The educational screen (c1922-c1956])

November, jg2^ Visual Instruction Association of America u:; We have delimited with some degree of precision the part played by sensation in the process of acquiring knowledge. There can be little quarrel, I think, with our rather cautious formula, that "Our knowledge of the world about us is derived chiefiy from our interpreation of our sense experiences." Since sensation, therefore, constitutes the first step which we must explore in our examination of the learning process, it may be helpful to reverse this formula, and center it upon the function of sensation itself. From this viewpoint, it would run somewhat as follows: "Sensation is the reaction of the ego (s^lf, soul) to stimuli from the outside world, transmitted through the nervous system, by means of which the individual arrives at a consciousness of self and of the world about him, and through the interpretation of which he derives some conception of the universe." ' Having thus outlined the function of sensaj tion as a factor in the acquisition of knowledge, it still remains to inquire into the character of those concrete experiences known as sensations. We must confess at the outset that we know absolutely nothing of their physical nature. That they are produced by vibration of the ether, or of air, and by physical impacts of some sort, acting upon the terminals of the afferent nerves and transmitted in some way to the brain and there in some way registered, recorded and co-ordinated, constitutes practically the sum of our knowledge. Whether the effect upon the nervous system, including the brain, is a chemical or a physical one is thus far a mere guess. To enter upon it here would lead us into an interminable discussion, nor is it of particular consequence for our purpose. What is of consequence is to note that the fact of sensation transcends all mechanical explanation, because it involves the profoundly baflfling fact of consciousness. No account or description of it is complete that does not briir it into the realm of the psychic, as distinguished from the physiological. Perhaps the one point to which we should adhere most tenaciously is that sensation is a psychic phenomenon, rather than a physiological reaction. Before sensation has been translated into perception, before there has arisen any faintest conception of the meaning or significance of this clamor from the outer world that is beating upon the seven doors of self, there awakens an awareness of self and of a something outside of self. Long before 1 have any idea what 1 am listening to, I not only hear but I am aware that I hear. Long before I have any notion what I am looking at, 1 not only sec but I am conscious that I see. I may add, at the risk of making a distinction without a difference, that I am aware that it is I that see, and that what I sec is not L Thus the very simplest sensation brings us not only to the threshold but across the threshold of that world which we instinctively recognize as a separate realm, the realm of personality, of subjectivity, of the self, the soul, the ego. From this point on we may trust our intuition and accept the human soul as an entity, measurably master of its surroundings and captain of its own destiny, tenanting a body which serves it as a medium of communication with the world about it and with other psychic entities; or we may accept the Hegelian formula of thought, feeling and will as mere functions of the cerebral gland, just as digestion is the function of the stomach, or respiration of the lungs. To my mind it will make a tremendous difference in our teaching which view we accept, but in either event one thing is very clear. If thought, feeling and will are mere functions, we must be careful at every step to distinguish between the secretion and the gland. The products of sensation constitute the facts of consciousness and from the moment that sensation is complete, we are dealing not with physiological reactions, but with a vast complex of phenomena which have their existence entirely apart from the reaction which precipitated them and which are linked with external stimuli only at the point and in the moment of original impact. In proportion as we recognize this truth shall we proceed intelligently to build upon our own sense experiences, or those of our pupils. In the realization of this distinction lies all the difference between training the senses, as one trains white mice and pet pigs, and cultivating the mind through the skillful use of the senses. Proceeding now to a closer view of the intellectual process and beginning with the sensations themselves, the first step would seem to be to observe the outstanding characteristics common to all sensations. I have placed at the head of this article an outline, or rather a sort of table, by which I have hoped to convey some graphic impression of the elaborate train of psychic phenomena set in motion by sensa