Before We Start

We will start with sight since man is predominantly a visual animal. It must be said that Darwin had some difficulty in coming to terms with the relative perfection of the human eye and his understanding that it must have evolved. He concluded that there must have been intermediate stages, though some of these are now difficult to trace. However, he did observe that no organ is ever perfected but is only developed to a level which enables it to cope with the present situation. So let us consider the ways in which the eyes are limited.

To start with we only look in one direction at any one time and therefore only see what is going on in front of our eyes at that time. Even collectively people cannot observe everything, not even with surveillance systems. Further, evolution has adapted our eyes in such a way that we observe the world at a certain level of magnification. This is generally known as the classical level. However with the passage of time instruments such as the telescope and the microscope have been invented, which have greatly extended our understanding of the world around us and indeed the universe. The microscope was instrumental in revealing the cellular nature of living things and the world of bacteria. The electron microscope further revealed the world of viruses. Great achievements as these have been, the instruments can only view a limited field at one time. They do not plug into the world around us in the way that we observe things at the classical level.

There are many subtleties to the human eye. The brain interprets what the eyes see and since the visual field is usually flooded with all kinds of information at any one time the brain has evolved a complex system of attention known as the schemata. We shall return to the subject of the schemata in the section on psychology for a detailed study. Some practical examples from life will show us how subtle the system of attention is. While a child may be captivated by the observation of a flower or some animal, perhaps a pet, other people can find that more abstract things can often occupy the mind. The story of a philosophy professor wandering in a formal park is instructive in such cases. The professor was so lost in his thoughts that he did not notice the ‘Keep off the Grass’ notice and began to wander across the grass. When the park keeper saw him he shouted after him “Who do you think you are and where do you think you are going?” The professor, still lost in thought said “If only I knew the answers to those questions”. It is an amusing story but we should observe that although the professor was lost in his thoughts he was also aware at the same time of the general direction in which he was walking and that someone had spoken to him. Even with his concentration turned inwards his mind was also recording other aspects of his surroundings. This example reminds us how the different modalities are integrated. Most of the time sight and hearing are integrated, as is muscular feedback when we are moving. A person walking along a street may at the same time be aware of a bird singing in a tree and see the bird.

Returning to sensory perception, it is possible to delude our senses. Some people are interested in optical illusions although common experiences of modern life illustrate this. 3D images produced on flat surfaces by vertical scanning techniques are examples, as are holographic images. In these cases we see 3D images which are not there in reality. The illusion of movement is created on the television and film screen and we even have 3D versions of moving pictures. At the same time, sound projected in stereo can further add to the illusion by making the sound appear to come from some point in the projected image. If a car moves across the screen and disappears into the distance the sound can be made to seem to come from the moving car. When a car or plane comes towards you and then recedes into the distance, the pitch of the engine varies, becoming louder and higher pitched as it approaches and lower pitched and quieter as it recedes into the distance. All this can be reproduced by modern communications technology, to make the illusion complete. We all use mirrors which seem to create images behind them, and much fun can be had in rooms where there are mirrors which deliberately distort the image. However, you may argue that this is part of the wonder of the human mind. The film ‘The Matrix’ takes the deluding of the mind to the logical conclusion by subjecting an individual to complete virtual reality.

Even feelings of spatial awareness can be deluded. There is a party game where a person is blindfolded and asked to stand on a board while two other people hold the board and a third person rests their hands on the shoulders of the blindfolded person. The third person presses down on the shoulders while the two persons holding the board slowly raise it about 3 inches above the ground. Then the blindfolded person is asked to jump off the board and onto the floor. To the blindfolded person the illusion is that at that point they think they are several feet above the floor. After the jump they are surprised to find that the board was only 3 inches off the ground, as is clear not only from the jump but also when the blindfold is removed.

Being blindfolded reminds us of the difficulties we experience when trying to find our way in the dark. Blind people, of course, have to cope with this all the time but most of us find the experience difficult. Even limited vision can prove difficult as anyone who has had to find their way in very foggy conditions would realise. Clear vision is extremely important to us.

Some of the anomalies of human experience are due to our anatomy and physiology. Young children sometimes play the game of spinning round fairly rapidly to make themselves feel giddy. It is a peculiar fact that this experience can have this effect which is due to the physiology of the inner ear. None of our senses are perfected and there are situations in which the senses limitations become obvious.