thinking for the sake of thinking to escape the limits of routine and custom. Interest in knowledge for the sake of knowledge, in thinking for the sake of the free play of thought, is necessary then to the _emancipation_ of practical life--to make it rich and progressive.
We may now recur to the pedagogic maxim of going from the concrete to the abstract.
[Sidenote: Begin with the concrete means begin with practical manipulations] 1. Since the _concrete_ denotes thinking applied to activities for the sake of dealing effectively with the difficulties that present themselves practically, "beginning with the concrete" signifies that we should at the outset make much of _doing_; especially, make much in occupations that are not of a routine and mechanical kind and hence require intelligent selection and adaptation of means and materials. We do not "follow the order of nature" when we multiply mere sensations or accumulate physical objects. Instruction in number is not concrete merely because splints or beans or dots are employed, while whenever the use and bearing of number relations are clearly perceived, the number idea is concrete even if figures alone are used. Just what sort of symbol it is best to use at a given time--whether blocks, or lines, or figures--is entirely a matter of adjustment to the given case. If physical things used in teaching number or geography or anything else do not leave the mind illuminated with recognition of a _meaning_ beyond themselves, the instruction that uses them is as abstract as that which doles out ready-made definitions and rules; for it distracts attention from ideas to mere physical excitations.
[Sidenote: Confusion of the concrete with the sensibly isolated] The conception that we have only to put before the senses particular physical objects in order to impress certain ideas upon the mind amounts almost to a superstition. The introduction of object lessons and sense-training scored a distinct advance over the prior method of linguistic symbols, and this advance tended to blind educators to the fact that only a halfway step had been taken. Things and sensations develop the child, indeed, but only because he _uses_ them in mastering his body and in the scheme of his activities. Appropriate continuous occupations or activities involve the use of natural materials, tools, modes of energy, and do it in a way that compels thinking as to what they mean, how they are related to one another and to the realization of ends; while the mere isolated presentation of things remains barren and dead. A few generations ago the great obstacle in the way of reform of primary education was belief in the almost magical efficacy of the symbols of language (including number) to produce mental training; at present, belief in the efficacy of objects just as objects, blocks the way. As frequently happens, the better is an enemy of the best.
[Sidenote: Transfer of interest to intellectual matters] 2. The interest in results, in the successful carrying on of an activity, should be gradually transferred to study of objects--their properties, consequences, structures, causes, and effects. The adult when at work in his life calling is rarely free to devote time or energy--beyond the necessities of his immediate action--to the study of what he deals with. (_Ante_, p. 43.) The educative activities of childhood should be so arranged that direct interest in the activity and its outcome create a demand for attention to matters that have a more and more _indirect and remote_ connection with the original activity.
The direct interest in carpentering or shop work should yield organically and gradually an interest in geometric and mechanical problems. The interest in cooking should grow into an interest in chemical experimentation and in the physiology and hygiene of bodily growth. The making of pictures should pass to an interest in the technique of representation and the æsthetics of appreciation, and so on. This development is what the term _go_ signifies in the maxim "_go_ from the concrete to the abstract"; it represents the dynamic and truly educative factor of the process.
[Sidenote: Development of delight in the activity of thinking] 3. The outcome, the _abstract_ to which education is to proceed, is an interest in intellectual matters for their own sake, a delight in thinking for the sake of thinking. It is an old story that acts and processes which at the outset are incidental to something else develop and maintain an absorbing value of their own. So it is with thinking and with knowledge; at first incidental to results and adjustments beyond themselves, they attract more and more attention to themselves till they become ends, not means. Children engage, unconstrainedly and continually, in reflective inspection and testing for the sake of what they are interested in doing successfully. Habits of thinking thus generated may increase in volume and extent till they become of importance on their own account.
[Sidenote: Examples of the transition] The three instances cited in Chapter Six represented an ascending cycle from the practical to the theoretical. Taking thought to keep a personal engagement is obviously of the concrete kind. Endeavoring to work out the meaning of a certain part of a boat is an instance of an intermediate kind. The reason for the existence and position of the pole is a practical reason, so that to the architect the problem was purely concrete--the maintenance of a certain system of action. But for the passenger on the boat, the problem was theoretical, more or less speculative. It made no difference to his reaching his destination whether he worked out the meaning of the pole. The third case, that of the appearance and movement of the bubbles, illustrates a strictly theoretical or abstract case. No overcoming of physical obstacles, no adjustment of external means to ends, is at stake. Curiosity, intellectual curiosity, is challenged by a seemingly anomalous occurrence; and thinking tries simply to account for an apparent exception in terms of recognized principles.
