Part 7 (1/2)
1 THE FUNCTION OF PERCEPTION
NEED OF KNOWING THE MATERIAL WORLD--It is the business of perception to give us knowledge of our world of material _objects_ and their relations in _space_ and _tiateways of the senses is more marvelous by far than any fairy world created by the fancy of story-tellers; for it contains the elements of all they have conceived and much more besides It is more marvelous than any structure planned and executed by the mind of man; for all the wonders and beauties of the Coliseum or of St Peter's existed in nature before they were discovered by the architect and thrown together in those nificent structures The material advancement of civilization has been but the discovery of the objects, forces, and laws of nature, and their use in inventions serviceable to men And these forces and laws of nature were discovered only as they were h objects in thebefore each individual ould enter fully into this rich world of environe a part of the material world about him as possible In the most humble environment of the most uneventful life is to be found the material for discoveries and inventions yet undrea in the shade of an apple tree under the open sky, Newton read froravitation which has revolutionized science; sitting at a hu froine therefro froh studying a ball, the ancient scholars conceived the earth to be a sphere, and Columbus discovered America
THE PROBLEM WHICH CONFRONTS THE CHILD--Well it is that the child, starting his life's journey, cannot see the nitude of the task before him Cast anorant, and whoseand uses have to be learned by slow and often painful experience, he proceeds step by step through the senses in his discovery of the objects about hiain, we ourselves are after all but a step in advance of the child Though we are somewhat more familiar with the use of our senses than he, and know a few e of the wisest of us is at best pitifully er compared with the richness of nature So impossible is it for us to know all ourspecialists One man will spend his life in the study of a certain variety of plants, while there are hundreds of thousands of varieties all about him; another will study a particular kind of animal life, perhaps too minute to be seen with the naked eye, while the world is tee with animal forms which he has not time in his short day of life to stop to examine; another will study the land forical strata, but here again nature's volue that he has time to read but a small fraction of the whole Another studies the huns of health and sickness, and to prescribe remedies for its ills; but in this field also he has found it necessary to divide the work, and so we have specialists for alan of the body
2 THE NATURE OF PERCEPTION
HOW A PERCEPT IS FORMED--How, then, do we proceed to the discovery of this world of objects? Let us watch the child and learn the secret from him Give the babe a ball, and he applies every sense to it to discover its qualities He stares at it, he takes it in his hands and turns it over and around, he lifts it, he strokes it, he punches it and jabs it, he puts it to his mouth and bites it, he drops it, he throws it and creeps after it He leaves no stone unturned to find out what that thing really is By h the avenues of sense, he constructs the _object_ And not only does he come to know the ball as a material object, but he co his own best definition of a ball in terets from it and the uses to which he puts it, and all this even before he can nanize its name when he hears it How much better his method than the one he will have to follow a little later when he goes to school and learns that ”A ball is a spherical body of any substance or size, used to play with, as by throwing, kicking, or knocking, etc!”
