Chapter XIV: Science and Scientific Method (1)

WHAT SCIENCE IS. Science may be considered either as the product of a certain type of human activity, or as a human activity satisfactory even apart from its fruits. As an activity, it is a highly refined form of that process of reflection by which man is, in the first place, enabled to make himself at home in the world. It differs from the ordinary or common-sense process of thinking, as we shall presently see, in being more thoroughgoing, systematic, and sustained. It is common sense of a most extraordinarily refined and penetrating kind. But before examining the procedure of science, we must consider briefly its imposing product, that science whose vast structure seems to the layman so final, imposing, and irrefragable.

From the point of view of the product which is the fruit of reflective activity, Science may be defined as _a body of systematized and verified knowledge, expressing in general terms the relations of exactly defined phenomena._ In all the respects here noted, science may be contrasted with those matters of _common knowledge_, of _opinion_ or _belief_ which are the fruit of our casual daily thinking and experience. Science is, in the first place, a body of _systematized_ knowledge. One has but to contrast the presentation of facts in an ordinary textbook in zoölogy with the random presentation of facts in a newspaper or in casual conversation. In science the facts bearing on a given problem are presented as completely as possible and are classified with reference to their significant bearings upon the problem. Moreover the facts gathered and the classifications of relationship made are not more or less accurate, more or less true; they are tested and verified results. That putrefaction, for example, is due to the life of micro-organisms in the rotting substance is not a mere assumption. It has been proved, tested, and verified by methods we shall have occasion presently to examine.

Scientific knowledge, moreover, is general knowledge. The relations it expresses are not _true_ in some cases of the precise kind described, _untrue_ in others. The relations hold true whenever these precise phenomena occur. This generality of scientific relations is closely connected with the fact that science expresses relations of exactly defined phenomena. When a scientific law expresses a certain relation between _A_ and _B_, it says in effect: Given _A_ as meaning this particular set of conditions and no others, and _B_ as meaning this particular set of conditions and no others, then this relation holds true. The relations between _exactly_ defined phenomena are expressed in general terms, that is, the relations expressed hold true, given certain conditions, whatever be the accompanying circumstances. It makes no difference what be the kind of objects, the law of gravitation still holds true: the attraction between objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

Thus science as an activity is marked off by its method and its intent rather than by its subject-matter. As a method it is characterized by thoroughness, persistency, completeness, generality, and system. As regards its intent, it is characterized by its freedom from partiality or prejudice, and its interest in discovering what the facts are, apart from personal expectations and desires. In the scientific mood we wish to know what the nature of things is. There are men who seem to have a boundless, insatiable curiosity, who have a lifelong passion for acquiring facts and understanding the relationship between them.

SCIENCE AS EXPLANATION. The satisfactions which scientific investigators derive from their inquiries are various. There is, in the first place, the sheer pleasure of gratifying the normal human impulse of curiosity, developed in some people to an extraordinary degree. Experience to a sensitive and inquiring mind is full of challenges and provocations to look further. The appearance of dew, an eclipse of the sun, a flash of lightning, a peal of thunder, even such commonplace phenomena as the falling of objects, or the rusting of iron, the evaporation of water, the melting of snow, may provoke inquiry, may suggest the question, "Why?" Experience, as it comes to us through the senses, is broken and fragmentary. The connections between the occurrences of Nature seem casual, and connected, as it were, purely by accident. A black sky portends rain. But such an inference made by the untrained mind is merely the result of habit. A black sky has been followed by rain in the past; the same sequence of events may be expected in the future. But the connection between the two is not really understood. Sometimes experiences seem to contradict each other. The straight stick looks crooked or broken in water. The apparent anomalies and contradictions, the welter of miscellaneous facts with which we come in contact through the experiences of the senses, are clarified by the generalizations of science. The world of facts ceases to be random, miscellaneous, and incalculable. Every phenomenon that occurs is seen to be an instance of a general law that holds among all phenomena that resemble it in certain definable respects. Thus the apparent bending of the stick in water is seen to be a special case of the laws of the refraction of light; the apparent anomaly or contradiction of our sense experiences is, as we say, explained. What seemed to be a contradiction and an exception is seen to be a clear case of a regular law.

