Light: A Form of Energy
Max Planck’s discovery shows that light exhibits the properties of both a wave and a particle. Since Planck’s day, countless experiments and observations have revealed this as an incontrovertible fact. That being so, in order to better comprehend this definition we can refer to another kind of waves, those that occur in water. Those waves are not made up of water, but are made up of the energy transmitted through the water. If a wave moves from one end of a swimming pool to another, this does not mean that the water in one side of the pool passes to the other. The water remains where it was. Only the wave itself moves, transmitting energy. When you move your hand in a bathtub filled with water you produce a small wave in the form of ripples, because you are imparting energy to the water. That energy manifests in the water in the form of a wave. This is the true account: there is no other god besides Allah. Allah—He is the Almighty, the All-Wise. (Surah Al ‘Imran, 62) |
Light waves, understandably, are rather more complicated than waves in water and do not require a medium in order to travel. They can travel through an empty vacuum. 31 Light is dependent on matter only at the initial stage. Once light has been emitted, it can move independently with no material element. Light energy can be found even where there is no matter at all.
Light and heat are different forms of the energy known as electromagnetic radiation. All the various forms of electromagnetic radiation act in the form of energy waves in space. Again, this can be compared—albeit simplistically—to ripples created when a stone is thrown into a lake. In the same way that those ripples may be of different width and amplitude, so electromagnetic radiation can have different wavelengths.
Light is an energy that behaves in the form of a wave. Light waves resemble waves in water. But unlike the energy in water, this energy here has no need of a medium to travel through. It can move within a total vacuum. Thus light energy can be found where there is no matter. |
The spectrum of wavelengths is extraordinary wide. The shortest length is 1025 times smaller than the longest. Numerically, this is expressed by the figure 1 followed by 25 zeroes. In order to better comprehend this number—which may be written as 10,000,000,000,000,000,000,000,000—let’s provide some comparisons. For example, the number of seconds that have passed during the 4 billion years of the Earth’s existence is only 1017. If we wanted to count to 1025, day and night and non-stop, it would take us 100 million times longer than the age of the Earth! If we tried to place 1025 playing cards on top of one another, we would find ourselves far beyond the Milky Way and we would need to travel half the length of the observable universe.
Radio frequency and measurement device |
In that range, there are three kinds of light: visible light, near infrared rays and ultraviolet rays.But these three types of light represent just one unit in the electromagnetic spectrum! In other terms, all the Sun’s light, when put together, represents just one out of the 1025 playing cards. That the Sun’s rays are restricted to such a narrow range is important, since only these rays can support life on Earth.
A six-mirror, giant gamma-ray telescope on Mount Hopkins |
Bearing this in mind, you can realize how the light you see represents only a very small fraction of the light that you perceive to be out there. Your retina perceives images formed by light consisting of a rather small band. The realm of other frequency bands apart from this one is unknown to us.
The visible light, the near infrared and ultraviolet rays that reach us from the Sun occupy the space of a single unit on the electromagnetic spectrum. In other words, the light reaching us from the Sun is the equivalent of just one out of 1025 playing cards laid one atop the other. It is only these rays that support life on Earth. |
The chief property of light is the effect it has on matter. In general, matter possesses inertia, resisting all the pressures placed on it by pushing or pulling. And whenever we push or pull an object, we feel pushing or pulling forces on ourselves. Newton called this action and reaction. Light also acts on matter, but light particles have no inertial property. We can see light reacting with objects, as when a laser beam cuts through metal or repairs a damaged retina. But we can never perceive the actions and reactions that matter has on light. Physicists refer to light’s inability to be pushed or pulled as “its absence of any rest mass.” 33
When we see light, we really don’t see light at all: we see an effect appearing as a result of light pushing and pulling on the matter making up our sensory bodies. We see matter moving. Light itself is really out of this world . . . 34
Like sounds, light is made up of octaves. The light octave is determined by the frequency of the light waves. For example, 48th octave represents infrared light, 49th octave visible light, and 50th octave ultraviolet light. Every light wave, from infrasound and ultrasound vibrations to radio waves and microwaves, infrared, visible light, ultraviolet light, gamma rays and solar rays, is a different octave in the electromagnetic spectrum. |
Where Is Light, Actually?
Is it light that makes the outside world visible to us, and is the means whereby our brains form images of the outside world? Does light cause all corporeal entities to come into being when we step outside and cause them to disappear for us in a completely darkened room? Were it not for light, would the whole world around us cease to exist?X-ray machines take photographs by converting the effect of radio waves into visible light on photographic film. |
The Sun and other sources of light emit electromagnetic particles (photons) at varying wavelengths. These particles spread outward through the universe as dictated by their structures. For example, many radioactive particles pass right through your body. Only a lead shield can halt them. Some of these particles are so heavy and so charged with energy that they generally destroy any molecules they meet and continue on their way without changing course. This is the underlying reason why radiation causes cancer. X-ray machines make use of a weaker form of radiation. Via photosensitive film, these machines convert the effect set up by radio waves into visible light, converting them into a form that our retinas can detect. In other words, light exists as long as it is percieved by the eye and interpreted by the brain. But light and illumination do not exist outside in the terms with which we are familiar.
