What Is the Correlation Between Light and Sight?
Many people wonder and question whether the universe that we see and perceive from the first to the last hour of a day is real or not. Like many people, philosophers in the past have argued a lot about the human view because philosophy is also the basis of biological sciences, and in the past, human vision, light, and perception of the universe have been discussed by many philosophers. For example, in the New Theory of Vision, Berkeley argues that visual objects are in the mind, and the act of seeing is a mind-dependent idea, (1709). In other words, according to Berkeley, the coming of a transparent and fluid liquid that comes to mind when water is mentioned is that the act of seeing is realized with experience and mind. The substances seen are not real, but substances can only be realized with the mind. On the other hand, in the article ‘’Aristotle’s Reality: How Was It Different from His Teacher’s Theory?’’ Gimbel mentions that, according to the vision of Aristoteles, all matter exists independently from the mind, and Aristotle admits that all concrete matter seen is real (2020). In addition to all these optical reality debates in history, in the book ‘’Arabic Sciences and Philosophy’’, Peterson refers to the Al-Kindi, who is one of the oldest and most important optical writers in the Islamic world according to Peterson, Al-Kindi laid the first foundations of optics in human vision and emphasized the importance of light in perception in 17th century. Al-Kindi argued that the vision is voluminous, and it is formed by the reflection of three-dimensional volumes (2006). In later years, modern theories about light and vision were produced, and in the article ‘’ How Light Works?’’ Harris mentions Dutch mathematician-astronomer Christiaan Huygens suggested in 1960 that light reflected from objects to the eye and activates the act of vision (2000). The issue of optics, which has led to various discussions, has brought along various debates and theories such as why people cannot see in the darkness, why some animals, unlike humans, can see better in the darkness, and whether there are differences of vision or not from person to person. This paper will explain all these optical questions and debates objectively.
In the act of seeing to understand the importance of light and why we cannot see in the dark, it is necessary to first understand the eye structure and how the act of vision takes place. The cornea is located at the forefront of the eye and helps the eye to focus light. Behind the pupil, there is a transparent structure called the crystal lens, and after the cornea focuses the light, the light passes through this lens. In addition, there is another structure called the iris behind the cornea, and the iris contracts and expands to adjust the amount of light entering the eye. The inside of the eyeball is filled with a jelly-like tissue called the vitreous humor, and light must pass through the humor for vision to occur (Than, 2016). The most important requirement for the act of seeing to take place is light, and therefore light is vital to the act of seeing. For example, while people can distinguish colors and objects better during daylight hours or in areas with high light, they cannot perceive colors and objects clearly at night or in places with low light, and their vision is limited with low light. Because there are two types of light-sensitive organs behind the eye, called rods and cones. Although their functions are somewhat similar, they have differences in terms of tasks. Rods and cones are sensitive to light, but while rods allow vision in dim light, they do not perceive colors, cones allow color perception, but they do not operate in dim light. cones need more light to work (Glass, 2012). Therefore, in places with less light, human vision is insufficient to perceive objects and colors, and neither colors nor objects can be perceived completely. In addition, a study of cones and rods recently discovered a mechanism in the functioning of the eye that might help people see in bright and low light. The researchers first removed the pigment epithelium in the retina, which regulates the amount of light entering the eye. Thus, the pigment molecules could not be recycled. They exposed the retinal cells to both bright light and darkness which is why they observed that the rods stopped working. However, the cones continued to work despite the absence of pigment epithelium. Kefalov, who is principal investigator Vladimir J. Kefalov, Ph.D., assistant professor of ophthalmology and visual sciences and principal investigator, applied the same experiment on mice after this discovery and reached the same conclusion. As a result of this discovery Kefalov, age-related vision disorders, and other diseases that affect the retina can be better-understood thanks to this discovery and even developed some treatments can be improved, he said (Dryden, 2009). Light is of great importance for the full realization of the vision, but today, there is a widely believe in a society that reading in dim light is harmful to the eyes, and this idea is scientifically incorrect. The human eye is cleverly designed to adapt to different light levels. If you are trying to read in a gloomy environment, your pupils dilate to get more light through the lenses into your retinas. The rods and cones in your retina use this light to provide information to the brain about what is seen. In this way, the eye can adapt to the rapid transition between dark and bright light, and no deterioration is observed in the eye (Hammond, 2012). All these discoveries, research, and the fact that light is the most basic requirement in the working principle of the eye underline the importance of light. In addition to having light, the angle of incidence of the light, or depending on the parts of the eye such as the retina, cone, and rod whose function is to filter the light, the vision may differ from person to person and depending on the light received from the light.
