III. Mind and Body
The relationship between mind and body has been pondered by most cultures throughout history. In western culture it is generally believed that the spirit is something independent of the body, and that the body was a burden to it. There is no scientific evidence of a consciousness independent of the body, and this remains a topic for religion.
The relationship between mind and body is evident, particularly in the dramatic changes of individuals who have survived trauma to the brain, and we recognize that this is where our consciousness is housed.
The various parts of the body are connected to the min. It is the eyes that that sense light, shape, color, etc. but they eyes do not see - they transmit the sensations to the mind, which makes sense of the data that they eyes provide. In the same way it is the hands that work, but the skill of working is not in the hands - they are directed in their operations by the mind.
Nerves and Brain
It may, perhaps, be said that our bodies are largely extensions of the mind - whether conveying information to the brain or receiving impulses to move from it through a network of neural connections.
(EN: Pyle is a bit vague or wrong-headed about the method through which information is transmitted - referring to the activity as an "excitation" in the nerves and the brain. I'm not entirely certain whether, in taking notes, I will amend this, and will likely leave it vague.)
The sensory organs support the mind by receiving stimulation fro the outside world - the eye senses light, the ear senses vibrations - and then transmits this information through the nerves to the brain. Unless these signals reach the brain, we are not conscious of the sensation, or of what it means, or of whatever produced it.
It has been seen that injuries that disrupt these connections render the sense organs useless. They eye itself may be undamaged and functional as an organ, but if the optic nerve is severed the individual is unable to receive any information from the eye - he cannot "see" in spite of the fact that the eye is responsive to light.
(EN: His argument here goes on for a while and becomes a bit tedious, but remember that this was written in 1917, and there was in that time very little understanding of this, and much of what was believed about neurology were philosophical theories of varying plausibility).
He intends in this chapter to consider primarily the sense organs, as they are fundamental to human experience. All of our knowledge comes to us, initially, through our senses - and while it may be admitted that there are mental/conceptual details that are created wholly within the mind, even these are assembled from data that was received through our sensations of the outside world.
Vision
Vision is our primary sense. There is no condition more debilitating than losing the ability to see, and as such it is and has long been the sensation that is of greatest concern to psychologists. While all sensations contribute to our understanding of the world, most of the data we have to process is visual.
The visual sensory organ, the eye, is a very basic physical structure that works much like a camera: it consists largely of an aperture over which there is a lens, which receives light and focuses it on a plate that translates the information it receives into an image. This image is then transmitted through the optic nerve to the back of the brain, where our processing of sensory data begins.
(EN: More recent investigations suggest that the information received is not a coherent image, but merely a sensation of colors and shapes, and it is the brain that translates this raw data into imagery, discerning specific objects, assessing their distance, determining which sensations are a "thing" and considering the nature of that thing.)
Light is conceived as a wave pattern in which colors are themselves dependent on the frequency of vibrations, and the intensity of color are based on the amplitude. The eye has a limited capacity to perceive distinctions - such that outside of the limited range of vision things become invisible: either fading to darkness or being perceived only as brightness.
It's also mentioned, indirectly, that the eye has a limitation of density such that the light waves received are "averaged." So we may perceive two points of red and yellow light, but if the two are small and proximate, we perceive the color orange (even though there is no source of orange light) - some colors combine and other colors neutralize one another.
This is also the reason that powdered pigments create a variety of hues: it is not that the powders physically combine, but because the granules are too small to be perceived as distinct objects. Seen with the naked eye, the paint appears to be orange - but viewed with a powerful enough lens, the separate granules of red and yellow can be clearly discerned.
Another phenomenon that causes colors to average or neutralize is speed of perception. Consider a projector mounted with a disk that has red and yellow filters. If the disk rotates slowly, the subject perceives them as different colors - but if the disk rotates rapidly, the subject perceives the color orange, an average of the two stimuli.
(EN: All of this should be very familiar in the present day, given the manner in which television uses red, green, and blue to produce millions of different colors - but in the author's time this was quite a discovery, and difficult to demonstrate in the real world.)
Because of this averaging/neutralizing effect, an object of intense color may distort the perception of objects nearby it - shifting them to a complementary color: red makes objects nearby it appear greenish, and vice versa. Shade has a similar effect, in that a light object makes those nearby appear to be darker than they are.
Visual after-images are another phenomenon. Place on a table two sheets of paper, one which is white and the other red. Ask the subject to stare intently at the red sheet for a few minutes, then move his gaze immediately to the white one, and it will appear to be green (the complementary color to red). If the white sheet is larger, he will perceive a green field n the size and shape of the red sheet.
