The use of familiar notions in acquiring an insight into new things is a natural tendency or drift of the mind. As soon as we see something new and desire to understand it, at once we involuntarily begin to ransack our old stock of ideas to discover anything in our previous experience which corresponds to this or is like it. For whatever is like it or has an analogy to it, or serves the same uses, will explain this new thing, though the two objects be in other points essentially different. We are, in short, constantly falling back upon our old experiences and classifications for the explanation of new objects that appear to us.
So far is this true that the most ordinary things can only be explained in the light of experience. When John Smith wrote a note to his companions at Jamestown, and thus communicated his desires to them, it was unintelligible to the Indians. They had no knowledge of writing and looked on the marks as magical. When Columbus' ships first appeared on the cost of the new world, the natives looked upon them as great birds. They had never seen large sailing vessels. To vary the illustration, the art of reading, so easy to a student, is the accumulated result of a long collection of knowledge and experience. There is an unconscious employment of apperception in the practical affairs of life that is of interest. We often see a person at a distance and by some slight characteristic of motion, form, or dress, recognize him at once. From this slight trace we picture to ourselves the person in full and say we saw him in the street. Sitting in my room at evening I hear the regular passenger train come in. The noise alone suggests the engine, cars, conductor, passengers, and all the train complete. As a matter of fact I saw nothing at all but have before my mind the whole picture. On Sunday morning I see some one enter a familiar church door, and going on my way the whole picture of church, congregation, pastor, music and sermon come distinctly to my mind. Only a passing glance at one person entering suggests the whole scene. In looking at a varied landscape we see many things which the sensuous eye alone would not detect, distances, perspective and relative size, position and nature of objects. This apperceptive power is of vast importance in practical life as it leads to quick judgment and action, when personal examinations into details would be impossible.
In apperception we never pass from the known to things which are entirely new. Absolutely new knowledge is gained by perception or intuition. When an older person meets with something totally new, he either does not notice it or it staggers him. Apperception does not take place. In many cases we are disturbed or frightened, as children, by some new or sudden noise or object. But most so-called new things bear sufficient resemblance to things seen before to admit of explanation. Strange as the sights of a Chinese city might appear, we should still know that we were in a city. In most "new" objects of observation or study, the familiar parts greatly preponderate over the unfamiliar. In a new reading lesson, for example, most of the words and ideas are well known, only an occasional word requires explanation and that by using familiar illustrations. The flood of our familiar and oft-repeated ideas sweeps on like a great river, receiving here and there from either side a tributary stream, that is swallowed up in its waters without perceptible increase.
So strong is the apperceiving force of familiar notions that they drag far-distant scenes in geography and history into the home neighborhood and locate them there. The imagination works in conjunction with the apperceiving faculty and constructs real pictures. Children are otherwise inclined to substitute one thing for another by imagination. With boys and girls, geographical objects about home are often converted by fancy into representatives of distant places. It is related of Byron that while reading in childhood the story of the Trojan war, he localized all the places in the region of his home. An old hill and castle looking toward the plain and the sea were his Troy. The stream flowing through the plain was the Simois. The places of famous conflicts between the Trojans and Greeks were located. So vivid were the pictures which these home scenes gave to the child, that years later in visiting Asia Minor and the sight of the real Troy, he was not so deeply impressed as in his boyhood. A German professor relates that he and his companions, while reading the Indian stories of Cooper, located the important scenes in the hills and valleys about Eisenach in the Thuringian mountains. Many other illustrations of the same imaginative tendency to substitute home objects for foreign ones are given. But whether or not this experience is true of us all, it is certain that we can form no idea of foreign places and events except as we construct the pictures out of the fragments of things that we have known. What we have seen of rivers, lands, and cities must form the materials for picturing to ourselves distant places.
Since the old ideas have so much to do with the proper reception of the new, let us examine more closely the interaction of the two. If a new idea drops into the mind, like a stone upon the surface of the water, it produces a commotion. It acts as a stimulus or wakener to the old ideas sleeping beneath the surface. It draws them up above the surface-level; that is, into consciousness. But what ideas are thus disturbed? There are thousands of these latent ideas, embryonic thoughts, beneath the surface. Those which possess sufficient kinship to this new-comer to hear his call, respond. For in the mind "birds of a feather flock together." Ideas and thoughts which resemble the new one answer, the others sleep on undisturbed, except a few who are so intimately associated with these kinsmen as to be disturbed when they are disturbed. Or, to state it differently, certain thought-groups or complexes, which contain elements kindred to the new notion, are agitated and raised into conscious thought. They seem to respond to their names. The new idea may continue for some time to stimulate and agitate. There appears to be a sort of telegraphic inquiry through the regions of the mind to find out where the kindred dwell. The distant relatives and strangers (the unrelated or unserviceable ideas) soon discover that they have responded to the wrong call and drop back to sleep again. But the real kindred wake up more and more. They come forward to inspect the new-comer and to examine his credentials. Soon he finds that he is surrounded by inquisitive friends and relatives. They threaten even to take possession of him. Up to this point the new idea has taken the lead, he has been the aggressor. But now is the time for the awakened kindred ideas to assume control and lead the stranger captive, to bring him in among themselves and give him his appropriate place and importance. The old body of ideas, when once set in motion, is more powerful than any single-handed stranger who happens to fall into their company. The outcome is that the stranger, who at first seemed to be producing such a sensation, now discovers that strong arms are about him and he is carried captive by vigorous friends. New ideas when first entering the mind are very strong, and, if they come through the senses, are especially rich in the color and vigor of real life. They therefore absorb the attention at first and seem to monopolize the mental energies; but the older thought masses, when fully aroused, are better organized, more firmly rooted in habit, and possess much wider connections. They are almost certain, therefore, to apperceive the new idea; that is, to conquer and subdue it, to make it tributary to their power.