The desire for explanation in some minds is very strong. Science _explains_ in the sense that _it reduces a phenomenon to the terms of a general principle, whatever that principle may be._ When we meet a phenomenon that seems to come under no general law, we are confronted with a mystery and a miracle. We do not know what to expect from it. But when we can place a phenomenon under a general law, applicable in a wide variety of instances, everything that can be said of all the other instances in which the law applies, applies also to this particular case.

Think of heat as motion, and whatever is true of motion will be true of heat; but we have had a hundred experiences of motion for everyone of heat. Think of the rays passing through this lens as bending toward the perpendicular, and you substitute for the comparatively unfamiliar lens the very familiar notion of a particular change in direction of a line, of which motion every day brings us countless examples.[1]

[Footnote 1: James: _Psychology_, vol. II, p. 342.]

It must be noticed that the explanation which science gives, is really in answer to the question, "How?" not the question, "Why?" We are said to understand phenomena when we understand the laws which _govern_ them. But to say that certain given phenomena--the appearance of dew, the falling of rain, the flash of lightning, the putrefaction of animal matter--_obey_ certain laws is purely metaphorical. Phenomena do not _obey_ laws in the sense in which we say the child follows the commands of his parents, or the soldier those of his officer. The laws of science simply describe the relations which have repeatedly been observed to exist between phenomena. They are laws in the sense that they are invariably observed successions. When it has been found that whenever _A_ is present, _B_ is also present, that the presence of _A_ is always correlated with the presence of _B_, and the presence of _B_ is always correlated with the presence of _A_, we say we have discovered a scientific law.

Science thus explains in the sense that it reduces the multiplicity and variety of phenomena to simple and general laws. The ideal of unity and simplicity is the constant ideal toward which science moves, and its success in thus reducing the miscellaneous facts of experience has been phenomenal. The history of science in the nineteenth century offers some interesting examples. The discovery of the conservation of energy and its transformations has revealed to us the unity of force. It has shown, for example, that the phenomenon of heat could be explained by molecular motions. "Electricity annexed magnetism." Finally the relations of electricity and light are now known; "the three realms of light, of electricity and of magnetism, previously separated, form now but one; and this annexation seems final."

There has been thus an increasing approach toward unity, toward the summation of phenomena under one simple, general formula.[1] Poincaré, in reviewing this progress, writes:

[Footnote 1: Poincaré notes also the opposite tendency, for science to grow more complex. As he says: "And Newton's law itself? Its simplicity, so long undetected, is perhaps only apparent. Who knows whether it is not due to some complicated mechanism, to the impact of some subtile matter animated by irregular movements, and whether it has not become simple only through the action of averages and of great numbers? In any case it is difficult not to suppose that the true law contains complementary terms, which would become sensible at small distances." (_Foundations of Science_, p. 132.)]

The better one knows the properties of matter the more one sees continuity reign. Since the labors of Andrews and Van der Wals, we get an idea of how the passage is made from the liquid to the gaseous state and that this passage is not abrupt. Similarly there is no gap between the liquid and solid states, and in the proceedings of a recent congress is to be seen, alongside of a work on the rigidity of liquids, a memoir on the flow of solids....

Finally the methods of physics have invaded a new domain, that of chemistry; physical chemistry is born. It is still very young, but we already see that it will enable us to connect such phenomena as electrolysis, osmosis, and the motions of ions.

From this rapid exposition what shall we conclude?

Everything considered, we have approached unity; we have not been as quick as we had hoped fifty years ago, we have not always taken the predicted way; but, finally, we have gained ever so much ground.[2]

[Footnote 2: Poincaré: _loc. cit._, pp. 153-54.]

