Chapter XIV: Science and Scientific Method (2)

[Footnote 1: James gives an illuminating passage 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 association 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 analyzing mind. Ease of suggestion, in the first place, depends on innate individual differences. There are some minds so constituted that every fact provokes a multitude 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 analyzing 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 passion," 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 emancipated from the compulsions of habit and circumstances, 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.

CLASSIFICATION. Next only in importance to accurate observation of the facts is their classification. 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 classify them, place them in a class, 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 classification. In the words of Poincaré:

The most interesting facts are those which may serve many times; these are the facts which have a chance of coming up again. We have been so fortunate as to have been born in a world where there are such. Suppose that instead of sixty chemical elements there were sixty milliards of them, that they were not some common, the others rare, but that they were equally distributed. Then, every time we picked up a new pebble there would be great probability of its being formed of some unknown substance; all that we knew of other pebbles would be worthless for it; before each new object we should be as the new-born babe; like it we could only obey our caprices or our needs. Biologists would be just as much at a loss if there were only individuals and no species, and if heredity did not make sons like their fathers.[1]

[Footnote 1: Poincaré: _Foundations of Science_, p. 363.]

The aim of classification in science is grouping in such a way as to make manifest at once similarities in the behavior of objects. That characteristic is selected as a basis of classification with which is correlated the greatest number of other characteristics belonging to the facts in question. It would be possible to classify all living things according to color, but such a classification would be destitute of scientific value. Biology offers some interesting examples of how an illuminating classification may be made on the basis of a single characteristic. It has been found, for example, that the differences or resemblances of animals are correlated with corresponding differences or resemblances in their teeth. In general, the function of classification may be summarized in Huxley's definition as modified by Jevons:

By the classification of any series of objects is meant the actual or ideal arrangement together of those things which are like and the separation of those things which are unlike, the purpose of the arrangement being, primarily, to disclose the correlations or laws of union of properties and circumstances, and, secondarily, to facilitate the operations of the mind in clearly conceiving and retaining in memory the characters of the object in question.

It should be noted that the object of classification is not simply to indicate similarities but to indicate distinctions or differences. In scientific inquiry, differences are as crucial in the forming of generalizations as similarities. It is only possible to classify a given fact under a scientific generalization when the given fact is set off from other facts, when it is seen to be the result of certain special conditions.

If a man infers from a single sample of grain as to the grade of wheat of the car as a whole, it is induction, and under certain circumstances, a _sound_ induction; other cases are resorted to simply for the sake of rendering that induction more guarded and correct. In the case of the various samples of grain, it is the fact that the samples are unlike, at least in the part of the carload from which they are taken, that is important. Were it not for this unlikeness, their likeness in quality would be of no avail in assisting inference.[1]

[Footnote 1: Dewey: _How We Think_, pp. 89-90.]

EXPERIMENTAL VARIATION OF CONDITIONS. In forming our generalizations from the observation of situations as they occur in Nature, we are at a disadvantage. If we observe cases just as we find them, there is much present that is irrelevant to our problem; much that is of genuine importance in its solution is hidden or obscure. In experimental investigation we are, in the words of Sir John Herschel, "active observers"; we deliberately invent crucial or test cases. That is, we deliberately arrange conditions so that every factor is definitely known and recognized. We then introduce into this set of completely known conditions one change, one new circumstance, and observe its effect. In Mill's phrase, we "take a phenomenon home with us," and watch its behavior. Mill states clearly the outstanding advantage of experimentation over observation:

When we can produce a phenomenon artificially, we can take it, as it were, home with us, and observe it in the midst of circumstances with which in all other respects we are accurately acquainted. If we desire to know what are the effects of the cause _A_, and are able to produce _A_ by means at our disposal, we can generally determine at our own discretion ... the whole of the circumstances which shall be present along with it; and thus, knowing exactly the simultaneous state of everything else which is within the reach of _A's_ influence, we have only to observe what alteration is made in that state by the presence of _A_.

For example, by the electric machine we can produce, in the midst of known circumstances, the phenomena which Nature exhibits on a grander scale in the form of lightning and thunder. Now let any one consider what amount of knowledge of the effects and laws of electric agency mankind could have obtained from the mere observation of thunderstorms, and compare it with that which they have gained, and may expect to gain, from electrical and galvanic experiments....

