# Truth and Error or the Science of Intellection/Chapter 15
## CHAPTER XV PERCEPTION

It has been shown that there is a faculty of the mind, by which judgments and concepts of kind are produced, which has been called sensation. It is now proposed to demonstrate that there is a faculty of the mind by which judgments and concepts of form are produced which will be called perception. It is difficult to select a term for this purpose. It might be best to coin one, but the term perception seems to be more often used in this sense than in any other. There is a general sense in which it is used to denote all intellections, and there is a general sense in which it is used to designate all presentative judgments, but I use it to designate the making of judgments both presentative and representative, and also of concepts of form.
We must now set forth the process of perception as judgment. Here again we have a sense impression, a consciousness, a choice, a concept, and a comparison as the foundation of a judgment. The judgment or inference is that the two compared are caused by objects having the same or a similar form. In making the judgment there must be a discrimination and an identification. The mind having an object presented to it by a sense impression must choose some other concept of a form supposed to be like this form and compare the two and make a judgment of likeness or of unlikeness as the case may be. We thus see that the external form determines the internal judgment of form.
Like a judgment of sensation, a judgment of perception may be a certitude or a fallacy. If it is a fallacy it must be corrected, and if a certitude it must be verified. If the form were determined by consciousness there would be no need of verification, but as it is external, verification is necessary. A judgment of perception is imperfectly verified by repetition, for if the likeness is discovered a second time the judgment may be supposed valid, though the same conditions for error may still exist.
In perception, as in sensation, one judgment is certified by another of a disparate sense. If I taste and touch the apple I am sure that it is an apple, or if I taste, touch, and see the apple there is still further verification.
A sense impression of light falls on my eye and I infer that it was caused by a horse of which I had a previous concept. The inference or choice of this cause recalls this concept and I conclude that the impression and the memory consciousness are alike. The concept of the horse was the concept of a form; thus the cause was conceived as a form. Perception is cognition of the cause of a sense impression, considered as a form.
When we have recognized an object many times, the process of judging seems to be abbreviated by the cancellation of the act of choice; certain it is there is no conscious act of choice and apparently the judgment follows immediately upon the consciousness of the sense impression. This cancellation of some of the elements of a judgment is particularly observable with sense impressions of vision when introspection seems to reveal no intermediate elements. It is only in cases where original judgments are made and those where there is some obscurity in the sense impression, that all of the elements of the judgment are revealed. This phenomenon of apparent cancellation of elements of judgment that are made in the act of perception cannot too strongly be emphasized. Not only are elements frequently obscure or entirely lost, but whole groups of judgments seem to be canceled in the stream of thought.
That which has been called the choice, the guess, or the hypothesis, is not a random choice but is a choice which arises from experience.
I am wandering on the shore of the lake. Weary with a long walk, I climb to the summit of a rock, from which vantage ground I hope to obtain a better view while resting. In climbing I grasp the angle of a boulder over my head and immediately feel a pain thrilling through my nerves. From the sensation of touch I gather other knowledge, as I think that I have cut my finger on the sharp edge of a crystal. From where I stand I cannot see the crystal, but my knowledge of these rocks is such that I know that sharp crystals of feldspar sometimes protrude from them, and I think of it as such. My mind neglects the effect upon myself to discover its cause—a sharp crystal on the rock—and I have made a discovery. It is my present knowledge of boulders and crystals that guides me to this discovery. Without knowledge of this kind I might give some other interpretation to the sensation. If a moment ago I had seen a rattlesnake crawling over the grass, I might have made a false interpretation and fancied myself wounded by the fang of a serpent. Or suppose I had seen a sweet-brier growing over the rock; then I might have concluded that my wound was from a thorn. This same sense impression, under different conditions of knowledge, may have different interpretations. The true interpretation is reached only because there already exists in my mind the related facts necessary to correct interpretation. The inference, therefore, is controlled by previous knowledge, and, in this case, guided to the truth.
Sitting upon the rock and gazing around the lake, my eye follows the meandering of the shore, and I readily distinguish the blue waters from the green banks. This perception is much like that by which the crystal was discovered. Let us see in what respect it is the same and in what respect it is different. In the one there was a sense impression of touch and a feeling impression of pain in my ringer when the nerve was pricked, and in the other a sense impression on my eye when the nerves were touched by light, but no feeling of pain. The light reflected from the waters beats upon my eye and produces an effect, but I do not think of the sense impression as an effect, but only of its cause. The mind goes out beyond the consciousness to the object which produces it.
