Instead of trying to fit all unusual, contradictory, or exceptional facts into _a priori_ ideas based on miscellaneous and unsifted facts, it starts without any _fixed_ conclusions beforehand, but carefully observes all the facts which it can secure with reference to a particular problem, deliberately seeking the exceptional and unusual as crucial instances. Thus in a sociological inquiry, the scientist, instead of accepting "common-sense" judgments (based on a variety of miscellaneous, incomplete, and unsifted facts) that certain races are inferior or superior, tries, by specific inquiries, to establish the facts of racial capacities or defects. Instead of accepting proverbial wisdom and popular estimates of the relative capacities of men and women, he tries by careful observation and experiment accurately to discover all the facts bearing on the question, and to generalize from those facts.

Scientific method thus discounts prejudice or dogmatism.

A prejudice is literally a pre-judgment. Common sense sizes up the situation beforehand. Instead of examining a situation in its own terms, and _arriving_ at a conclusion, it _starts_ with one. The so-called hard-headed man of common sense _knows_ beforehand. He has a definite and stereotyped reaction for every situation with which he comes in contact.

These rubber-stamp responses, these unconsidered generalizations, originate in instinctive desires, or in preferences acquired through habit. Common sense finds fixed pigeon holes into which to fit all the variety of specific circ.u.mstances and conditions which characterize experience. "When its judgments happen to be correct, it is almost as much a matter of good luck as of method.... That potatoes should be planted only during the crescent moon, that near the sea people are born at high tide and die at low tide, that a comet is an omen of danger, that bad luck follows the cracking of a mirror," all these are the results of common-sense observation.

Matters of common knowledge are thus not infrequently matters of common misinformation.

Common-sense knowledge is largely a matter of uncritical belief. When there is absent scientific examination of the sources and grounds of belief, those judgments and conclusions are likely to be accepted which happen to have wide social currency and authority. In an earlier chapter, it was shown how the mere fact of an opinion prevailing among a large number of one's group or cla.s.s gives it great emotional weight. Where opinions are not determined by intelligent examination and decision, they are determined by force of habit, early education, and the social influences to which one is constantly exposed.

The scientific spirit is a spirit of emanc.i.p.ated inquiry as contrasted with blind acceptance of belief upon authority.

The phenomenal developments of modern science began when men ceased to accept authoritatively their beliefs about man and nature, and undertook to examine phenomena in their own terms. The phenomenal rise of modern science is coincident with the collapse of unquestioning faith as the leading ingredient of intellectual life.

Common sense renders men peculiarly insensitive to the possibilities of the novel, peculiarly susceptible to the influence of tradition. It was common sense that credited the influence of the position of the stars upon men's welfare, the power of old women as witches, and the unhealthiness of night air. It was common sense also that ridiculed Fulton's steamboat, laughed at the early attempts of telegraphy and telephony, and dismissed the aeroplane as an interesting toy. The characteristic feature of common sense or empirical thinking is its excess traditionalism, its wholesale acceptance of authority,[1]

its reliance upon precedent. Where beliefs are not subjected to critical revision and examination, to the constant surveillance of the inquiring intelligence, there will be no criterion by which to estimate the true and the false, the important and the trivial. All beliefs that have wide social sanction, or that chime in with immediate sense impressions, established individual habits, or social customs will be accepted with the same indiscriminate hospitality. To common sense the sun _does_ appear to go round the earth; the stick _does_ appear broken in water. Thus "totally false opinions may appear to the holder of them to possess all the character of rationally verifiable truth."

[Footnote 1: "Authority" in this sense of social prestige must be distinguished from "authority" in the sense of scientific authority. The acceptance of the authority of the expert is the acceptance of opinions that we have good reason to believe are the result of scientific inquiry.]

The dangers and falsities of common-sense judgments are conditioned not only by expectations and standards fixed by the social environment, but by one's own personal predilections and aversions. Recent developments in psychology have made much of the fact that many of our so-called reasoned judgments are rationalizations, secondary reasons found after our initial, primary, and deep-seated emotional responses have been made. They are the result of emotional "complexes," fears, expectations, and desires of which we are not ourselves conscious.[1] It is from these limiting conditions of personal preference and social environment that scientific method frees us.