[Sidenote: Theoretical knowledge never the whole end] (_i_) Abstract thinking, it should be noted, represents _an_ end, not _the_ end. The power of sustained thinking on matters remote from direct use is an outgrowth of practical and immediate modes of thought, but not a substitute for them. The educational end is not the destruction of power to think so as to surmount obstacles and adjust means and ends; it is not its replacement by abstract reflection. Nor is theoretical thinking a higher type of thinking than practical. A person who has at command both types of thinking is of a higher order than he who possesses only one. Methods that in developing abstract intellectual abilities weaken habits of practical or concrete thinking, fall as much short of the educational ideal as do the methods that in cultivating ability to plan, to invent, to arrange, to forecast, fail to secure some delight in thinking irrespective of practical consequences.
[Sidenote: Nor that most congenial to the majority of pupils] (_ii_) Educators should also note the very great individual differences that exist; they should not try to force one pattern and model upon all.
In many (probably the majority) the executive tendency, the habit of mind that thinks for purposes of conduct and achievement, not for the sake of knowing, remains dominant to the end. Engineers, lawyers, doctors, merchants, are much more numerous in adult life than scholars, scientists, and philosophers. While education should strive to make men who, however prominent their professional interests and aims, partake of the spirit of the scholar, philosopher, and scientist, no good reason appears why education should esteem the one mental habit inherently superior to the other, and deliberately try to transform the type from practical to theoretical. Have not our schools (as already suggested, p.
49) been one-sidedly devoted to the more abstract type of thinking, thus doing injustice to the majority of pupils? Has not the idea of a "liberal" and "humane" education tended too often in practice to the production of technical, because overspecialized, thinkers?
[Sidenote: Aim of education is a working balance] The aim of education should be to secure a balanced interaction of the two types of mental attitude, having sufficient regard to the disposition of the individual not to hamper and cripple whatever powers are naturally strong in him. The narrowness of individuals of strong concrete bent needs to be liberalized. Every opportunity that occurs within their practical activities for developing curiosity and susceptibility to intellectual problems should be seized. Violence is not done to natural disposition, but the latter is broadened. As regards the smaller number of those who have a taste for abstract, purely intellectual topics, pains should be taken to multiply opportunities and demands for the application of ideas; for translating symbolic truths into terms of social life and its ends. Every human being has both capabilities, and every individual will be more effective and happier if both powers are developed in easy and close interaction with each other.
CHAPTER ELEVEN EMPIRICAL AND SCIENTIFIC THINKING [Sidenote: Empirical thinking depends on past habits] Apart from the development of scientific method, inferences depend upon habits that have been built up under the influence of a number of particular experiences not themselves arranged for logical purposes. A says, "It will probably rain to-morrow." B asks, "Why do you think so?"
and A replies, "Because the sky was lowering at sunset." When B asks, "What has that to do with it?" A responds, "I do not know, but it generally does rain after such a sunset." He does not perceive any _connection_ between the appearance of the sky and coming rain; he is not aware of any continuity in the facts themselves--any law or principle, as we usually say. He simply, from frequently recurring conjunctions of the events, has associated them so that when he sees one he thinks of the other. One _suggests_ the other, or is _associated_ with it. A man may believe it will rain to-morrow because he has consulted the barometer; but if he has no conception how the height of the mercury column (or the position of an index moved by its rise and fall) is connected with variations of atmospheric pressure, and how these in turn are connected with the amount of moisture in the air, his belief in the likelihood of rain is purely empirical. When men lived in the open and got their living by hunting, fishing, or pasturing flocks, the detection of the signs and indications of weather changes was a matter of great importance. A body of proverbs and maxims, forming an extensive section of traditionary folklore, was developed. But as long as there was no understanding _why_ or _how_ certain events were signs, as long as foresight and weather shrewdness rested simply upon repeated conjunction among facts, beliefs about the weather were thoroughly empirical.
