Science tells us that of all the five senses, that of Touch or Feeling was the original— the fundamental sense. All the rest are held to be but modifications of, and specialized forms of, this original sense of feeling. I am telling you this not merely in the way of interesting and instructive scientific information, but also because an understanding of this fact will enable you to more clearly comprehend that which I shall have to say to you about the higher faculties or senses.
Many of the very lowly and simple forms of animal life have this one sense only, and that but poorly developed. The elementary life form “feels” the touch of its food, or of other objects which may touch it. The plants also have something akin to this sense, which in some cases, like that of the Sensitive Plant, for instance, is quite well developed. Long before the sense of sight, or the sensitiveness to light appeared in animal-life, we find evidences of taste, and something like rudimentary hearing or sensitiveness to sounds. Smell gradually developed from the sense of taste, with which even now it is closely connected. In some forms of lower animal life the sense of smell is much more highly developed than in mankind. Hearing evolved in due time from the rudimentary feeling of vibrations. Sight, the highest of the senses, came last, and was an evolution of the elementary sensitiveness to light.
But, you see, all these senses are but modifications of the original sense of feeling or touch. The eye records the touch or feeling of the light-waves which strike upon it. The ear records the touch or feeling of the sound-waves or vibrations of the air, which reach it. The tongue and other seats of taste record the chemical touch of the particles of food, or other substances, coming in contact with the taste-buds. The nose records the chemical touch of the gases or fine particles of material which touch its mucous membrane. The sensory-nerves record the presence of outer objects coming in contact with the nerve ends in various parts of the skin of the body. You see that all of these senses merely record the contact or “touch” of outside objects.
But the sense organs, themselves, do not do the knowing of the presence of the objects. They are but pieces of delicate apparatus serving to record or to receive primary impressions from outside. Wonderful as they are, they have their counterparts in the works of man, as for instance: the camera, or artificial eye; the phonograph, or, artificial ear; the delicate chemical apparatus, or artificial taster and smeller; the telegraph, or artificial nerves.
Not only this, but there are always to be found nerve telegraph wires conveying the messages of the eye, the ear, the nose, the tongue, to the brain— telling the something in the brain of what has been felt at the other end of the line. Sever the nerves leading to the eye, and though the eye will continue to register perfectly, still no message will reach the brain. And render the brain unconscious, and no message will reach it from the nerves connecting with eye, ear, nose, tongue, or surface of the body. There is much more to the receiving of sense messages than you would think at first, you see.
By Swami Panchadasi – Courtesy of Project Gutenberg