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.
General causes of bad thinking: Bacon's "idols"
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.
Locke on the influence of
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:
(a) dependence on others,
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."
(b) self-interest,
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
(c) circumscribed experience
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
In another portion of his writings,7 Locke states the same ideas in slightly different form.
Effect of dogmatic principles,
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."
of closed minds,
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.
of strong passion,
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.
of dependence upon authority of others
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."
Causes of bad mental habits are social as well as inborn
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.
§ 4. Regulation Transforms Inference into Proof
A leap is involved in all thinking
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