By means of our so-called "sensory exercises" we make it possible for the child to distinguish and to classify. Our sensory material, in fact, analyses and represents the attributes of things: dimensions, forms, colors, smoothness or roughness of surface, weight, temperature, flavor, noise, sounds. It is the qualities of the objects, not the objects themselves which are important; although these qualities, isolated one from the other, are themselves represented by objects. For the attributes long, short, thick, thin, large, small, red, yellow, green, hot, cold, heavy, light, rough, smooth, scented, noisy, resonant, we have a like number of corresponding "objects" arranged in graduated series. This gradation is important for the establishment of order; indeed, the attributes of the objects differ not only in quality, but also in quantity. They may be more or less high or more or less low, more or less thick or more or less thin; the sounds have various tones; the colors have various degrees of intensity; the shapes may resemble each other in varying degrees; the states of roughness and smoothness are by no means absolute.
The material for the education of the senses lends itself to the purpose of distinguishing between these things. First of all it enables the child to ascertain the identity of two stimuli by means of numerous exercises in matching and fitting. Afterwards difference is appreciated when the lessons direct the child's attention to the external objects of a series: light, dark, long, short.
At last he begins to distinguish the degrees of the various attributes, arranging a series of objects in gradation, such as the tablets which show the various degrees of intensity of the same chromatic tone; the bells which produce the notes of an octave, the objects which represent length in decimal proportions, or thickness in centimetric proportions, etc.
These exercises, which are so attractive to children, are, as we have seen, repeated by them indefinitely. The teacher puts the seal upon each acquisition with a word; thus the classification is complete, and finally has its schedule: that is, it becomes possible to recall the attribute and its image by a name.
Now as we have no possible means of distinguishing things other than by their attributes, the classification of these entails a fundamental order of arrangement comprehending everything. Henceforth the world is no longer a chaos for the child; his mind bears some resemblance to the orderly shelves of a library or a rich museum; each object is in its place, in its proper category. And each acquisition he makes will be no longer merely "stored," but duly "allocated." This primitive order will never be disturbed, but only enriched by fresh material.
Thus the child, having acquired the power of distinguishing one thing from another, has laid the foundations of the intelligence. It is unnecessary to repeat what an internal impulse the acquired order contributes towards the seeking after objects in the environment; henceforth the child "recognizes" the objects which surround him. When he discovers with so much emotion that the sky is blue, that his hand is smooth, that the window is rectangular, he does not in reality discover sky, nor hand, nor window, but he discovers their position in the order of his mind by arrangement of his ideas. And this determines a stable equilibrium in the internal personality, which produces calm, strength, and the possibility of fresh conquests, just as the muscles which have coordinated their functions enable the body to maintain its equilibrium, and to acquire that stability and security which facilitate all movements. This order conduces to an economy of time and strength; like a well-arranged museum, it saves the time and strength of inquirers. The child can therefore perform a greater quantity of work without fatigue, and can react to stimuli in a briefer space of time.
To be able to distinguish, classify, and catalogue external things on the basis of a secure order already established in the mind—this is at once intelligence and culture. This is, indeed, the popular conception; when an educated person can recognize an author by his style, or the characteristics of the literary compositions of a period, he is pronounced "versed (intelligente) in literature." In the same way we say of one who can recognize a painter by the manner in which he lays his colors on the canvas, or fix the period of a sculptor from the fragment of a bas-relief, that he is "versed (intelligente) in art." The scientist is of the same type. He is able to observe things, and to give due value even to their minutest details; hence the differences between the characteristics of things are clearly perceived and classified. The scientist distinguishes objects in accordance with the orderly content of his mind. A seedling, a microbe, an animal or the remains of an animal, are not enigmas to him, though in themselves they may be strange to him. We may say the same of the chemist, the physicist, the geologist, the archæologist.
It is not the accumulation of a direct knowledge of things which forms the man of letters, the scientist, and the connoisseur; it is the prepared order established in the mind which is to receive such knowledge. On the other hand, the uncultivated person has only the direct knowledge of objects; such a person may be a lady who spends a great part of the night reading books, or a gardener who spends his life making material distinctions between the plants in his garden. The knowledge of such uncultured minds is not only disorderly, but it is confined to the objects with which it comes into direct contact, whereas the knowledge of the scientist is infinite, because, possessing the power of classifying the attributes of things, he can recognize them all, and determine now the class, now the relationships, now the origins of each; facts much more profound than the actual things could of themselves reveal.
Now our children, after the manner of the connoisseur of art and the man of science, recognize objects in the external world by means of their attributes and classify them; hence they are sensitive to all objects; everything possesses a value for them. Uncultured children, on the other hand, pass blind and deaf close to things, just as an ignorant man passes by a work of art or listens to a performance of classical music without recognition or enjoyment.