[Sidenote: It is fairly adequate in some matters,] In similar fashion learned men in the Orient learned to predict, with considerable accuracy, the recurrent positions of the planets, the sun and the moon, and to foretell the time of eclipses, without understanding in any degree the laws of the movements of heavenly bodies--that is, without having a notion of the continuities existing among the facts themselves. They had learned from repeated observations that things happened in about such and such a fashion. Till a comparatively recent time, the truths of medicine were mainly in the same condition. Experience had shown that "upon the whole," "as a rule," "generally or usually speaking," certain results followed certain remedies, when symptoms were given. Our beliefs about human nature in individuals (psychology) and in masses (sociology) are still very largely of a purely empirical sort. Even the science of geometry, now frequently reckoned a typical rational science, began, among the Egyptians, as an accumulation of recorded observations about methods of approximate mensuration of land surfaces; and only gradually assumed, among the Greeks, scientific form.
The _disadvantages_ of purely empirical thinking are obvious.
[Sidenote: but is very apt to lead to false beliefs,] 1. While many empirical conclusions are, roughly speaking, correct; while they are exact enough to be of great help in practical life; while the presages of a weatherwise sailor or hunter may be more accurate, within a certain restricted range, than those of a scientist who relies wholly upon scientific observations and tests; while, indeed, empirical observations and records furnish the raw or crude material of scientific knowledge, yet the empirical method affords no way of discriminating between right and wrong conclusions. Hence it is responsible for a multitude of _false_ beliefs. The technical designation for one of the commonest fallacies is _post hoc, ergo propter hoc_; the belief that because one thing comes _after_ another, it comes _because_ of the other. Now this fallacy of method is the animating principle of empirical conclusions, even when correct--the correctness being 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, that a patent medicine cures a disease--these and a thousand like notions are asseverated on the basis of empirical coincidence and conjunction. Moreover, habits of expectation and belief are formed otherwise than by a number of repeated similar cases.
[Sidenote: and does not enable us to cope with the novel,] 2. The more numerous the experienced instances and the closer the watch kept upon them, the greater is the trustworthiness of constant conjunction as evidence of connection among the things themselves. Many of our most important beliefs still have only this sort of warrant. No one can yet tell, with certainty, the necessary cause of old age or of death--which are empirically the most certain of all expectations. But even the most reliable beliefs of this type fail when they confront the _novel_. Since they rest upon past uniformities, they are useless when further experience departs in any considerable measure from ancient incident and wonted precedent. Empirical inference follows the grooves and ruts that custom wears, and has no track to follow when the groove disappears. So important is this aspect of the matter that Clifford found the difference between ordinary skill and scientific thought right here. "Skill enables a man to deal with the same circumstances that he has met before, scientific thought enables him to deal with different circumstances that he has never met before." And he goes so far as to define scientific thinking as "the application of old experience to new circumstances."
[Sidenote: and leads to laziness and presumption,] 3. We have not yet made the acquaintance of the most harmful feature of the empirical method. Mental inertia, laziness, unjustifiable conservatism, are its probable accompaniments. Its general effect upon mental attitude is more serious than even the specific wrong conclusions in which it has landed. Wherever the chief dependence in forming inferences is upon the conjunctions observed in past experience, failures to agree with the usual order are slurred over, cases of successful confirmation are exaggerated. Since the mind naturally demands some principle of continuity, some connecting link between separate facts and causes, forces are arbitrarily invented for that purpose. Fantastic and mythological explanations are resorted to in order to supply missing links. The pump brings water because nature abhors a vacuum; opium makes men sleep because it has a dormitive potency; we recollect a past event because we have a faculty of memory.
In the history of the progress of human knowledge, out and out myths accompany the first stage of empiricism; while "hidden essences" and "occult forces" mark its second stage. By their very nature, these "causes" escape observation, so that their explanatory value can be neither confirmed nor refuted by further observation or experience.
Hence belief in them becomes purely traditionary. They give rise to doctrines which, inculcated and handed down, become dogmas; subsequent inquiry and reflection are actually stifled. (_Ante_, p. 23.)
[Sidenote: and to dogmatism] Certain men or classes of men come to be the accepted guardians and transmitters--instructors--of established doctrines. To question the beliefs is to question their authority; to accept the beliefs is evidence of loyalty to the powers that be, a proof of good citizenship.