The satisfaction which disinterested science gives to the investigator is thus, in the first place, one of clarification. Science, by enabling us to see the wide general laws of which all phenomena are particular instances, emancipates the imagination. It frees us from being bound by the accidental suggestions which come to us from mere personal caprice, habit, and environment, and enables us to observe facts uncolored by passions and hope, and to discover those laws of the universe which, in the words of Karl Pearson, "hold for all normally constituted minds." In ordinary experience, our impressions and beliefs are the results of inaccurate sense observation colored by hope and fear, aversion and revulsion, and limited by accidental circumstance. Through science we are enabled to detach ourselves from the personal and the particular and to see the world, as, undistorted, it must appear to any man anywhere:

The scientific attitude of mind involves a sweeping away of all other desires in the interests of the desire to know--it involves suppression of hopes and fears, loves and hates, and the whole subjective emotional life, until we become subdued to the material, able to see it frankly, without preconceptions, without bias, without any wish except to see it as it is, and without any belief that what it is must be determined by some relation, positive or negative, to what we should like it to be, or to what we can easily imagine it to be.[1]

[Footnote 1: Bertrand Russell: _Mysticism and Logic_, p. 44.]

Besides the satisfactions of system and clarity which the sciences give, they afford man power and security. "Knowledge is power," said Francis Bacon, meaning thereby that to know the connection between causes and effects was to be able to regulate conditions so as to be able to produce desirable effects and eliminate undesirable ones. Even the most disinterested inquiry may eventually produce practical results of a highly important character. "Science is," as Bertrand Russell says, "to the ordinary reader of newspapers, represented by a varying selection of sensational triumphs, such as wireless telegraphy and aeroplanes, radio-activity, etc." But these practical triumphs in the control of natural resources are often casual incidents of patiently constructed systems of knowledge which were built up without the slightest reference to their fruits in human welfare. Wireless telegraphy, for example, was made possible by the disinterested and abstract inquiry of three men, Faraday, Maxwell, and Hertz.

In alternating layers of experiment and theory these three men built up the modern theory of electromagnetism, and demonstrated the identity of light with electromagnetic waves. The system which they discovered is one of profound intellectual interest, bringing together and unifying an endless variety of apparently detached phenomena, and displaying a cumulative mental power which cannot but afford delight to every generous spirit. The mechanical details which remained to be adjusted in order to utilize their discoveries for a practical system of telegraphy demanded, no doubt, very considerable ingenuity, but had not that broad sweep and that universality which could give them intrinsic interest as an object of disinterested contemplation.[1]

[Footnote 1: Bertrand Russell: _Mysticism and Logic_, p. 34 ("Science and Culture").]

SCIENCE AND A WORLD VIEW. One of the values of disinterested science that is of considerable psychological importance is the change in attitude it brings about in man's realization of his place in the universe. Lucretius long ago thought to free men's minds from terror and superstition by showing them how regular, ordered, and inevitable was the nature of things. The superstitious savage walks in dread among natural phenomena. He lives in a world which he imagines to be governed by capricious and incalculable forces. To a certain extent he can, as we have seen, control these. But he is ill at ease. He is surrounded by vast ambiguous forces, and moves in a trembling ignorance of what will happen next.

To those educated to the scientific point of view, there is a solidity and assurance about the frame of things. Beneath the variability and flux, which they continually perceive, is the changeless law which they have learned to comprehend. Although they discover that the processes of Nature move on indifferent to the welfare of man, they know, nevertheless, that they are dependable and certain, that they are fixed conditions of life which, to a certain extent, can be controlled, and the incidental goods and ills of which are definitely calculable. Heraclitus, the ancient Greek philosopher, noted the eternal flux, yet perceived the steady order beneath, so that he could eventually assert that all things changed save the law of change. The magnificent regularity of natural processes has been repeatedly remarked by students of science.