When we have succeeded in isolating the phenomenon which is the subject of inquiry, by placing it among known circumstances, we may produce further variations of circumstances to any extent, and of such kinds as we think best calculated to bring the laws of the phenomenon into a clear light. By introducing one well-defined circumstance after another into the experiment, we obtain assurance of the manner in which the phenomenon behaves under an indefinite variety of possible circumstances. Thus, chemists, after having obtained some newly discovered substance in a pure state, ... introduce various other substances, one by one, to ascertain whether it will combine with them, or decompose them, and with what result; and also apply heat or electricity or pressure, to discover what will happen to the substance under each of these circumstances.[1]

[Footnote 1: Mill: _Logic_ (London, 1872), vol. I, pp. 441-42.]

Through experiment, we are thus enabled to observe the relation of specific elements in a situation. We are, furthermore, enabled to observe phenomena which are so rare in occurrence that it is impossible to form generalizations from them or improbable that we should even notice them: "We might have to wait years or centuries to meet accidentally with facts which we can readily produce at any moment in a laboratory; and it is probable that many of the chemical substances now known, and many excessively useful products, would never have been discovered at all, by waiting till Nature presented them spontaneously to our observation." And phenomena, such as that of electricity, which can only be understood when the conditions of their occurrence are varied, are presented to us in Nature most frequently in a fixed and invariable form.

GENERALIZATIONS, THEIR ELABORATION AND TESTING. So far we have been concerned with the steps in the control of suggestion, the reëxamination of the facts so that significant suggestions may be derived, and the elimination of the significant from the insignificant in the elements of the situation as it first confronts us. In logically elaborating a suggestion, as we have already seen, we trace out the bearings of a given situation. We expand it; we see what it _implies_, what it means. Thus, if we came, for example, to a meeting that had been scheduled, and found no one present, we might have several solutions arise in our minds. The meeting, we might suppose, had been transferred to another room. If that were the case, there would probably be some notice posted. In all cases of deductive elaboration, we go through what might be called the If-Then process. If _such-and-such_ is the case, then _such-and-such_ will follow. We can then verify our suggested solution to a problem, by going back to the facts, to see whether they correspond with the implications of our suggestion. We may, to take another example, think that a man who enters our office is an insurance agent, or a book solicitor who had said he would call upon us at a definite date. If such is the case, he will say such-and-such things. If he does say them, then our suggestion is seen to be correct. The advantages of developing a suggestion include the fact that some link in the logical chain may bear a more obvious relation to our problem than did the undeveloped suggestion itself.

The systematic sciences consist of such sets of principles so related that any single term implies certain others, which imply certain others and so on _ad infinitum_.

After the facts have been elaborated, the generalization, however plausible it may seem, must be subjected to experimental corroboration. That is, if a suggestion is found through local elaboration to mean _A, B, C_, then the situation must be reëxamined to see if the facts to be found tally with the facts deduced. In the case cited, the suggestion that the man who entered the room was the insurance agent we expected would be verified if he immediately broached the subject and the fact, say, of a previous conversation. In the case of disease, if the illness is typhoid, we shall find certain specific conditions in the patient. If these are found, the suggestion of typhoid is verified.

The _reliability_ of generalizations made by this scientific procedure varies according to several factors. It varies, in the first place, according to the correspondence of the predictions made on the basis of the generalization, with subsequent events. The reason we say the law of gravitation holds true is because in every instance where observations or experiments have been made, the results have tallied precisely with expectations based upon the generalization. We can, to a certain extent, determine the reliability of a generalization before comparing our predictions with subsequent events. If a generalization made contradicts laws that have been established in so many instances that they are practically beyond peradventure, it is suspect. A law, for example, that should be an exception to the laws of motion or gravitation, is _a priori_ dubious.

If an induction conflicts with stronger inductions, or with conclusions capable of being correctly deduced from them, then, unless on reconsideration it should appear that some of the stronger inductions have been expressed with greater universality than their evidence warrants, the weaker one must give way. The opinion so long prevalent that a comet, or any other unusual appearance in the heavenly regions, was the precursor of calamities to mankind, or to those at least who witnessed it; the belief in the veracity of the oracles of Delphi or Dodona; the reliance on astrology, or on the weather prophecies in almanacs, were doubtless inductions supposed to be grounded on experience.... What has really put an end to these insufficient inductions is their inconsistency with the stronger inductions subsequently obtained by scientific inquiry, respecting the causes on which terrestrial events really depend.[1]

[Footnote 1: Mill: _Logic_ (London, 1872), vol. I, pp. 370-71.]