In the group of mental operations by which the crystal is recognized the particular feeling of pain is conspicuous; but in the operations by which the water is discovered, the beating of light does not cause a feeling as a pleasant or as an unpleasant effect. The discovery of blue waters and green banks cannot be made without previous knowledge. Suppose that I have never seen water—that I have suddenly been transported from some mythic land where basins of glass are embosomed in the landscape; with only such knowledge in my mind I think of a beautiful sheet of glass, and, though erroneous, the interpretation is believed as true, unless I submit it to verification.
Or suppose that I climb to the top of a mountain, where bays and inlets are thrust into the land. On arriving at the summit I look about, and the mountain seems to be an island. From the foot of the mountain on every side there seems to be a stretch of gray water. After a time a breeze starts up, and the water seems to be agitated in great waves, and at last the waves are driven away in tumultuous cloudlets. Now the blue lake stretches from the foot of the mountain on one side and valleys and hills from the other. My first inference was a fallacy; my second inference is a certitude.
I look along the shore again, and I see a white object on the water. What really happens is that arranged light reflected from the distant object beats upon the nerve of my eye, which differs from other light entering it. I do not stop to observe the effect on me, but my mind is occupied with the external cause. I am just from the seaside, and have been watching the gulls soaring through the air and gathering flotsam. I interpret the beating of this white light as caused by the reflection of light by a gull. I believe I see a gull; but it moves not, and I doubt the veracity of my vision. Looking again with care, I believe that the cause of this beating is a white boulder with its crest emerging from the water. Satisfied with this interpretation, my attention is directed to a boy coming down to the shore. As a sansculotte he wades into the water and follows the floats of a net until he comes to the white object which was to me first a bird and then a boulder. Now I make the true inference and see that the white object is a white cloth—a signal on the top of a stake to mark the fishing ground—and verify it. The facts uppermost in my mind caused me to make false interpretations, each of which I could not verify, and rested satisfied only when I made an inference that was verified. As perception by touch is the interpretation of a sense impression, so perception by sight is the interpretation of a sense impression. Here again we have an interpretation which gives a judgment of the external cause of the sense impression.
Still sitting on the rock, I hear a noise. It is but waves of air beating upon the nerves of my ear; but I go beyond the consciousness and turn my head in the supposed direction of the sound, expecting to see a man coming in the distance; for have I not heard his voice? At this I am disappointed; and yet it does not seem strange, for I have made erroneous interpretations many times. I continue to watch the fisherboy in the river below. The noise is heard again, and this time it is the caw of a raven in a distant tree. I have chosen the right cause. I muse on this error. Why is the voice of a crow mistaken for the voice of a man? Because I am expecting my friend who stopped by the way where blooming plants attracted his interest. A false interpretation of a consciousness often comes from expectancy. In this manner the deluded victims of the thaumaturgic seance are made to see and often to hear the very spirits of the dead and to find confirmation of fond belief. The human mind can discover any wonder the imagination can picture, however unreal or impossible it may be, if expectancy first be wrought to the requisite intensity. All perception is by interpretation, but the data by which we interpret are memories, and correct interpretation depends upon the right guessing in the first instance and ultimately on verification; once more we have verification necessary to cognition.
Inductive or presentative perception having been set forth, it is now required to explain deductive or representative perception. A concept of perceptive judgments may be brought into consciousness by an effort of the will or adventitiously by association, and this concept of form may be compared with other concepts of form and a representative judgment made about two concepts, both of which are recalled from memory.
Thus from the storehouse of memory we may take up by choice the innumerable concepts therein and make new judgments and combine them into concepts. These representative concepts can all be traced back to presentative elements.
A representative judgment of perception, like that of sensation, has five elements. Instead of the consciousness of the sense impression we have the consciousness of a concept brought about by an act of choice arising from association or exercise of the will. Then a second concept must be chosen or recollected, and then we must have a consciousness of this second concept, and when the one concept is compared with the other a judgment is formed.
In presentative judgments we compare an impression consciousness with a memory consciousness. In a representative judgment we compare a memory consciousness with another memory consciousness. In both cases we judge of likeness or unlikeness between the terms compared. In presentative judgments we discover facts and classify them; hence presentative judgments are inductive. In making representative judgments we discover laws and apply them; hence representative judgments are deductive.