[Footnote 1: "When a party politician is called upon to consider a new measure, his verdict is largely determined by certain constant systems of ideas and trends of thought, const.i.tuting what is generally known as 'party bias.' We should describe these systems in our newly acquired terminology as his 'political complex.' The complex causes him to take up an att.i.tude toward the proposed measure which is quite independent of any absolute merits that the latter may possess. If we argue with our politician, we shall find that the complex will reinforce in his mind those arguments which support the view of his party, while it will infallibly prevent him from realizing the force of the arguments propounded by the opposite side. Now, it should be observed that the individual himself is probably quite unaware of this mechanism in his mind. He fondly imagines that his opinion is formed solely by the logical pros and cons of the measure before him. We see, in fact, that not only is his thinking determined by a complex of whose action he is unconscious, but that he believes his thoughts to be the result of other causes which are in reality insufficient and illusory. This latter process of self-deception, in which the individual conceals the real foundation of his thought by a series of advent.i.tious props, is termed 'rationalization.'

"The two mechanisms which manifest themselves in our example of the politician, the unconscious origin of beliefs and actions, and the subsequent process of rationalization to which they are subjected, are of fundamental importance in psychology."

(Bernard Hart: _The Psychology of Insanity_, pp. 64-66.)]

Again, even where common-sense judgments are not particularly qualified by such conditions, they are frequently based upon the observation of purely accidental conjunctions of circ.u.mstances. A sequence once or twice observed is taken as the basis of a causal relation. This gives rise to what is known in technical logic as the _post hoc ergo propter hoc_ fallacy; that is, the a.s.sumption that because one thing happens after another, therefore it happens _because_ of it. Many superst.i.tions probably had their origin in such chance observations, and belief in them is strengthened by some accidental confirmation. Thus if a man walks under a ladder one day and dies the next, the believer in the superst.i.tion that walking under a ladder brings fatal results will find in this instance a clear ratification of his belief. There seems to be an inveterate human tendency to seek for causes, and by those who are not scientific inquirers causes are lightly a.s.signed. It is easiest and most plausible to a.s.sign as a cause an immediately preceding circ.u.mstance. Exceptional or contradictory circ.u.mstances are then either unnoticed or pared down to fit the belief.

Scientific method does not depend on such chance conjunctions of circ.u.mstance, but controls its observations or experimentally arranges conditions so as to discover what are the conditions necessary to produce given effects, or what effects invariably follow from given causes. It does not accept a chance conjunction as evidence of an invariable relation, but seeks, under regulated conditions, to discover what the genuinely invariable relations are. This method of controlling our generalizations about the facts of experience, we shall presently examine in some detail.

CURIOSITY AND SCIENTIFIC INQUIRY. Curiosity, the instinctive basis of the desire to know, is the basis of scientific inquiry.

Without this fundamental desire, there could be no sustaining motive to deep and thoroughgoing scientific research, for theoretical investigations do not always give promise of immediate practical benefits. The scientific interest is a development of that restless curiosity for a knowledge of the world in which they are living which children so markedly exhibit.

Beginning as a kind of miscellaneous and omnivorous appet.i.te for facts of whatever description, it grows into a desire to understand the unsuspected and hidden relations between facts, to penetrate to the unities discoverable beneath the mysteries and multiplicities of things.

The scientific mood is thus in the first place a sheer instinctive curiosity, a basic pa.s.sion for facts. It is this which sustains the scientific worker in the sometimes long and dreary business of collecting specimens, instances, details. Many of the most notable scientific advances, as Lord Kelvin pointed out, must be attributed to the most protracted and unmitigated drudgery in the collection of facts, a thoroughgoing and trying labor in which the scientific worker could persist only when fortified by an eager and insistent curiosity. This "hodman's work" is the basis of the great generalizations which const.i.tute the framework of the modern scientific systems. "The monotonous and quant.i.tative work of star-cataloguing has been continued from Hipparchus, who began his work more than a century before Christ, work which is continued even to the present day. This work, uninspiring as it seems, is yet an essential basis for the applications of astronomy, the determination of time, navigation, surveying.