THE QUANTITATIVE BASIS OF SCIENTIFIC PROCEDURE. Science _is_ science, some scientists insist, in so far as it is mathematical. That is, in the precise determination of facts, and in their repetition with a view to their exact determination, quantities must be known. The sciences have developed in exactness, in so far as they have succeeded in expressing their formulations in numerical terms. The physical sciences, such as physics and chemistry, which have been able to frame their generalizations from precise quantities, have been immeasurably more certain and secure than such sciences as psychology and sociology, where the measurement of exact quantities is more difficult and rare. Jevons writes in his _Principles of Science_:

As physical science advances, it becomes more and more accurately quantitative. Questions of simple logical fact resolve themselves after a while into questions of degree, time, distance, or weight. Forces hardly suspected to exist by one generation are clearly recognized by the next, and precisely measured by the third generation.[1]

[Footnote 1: Jevons: _Principles of Science_, p. 270.]

The history of science exhibits a constant progress from rude guesses to precise measurement of quantities. In the earliest history of astronomy there were attempts at quantitative determinations, very crude, of course, in comparison with the exactness of present-day scientific methods.

Every branch of knowledge commences with quantitative notions of a very rude character. After we have far progressed, it is often amusing to look back into the infancy of the science, and contrast present with past methods. At Greenwich Observatory in the present day, the hundredth part of a second is not thought an inconsiderable portion of time. The ancient Chaldreans recorded an eclipse to the nearest hour, and the early Alexandrian astronomers thought it superfluous to distinguish between the edge and center of the sun. By the introduction of the astrolabe, Ptolemy, and the later Alexandrian astronomers could determine the places of the heavenly bodies within about ten minutes of arc. Little progress then ensued for thirteen centuries, until Tycho Brahe made the first great step toward accuracy, not only by employing better instruments, but even more by ceasing to regard an instrument as correct.... He also took notice of the effects of atmospheric refraction, and succeeded in attaining an accuracy often sixty times as great as that of Ptolemy. Yet Tycho and Hevelius often erred several minutes in the determination of a star's place, and it was a great achievement of Roemer and Flamsteed to reduce this error to seconds. Bradley, the modern Hipparchus, carried on the improvement, his errors in right ascension, according to Bessel, being under one second of time, and those of declination under four seconds of arc. In the present day the average error of a single observation is probably reduced to the half or the quarter of what it was in Bradley's time; and further extreme accuracy is attained by the multiplication of observations, and their skillful combination according to the theory of error. Some of the more important constants... have been determined within a tenth part of a second of space.[2]

[Footnote 2: _Ibid._, pp. 271-72.]

The precise measurement of quantities is important because we can, in the first place, only through quantitative determinations be sure we have made accurate observations, observations uncolored by personal idiosyncrasies. Both errors of observation and errors of judgment are checked up and averted by exact quantitative measurements. The relations of phenomena, moreover, are so complex that specific causes and effects can only be understood when they are given precise quantitative determination. In investigating the solubility of salts, for example, we find variability depending on differences in temperature, pressure, the presence of other salts already dissolved, and the like. The solubility of salt in water differs again from its solubility in alcohol, ether, carbon, bisulphide. Generalization about the solubility of salt, therefore, depends on the exact measurement of the phenomenon under all these conditions.[1]

[Footnote 1: See Jevons, p, 279 ff.]

The importance of exact measurement in scientific discovery and generalization may be illustrated briefly from one instance in the history of chemistry. The discovery of the chemical element _argon_ came about through some exact measurements by Lord Rayleigh and Sir William Ramsay of the nitrogen and the oxygen in a glass flask. It was found that the nitrogen derived from air was not altogether pure; that is, there were very minute differences in the weighings of nitrogen made from certain of its compounds and the weight obtained by removing oxygen, water, traces of carbonic acid, and other impurities from the atmospheric air. It was found that the very slightly heavier weight in one case was caused by the presence of argon (about one and one third times as heavy as nitrogen) and some other elementary gases. The discovery was here clearly due to the accurate measurement which made possible the discovery of this minute discrepancy.

It must be noted in general that accuracy in measurement is immediately dependent on the instruments of precision available. It has frequently been pointed out that the Greeks, although incomparably fresh, fertile, and direct in their thinking, yet made such a comparatively slender contribution to scientific knowledge precisely because they had no instruments for exact measurement. The thermometer made possible the science of heat. The use of the balance has been in large part responsible for advances in chemistry.