We may now more adequately define perception as the process of making a judgment about form or its reciprocal space, and of verifying the same so as to produce a cognition. Verification is accomplished by repetition, by the same sense, by submitting the judgment to another sense, that is, by congruity of judgments or by submitting it to experimentation, which is also by congruity of judgments, or by submitting the judgment of form as its reciprocal space to measurement and computation, which is only another method of verification by congruity of concepts.
A strange confusion is found among some metaphysical writers in confounding the presentative judgment with image forming. Touch is the primal sense of form, but other senses perform the same task vicariously. As taste and odor are the senses by which we discover kind and the concept of form becomes the symbol of the kind, so on the other hand while touch gives us form the kind may become the symbol of the form. Now the sense of vision is highly adapted to the performance of this symbolic or vicarious function. The image which is cast upon the retina is but arranged color with an outline which is interpreted by vision to be the mark, sign, or symbol of a form, and the perceived image is a judgment. It is thus from vision that we derive symbolic judgments of form, and the judgment which we make is the image of the form. In vision the judgment of form is but one of the judgments we make; and there are as many kinds of judgments of form as there are organs of sense. Now the metaphysical doctrine which makes images and ideas to mean the same thing as presentative and representative judgments doubly confuses the subject, for thought is a succession of judgments of all kinds and image making is a presentative judgment of vision.
We more often make the form the symbol of the other properties of a body than any of its other properties. While form is primordially cognized by touch, and touch is the final arbiter in verification of judgments of form, yet vision is more facile in making such judgments and multitudes of judgments of form are made through the sense of vision where one is made by the sense of touch; notwithstanding this the judgments of vision are greatly subject to error and often require verification.
It is due to facile cognition and recognition of form by vision that the forms of bodies become symbols of all their properties. Bodies through their forms subserve many purposes, but they also subserve many purposes through their kinds and through the other properties which inhere in them, as forces, causes, and concepts. But we seem often to cognize them first as form. We see the forms of a thousand apples, peaches, or pears, where we taste but one, and so we habitually know apples, peaches, and pears by their forms; so we know all plants by their forms, but few by their tastes and odors; so also we know all animals by their forms and but few by their tastes and odors, though it would seem that the dog knows many more things by their odors; most rocks are known by their forms, few by their tastes; altogether bodies are known as forms much more than as kinds, forces, causes, and concepts, all of which is due to the fact that vision reveals form with such marvelous rapidity, while the medium of ether is unrecognized in making presentative judgments, and is discovered only through a long course of history in the development of representative judgments. It is not strange, therefore, that early metaphysical reasoning made such a profound distinction between impressions and ideas and confused judgments of form with images by reaching the conclusion that all presentative judgments are images pictured upon the retina. We paint images and the art is coetaneous with human culture. What we do by art in painting it was supposed that nature does in light upon the retina, and this is true within certain limitations, but the picture upon the retina must be judged like the picture upon the canvas, and in both cases the arranged colors are but symbols of form which is primarily learned by touch.
In forming deductive judgments of perception, that is, judgments of form, we may find that our concepts are incongruous, that one judgment contradicts the other. When this is the case one or the other must be erroneous; we are then thrown back upon experimentation for a verification of the past judgments of which these concepts are composed. Experimentation thus becomes the great agency in time for clarifying concepts and for purging them from error, that the inductive basis for deductive reasoning 1 may be sound.
It has been seen how a stream of sense impressions pours into consciousness a body of symbols, which are there organized into systematic knowledge. Clouds assemble, change their hues and vanish; storms devastate the land and tempests vex the sea; the waters of the sea are lifted into the clouds, and the clouds themselves gather about the mountains and roll as river torrents in return to the sea; continents, islands, and mountains are upheaved, rains and rivers carve them into wonderful forms; volcanoes endeluge the land and trouble the sea; geologic formations are built and destroyed; the mountains, hills, plateaus, plains, and valleys are covered with the verdure of life; the air, the land, and the waters teem with animal forms; man himself is distributed over all land between the ice-formed walls of the polar regions—all the multitudinous objects of the cosmos are forever signalling to the human soul through vision and demanding its attention. Now one is seen, and now another; now one is heard, and now another; now one signals with fragrance, and now another; now one signals with flavor, and now another; and now one beckons with tactual signs, and now another; and the human soul gathers all these symbols into one gigantic body known as the human mind. The external world is thus coined into symbols, and of these symbols the foundations of mind are laid, and of these symbols the walls are constructed, and of these symbols the dome is reared, until the temple of the soul is perfected—a symbol structure built in every soul by the phenomena of the universe.