Pyle reckons this is due to adaptation: if the eyes are stimulated by the same color for a time, they adapt to that color. He asserts that if you stare at a field of color for some time, that color will begin to fade and even become white. This is the effect of the mind dismissing the color as irrelevant and attempting to focus on more important information - that which is different to what is perceived.
(EN: This explanation seemed a bit contrived, but looking into it even modern neurologists maintain this theory and correlate it to survival skills. When all is still, the moving object presents the greatest opportunity or danger; when all is dark we focus on what is light; we tune out regular patterns of noise to focus on the unusual; etc. So the mind tunes out things that do not change and focuses on those that do - but in so doing they "trick" perception and this takes a few seconds to cease.)
Hearing
Pyle spends only a few paragraphs on the auditory sense: it is perceived as waves of compression in the air which strike a membrane in the ear and are translated into sound, which is likewise transmitted to the occipital region of the brain for identification and interpretation.
The frequency of vibration causes sound to have a given tone, and the intensity of vibration causes a sound to have volume. And as with vision, there are limitations to both the pitch we can perceive and the volume we can tolerate - such that sound of too great intensity becomes a ringing sensation and sound of too little intensity is not heard at all.
Other Senses
The author explicitly states that "we need not give a detailed statement of facts concerning the other senses" - the basic properties of perception are the same, it is merely the mechanism by which stimuli are received that differ,
- Taste, perceived through the tongue, is the chemical analysis of substances that come in contact with the tongue, somewhat distorted as the acidic compounds in saliva alter its properties
- Scent is also a chemical analysis, similar to taste, that is performed on airborne particles that enter the nose, and are likewise distorted by digestion
- Touch is a combination of sensations received by sense organs in the skin, which combine temperature and pressure to a tactile sensation.
- Motion is perceived by sense organs in the joints, tendons, and muscles which provide our basic perception of motion, the position and status of the body, and so on. (EN: This seems a bit specious, but somatic sensations are recognized by modern science, though they are categorized under the sense of touch.)
- Attitude is perceived through the canals of the inner ear, which give us a sense of our body's general position as well as a sense of motion and our perception of up-and-down (EN: This is also recognized by modern science, though curiously it is not often included in discussions about the senses.)
For each sense there are similarities to the properties described in the context of vision: our ability to perceive quality and intensity, the blurring of sensation due to proximity and frequency of change, etc.
Sensory Defects
Since our sensations of the outside world become the material upon which the mind works, the brain is very much dependent on our sensory organs. If they are disabled, so is the mind - and if they function improperly, so does the mind.
(EN: Pyle is more functional than philosophical in his approach, but this last sentence is of particular interest. Consider the allegory of the cave: people with impaired perception have a sense that what they are able to perceive is reality and they know no other perspective except in an abstract and second-hand sense, which they trust less than their senses. It is distorted or imperfect information that leads to the most interesting and insidious defects of philosophy and psychology.)
However, to speak of something as being defective requires us to have a concept of what is normal - and this should be approached with caution. Each person perceives himself to be normal, provided that his perceptions are superficially confirmed by others, and believes that the perceptions of others, particularly when they disagree with one's own beliefs, are abnormal.
In nature, no two things are perfectly alike and no one thing is intrinsically perfect - and this includes the organs of perception. That is, there is no perfect eye and no two eyes are alike - they are all made of a basic template but their shape, curvature, and structure all have subtle variations.
For about two-thirds of the population, their vision is good enough for most tasks (given that about a third of school children require glasses to correct defects in vision that are severe enough to impair their ability to focus) - but "functional" is not identical. Pyle lists and describes various defects of the eye: nearsightedness, farsightedness, astigmatism, color blindness, and the like.
Much has been discovered about optics in the author's time - largely because the tasks that people perform in the industrial era require discernment of fine details. The activities of the agrarian society - farming, herding, fishing, and the like - have no such requirements. So it is not that defects of the eye are arising in the author's time, but they have been there all along and have only recently been discovered because of the requirement of visual acuity for tasks that have only recently been needed.
Thus considered, we may not be aware of all the defects that exist, only those that evidence themselves by impairing an ability to do some task. The number of individuals who have defects of the eye may yet be underestimated because of the number of people who can get by with substandard vision. And as new tasks are created, additional forms of optical defect may be uncovered.
The point to all of this is the need for caution in any discussion of what is standard what is unusual - as well as to recognize that even people who do not encounter any functional impediment due to their sensory limitations and defects may not be as perfect as they assume themselves to be. They have simply not discovered their defectiveness and assume their perception to be reliable.