Furthermore, without good star places, we can have no theory of the motions of the solar system, and without accurate catalogues of the stars we can know nothing of the grander problems of the universe, the motion of our sun among the stars, or of the stars among themselves."[1]

[Footnote 1: Hinks: _Astronomy_, p. 162.]

Not only is curiosity a sustaining motive in the drudgery of collection and research incident and essential to scientific generalization; it alone makes possible that suspense of judgment which is necessary to fruitful scientific inquiry. This suspense is, as we have already seen, difficult for most men.

Action demands immediate decision, and inquiry deliberately postpones decision. It is only a persistent desire to "get at the bottom of the matter" that will act as a check upon the demands of social life and of individual impatience which rush us to conclusions. In most men, as earlier noted, the sharp edge of curiosity becomes easily blunted. They are content, outside their own immediate personal interests, "to take things for granted." They glide over the surfaces of events, they cease to query the authenticity of facts, or to examine their relevance and their significance, or to be concerned about their completeness. For an example, one has but to listen to or partake in the average discussion of any political or social issue of the present day. There are few men who retain, even as far as middle life, a genuinely inquiring interest in men and affairs. Their curiosity is dulled by fatigue and the pressure of their own interests and preoccupations, and they allow their prejudices and formulas to pa.s.s for judgments and conclusions.

The scientist is the man in whom curiosity has become a permanent pa.s.sion, who, as long as he lives, is unwilling to forego inquiry into the processes of Nature, or of human relations.

THINKING BEGINS WITH A PROBLEM. While the general habit of inquiry is developed in the satisfaction of the instinct of curiosity, any particular investigation begins with a felt difficulty. By difficulty is not meant one of an imperative and practical kind, but any problem whether theoretical or practical. For many men, it is true, thinking occurs only when instinct and habit are inadequate to adjust them to their environment. Any problem of daily life affords an example. To borrow an ill.u.s.tration from Professor Dewey:

A man traveling in an unfamiliar region comes to a branching of the roads. Having no sure knowledge to fall back upon, he is brought to a standstill of hesitation and suspense. Which road is right? And how shall the perplexity be resolved? There are but two alternatives. He must either blindly and arbitrarily take his course, trusting to luck for the outcome, or he must discover grounds for the conclusion that a given road is right.[1]

[Footnote l: Dewey: _How We Think_, p. 10.]

To the inquiring mind, purely theoretical difficulties or discrepancies will provoke thought. To the astronomer an unaccounted-for perturbation in the path of a planet provokes inquiry; the chemist is challenged by a curious unexplained reaction of two chemical elements, the biologist, anterior to the discovery of micro-organisms, by the putrefaction of animal tissues. The degree to which curiosity persists and the extent of training a man has had in a given field largely determine the kind of situations that will provoke inquiry.

"A primrose by the river's brim" may be simply a primrose to one man, while to another, a botanist, it may suggest an interesting and complex problem of cla.s.sification.

But however remote and recondite thinking becomes, however far removed from immediate practical concerns, it occurs essentially in a situation a.n.a.logous to the "forked-road situation"

described above. The situation as it stands is confused, ambiguous, uncertain. In a practical problem, for example, there are two or more courses of action open to us, all of them giving promise as solutions of our difficulties. We aim through reflection to reduce the uncertainty, to clarify the situation, to discover more clearly the consequences of the various alternatives which suggest themselves to us. When action is unimpeded, suggestions flow on just as they arise in our minds. This is ill.u.s.trated best in the reveries of a day-dream when casual and disconnected fancies follow each other in random and uncontrolled succession. But when there is a problem to be settled, an ambiguity to be resolved, suggestions are held in check and controlled with reference to the end we have in view; each suggestion is estimated with regard to its relevance to the problem in hand. Every idea that arises is, so to speak, queried: "Is it or is it not a solution to our present difficulty?"

