also encourage and reinforce bad habits of thought. They do so through authority and deliberate instruction. They also do so through the even more subtle, half conscious influences of language, imitation, sympathy, and suggestion. Education must therefore protect individuals against the persistent errors their own minds tend to make. These include rashness, presumption, and the preference for what suits their self interest over objective evidence. Education must also undermine and destroy the accumulated, self perpetuating prejudices of many ages. When social life in general has become more reasonable and guided more by reasoned conviction, educational agencies may work more positively and constructively than they do now. Social life must also become less driven by rigid authority and blind passion. Educational agencies will then work in harmony with the influence that other social surroundings inevitably have on an individual's habits of thought and belief. At present, teaching must not only turn natural tendencies into trained habits of thought. It must also strengthen the mind against irrational tendencies common in the social environment and help replace erroneous habits already formed.

Thinking is important because, as we have seen, it is that function in which given or ascertained facts stand for or indicate others which are not directly ascertained. But the process of reaching the absent from the present is peculiarly exposed to error; it is liable to be influenced by almost any number of unseen and unconsidered causes,—past experience, received dogmas, the stirring of self-interest, the arousing of passion, sheer mental laziness, a social environment steeped in biased traditions or animated by false expectations, and so on. The exercise of thought is, in the literal sense of that word, inference; by it one thing carries us over to the idea of, and belief in, another thing. It involves a jump, a leap, a going beyond what is surely known to something else accepted on its warrant. Unless one is an idiot, one simply cannot help having all things and events suggest other things not actually present, nor can one help a tendency to believe in the latter on the basis of the former. The very inevitableness of the jump, the leap, to something unknown, only emphasizes the necessity of attention to the conditions under which it occurs so that the danger of a false step may be lessened and the probability of a right landing increased.

Thinking is important because, as we have seen, known or established facts point to other facts not directly established. But the process of reaching what is absent from what is present is especially open to error. Almost any number of unseen and unconsidered causes can influence it. These include past experience, accepted beliefs, self-interest, passion, sheer mental laziness, and the social environment. That environment may be steeped in biased traditions or driven by false expectations, and so on. Thinking is, in the literal sense, inference. Through inference, one thing carries us over to the idea of another thing and to belief in it. Thinking involves a jump, a leap beyond what is surely known to something else accepted on its authority. Unless a person is an idiot, things and events inevitably suggest other things not actually present. A person also cannot help tending to believe in those other things on the basis of what is present. Because the leap to something unknown is inevitable, we must pay attention to the conditions under which it occurs. That way, we can reduce the danger of a false step and increase the chance of a sound landing.

Such attention consists in regulation (1) of the conditions under which the function of suggestion takes place, and (2) of the conditions under which credence is yielded to the suggestions that occur. Inference controlled in these two ways (the study of which in detail constitutes one of the chief objects of this book) forms proof. To prove a thing means primarily to try, to test it. The guest bidden to the wedding feast excused himself because he had to prove his oxen. Exceptions are said to prove a rule; i.e. they furnish instances so extreme that they try in the severest fashion its applicability; if the rule will stand such a test, there is no good reason for further doubting it. Not until a thing has been tried—"tried out," in colloquial language—do we know its true worth. Till then it may be pretense, a bluff. But the thing that has come out victorious in a test or trial of strength carries its credentials with it; it is approved, because it has been proved. Its value is clearly evinced, shown, i.e. demonstrated. So it is with inferences. The mere fact that inference in general is an invaluable function does not guarantee, nor does it even help out the correctness of any particular inference. Any inference may go astray; and as we have seen, there are standing influences ever ready to assist its going wrong. What is important, is that every inference shall be a tested inference; or (since often this is not possible) that we shall discriminate between beliefs that rest upon tested evidence and those that do not, and shall be accordingly on our guard as to the kind and degree of assent yielded.

Such attention involves managing two things: (1) the conditions under which suggestions occur, and (2) the conditions under which we accept them as true. Inference controlled in these two ways forms proof. Studying this control in detail is one of the chief aims of this book. To prove something means, first of all, to try or test it. A guest invited to a wedding feast excused himself because he had to prove his oxen. Exceptions are said to prove a rule, meaning that they test its applicability with extreme cases. If the rule can stand such a severe test, there is no good reason to doubt it further. We do not know a thing’s true worth until it has been tried, or "tried out," in everyday language. Until then, it may be a pretense or a bluff. But a thing that has come through a test or trial of strength successfully carries its credentials with it. It is approved because it has been proved. Its value has been clearly shown, or demonstrated. The same is true of inferences. The fact that inference in general is invaluable does not guarantee that any particular inference is correct. It does not even make that inference any more likely to be correct. Any inference may go wrong. As we have seen, there are constant influences ready to help it go wrong. What matters is that every inference should be tested, or, since this is often impossible, that we distinguish beliefs based on tested evidence from those that are not. We should then be careful about how, and how far, we accept each kind of belief.

While it is not the business of education to prove every statement made, any more than to teach every possible item of information, it is its business to cultivate deep-seated and effective habits of discriminating tested beliefs from mere assertions, guesses, and opinions; to develop a lively, sincere, and open-minded preference for conclusions that are properly grounded, and to ingrain into the individual's working habits methods of inquiry and reasoning appropriate to the various problems that present themselves. No matter how much an individual knows as a matter of hearsay and information, if he has not attitudes and habits of this sort, he is not intellectually educated. He lacks the rudiments of mental discipline. And since these habits are not a gift of nature (no matter how strong the aptitude for acquiring them); since, moreover, the casual circumstances of the natural and social environment are not enough to compel their acquisition, the main office of education is to supply conditions that make for their cultivation. The formation of these habits is the Training of Mind.

Education is not responsible for proving every statement, any more than it is responsible for teaching every possible fact. But education is responsible for cultivating deep-rooted, effective habits of distinguishing tested beliefs from mere assertions, guesses, and opinions. It must develop an active, sincere, and open-minded preference for well-grounded conclusions. It must also make methods of inquiry and reasoning suited to different problems part of a person's everyday habits. No matter how much people know from hearsay and information, they are not intellectually educated without such attitudes and habits. They lack the basics of mental discipline. These habits are not a gift of nature, no matter how strong a person's natural ability to acquire them. Nor are the ordinary circumstances of the natural and social environment enough to ensure that people acquire them. The main role of education is therefore to provide conditions that encourage their development. Forming these habits is the Training of Mind.