THE ÆSTHETIC VALUE OF SCIENCE. As pointed out in the chapter on Art, scientific discovery is more than a mere tabulation of facts. It is also a work of the imagination, and gives to the worker in the scientific field precisely the same sense of satisfaction as that experienced by the creative artist. Of Kelvin his biographer writes:

Like Faraday and the other great masters in science, he was accustomed to let his thoughts become so filled with the facts on which his attention was concentrated that the relations subsisting between the various phenomena gradually dawned upon him, and he _saw_ them, as if by some process of instinctive vision denied to others. ... His imagination was vivid; in his intense enthusiasm, he seemed to be driven rather than to drive himself. The man was lost in his subject, becoming as truly inspired as is the artist in the act of creation.[1]

[Footnote 1: Sylvanus P. Thompson; _The Life of William Thomson, Baron Kelvin of Largs_, pp. 1125 ff.]

In the working-out of a principle, the systematizing of many facts under a sweeping generalization, the scientist finds a creator's joy. He is giving form and significance to the disordered and chaotic materials of experience. The scientific imagination differs from the artistic imagination simply in that it is controlled with reference to facts. The first flash is subjected to criticism, examination, revision, and testing. But the grand generalizations of science originate in just such an unpredictable original vision. The discovery of the fitting formula which clarifies a mass of facts hitherto chaotic and contradictory is very closely akin to the process by which a poet discovers an appropriate epithet or a musician an apposite chord.

But in its products as well as in its processes, scientific investigations have a high æsthetic value. There is symmetry, order, and splendor in the relations which science reveals. The same formal beauty that appeals to us in a Greek statue or a Beethoven symphony is to be found in the universe, but on a far more magnificent scale. There is, in the first place, the sense of rhythm and regularity:

There comes [to the scientific investigator] a sense of pervading order. Probably this began at the very dawn of human reason--when man first discovered the year with its magnificent object-lesson of regularly recurrent sequences, and it has been growing ever since. Doubtless the early forms that this perception of order took referred to somewhat obvious uniformities; but is there any essential difference between realizing the orderliness of moons and tides, of seasons and migrations, and discovering Bodes's law of the relations of the planets, or Mendeléeff's "Periodic Law" of the relations of the atomic weights of the chemical elements?[1]

[Footnote 1: Thomson: _Introduction to Science_, p. 174.]

Ever since Newton's day the harmony of the spheres has been a favorite poetic metaphor. The spaciousness of the solar system has captivated the imagination, as have the time cycles revealed by the paths of comets and meteors. The universe seems indeed, as revealed by science, to present that quality of æsthetic satisfaction which is always derived from unity in multiplicity. The stars are as innumerable as they are ordered. And it was Lucretius, the poet of naturalism, who was wakened to wonder and admiration at the ceaseless productivity, inventiveness, and fertility of Nature. We find in the revelations of science again the same examples of delicacy and fineness of structure that we admire so much in the fine arts. The brain of an ant, as Darwin said, is perhaps the most marvelous speck of matter in the universe. Again "the physicists tell us that the behaviour of hydrogen gas makes it necessary to suppose that an atom of it must have a constitution as complex as a constellation, with about eight hundred separate corpuscles."[2]

[Footnote 2: _Ibid._, p. 176.]

THE DANGER OF "PURE SCIENCE." The fascinations of disinterested inquiry are so great that they may lead to a kind of scientific intemperance. The abstracted scientific interest may become so absorbed in the working-out of small details that it becomes over-specialized, narrow, and pedantic. The pure theorist has always been regarded with suspicion by the practical man. His concern over details of flora or fauna, over the precise minutiæ of ancient hieroglyphics, seems absurdly trivial in comparison with the central passions and central purposes of mankind. There are workers in every department of knowledge who become wrapt up in their specialties, forgetting the forest for the trees. There are men so absorbed in probing the crevices of their own little niche of knowledge that they forget the bearings of their researches. Especially in time of stress, of war or social unrest, men have felt a certain callousness about the interests of the abstrusely remote scholar. We shall have occasion to note presently that it is in this coldness and emancipation from the pressing demands of the moment that science has produced its most pronounced eventual benefits for mankind. But an uncontrolled passion for facts and relations may degenerate into a mere play and luxury that may have its fascination for the expert himself, but affords neither sweetness nor light to any one else. One has but to go over the lists of doctors' dissertations published by German universities during the late nineteenth century to find examples of inquiry that seem to afford not the slightest justification in the way of eventual good to mankind.[1]

[Footnote 1: It is only fair to say that literary studies have been marked by more barren and fruitless investigations (purely philological inquiry, for example) than have the physical sciences.]