We are indebted to Professor Dewey, for an a.n.a.lysis of the thought process. Every instance of thinking reveals five steps:

(1) A felt difficulty, (2) its location and definition, (3) suggestions of possible solutions, (4) development by reasoning of the bearings of the most promising suggestion, (5) further observation or experiment leading to its acceptance or rejection, that is a conclusion either of belief or disbelief.

When instinct or habit suffices to adjust us to our environment, action runs along smoothly, freely, uninterruptedly. In consequence the provocation to thinking may at first be a mere vague shock or disturbance. We are, as it were, in trouble without knowing precisely what the trouble is. We must carefully inquire into the nature of the problem before undertaking a solution. To take a simple instance, an automobile may suddenly stop. We know there is a difficulty, but whether it is a difficulty with the transmission, with the carburetor, or with the supply of gasoline, we cannot at first tell. Before we do anything else in solving our problem, we find out literally and precisely _what the trouble is_. To take a different situation, a doctor does not undertake to prescribe for a patient until he has diagnosed the difficulty, found out precisely what the features of the problem are.

The second step after the situation has been examined and its precise elements defined, is _suggestion_. That is, we consider the various possibilities which _suggest_ themselves as solutions to our problem. There may be several ways of temporarily repairing our engine; the doctor may think of two or three possible treatments for a disease. In one sense, suggestion is uncontrollable. The kind of suggestions that occur to an individual depend on his "genius or temperament," on his past experiences, on his hopes or fears or expectations when that particular situation occurs. We can, however, through the methods of science, control suggestions indirectly. We can do this, in the first place, by reexamining the facts which give rise to suggestion. If upon close examination, the facts appear differently from what they did at first, we will derive different inferences from them. Different suggestions will arise from the facts _A, B, C_, than from the facts _A', B', C'_.

Again we can regulate the conditions under which credence is given to the various suggestions that arise. These suggestions are entertained merely as tentative, and are not accepted until experimentally verified. "The suggested conclusion as only tentatively entertained const.i.tutes an idea."

After the variety of suggestions that proffer themselves as solutions to a problem have been considered, the third step is the logical development of the idea or suggestion that gives most promise of solving the difficulty. That is, even before further facts are sought, the idea that gives promise of being a solution is followed out to its logical consequences. Thus, for example, astronomers were for a long time puzzled by unexplained perturbations in the path of the planet Ura.n.u.s. The suggestion occurred that an unseen planet was deflecting it from the path it should, from observation and calculation, be following. If this were the case, from the amount of deflection it was mathematically calculated, prior to any further observation, that the supposed planet should appear at a certain point in s.p.a.ce. It was by this deductive elaboration that the planet Neptune was discovered. It was figured out deductively that a planet deflecting the path of the planet Ura.n.u.s by just so-and-so much should be found at just such and such a particular point in the heavens. When the telescopes were turned in that direction, the planet Neptune was discovered at precisely the point deductively forecast.

The elaboration of an idea through reasoning it out may sometimes lead to its rejection. But in thinking out its details we may for the first time note its appositeness to the solution of the problem in hand. The gross suggestion may seem wild and absurd, but when its bearings and consequences are logically developed there may be some item in the development which dovetails into the problem as its solution. William James gives as the outstanding feature of reasoning, "sagacity, or the perception of the essence."[1] By this he meant the ability to single out of a complex situation or idea the significant or key feature. It is only by a logical development of a suggested solution to a problem that it is possible to hit upon the essence of the matter for a particular situation, to single out of a gross total situation, the key to the phenomenon. "In reasoning, _A_ may suggest _B_; but _B_, instead of being an idea which is simply _obeyed_ by us, is an idea which suggests the distinct additional idea _C_. And where the train of suggestion is one of reasoning distinctively so-called as contrasted with mere 'revery,' ... the ideas bear certain inward relations to each other which we must carefully examine. The result _C_ yielded by a true act of reasoning is apt to be a thing voluntarily _sought_, such as the means to a proposed end, the ground for an observed effect, or the effect of an a.s.sumed cause."[2] Thus what at first sight might seem a fantastic suggestion may, when its bearings are logically followed out, be seen in one of its aspects to be the key to the solution of a problem. To primitive man it might have seemed absurd to suggest that flowing water might be used as power; to the man in Franklin's day that the same force that was exhibited in the lightning might be used in transportation and in lighting houses.[1]

[Footnote 1: James: _Psychology_, vol. II, p. 343.]