The degree to which sciences have attained quantitative accuracy varies among the physical sciences. The phenomena of light are not yet subject to accurate measurement; many natural phenomena have not yet been made the subject of measurement at all. Such are the intensity of sound, the phenomena of taste and smell, the magnitude of atoms, the temperature of the electric spark or of the sun's atmosphere.[1]

[Footnote 1: See Jevons, p. 273.]

The sciences tend, in general, to become more and more quantitative. All phenomena "exist in space and involve molecular movements, measurable in velocity and extent." The ideal of all sciences is thus to reduce all phenomena to measurements of mass and motion. This ideal is obviously far from being attained. Especially in the social sciences are quantitative measurements difficult, and in these sciences we must remain therefore at best in the region of shrewd guesses or fairly reliable probability.

STATISTICS AND PROBABILITY. While in the social sciences, exact quantitative measurements are difficult, they are to an extent possible, and to the extent that they are possible we can arrive at fairly accurate generalizations as to the probable occurrence of phenomena. There are many phenomena where the elements are so complex that they cannot be analyzed and invariable causal relations established.

In a study of the phenomena of the weather, for example, the phenomena are so exceedingly complex that anything approaching a complete statement of their elements is quite out of the question. The fallibility of most popular generalizations in these fields is evidence of the difficulty of dealing with such facts. Must we be content then simply to guess at such phenomena? ... In instances of this sort, another method ... becomes important: The Method of Statistics. In statistics we have an _exact_ enumeration of cases. If a small number of cases does not enable us to detect the causal relations of a phenomenon, it sometimes happens that a large number, accurately counted, and taken from a field widely extended in time and space, will lead to a solution of the problem.[1]

[Footnote 1: Jones; _Logic, Inductive and Deductive_, p. 190.]

If we find, in a wide variety of instances, two phenomena occurring in a certain constant correlation, we infer a causal relation. If the variations in the frequency of one correspond to variations in the frequency of the other, there is probability of more than connection by coincidence.

The correlation between phenomena may be measured mathematically; it is possible to express in figures the exact relations between the occurrence of one phenomenon and the occurrence of another. The number which expresses this relation is called the coefficient of correlation. This coefficient expresses relationship in terms of the mean values of the two series of phenomena by measuring the amount each individual phenomenon varies from its respective mean. Suppose, for example, that in correlating crime and unemployment, the coefficient of correlation were found to be .47. If in every case of unemployment crime were found and in every case of crime, unemployment, the coefficient of correlation would be +1. If crime were never found in unemployment, and unemployment never in crime, the coefficient of correlation would be -1, indicating a perfect inverse relationship. A coefficient of 0 would indicate that there is no relationship. The coefficient of .47 would accordingly indicate a significant but not a "high" correlation between crime and unemployment.

We cannot consider here all the details of statistical methods, but attention may be called to a few of the more significant features of the process. Statistics is a science, and consists in much more than the mere counting of cases.

With the collection of statistical data, only the first step has been taken. The statistics in that condition are only raw material showing nothing. They are not an instrument of investigation any more than a kiln of bricks is a monument of architecture. They need to be arranged, classified, tabulated, and brought into connection with other statistics by the statistician. Then only do they become an instrument of investigation, just as a tool is nothing more than a mass of wood or metal, except in the hands of a skilled workman.[1]

[Footnote 1: Mayo-Smith: _Statistics and Sociology_, p. 18.]

The essential steps in a statistical investigation are: (1) the collection of material, (2) its tabulation, (3) the summary, and (4) a critical examination of the results. The terms are almost self-explanatory. There are, however, several general points of method to be noted.

In the collection of data a wide field must be covered, to be sure that we are dealing with invariable relations instead of with mere coincidences, "or overemphasizing the importance of one out of a number of coöperating causes." Tabulation of the data collected is very important, since classification of the data does much to suggest the causal relations sought. The headings under which data will be collected depend on the purposes of the investigation. In general, statistics can suggest generalizations, rather than establish them. They indicate probability, not invariable relation.[2]

[Footnote 2: See Jones: _Logic_, pp. 213-25, for a discussion of Probability.]