Under normal circumstances, radio waves cannot be detected by any of our senses. Radios convert these into sound waves that can be detected by our ears. |
In other words, the waves themselves do not really exist, since they have no material existence in the physical sense. They must be converted into a form that the ears can hear and the brain can interpret. The same applies to a television set. Various light waves that are invisible to us are converted by the set’s screen into a form we can perceive.
Ultraviolet rays, which carry higher energy due to their frequencies, can sometimes cause defects in the genetic code of living cells. |
In essence, there are no heat and light outside. The perception center in the brain converts particles traveling at different frequencies into a visible and perceptible form. |
The living, vivid world that we imagine exists outside our eyes is actually an illusion arising in the form of perceptions. The seascape we watch on a sunny day is merely an image formed by electrical signals transmitted to the brain. We can never have direct experience of the external original of the images we perceive. |
We are surrounded by particles of different frequencies and wavelengths. Only the perception centers in our brains make these “visible” and “detectable” for us.
The photons that fall onto the retinal layer are converted into electrical currents by the perception cells there. These currents are then transmitted by the nerves to the visual center in the brain. The visual center then forms an image by interpreting these electrical currents. This property of light is expressed thus in physics textbooks:
The word light was used in a physical or objective sense in reference to electromagnetic waves or photons. The same word is also used in a psychological sense in reference to the sensation that arises when electromagnetic waves and photons strike the retina of the eye. Let us express both the objective and subjective concepts of the word light: Light is a form of energy that manifests itself with the visual effects born from the stimulation of the retina in the human eye. 35
The bright and vibrant world that we imagine exists outside us does actually have a material existence—but its perception is in fact a kind of phantom produced within us, the original of which we can never see. The seascape you see on a sunny day actually consists entirely of darkness. There is no reflection on the water, sea-blue color, clarity of air or eye-catching white clouds at all. What enables us to perceive this image, so bright and vivid for us, is merely the electrical signals transmitted to our brain. Apart from effecting a perception in our brains, light exists on the outside solely as a form of energy. For that reason, light—which we may think of as the reason for our perception of matter, is actually nothing but an illusion.
Considering this fact, we arrive at a very striking conclusion: Your eyes actually have no property such as “sight” at all. The eye is merely a subordinate unit that converts photons into electrical signals. It has no ability to perceive. It is not the eye that watches the bright world that we imagine surrounds us. The sensation of light or color does not form in the eye itself—as we’ll explain in detail in the sections regarding vision.
It is He Who appointed the Sun to give radiance, and the Moon to give light, assigning it phases so you would know the number of years and the reckoning of time. Allah did not create these things except with truth. We make the signs clear for people who know. (Surah Yunus, 5) |
Are Colors Only in Our Brains?
The names of different colors are assigned to photons of various frequencies. We are able to distinguish colors such as red and yellow according to the degree of photon vibration: Thus different colors have different scales of vibration. Paper and snow appear white because they reflect all frequencies, and the combination of these gives rise to white. Leaves are green, because they reflect only photons at a frequency that gives rise to the appearance of green, while they absorb all the others. Glass is transparent, because photons can pass through it and reach our eyes without encountering any obstruction. A black fabric reflects very little light back because it absorbs almost all the photons that strike it. As a result, few photons reach our eyes, and we perceive the fabric as dark or black.
A mirror copies an image because it has a smooth reflective surface, and the moment that light rays strike it, almost all bounce off and their parallel nature is not distorted.
Color is perceived first in the retinal layer in the eye. The three main types of cone cells in the retina react to different wavelengths. Millions of different shades of color emerge as the result of the cone cells being stimulated in different proportions. These colors, converted into electrical signals in the cone cells, are transmitted to the optic nerve. As a result, the brightly colored world we see is formed. In fact, however, there is no color in any part of the brain. The colored world is merely what we perceive. |
All that a single cone can do is capture light and tell you something about its intensity . . . it tells you nothing about color. 36These color data perceived by the cone cells are converted into electrical signals, thanks to the varying pigments they possess. The nerve cells connected to these cells then transmit these signals to a special region in the brain, in which forms the vivid world we see throughout our lives.
This special visual center of the brain is completely dark, like all the other parts of the brain. There is no light there, and no colors. There is no red, green or yellow in this part of the brain. There is no white. There is no reflection of bright flower gardens or dazzling sunlight, no blue sky or verdant trees. The inside of the skull is pitch black. We imagine that light enters it directly through our eyes. But in fact, there is not the slightest trace of light anywhere behind the eyes.