PRACTICAL OR APPLIED SCIENCE. Thus far we have been considering science chiefly as an activity which satisfies some men as an activity in itself, by the æsthetic, emotional, and intellectual values they derive from it. But a fact at once paradoxical and significant in the history of human progress is that this most impersonal and disinterested of man's activities has been profoundly influential in its practical fruits. The practical application of the sciences rests on the utilization of the exact formulations of pure science. Through these formulations we can control phenomena by artificially setting up relations of which science has learned the consequences, thus attaining the consequences we desire, and avoiding those we do not.

The _direct_ influence of pure science on practical life is enormous. The observations of Newton on the relations between a falling stone and the moon, of Galvani on the convulsive movements of frogs' legs in contact with iron and copper, of Darwin on the adaptation of woodpeckers, of tree-frogs, and of seeds to their surroundings, of Kirchhoff on certain lines which occur in the spectrum of sunlight, of other investigators on the life-history of bacteria--these and kindred observations have not only revolutionized our conception of the universe, but they have revolutionized or are revolutionizing, our practical life, our means of transit, our social conduct, our treatment of disease.[1]

[Footnote 1: Karl Pearson: _The Grammar of Science_, pp. 35-36.]

Francis Bacon was one of the first to appreciate explicitly the possibilities of the control of nature in the interests of human welfare. He saw the vast possibilities which a careful and comprehensive study of the workings of nature had in the enlargement of human comfort, security, and power. In _The New Atlantis_ he envisages an ideal commonwealth, whose unique and singular institution is a House of Solomon, a kind of Carnegie Foundation devoted to inquiry, the fruits of which might be, as they were, exploited in the interests of human happiness: "The end of our foundation is the knowledge of causes and the secret motions of things; and the enlarging of the bounds of human empire to the effecting of all things possible."[2]

[Footnote 2: _The New Atlantis_.]

Science sometimes appears so remote and alien to the immediate concrete objects which meet and interest us in daily experience that we tend to forget that historically it was out of concrete needs and practical interests that science arose. Geometry, seemingly a clear case of abstract and theoretical science, arose out of the requirements of practical surveying and mensuration among the Egyptians. In the same way botany grew out of herb gathering and gardening.

The application of the exact knowledge gained by the pure sciences, may, if properly directed, immeasurably increase the sum of human welfare. One has but to review briefly the history of invention to appreciate this truth with vividness and detail. The great variety of the "applied sciences" shows the extent and multiplicity of the fruits of theoretical inquiry. Astronomy plays an important part in navigation; but it also earns its living by helping the surveyor and the mapmaker and by supplying the world with accurate time. Industrial chemistry offers, perhaps, the most striking examples. There is, for example, the fixation of nitrogen, which makes possible the artificial production of ammonia and potash; the whole group of dye industries made possible through the chemical production of coal tar; the industrial utilization of cellulose in the paper, twine, and leather industries; the promise of eventual production on a large scale of synthetic rubber; the electric furnace, which, with its fourteen-thousand-degree range of heat, makes possible untold increase in the effectiveness of all the chemical industries.