[Footnote 2: _Ibid._, p. 329.]

[Footnote 1: James gives an illuminating pa.s.sage on the importance of the effectiveness of _reasoning_ things out: "I have a student's lamp, of which the flame vibrates most unpleasantly unless the collar which bears the chimney be raised about a sixteenth of an inch. I learned the remedy after much torment by accident, and now always keep the collar up with a small wedge. But my procedure is a mere a.s.sociation of two totals, diseased object and remedy.

One learned in pneumatics could have named the _cause_ of the disease, and thence inferred the remedy immediately. By many measurements of triangles, one might find their area always equal to their height multiplied by half their base, and one might formulate an empirical law to that effect. But a reasoner saves himself all this trouble, by seeing that it is the essence (_pro hac vice_) of a triangle to be the half of a parallelogram whose area is the height into the entire base. To see this he must invent additional lines; and the geometer must often draw such to get at the essential properties he may require in a figure. The essence consists in some _relation of the figure to the new lines_, a relation not obvious at all until they are put in. The geometer's sagacity lies in the invention of the new lines." (_Psychology_, vol. II, pp. 339-40.)]

But no thinking is conclusive until after the experimental certification and warranting of the idea which has been held in mind as the solution of the problem. By deduction, by logical elaboration of an idea, we find its adoption involves certain consequences. Some of the logical consequences which follow from an idea may indicate that it is a plausible solution of our problem. But no matter how plausible a suggestion looks, until it is verified by observation or experiment the thinking process is not concluded, is not finished, as we say, _conclusively_. When an idea or a suggestion has been developed, and seen to involve--as an idea--certain inevitable logical consequences, the idea must be tested by further observation and experiment. Suggestions arise _from_ facts and must be tested _by_ them. Until the suggestion is verified, it remains merely a suggestion, a theory, a hypothesis, an idea. It is only when the consequences implied logically in the very idea itself are found in the actual situation that the idea is accepted as a solution to the problem. Sometimes the suggestion may be verified by observation; sometimes conditions must be deliberately arranged for testing its adequacy. In either case it is only when the facts of the situation correspond to the conditions theoretically involved that the tentative idea is accepted as a conclusion.

Thus a treatment that is regarded by the doctor as a possible cure can be called an actual cure only when its beneficent results are observed. The supposition about the planet Neptune is only verified when the planet is actually observed in the heavens. Thinking ends, as it begins, in observation.

At the beginning the facts are carefully examined to see precisely where the difficulty lies; at the end they are again examined to see whether an idea, an entertained hypothesis, a suggested solution, can be verified in actual observable results.

THE QUALITY OF THINKING--SUGGESTION. The quality of thinking varies, first, with the fertility of suggestion of the a.n.a.lyzing mind. Ease of suggestion, in the first place, depends on innate individual differences. There are some minds so const.i.tuted that every fact provokes a mult.i.tude of suggestions.

Readiness in responding with "ideas" to any experience is dependent primarily on initial differences in resilience and responsiveness. But differences in training and past experience are also contributory. A man who has much experience in a given field, say in automobile repairing, will, given a difficulty, not only think of more suggestions, but think more rapidly in that field.

Again persons differ in range or number of suggestions that occur. The quality of the thinking process and of the results it produces depends, in part, on the variety of suggestions which occur to an individual in the solution of a given problem. If too few suggestions occur one may fail to hit upon any promising solution. If too many suggestions occur one may be too confused to arrive at any conclusion at all. Whether an individual has few or many suggestions depends largely on native differences. It depends, also, however in part, on acquaintance with a given field. And the fertility of suggestions may be increased by a careful survey and re-survey of the facts at hand, and by the deliberate searching-out of further facts from which further suggestions may be derived.