The formation of colors stems from objects’ light-reflective properties. Since there is no light in the outside world, there can be no question of the existence of any color. Therefore, where is the colorful world we regard as “outside” our eyes? This world cannot reach us directly from the outside, nor does it form inside our brains. The colorful world is something we perceive. It assumes this form because we interpret it as such.
Peter Russell from the Cambridge University Department of Mathematics and Theoretical Physics describes this state of affairs:
To the surprise of many, the world “out there” has turned out to be quite unlike our experience of it. Consider our experience of the color green. In the physical world there is light of a certain frequency, but the light itself is not green. Nor are the electrical impulses that are transmitted from the eye to the brain. No color exists there. The green we see is a quality appearing in the mind in response to this frequency of light. It exists only as a subjective experience in the mind. 37
There is actually no color in the space we perceive as “the outside.” The movements of photons we perceive as light and color are nothing more than perceptual phenomena created in a pitch-black environment. |
Strictly speaking, light itself is not coloured: it gives rise to sensations of brightness and colour, but only in conjuction with a suitable eye and nervous system. 38
Any damage or structural alteration that occurs in the eye may cause the same object to be perceived in very different ways, even though the signals generated by the arriving photons and the visual center in the brain still have exactly the same properties. That is why color-blind people and those with normal vision perceive and interpret specific colors so very differently.
The conlusion emerging from this whole account is that what we perceive as “the outside world” is dark. In fact, even the concept of darkness may be misleading. There is no color at all there. The three-dimensional, bright world we see portrayed in vivid colors is entirely deceptive. The reflected photons we interpret as light or color are nothing more than physical events taking place in complete darkness. Our entire bodies, including our eyes, and the whole material world we see as a three-dimensional, brightly colored sphere, are actually contained within the brain, which alone interprets what we see in this way. However, the interesting thing is that the eye that perceives all this and the brain that interprets it are also in complete darkness. Light and color do not exist in the brain that interprets them.
Since color is related to the individual’s mode of perception, it is impossible for us to know whether or not the world we perceive looks the same to other people. An object we perceive as red may be a completely different shade for someone else. There is no way of comparing their perceptions of “red” with our own. |
The common wisdom is that modern science has removed the color from the physical world, replacing it with colorless electromagnetic radiation of various wavelengths. 39
In the same book, Dennett quotes from an introductory book on the brain by Ornstein and Thompson:
“Color” as such does not exist in the world; it exists only in the eye and brain of the beholder. Objects reflect many different wavelenghts of light, but these light waves themselves have no color. 40Since color is concerned with the way in which a person perceives external light, there is no way in which we can know whether the world we perceive is the same for any other person or not. You can never know whether the color that someone else sees as “red” is the same red that you see. For us, the concept of “colorful” may actually express millions of different hues altogether. Yet someone else may see a far more limited variety of colors and yet still interpret this as a full spectrum. We have no way of comparing our perception with that of anyone else looking at the same object. We imagine that we are looking at the same thing. But perhaps the things that we perceive and what another person sees are actually completely different to one another. Since our perception of the external world is limited to our five senses, we cannot know whether “blue” means the same thing for any other person, or whether coffee tastes the same. Neither can we describe these perceptions.
We need to realize that all the properties we ascribe to objects and other people actually belong to images in our brains, not to the “originals” in the outside world. Since we can never step outside of our own perceptions and reach the outside reality, we can never perceive the true existence of matter, of colors, much less of the universe as a whole. The famous 18th-century philosopher Bishop George Berkeley drew attention to this fact:
If the same things can be red and hot for some and the contrary for others, this means that we are under the influence of misconceptions and that "things" only exist in our brains. 41Oxford University’s Gerard O’Brien, working at the University of Adelaide in Australia, said this in a radio talk:
O’Brien’s analysis on this subject is highly important in terms of questioning what “external reality” is like. There is no evidence that other living things see light or perceive color in the same way as we do. It is impossible for us to obtain any scientific evidence to show the truth. That being the case, all we can state regarding the external world is conjecture and guesswork, because our perception of the outside world—in the way we are familiar with it—depends on our five senses.Now when we look out into the world, we see objects as coloured. We think those colours are actually attached to all the objects that we see. But now there is a very interesting question as to whether that is the case. . . . It might turn out—and there are a number of philosophers who argue—that the colours that we experience, those colour properties are in fact only features of our internal representation of the world, that there are no corresponding colours in the world itself. And so the world outside our heads, the world independent of our experience is actually colourless. . . . Is the apple red when you’re not looking at it, so to speak? And when we think about it, it’s a somewhat chauvinistic view of ours to think that the world actually contains the kinds of colours that we see it as having. Because we now know enough about other animals that we share this planet with, and they have different kinds of colour systems and they make in some cases less discriminations amongst colours than we do. And as a result, there’s the view that they actually see the world as differently coloured than us. So we see it having certain colours, other animals perhaps see it as having a different set of colours. Now, why should we think that our view is the correct one—that the colours that we see are in fact the colours the world actually has? Perhaps these are just two different internal ways of coding the world that is internal to the representations that we and other animals generate. 42
An image of flowers seen
through the human eye Bees see the same
flowers like this.