Industrial chemistry is only one instance. The application of theoretical inquiry in physics has made possible the telegraph, the telephone, wireless telegraphy, electric motors, and flying machines. Mineralogy and oceanography have opened up new stores of natural resources. Biological research has had diverse applications. Bacteriological inquiry has been fruitfully applied in surgery, hygiene, agriculture, and the artificial preservation of food. The principles of Mendelian inheritance have been used in the practical improvement of domestic animals and cultivated plants. The list might be indefinitely extended. The sciences arose as attempts, more or less successful, to solve man's practical problems. They became historically cut off, as they may in the case of the pure scientist still be cut off, from practical considerations. But no matter how remote and abstract they become, they yield again practical fruits.

Applied science, if it becomes too narrowly interested in practical results, limits its own resources. Purely theoretical inquiry may be of the most immense ultimate advantage. In a sense the more abstract and remote science becomes, the more eventual promise it contains. By getting away from the confusing and irrelevant details of particular situations, science is enabled to frame generalizations applicable to a wide array of phenomena differing in detail, but having in common significant characteristics. Men can learn fruitfully to control their experience precisely because they can emancipate themselves from the immediate demands of practical life, from the suggestions that arise in the course of instinctive and habitual action. "A certain power of _abstraction_, of deliberate turning away from the habitual responses to a situation, was required before men could be emancipated to follow up suggestions that in the end are fruitful."[1]

[Footnote 1: Dewey: _How We Think_, p. 156.]

Too complete absorption in immediate problems may operate to deprive action of that sweeping and penetrating vision which a freer inquiry affords. The temporarily important may be the less important in the long run. A practical adjustment of detail may produce immediate benefits in the way of improved industrial processes and more rapid and economical production, but some seemingly obscure discovery in the most abstruse reaches of scientific theory may eventually be of untold practical significance.

Only the extremely ignorant can question the utility of, let us say, the prolonged application of the Greek intellect to the laws of conic sections. Whether we think of bridges or projectiles, of the curves of ships, or of the rules of navigation, we must think of conic sections. The rules of navigation, for instance, are in part based on astronomy. Kepler's Laws are foundation stones of that science, but Kepler discovered that Mars moves in an ellipse round the sun in one of the foci by a deduction from conic sections.... Yet the historical fact is that these conic sections were studied as an abstract science for eighteen centuries before they came to be of their highest use.[2]

[Footnote 2: Thomson: _Introduction to Science_, pp. 239-40.]

Pasteur, whose researches are of such immediate consequence in human health, began his studies in the crystalline forms of tartrates. The tremendous commercial uses which have been made of benzene had their origin "in a single idea, advanced in a masterly treatise by Auguste Kekule in the year 1865."[1]

[Footnote 1: Quoted by Thomson from an address on "Technical Chemistry" by C. E. Munroe.]

Practical life has been continually enriched by theoretical inquiry. Scientific descriptions increase in value as they become absolutely impersonal, absolutely precise, and especially as they become condensed general formulas, which will be applicable to an infinite variety of particular situations. And such descriptions are necessarily abstract and theoretical.

ANALYSIS OF SCIENTIFIC PROCEDURE. Scientific method is merely common sense made more thoroughgoing and systematic. Reflection of a more or less effective kind takes place in ordinary experience wherever instinctive or habitual action is not adequate to meet a situation, whenever the individual has a problem to solve, an adjustment to make. Thinking, of some kind, goes on continually. Scientific thinking merely means careful, safeguarded, systematic thinking. It is thinking alert and critical of its own methods. As contrasted with ordinary common-sense thinking, it is distinguished by "caution, carefulness, thoroughness, definiteness, exactness, orderliness, and methodic arrangement." We think, in any case, because we have to, being creatures born with a set of instincts not adequate to meet the conditions of our environment. We can think carelessly and ineffectively, or carefully and successfully.

Scientific method, or orderly, critical, and systematic thinking, is not applicable to one subject-matter exclusively. Examples are commonly drawn from the physical or chemical or biological laboratory, but the elements of scientific method may be illustrated in the procedure of a business man meeting a practical problem, a lawyer sifting evidence, a statesman framing a new piece of legislation. In all these cases the difference between a genuinely scientific procedure and mere casual and random common sense is the same.

