- CHAPTER III SUMMARY Sensation. Evolution of the special senses. — Doctrine of relativity: noumenon, phenomenon. Limitations of sense perception. The threshold. The greatness and littleness of human intellect. Special senses, a refinement of tactile sense. The outward reference of sensation. The correla tion of the senses. Visual perceptions. - The inverted retinal image, current explanation of erect vision: tactile experience reinverts visual sensation; incorrect, because not analogous to other special senses. - - First sight of congenitally blind is always erect. ignorant of retinal image. Each mathematical point of object is referred back to its proper place, and we see not the retinal image, but the object itself in space. Mr. Hanna's experience. EVOLUTION OF SPECIAL SENSES Man SENSATION is the means of communication between an organism and the outside world, — the material universe. When a nutrient particle comes in contact with the periphery of an ameba, there would be no contractility, no ingestion, were it not for the fact that the cell possesses sensation, of which the various properties of protoplasm are manifestations. The organism would remain unconscious of its environment, would starve tho surrounded by an ocean of food. The nervous system is avowedly of the lowest order, but the point to be here noted is that it is sufficient for the needs of its own organization. However meager the knowledge thus obtained may be, it immensely transcends no knowledge at all. Without attempting to trace the stages from the ameba to man, it may suffice to say that there is evident all along the line an elevation of the function of sensation. This has followed the general law of evolution "from the simple to the relatively complex," that is, sensation has become specialized. Besides common sensation, man has the so-called five senses: touch, taste, smell, hearing, and sight. DOCTRINE OF RELATIVITY To most people it has never occurred that this beautiful array of talents leaves anything more to be desired. We think we know the material universe because we can touch, taste, smell, hear, and see some of it. But what reason have we to presume that these are the only phases of matter? The deaf mute has no conception of music. To him it is a sealed book. A race of deaf mutes would be sure that they knew the material universe, because they could touch, taste, smell, and see it. Imagine their idea of a piano or a barking dog. Is it not thus apparent that we are probably oblivious to many phases of matter? These five senses are like so many doorways, or windows thru which the ego catches glimpses of the outer world. Instead of saying that we have in matter some DOCTRINE OF RELATIVITY 37 thing we really know, it may be nearer true to say that we really know more of the attributes of mind, about which we are confessedly ignorant. For example, one may know certain facts about a table, that it is two feet wide and three feet long, that it is harder than his knuckles, but the sum of his knowledge may be so meager, and the special facts so unimportant, when compared with all the facts about it, that he may have an entirely erroneous conception. Perhaps this can be illustrated by this poem by John G. Saxe. "THE BLIND MEN AND THE ELEPHANT "A HINDOO FABLE “It was six men of Indostan, To learning much inclined, “The first approached the elephant, Against his broad and sturdy side, At once began to bawl: 'God bless me, but the elephant "The second, feeling of the tusk, Cried: 'Ho, what have we here So very round and smooth and sharp? This wonder of an elephant Is very like a spear.' "The third approached the animal, And happening to take The squirming trunk within his hands, Thus boldly up and spake : 'I see,' quoth he, the elephant "The fourth reached out his eager hand And felt above the knee. 'What most this wondrous beast is like Is mighty plain,' quoth he; ''Tis clear enough the elephant Is very like a tree.' "The fifth, who chanced to touch the ear, Said: E'en the blindest man Can tell what this resembles most: Deny the fact who can? "The sixth no sooner had begun "And so these men of Indostan Exceeding stiff and strong, Tho each was partly in the right And all were in the wrong. DOCTRINE OF RELATIVITY "MORAL "So oft in theologic wars Of what each other mean, Which none of them has seen." NOUMENON AND PHENOMENON 39 John Fiske expresses this in his "Cosmic Philosophy," thus: "The doctrine of relativity affirms the existence of an unknowable reality of which all phenomena whatever are the knowable manifestations." To this unknowable is given the name of noumenon or the real thing, in distinction from phenomenon, which is the increment man knows of the real thing. The story is told that when a missionary visited some Indians and explained to them the Christian theology, with considerable emphasis on the final state of the unredeemed, the chief showed considerable skepticism. With an arrow he drew a small circle in the sand, then a larger circle enclosing the first. Pointing to the inner circle, he said: "This is what Indian know." Pointing to the outer circle: "This is what white man know." Then sweeping the arrow outside the periphery of the larger circle: "Out here Indian know just as much as white man." As a further illustration may be mentioned the old story of the doctor who denied the existence of |