The Five Senses That Present the Outside World
If all that we ever know are the sensory images that appear in our minds, how can we be sure there is a physical reality behind our perceptions? Is it not just an assumption? My answer is: Yes, it is an assumption, nevertheless, it seems a most plausible one. 43
—Peter Russell
We learn everything about the outside world by means of our sense organs. When the electrical signals reaching us by way of our sense organs are interrupted, the world that exists on the outside will disappear for us alone. |
Recall, however, that actually there are neither colors, nor sounds nor images in our brains. All that occurs in our brains is electrical signals. The boundless landscape you imagine you see in front of you, a brightly colored flower in which you take such delight, loud music or a meal that tastes so delicious—all consist solely of electrical signals reaching the brain. This, however, does not mean that the outside world does not exist. It will not come to an end if the electrical signals reaching you from your sense organs are cut off. The outside world will come to an end “for you only,” because for you, the outside world consists only of the interpretation of electrical signals by your brain.
Each one [of the sense organs] is intricately adapted to deal with its own type of stimulus: molecules, waves or vibrations. But the answer does not lie here, because despite their wonderful variety, each organ does essentially the same job: it translates its particular type of stimulus into electrical pulses. A pulse is a pulse is a pulse. It is not the colour red, or the first notes of Beethoven’s Fifth—it is a bit of electrical energy. Indeed, rather than discriminating one type of sensory input from another, the sense organs actually make them more alike.
All sensory stimuli, then, enter the brain in more or less undifferentiated form as a stream of electrical pulses created by neurons firing, domino-fashion, along a certain route. This is all that happens. There is no reverse transformer that at some stage turns this electrical activity back into light waves or molecules. What makes one stream into vision and another into smell depends, rather, on which neurons are stimulated. 44
Jeffrey M. Schwartz describes how perceptions arise independently of the brain:
Peter Russell has described the problem in these terms:Every conscious state has a certain feel to it, and possibly a unique one: when you bite into a hamburger, it feels different from the experience of chewing a steak. And any taste sensation feels different from the sound of a Chopin étude, or the sight of a lightning storm . . . Identifying the locus where red is generated, in the visual cortex, is a far cry from explaining our sense of redness, or why seeing red feels different from tasting fettuccine Alfredo or hearing “Für Elise”—especially since all these experiences reflect neuronal firings in one or another sensory cortex. Not even the most detailed fMRI gives us more than the physical basis of perception or awareness; it doesn’t come close to explaining what it feels like from the inside. It doesn’t explain the first-person feeling of red. How do we know that it is the same for different people? And why would studying brain mechanisms, even down to the molecular level, ever provide an answer to those questions? 45
Every time we try to pin down the physical aspect we come away empty-handed. Every idea we have had of the physical has proven to be wrong, and the notion of materiality seems to be evaporating before our eyes. But our belief in the material world is so deeply engrained—and so powerfully reinforced by our experience—that we cling to our assumption that there must be some physical essence. Like the medieval astronomers who never questioned their assumption that the Earth was the center of the universe, we never question our assumption that the external world is physical in nature. Indeed it was quite startling to me when I realized that the answer might be staring us straight in the face. Maybe there really is nothing there. No “thing,” that is. No physical aspect. Maybe there is only a mental aspect to everything. 46
There is no little man sitting in the brain observing what is going on. Research into the brain can never answer the question of who really does the perceiving. Because it is the “soul” that perceives, independently of any person’s physical identity. |
American author Marilyn Ferguson notes this important search in the world of science and philosophy for who or what it is that performs such perceiving:
Philosophers since the Greeks have speculated about the “ghost in the machine” the “little man inside the little man” and so on. Where is the I—the entity that uses the brain?
Who does the actual knowing? Or, as Saint Francis of Assisi once put it, “What we are looking for is what is looking.” 47
Consciousness is a property belonging solely to the soul bestowed on human beings by Allah. It is through the soul that man becomes an entity able to think, perceive and decide. The mind and consciousness possessed by human beings are properties bestowed on them by the soul. In one verse Allah tells us that:
This subject will be clarified in detail later.Accordingly, We have revealed to you a Spirit by Our command. You had no idea of what the Book was, nor faith. Nonetheless We have made it a Light by which We guide those of Our servants We will. Truly you are guiding to a Straight Path. (Surat ash-Shura, 52)
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