SCIENCE AS AN INSTRUMENT OF HUMAN PROGRESS. We have, in an earlier section of this chapter, referred to the practical value of science. "Man's power of deliberate control of his own affairs depends upon ability to direct energies to use; an ability which is, in turn, dependent upon insight into nature's processes. Whatever natural science may be for the specialist,... it is knowledge of the conditions of human action."[3] And the wider, the more complete and the more penetrating our knowledge of the world in which we live, the more extended become the boundaries of human action. Through a knowledge of natural processes, men have passed from a frightened subjection to Nature to its conscious control. And the fruits of that control are, as we have already had occasion to notice, all-pervading in practical life. That complete transformation of life known as the Industrial Revolution, which came about with such swiftness and completeness in the early nineteenth century, and whose effects have not yet ceased to accumulate, was the direct outcome of the application of the experimental science which had begun in the sixteenth. Some of the consequences of the application of theoretical investigation to practical life have already been noted. There are first the more obvious facts of the inventions, great and small--the railways, steamships, electric transportation, automobiles, and telephones--which have changed in countless details our daily life. There are the profound and all-pervasive changes which have been brought about in industrial and social relations: the building-up of our vast industrial centers, the change from small-scale handicrafts to large-scale machine production, the factory system, with its concomitants of immensely increased resources and immensely complicated problems of human life. Science in the short span of three centuries has shown how rapid and immediate could be the fruits of human control of Nature, and its further fruits are incalculable.

[Footnote 3: Dewey: _Democracy and Education_, p. 267.]

Science has indeed already begun to affect men's attitude towards experience as well as their material progress. It is only when men set out with the conscious realization that intelligence does make a difference in the world, that science becomes articulate. Science is the guarantee of progress. It has shown men that the future is to some extent in their own hands; that by dint of a laborious and detailed application of intelligence to the processes of nature, those processes can be controlled in the interests of human welfare.

Science has led men to look to the future instead of the past. The coincidence of the ideal of progress with the advance of science is not a mere coincidence. Before this advance men placed the golden age in remote antiquity. Now they face the future with a firm belief that intelligence properly used can do away with evils once thought inevitable. To subjugate devastating disease is no longer a dream; the hope of abolishing poverty is not Utopian.[1]

[Footnote 1: Dewey: _Democracy and Education_, pp. 262-63.]

But science may be used for any end. It reveals the relations of phenomena, relations which hold for all men. It shows what causes are connected with what consequents, and, as already pointed out, in the knowledge of causes lies the possible control of effects. We can secure the results we desire, by discovering what antecedents must first be established. Science is thus a fund of common resources. Specific causes are revealed to be connected with specific effects, and men, by making a choice of antecedents, can secure the consequences they desire. But which effects they will desire depends on the instincts, standards, and habits of the individual, and the traditions and ideals of the group. A knowledge of chemistry may be used for productive industrial processes, or in the invention of poison gas. Expert acquaintance with psychology and educational methods may be used to impress upon a nation an arbitrary type of life (an accusation justly brought against the Prussian educational system), or to promote the specific possibilities that each individual displays.

Not only are the fruits of scientific inquiry used in different ways by different individuals and groups, but scientific inquiry is itself affected by the prevailing interests and mode of life. What inquiries shall be furthered depends on _what_ the individual or group feels it important to know. From a social point of view, certain scientific developments are of more urgency and imperativeness than others. During an emergency, as during the Great War, it might be necessary to turn all the energies of scientific men into immediately productive pursuits. And, since the pursuit of inquiry on a large scale demands large resources, those researches which give promise of beneficent human consequences will the more readily command social sanction and approval and will be developed at the expense of more remote speculations however intrinsically interesting these latter may be.

Science has proved so valuable a human instrument that it has attained a moral responsibility. Men have increasingly come to realize that the pressing problems of our industrial life require for their solution not the confusions and incompetences of passion and prejudice, but an application of the fruits of scientific inquiry. Science has already so completely demonstrated its vast fruitfulness in human welfare, that it must be watched with jealous vigilance. It must result as it began, in the improvement of human welfare.[1] But what constitutes human welfare is a question which leads us into the final activity of the Career of Reason, Morals and Moral Valuation, man's attempt to determine what happiness is, and how he may attain it.

[Footnote 1: We have already noted the danger of too complete a commitment of science to immediately practical results. This narrows instead of broadening possibility. As Mr. F. P. Keppel points out in a recent article, "Scholarship in War" (_Columbia University Quarterly_, July, 1919), some of the most important and immediately practical contributions during the Great War came from the ranks of those who would be regarded as "pure theorists."]