Passivity, docility, acquiescence, come to be primal intellectual virtues. Facts and events presenting novelty and variety are slighted, or are sheared down till they fit into the Procrustean bed of habitual belief. Inquiry and doubt are silenced by citation of ancient laws or a multitude of miscellaneous and unsifted cases. This attitude of mind generates dislike of change, and the resulting aversion to novelty is fatal to progress. What will not fit into the established canons is outlawed; men who make new discoveries are objects of suspicion and even of persecution. Beliefs that perhaps originally were the products of fairly extensive and careful observation are stereotyped into fixed traditions and semi-sacred dogmas accepted simply upon authority, and are mixed with fantastic conceptions that happen to have won the acceptance of authorities.
[Sidenote: Scientific thinking analyzes the present case] In contrast with the empirical method stands the scientific. Scientific method replaces the repeated conjunction or coincidence of separate facts by discovery of a single comprehensive fact, effecting this replacement by _breaking up the coarse or gross facts of observation into a number of minuter processes not directly accessible to perception_.
[Sidenote: Illustration from _suction_ of empirical method,] If a layman were asked why water rises from the cistern when an ordinary pump is worked, he would doubtless answer, "By suction." Suction is regarded as a force like heat or pressure. If such a person is confronted by the fact that water rises with a suction pump only about thirty-three feet, he easily disposes of the difficulty on the ground that all forces vary in their intensities and finally reach a limit at which they cease to operate. The variation with elevation above the sea level of the height to which water can be pumped is either unnoticed, or, if noted, is dismissed as one of the curious anomalies in which nature abounds.
[Sidenote: of scientific method] [Sidenote: Relies on differences,] Now the scientist advances by assuming that what seems to observation to be a single total fact is in truth complex. He attempts, therefore, to break up the single fact of water-rising-in-the-pipe into a number of lesser facts. His method of proceeding is by _varying conditions one by one_ so far as possible, and noting just what happens when a given condition is eliminated. There are two methods for varying conditions.[24] The first is an extension of the empirical method of observation. It consists in comparing very carefully the results of a great number of observations which have occurred under accidentally _different_ conditions. The difference in the rise of the water at different heights above the sea level, and its total cessation when the distance to be lifted is, even at sea level, more than thirty-three feet, are emphasized, instead of being slurred over. The purpose is to find out what _special conditions_ are present when the effect occurs and absent when it fails to occur. These special conditions are then substituted for the gross fact, or regarded as its principle--the key to understanding it.
[24] The next two paragraphs repeat, for purposes of the present discussion, what we have already noted in a different context. See p. 88 and p. 99.
[Sidenote: and creates differences] The method of analysis by comparing cases is, however, badly handicapped; it can do nothing until it is presented with a certain number of diversified cases. And even when different cases are at hand, it will be questionable whether they vary in just these respects in which it is important that they should vary in order to throw light upon the question at issue. The method is passive and dependent upon external accidents. Hence the superiority of the active or experimental method.
Even a small number of observations may suggest an explanation--a hypothesis or theory. Working upon this suggestion, the scientist may then _intentionally_ vary conditions and note what happens. If the empirical observations have suggested to him the possibility of a connection between air pressure on the water and the rising of the water in the tube where air pressure is absent, he deliberately empties the air out of the vessel in which the water is contained and notes that suction no longer works; or he intentionally increases atmospheric pressure on the water and notes the result. He institutes experiments to calculate the weight of air at the sea level and at various levels above, and compares the results of reasoning based upon the pressure of air of these various weights upon a certain volume of water with the results actually obtained by observation. _Observations formed by variation of conditions on the basis of some idea or theory constitute experiment._ Experiment is the chief resource in scientific reasoning because it facilitates the picking out of significant elements in a gross, vague whole.
[Sidenote: Analysis and synthesis again] Experimental thinking, or scientific reasoning, is thus a conjoint process of _analysis and synthesis_, or, in less technical language, of discrimination and assimilation or identification. The gross fact of water rising when the suction valve is worked is resolved or discriminated into a number of independent variables, some of which had never before been observed or even thought of in connection with the fact. One of these facts, the weight of the atmosphere, is then selectively seized upon as the key to the entire phenomenon. This disentangling constitutes _analysis_. But atmosphere and its pressure or weight is a fact not confined to this single instance. It is a fact familiar or at least discoverable as operative in a great number of other events. In fixing upon this imperceptible and minute fact as the essence or key to the elevation of water by the pump, the pump-fact has thus been assimilated to a whole group of ordinary facts from which it was previously isolated. This assimilation constitutes _synthesis_.