THE PERCEPT INVOLVES ALL RELATIONS OF THE OBJECT--Nor is the case in the least different with ourselves When ish to learn about a new object or discover new facts about an old one, we do precisely as the child does if we are wise We apply to it every sense to which it will afford a stih its various qualities And just in so far as we have failed to use in connection with it every sense to which it can ree e have an incomplete perception of it Indeed, just so far as we have failed finally to perceive it in terms of its functions or uses, in that far also have we failed to know it coarden plants before it was discovered that the toht The clothing of civilized e that it does to its owner, but he is so far fro it in the sao naked The Orientals, who disdain the use of chairs and prefer to sit cross-legged on the floor, can never perceive a chair just as we do who use chairs daily, and to whoestions and associations
THE CONTENT OF THE PERCEPT--The percept, then, always contains a basis of _sensation_ The eye, the ear, the skin or soan must turn in its supply of sensory material or there can be no percept
But the percept contains more than just sensations Consider, for exa past your s You really _see_ but very little of it, yet you _perceive_ it as a very faans furnish is a more or less blurred patch of black of certain size and contour, one or more objects of soers, and various sounds of a whizzing, chugging or roaring nature Your former experience with autoer sensory details the upholstered seats, the whirling wheels, the swayingof a motor car
The percept that contained only sensory s, would be no percept at all And this is the reason why a young child cannot see or hear like ourselves It lacks the associativeto the sensory eleans The dependence of the percept on material from past experience is also illustrated in the coets fros to it He who brings no knowledge, no es from other pictures orof little besides the iven” in the realm of perception
THE ACCURACY OF PERCEPTS DEPENDS ON EXPERIENCE--We h our motor response to them as well as in tere of a tennis racket fro one and looking it over in his room, can never know a tennis racket as does the boy who plays with it on the court Objects get their significance not alone from their qualities, but even more from their use as related to our own activities
Like the child, we et it well, from the objects theh descriptions of them by others The fact that there is so much of the material world about us that we can never hope to learn it all, has s which have been discovered concerning nature This necessity has, I fear, ledreality of things to the dead e cases of words, in whose enificance which resides in the things the satisfied with the _fore without its _substance_--with definitions contained in words instead of in qualities and uses
NOT DEFINITIONS, BUT FIRST-HAND CONTACT--In like manner we come to know distance, form and size If we have never beco aa horse a ht listen for a long time to someone tell how far a o to Denver, without knowing much about it in any way except word definitions In order to understand a mile, we h sense activities of our own
Although many children have learned that it is 25,000 miles around the earth, probably no one who has not encircled the globe has any reasonably accurate notion just how far this is For words cannot take the place of perceptions in giving us knowledge In the case of shorter distances, the same rule holds The eye must be assisted by experience of thedistance, and learn to associate these sensations with those of the eye before the eye alone can be able to say, ”That tree is ten rods distant” Form and size are to be learned in the same way The handsits hardness or sle feels, the ay it takes to pass the hand over this surface and along that line, the eye taking note all the while, before the eye can tell at a glance that yonder object is a sphere and that this surface is two feet on the edge
3 THE PERCEPTION OF spacE
Many have been the philosophical controversies over the nature of space and our perception of it The psychologists have even quarreled concerning whether we possess an _innate_ sense of space, or whether it is a product of experience and training Fortunately, for our present purpose we shall not need to concern ourselves with either of these controversies For our discussion we may accept space for what common sense understands it to be As to our sense of space, whatever of this we may possess at birth, it certainly has to be developed by use and experience to become of practical value In the perception of space we must come to perceive _distance_, _direction_, _size_, and _form_ As a matter of fact, however, size is but so much distance, and form is but so much distance in this, that, or the other direction
THE PERCEIVING OF DISTANCE--Unquestionably the eye co distance Yet the e of distance The babe reaches for the moon simply because the eye does not tell it that the moon is out of reach Only as the child reaches for its playthings, creeps or walks after them, and in a thousand ways uses itsdistance, does the perception of distance become dependable
At the sa distance But not for several years does visual perception of distance becoree accurate The eye's perception of distance depends in part on the sensations arising fro the eye, probably in part from the adjuste If one tries to look at the tip of his nose he easily feels the le of adjustment We come unconsciously to associate distance with the les of vision The part played by the retinal i at two trees, one thirty feet and the other three hundred feet distant We note that the nearer tree shows the _detail_ of the bark and leaves, while the more distant one lacks this detail The nearer tree also reflects ht_ and _color_ than the one farther away These e, come to stand for so much of distance
The ear also learns to perceive distance through differences in the quality and the intensity of sound Auditory perception of distance is, however, never very accurate
THE PERCEIVING OF DIRECTION--The ive us our first perception of direction, as they do of distance The child has to reach this way or that way for his rattle; turn the eyes or head so far in order to see an interesting object; twist the body, crawl or walk to one side or the other to secure his bottle In these experiences he is gaining his first knowledge of direction
Along with thesetrained The position of the ie on the retina comes to stand for direction, and the eye finally develops so re a half inch out of plumb is a source of annoyance The ear develops some skill in the perception of direction, but is less dependable than the eye
4 THE PERCEPTION OF TIME
The philosophers and psychologists agree little better about our sense of time than they do about our sense of space Of this much, however, we may be certain, our perception of ti