Science is nothing but _trained and organized common sense_, differing from the latter only as a veteran may differ from a raw recruit: and its methods differ from those of common sense only so far as the guardsman's cut and thrust differ from the manner in which a savage wields his club. The primary power is the same in each case, and perhaps the untutored savage has the more brawny arm of the two. The _real_ advantage lies in the point and polish of the swordsman's weapon; in the trained eye quick to spy out the weakness of the adversary; in the ready hand prompt to follow it on the instant. But, after all, the sword exercise is only the hewing and poking of the clubman refined and developed.

So, the vast results obtained by science are won by ... no mental processes, other than those which are practiced by everyone of us, in the humblest and meanest affairs of life. A detective policeman discovers a burglar from the marks made by his shoe, by a mental process identical with that by which Cuvier restored the extinct animals of Montmartre from fragments of their bones.... Nor does that process of induction and deduction by which a lady finding a stain of a peculiar kind upon her dress, concludes that somebody has upset the inkstand thereon, differ, in any way, in kind, from that by which Adams and Leverrier discovered a new planet.

The man of science, in fact, simply uses with scrupulous exactness the methods which we all, habitually and at every moment, use carelessly; and the man of business must as much avail himself of the scientific method--must as truly be a man of science--as the veriest bookworm of us all.[1]

[Footnote 1: Huxley: _Lay Sermons, Addresses, and Reviews_, pp. 77, 78 (in "The Educational Value of the Natural History Sciences").]

The scientific procedure becomes, as we shall see, highly complicated, involving elaborate processes of observation, classification, generalization, deduction or development of ideas, and testing. But it remains thinking just the same, and originates in some problem or perplexity, just as thinking does in ordinary life.

SCIENCE AND COMMON SENSE. It is profitable to note in some detail the ways in which scientific method, in spirit and technique, differs from common-sense thinking. It is more insistent in the first place on including the whole range of relevant data, of bringing to light all the facts that bear on a given problem. In common-sense thinking we make, as we say, snap judgments; we jump at conclusions. Anything plausible is accepted as evidence; anything heard or seen is accepted as a fact. The scientific examiner insists on examining and subjecting to scrutiny the facts at hand, on searching for further facts, and on distinguishing the facts genuinely significant in a given situation from these that happen to be glaring or conspicuous. This is merely another way of saying that both accuracy and completeness of observation are demanded, accuracy in the examination of the facts present, and completeness in the array of facts bearing on the question at hand.

Scientific thinking is thus primarily inquiring and skeptical. It queries the usual; it tries, as we say, to penetrate beneath the surface. Common sense, for example, gives suction as the explanation of water rising in a pump. But where, as at a great height above sea level, this mysterious power of suction does not operate, or when it is found that it does not raise water above thirty-two feet, common sense is at a loss. Scientific thinking tries to analyze the gross fact, and by accurately and completely observing all the facts bearing on the phenomenon endeavors to find out "what _special_ conditions are present when the effect occurs" and absent when it does not occur. 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 circumstances 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 class 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 emancipated 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, constituting 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 attitude 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 adventitious 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 circumstances. 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 assumption that because one thing happens after another, therefore it happens _because_ of it. Many superstitions 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 superstition 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 assigned. It is easiest and most plausible to assign as a cause an immediately preceding circumstance. Exceptional or contradictory circumstances are then either unnoticed or pared down to fit the belief.

Scientific method does not depend on such chance conjunctions of circumstance, 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 appetite 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 passion 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 constitute the framework of the modern scientific systems. "The monotonous and quantitative 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 pass for judgments and conclusions. The scientist is the man in whom curiosity has become a permanent passion, 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 illustration 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 classification.

But however remote and recondite thinking becomes, however far removed from immediate practical concerns, it occurs essentially in a situation analogous 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 illustrated 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 analysis 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 reëxamining 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 constitutes 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 Uranus. 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 space. 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 Uranus 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 assumed 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.]