Suggestions differ, finally, in regard to depth or significance; by nature and by training, individuals produce ideas of varying degrees of significance in the solution of problems. Ease and versatility of suggestion not infrequently connote superficiality; to make profound and far-reaching suggestions takes time.

It is further requisite, as already pointed out, that the a.n.a.lyzing mind be free from prejudice. Thinking is continually qualified, as we have seen, by preferences and aversions.

Every prejudice, every _a priori_ belief we have, literally prejudges the inquiry. Whenever we are moved by a "predominant pa.s.sion," we cannot survey the facts impartially.

It is hard to think clearly and justly about people whom we love or hate, or to estimate with precision the morality of actions toward which we are moved by very strong impulses.

It is only the mind that remains resolutely emanc.i.p.ated from the compulsions of habit and circ.u.mstances, that persists in surveying facts as they are, letting the chips, so to speak, fall where they will, that can be really effective in thinking. In the physical sciences it is comparatively easy to start with no prejudices; in social inquiries where we are bound by traditions, loyalties, and antipathies it is much more difficult.

Not the least essential to effective thinking is persistence and thoroughness of investigation. Since we are primarily creatures of action, we crave definiteness and immediacy of decision, and there is a constant temptation to rush to a conclusion. In order to attain genuine completeness of the facts and certainty and accuracy as to what the facts are, long, unwavering persistence is required. There must be persistence, moreover, not merely because of the length of time and the amount of labor involved in the collection of data; steadiness is required in holding in mind the end or purpose of the investigation.

Too often in inquiry into the facts of human relations, the specific problem is forgotten and facts are collected with an indiscriminate omnivorousness. There is in such cases plodding, but of an unenlightened and fruitless sort.

Not only _persistency_ but _consistency_ is required. The investigation must be steadily carried on with persistent and unwavering reference to the specific business in hand.

Effective thinking depends further on familiarity with the field of facts under investigation. Even the most ready and fertile of minds, the most orderly habits of thought, are at a loss without a store of material; that is, facts from which suggestions may arise. And this store of materials can only be attained through a thoroughgoing acquaintance with the particular field of inquiry. Thinking aims to explain the relations between facts, and an intimate acquaintance with facts involved in a given situation is prerequisite to any generalization whatsoever.

While the native fertility of given minds cannot be controlled, suggestions can be controlled indirectly. Suggestions arise from the data at hand, but the data themselves change under more precise conditions of observation, and the suggestions that arise from them change in consequence. The whole elaborate apparatus of science, its instruments of precision, are designed to yield an exact determination of the precise nature of the data at hand. The scientist attempts to prevent "reading-in" of meanings. "Reading-in" of meanings may be due to various causes. In the first place there may be purely physical causes: a dim light, a fog, a cracked window-pane are examples of how ordinary observation may lead us astray. Again, physiological causes may be at work to distort sensations: imperfection's in the sense organs, fatigue, illness, and the like are examples. But not least among the causes of error must be set psychological causes. That is, we read facts differently in the light of what we fear or hope, like or dislike, expect or recall. We see things the way we want them to be, or the way previous experience has taught us to expect them to be.

Both physiological and psychological causes may be checked up by instruments. Indeed, one of the chief utilities of instruments of precision is that they do serve to check up personal error. They prevent scientific inquirers from reading in meanings to which they are led by hope, fear, preference, or aversion. They help us to see the facts as they are, not as for various social and personal reasons we want or expect them to be. They help to give precise and permanent impressions which are not dependent for their discovery or for their preservation on the precariousness of human observation or memory.

CLa.s.sIFICATION. Next only in importance to accurate observation of the facts is their cla.s.sification. Objects of experience as they come to us through the senses appear in a sequence which is random and chaotic. But in order to deal effectively with our experience we must arrange facts according to their likenesses and differences. Whenever we discover certain striking similarities between facts, we cla.s.sify them, place them in a cla.s.s, knowing that what will apply to one will apply to all. Some logicians go so far as to say that science cannot go any further than accurate cla.s.sification.