Moreover, the fact of atmospheric pressure is itself a case of one of the commonest of all facts--weight or gravitational force. Conclusions that apply to the common fact of weight are thus transferable to the consideration and interpretation of the _relatively_ rare and exceptional case of the suction of water. The suction pump is seen to be a case of the same kind or sort as the siphon, the barometer, the rising of the balloon, and a multitude of other things with which at first sight it has no connection at all. This is another instance of the synthetic or assimilative phase of scientific thinking.
If we revert to the advantages of scientific over empirical thinking, we find that we now have the clue to them.
[Sidenote: Lessened liability to error] (_a_) The increased security, the added factor of certainty or proof, is due to the substitution of the _detailed and specific fact_ of atmospheric pressure for the gross and total and relatively miscellaneous fact of suction. The latter is complex, and its complexity is due to many unknown and unspecified factors; hence, any statement about it is more or less random, and likely to be defeated by any unforeseen variation of circumstances. _Comparatively_, at least, the minute and detailed fact of air pressure is a measurable and definite fact--one that can be picked out and managed with assurance.
[Sidenote: Ability to manage the new] (_b_) As analysis accounts for the added certainty, so synthesis accounts for ability to cope with the novel and variable. Weight is a much commoner fact than atmospheric weight, and this in turn is a much commoner fact than the workings of the suction pump. To be able to substitute the common and frequent fact for that which is relatively rare and peculiar is to reduce the seemingly novel and exceptional to cases of a general and familiar principle, and thus to bring them under control for interpretation and prediction.
As Professor James says: "Think of heat as motion and whatever is true of motion will be true of heat; but we have a hundred experiences of motion for every one of heat. Think of rays passing through this lens as cases of 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 notion every day brings us countless examples."[25] [Sidenote: Interest in the future or in progress] (_c_) The change of attitude from conservative reliance upon the past, upon routine and custom, to faith in progress through the intelligent regulation of existing conditions, is, of course, the reflex of the scientific method of experimentation. The empirical method inevitably magnifies the influences of the past; the experimental method throws into relief the possibilities of the future. The empirical method says, "_Wait_ till there is a sufficient number of cases;" the experimental method says, "_Produce_ the cases." The former depends upon nature's accidentally happening to present us with certain conjunctions of circumstances; the latter deliberately and intentionally endeavors to bring about the conjunction. By this method the notion of progress secures scientific warrant.
[Sidenote: Physical _versus_ logical force] Ordinary experience is controlled largely by the direct strength and intensity of various occurrences. What is bright, sudden, loud, secures notice and is given a conspicuous rating. What is dim, feeble, and continuous gets ignored, or is regarded as of slight importance.
Customary experience tends to the control of thinking by considerations of _direct and immediate strength_ rather than by those of importance in the long run. Animals without the power of forecast and planning must, upon the whole, respond to the stimuli that are most urgent at the moment, or cease to exist. These stimuli lose nothing of their direct urgency and clamorous insistency when the thinking power develops; and yet thinking demands the subordination of the immediate stimulus to the remote and distant. The feeble and the minute may be of much greater importance than the glaring and the big. The latter may be signs of a force that is already exhausting itself; the former may indicate the beginnings of a process in which the whole fortune of the individual is involved. The prime necessity for scientific thought is that the thinker be freed from the tyranny of sense stimuli and habit, and this emancipation is also the necessary condition of progress.
[Sidenote: Illustration from moving water] Consider the following quotation: "When it first occurred to a reflecting mind that moving water had a property identical with human or brute force, namely, the property of setting other masses in motion, overcoming inertia and resistance,--when the sight of the stream suggested through this point of likeness the power of the animal,--a new addition was made to the class of prime movers, and when circumstances permitted, this power could become a substitute for the others. It may seem to the modern understanding, familiar with water wheels and drifting rafts, that the similarity here was an extremely obvious one.
But if we put ourselves back into an early state of mind, when running water affected the mind _by its brilliancy, its roar and irregular devastation_, we may easily suppose that to identify this with animal muscular energy was by no means an obvious effort."[26] [26] Bain, _The Senses and Intellect_, third American ed., 1879, p.
492 (italics not in original).
[Sidenote: Value of abstraction] If we add to these obvious sensory features the various social customs and expectations which fix the attitude of the individual, the evil of the subjection of free and fertile suggestion to empirical considerations becomes clear. 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.