Let us examine more closely the effect of the process of apperception upon the new and old ideas that are brought in contact. First, observe the effect upon the new: Many an idea which is not strong enough in itself to make a lasting impression, upon the mind would quickly fade out and be forgotten were it not that in this process the old ideas throw it into a clear light, give it more meaning, associate it closely with themselves, and thus save it. Two persons look at the sword of Washington; one examines it with deep interest, the other scarcely gives it a second glance. The one remembers it for life, the other forgets it in an hour. The sense perception was the same in both persons at first, but the reception given to the idea by one converts it into a lasting treasure. A little lamp-black, rolled up between finger and thumb, suggested to Edison his carbon points for the electric light. A piece of lamp-black would produce no such effect in most peoples minds. The difference is in the reception accorded to an idea. The meaning and importance of an idea or event depend upon the interpretation put upon it by our previous experience. "Many a weak, obscure, and fleeting perception would pass almost unnoticed into obscurity, did not the additional activity of apperception hold it fast in consciousness. This sharpens the senses, i.e., it gives to the organs of sense a greater degree of energy, so that the watching eye now sees, and the listening ear now hears, that which ordinarily would pass unnoticed. The events of apperception give to the senses a peculiar keenness, which underlies the skill of the money-changer in detecting a counterfeit among a thousand bank-notes, notwithstanding its deceptive similarity; of the jeweler who marks the slightest, apparently imperceptible, flaw in an ornament; of the physicist who perceives distinctly the overtones of a vibrating string. According to this we see and hear not only with the eye and ear, but quite as much with the help of our present knowledge, with the apperceiving content of the mind." (Apperception, Lange, De Garmo, p. 21.)
Some even intelligent and sensible people can walk through Westminster Abbey and see nothing but a curious old church with a few graves and monuments. To a person well-versed in English history and literature it is a shrine of poets, a temple of heroes, the common resting-place of statesmen and kings.
Secondly, what is the effect on the old ideas? Every idea that newly enters the mind produces changes in the older groups and series of thought. Any one new idea may cause but slight changes, but the constant influx of new experiences works steadily at a modification and rearrangement of our previous stores of thought. Faulty and incomplete groups and concepts are corrected or enlarged; that is, changed from psychical into logical notions. Children are surprised to find little flowers on the oaks, maples, walnuts, and other large forest trees. On account of the small size of the blossoms, heretofore unnoticed, they had not thought of the great trees as belonging to the flowering plants. Their notion of flowering plants is, therefore, greatly enlarged by a few new observations. The bats flying about in the twilight have been regarded as birds; but a closer inspection shows that they belong to another class, and the notion bird must be limited. As already observed in the discussion of induction, most of our psychical notions are thus faulty and incomplete; e.g., the ideas fruit, fish, star, insect, mineral, ship, church, clock, dog, kitchen, library, lawyer, city, etc. Our notions of these and of hundreds of other such classes are at first both incomplete and faulty. The inflow of new ideas constantly modifies them, extending, limiting, explaining, and correcting our previous concepts.
Sometimes, however, a single new thought may have wide-reaching effects; it may even revolutionize one's previous modes of thinking and reorganize one's activities about a new center. With Luther, for instance, the idea of justification by faith was such a new and potent force, breaking up and rearranging his old forms of thought. St. Paul's vision on the way to Damascus is a still more striking illustration of the power of a new idea or conviction. And yet, even in such cases, the old ideas reassert themselves with great persistence and power. Luther and St. Paul remained, even after these great changes, in many respects the same kind of men as before. Their old habits of thinking were modified, not destroyed; the direction of their lives was changed, but many of their habits and characteristics remained almost unaltered.
Apperception, however, is not limited to the effects of external objects upon us, to the influence of ideas coming from without upon our old stores of knowledge. Old ideas, long since stored in the mind, may be freshly called up and brought into such contact with each other that new results follow, new apperceptions take place. In moments of reflection we are often surprised by conclusions that had not presented themselves to us before. A new light dawns upon us and we are surprised at not having seen it before. In fact, it makes little difference whether the idea suggested to the mind comes from within or from without if, when it once enters fairly into consciousness, it has power to stimulate other thoughts, to wake up whole thought complexes and bring about a process of action and reaction between itself and others. The result is new associations, new conclusions, new mental products—apperceptions.