Light, which is the most basic requirement for the act of seeing to take place, also causes the differences in the act of seeing from person to person, according to the angle of incidence, wavelengths, function, and density of the cone cells in the eye structure, and the human mind. Even if people can see, they may not see the same with each other. The human eye can distinguish between hundreds of wavelengths of light received by cones, which are the color-sensing cells of the retina. There are three types of cones in the human eye, each containing a different type of pigment. One cone absorbs red, the other cone green, and the other cone absorbs blue-violet light waves. The red wavelength is the longest, while the blue-violet wavelengths are the shortest. Reflected light from a specific color stimulates all three cones in an effective amount, allowing the perceived color to be seen (Britannica T. Editors of Encyclopedia, 2008). For example, on the once popular debate about the color of the dress, in a study conducted by Bevil Conway who is a neuroscientist and a lecturer at Wellesley College, and the Massachusetts Institute of Technology and his colleagues asked 1,401 people what color the dress was. 57% of the respondents saw the dress as blue-black, 30% as white-gold, 11% as blue-brown, and 2% as something else. According to Conway and his team, the differences in color perception were caused by assumptions the brain made about the illumination of the garment. People who saw the dress in white and gold, probably assumed that the dress was lit in daylight. That is why their brains ignored the shorter blue-violet wavelengths. On the other hand, those who saw the dress as a blue and black, shade imagined artificial and warm lighting. For this reason, their brains ignored the longer, redder wavelengths. The researchers also said that those who saw the dress in blue and brown probably assumed that the dress was illuminated in neutral light (Lewis, Writer, 2015). Moreover, the act of seeing and its reality, which has been the subject of discussions of philosophers such as Aristotle and Berkeley in philosophy in history, because of studies such as Conway and his team's work from past to present, together with Berkeley's hypothesis that `` everything we see is in our mind '' (1709), the act of seeing turned out that it can vary from person to person, depending on imagination. Besides the act of seeing, the most basic feature that distinguishes humans from animals is the ability to think and imagine. The perception of color in humans is subjectively formed in the mind and depends on personal experience. As another example, synesthesia patients, who have the ability that experiences color perception with letters and numbers, and can hear colors by combining the senses, also have senses, and how they perceive colors may vary depending on their own experiences and their minds (Cosaponsa, 2018). Although experience and imagination are influential on the act of seeing in humans, the most basic requirement of the act of vision is always light and the cones and rod cells play a major role in the realization of the act of vision. In animals, although the situation may seem the same, cone and rod cells work differently, and compared to humans, there is some difference in how vision occurs in animals.
Although there are minor differences in human vision, when compared to human and animal views, these differences are greater in all respects. There are some similarities in the comparison of views between humans and animals, but animals experience the world differently than humans and each other. For example, the eye structure of terrestrial mammals and fish is biologically more like humans. Terrestrial mammals and fishes sight work biologically with the eyes of the lens, the pupil, and the cornea as humans. Like people, land mammals and fishes, also have cells that detect light. Otherwise, the views of some animals, such as insects or lobsters, are very different. They do not need light as much as humans, and they rely on water to reflect small amounts of light. In addition, they only see what they need to survive. Some animal eyes have the same system as humans, and they can see colors the same as humans. Other nocturnal animals, on the other hand, do not have the same system and they use light-sensing cells to help them see better in the darkness (Creekmore, 2016). While the basic need for the act of seeing in humans is light, depending on the characteristics of the light and the imagination of humans, how the act of seeing is experienced may differ slightly from person to person, but the vision has more diversity among animals. For instance, there are 3 different cone cells in the human eye that distinguish between colors, but dogs have only 2 different types of cone cells, and dogs cannot distinguish colors as much as humans. Lizards, which are other animal species that have a different vision from humans, have denser rod cells than humans and that is why they see 350 times better than humans in the darkness. Snails, on the other hand, although they cannot distinguish colors, they can distinguish light intensity and snails are more capable of detecting light than humans, therefore, they can survive hiding in dark areas (Hendry, 2020). In addition, when the eye structure of animals with night vision is biologically compared to the eye structure of humans, it is understood that because the animals with night vision have fewer cones and more rods, they see much better at night compared to humans (weir, 2015). Vision can be experienced differently by humans and animals, but still, the basic principle functions and requirements are the same. In both animals and humans, the act of vision occurs through cones, rods, and light. The reason for all these differences in vision is only the biological differences between the cone and rods. The differences in densities of cones and rods cause different experiences of vision between species. Nature has evolved all living beings in such a way that they can survive. For example, since animals not only experience the world like humans but also meet basic life needs such as survival, shelter, feeding, fighting, and protection with their eyes, all species have evolved biologically differently from humans and within themselves (Erichsen, 2012). In particular, the difference in vision among animal species, as well as biological diversity, is also due to the natural environment in which they are located, and each species has evolved with different abilities according to its habitats. Despite all this biological and physical diversity between species, both humans and animals eventually need light, albeit a small amount, for vision to occur.
To sum up, the act of seeing, which is the first aid for all living creatures to experience the world, has led to various studies, both philosophically and medically, and especially people have wondered whether they experience the world in the same way. As a result of studies and research carried out in addition to humans, it has been revealed that all living creatures evolve differently due to their nature. That is why they can experience the world as much as in line with their needs. Although there is not as much diversity among humans as in the animal kingdom, it has been understood that humans may also experience differences in their visions depending on their special abilities, and imagination. Despite all these differences, the only thing needed for the act of seeing to take place fully and in high quality in all living creatures with the ability to see is light. The world is experienced differently due to only the properties of light and biological differences because every living being has different reasons to use the act of vision. For example, snails use light to survive, while humans only use it for their routine work (Creekmore, 2016). Despite all this diversity, the principle is the same in all living things. While how they experience the world is variable, all living beings need light for the act of seeing. As a result of biodiversity, how much they need light or how they reflect light is different. But there is only one rule for every living thing; there is no vision without light and light is essential for the act of vision to take place.
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