[Sidenote: Experience as inclusive of thought] In short, the term _experience_ may be interpreted either with reference to the _empirical_ or the _experimental_ attitude of mind. Experience is not a rigid and closed thing; it is vital, and hence growing. When dominated by the past, by custom and routine, it is often opposed to the reasonable, the thoughtful. But experience also includes the reflection that sets us free from the limiting influence of sense, appetite, and tradition. Experience may welcome and assimilate all that the most exact and penetrating thought discovers. Indeed, the business of education might be defined as just such an emancipation and enlargement of experience. Education takes the individual while he is relatively plastic, before he has become so indurated by isolated experiences as to be rendered hopelessly empirical in his habit of mind. The attitude of childhood is naïve, wondering, experimental; the world of man and nature is new. Right methods of education preserve and perfect this attitude, and thereby short-circuit for the individual the slow progress of the race, eliminating the waste that comes from inert routine.
PART THREE: THE TRAINING OF THOUGHT CHAPTER TWELVE ACTIVITY AND THE TRAINING OF THOUGHT In this chapter we shall gather together and amplify considerations that have already been advanced, in various passages of the preceding pages, concerning the relation of _action to thought_. We shall follow, though not with exactness, the order of development in the unfolding human being.
[Sidenote: 1. The baby's problem determines his thinking] The sight of a baby often calls out the question: "What do you suppose he is thinking about?" By the nature of the case, the question is unanswerable in detail; but, also by the nature of the case, we may be sure about a baby's chief interest. His primary problem is mastery of his body as a tool of securing comfortable and effective adjustments to his surroundings, physical and social. The child has to learn to do almost everything: to see, to hear, to reach, to handle, to balance the body, to creep, to walk, and so on. Even if it be true that human beings have even more instinctive reactions than lower animals, it is also true that instinctive tendencies are much less perfect in men, and that most of them are of little use till they are intelligently combined and directed. A little chick just out of the shell will after a few trials peck at and grasp grains of food with its beak as well as at any later time. This involves a complicated coördination of the eye and the head.
An infant does not even begin to reach definitely for things that the eye sees till he is several months old, and even then several weeks' practice is required before he learns the adjustment so as neither to overreach nor to underreach. It may not be literally true that the child will grasp for the moon, but it is true that he needs much practice before he can tell whether an object is within reach or not. The arm is thrust out instinctively in response to a stimulus from the eye, and this tendency is the origin of the ability to reach and grasp exactly and quickly; but nevertheless final mastery requires observing and selecting the successful movements, and arranging them in view of an end. _These operations of conscious selection and arrangement constitute thinking_, though of a rudimentary type.
[Sidenote: Mastery of the body is an intellectual problem] Since mastery of the bodily organs is necessary for all later developments, such problems are both interesting and important, and solving them supplies a very genuine training of thinking power. The joy the child shows in learning to use his limbs, to translate what he sees into what he handles, to connect sounds with sights, sights with taste and touch, and the rapidity with which intelligence grows in the first year and a half of life (the time during which the more fundamental problems of the use of the organism are mastered), are sufficient evidence that the development of physical control is not a physical but an intellectual achievement.
[Sidenote: 2. The problem of social adjustment and intercourse] Although in the early months the child is mainly occupied in learning to use his body to accommodate himself to physical conditions in a comfortable way and to use things skillfully and effectively, yet social adjustments are very important. In connection with parents, nurse, brother, and sister, the child learns the signs of satisfaction of hunger, of removal of discomfort, of the approach of agreeable light, color, sound, and so on. His contact with physical things is regulated by persons, and he soon distinguishes persons as the most important and interesting of all the objects with which he has to do. Speech, the accurate adaptation of sounds heard to the movements of tongue and lips, is, however, the great instrument of social adaptation; and with the development of speech (usually in the second year) adaptation of the baby's activities to and with those of other persons gives the keynote of mental life. His range of possible activities is indefinitely widened as he watches what other persons do, and as he tries to understand and to do what they encourage him to attempt. The outline pattern of mental life is thus set in the first four or five years. Years, centuries, generations of invention and planning, may have gone to the development of the performances and occupations of the adults surrounding the child.
Yet for him their activities are direct stimuli; they are part of his natural environment; they are carried on in physical terms that appeal to his eye, ear, and touch. He cannot, of course, appropriate their meaning directly through his senses; but they furnish stimuli to which he responds, so that his attention is focussed upon a higher order of materials and of problems. Were it not for this process by which the achievements of one generation form the stimuli that direct the