Something very fundamental and significant occurs in an infant's life at a certain age when it looks into a mirror and recognizes for the first time that the image it sees is that of itself. It stares into its own eyes with a new recognition, thinking 'this is me!' The ability to think about yourself and examine yourself as an outside observer is probably unique to humans and higher apes, and is a manifestation of a deep understanding of our place in the world.

There is a similar but deeper insight that is not so clear to most people, but is every bit as fundamental and earth shaking to your view of the world and your place in it. It is an insight I will try to present to you in this work, but like all deep insights, this one requires careful thought and deep concentration on your part, as it does for the infant observing itself in the mirror. Like the infant, I would like you to look at yourself, and see yourself in a new place where you may have never seen yourself before. The image of yourself that I would like to present is not the one in the mirror, nor the normal conception you have of yourself. I would like to present to you, your own self in the world around you.

When patterns of light, sound and touch from the outside world impinge on our senses we experience a very vivid sensation that we are observing and experiencing the actual outside world. That we are in the world, and interacting with solid objects of that world. You feel this book in your hands as very real and very present. The idea that this book is an illusion seems completely absurd, and yet, in fact your perception of this book is indeed an illusion. I don't mean to say that the book does not exist, but that every aspect of it that you observe, the look of the letters on the page, the feel of the pages as you turn them, the sound they make and the smell of the paper, even the notion that this book exists after you have put it away, all of these sensations are mere images or models of the book, and are not the book itself. If you think that this is merely toying with words, read on carefully and I will try to show you the vast differences between the book you see in your hands, and the real book that is supposedly the origin of all the sights and sensations that you observe.

Imagine if you will, that somewhere there exists such a real book. We know from the laws of physics that every tiny shred of paper from that book is composed of millions of molecules of matter. Each molecule is made up of numerous atoms, hundreds or thousands of them form organic molecules like those of the wood pulp, arrayed in fantastically improbable geometric configurations and interacting wildly with each other, bouncing, twisting and jerking in a crazy blur of Brownian motion. And every atom of those molecules is composed of protons and neutrons locked together by immense forces and surrounded by clowds of electrons spinning in complex shells and orbits. If we could really see all the action in the tiniest shred of paper in this book our mind would boggle at the fantastic galaxies of crazy patterns and wild motions. And yet all that we observe is a white surface remarkable only by its uniformity of color and texture. Can you now say that what we see is the real book?

Consider also the fantastic pulses of radiation that scientists tell us are cascading through this book every second, reflecting or refracting, jiggling the electrons in their orbits on their way through. There are radio waves of all frequencies, coded with sounds and images of all the channels in your listening area. Infra-red, ultra-violet, x-rays and cosmic rays arriving from space, radiating from the earth or even glowing from the book's own atoms. Streams of sub-atomic particles and neutrinos course through the solid structure of the book knocking atoms out of place or passing between them. How can you say that you are looking at the real book, when you don't even possess sensors for these forms of radiation, for even the cognitive machinery to picture such information if you did.

On a different scale the bleached and dessicated fibers of wood pulp that are intertwined in a tangled mat are also invisible to us, as are the crystals of various chemicals trapped between the strands, patches of oil left by your fingers and the multitudes of micro-organisms that have made a home among the fibers. In fact, our experience of the book is restricted to the tiny set of patterns that can filter through the biological sensors with which the human body is equipped.

So, you may say, our view of the world is restricted to a narrow window of observation. But you may argue that through this window, what we do see of the world is as it is. That in a sense, what we see is the world. The vividness of our impression of the book seems to confirm this, as does the fact that as we observe the world around us we never seem to miss anything of real importance to us. This fact is really a tribute to the wonderful capability of our mind to reconstruct so clear a picture of the world from the distorted and incomplete evidence provided by our senses. There is much 'filling in' that our brain performs to complete information that is not directly sensed, and this filling in is accomplished so smoothly and efficiently that we are not aware of any difference between what we have observed directly and what our minds have filled in. In fact, the reason for this is that the only thing we actually perceive is the filling in, we do not actually sense anything directly.

Let me illustrate this point using the book as an example. Stop reading for a moment and fixate on one word of the text. Now, without moving your eyes, observe what you see of the rest of the page. Whereas your conscious perception while reading is that the entire page is clear to you at any time, like a television picture, the reality is that you can only read the part of the page at which you are actually looking. This illusion results from the fact that if you are ever curious about any other portion of the page, your eyes flit over to that spot so effortlessly and automatically that you are hardly aware of any eye motion.

More interestingly, observe that part of the page that you cannot read. At a certain distance from your foveal point your eye picks out meaningless geometrical patterns from the chance alignment of spaces between words, and meaningful patterns of blocks of text surrounded by blank space. Try to read a word in the periphery, and see how the letters appear to change their appearance as your eye tries to match them to known words.

The distorted images of words in your peripheral vision are obviously illusions constructed by your visual system, as you can see by just looking over at them. But even the images in your foveal vision are similar illusions, as you can see by using a magnifying glass, or by trying to read very small text. The point is that when your eye makes a guess at the probable interpretation of any visual scene this guess is perceived as a real solid image. Think about the significance of this. What I am saying is that your eye constructs a visual scene based on a multitude of visual clues, and presents this to your perception as a solid and real image. Everything that you see, feel and hear is a clever reconstruction built by your mind, and is not the actual real world that it seems to be. The room that you see around you is not really a room, but a pattern of neural activity in your brain, like electrons dancing on the phosphor dots of a television screen that create an illusion of a scene in color and motion, so the activity of multitudes of neurons generates this illusion of a space around you, and of yourself in the middle of it, when in fact the entire space with all its colors, smells, sounds and patterns is actually inside of you.

A good analogy to this situation is an air traffic controller who is seated in front of a radar scope, talking to glowing blips on his screen, giving them directions and asking them for information. In the controller's mind, the blips represent real aircraft, but he commands them. The blips are a result of radar reflections, enhanced by computer processing, and labeled by the computer with identifying letters and symbols denoting altitude and heading. The controller is interacting with this miniature artificial world that is a mere echo of the real outside world that contains real airplanes. For practical purposes though, this is irrelevant to the controller, who need concern himself only with the miniature artificial world on his screen, and give commands to prevent the little blips from colliding on the screen. In the same sense, your brain constructs a miniature artificial world which, like the radar screen, is closely coupled with the real outside world by way of sophisticated sensors and enhanced by internal processing. Like the radar screen, the various streams of information from the various sensors are presented in a single place, spatially related to each other to form a cohesive miniature world instead of a mass of independant signals.

In order to fully understand this concept, it may help to form a mental image. Think of the most distant objects that you can imagine. You may think of the sky above your head, and the earth below your feet, or you might stretch it farther to the sphere of stars around the earth in all directions, or if you are an astronomer, you can stretch it farther still. However far you can stretch your imagination, when you reach a limit, then imagine, if you will, the inside surface of your own skull encompassing all around the farthest reaches of the space that you know. For indeed, your entire perceptual and intellectual world all lies within the confines of your own skull. It is appropriate therefore to picture your skull as surrounding everything you know in the universe. But, you might ask, what about the skull that I feel at the top of my body? How can my skull be both here where I feel it, and out there beyond the farthest reaches of space? Herein lies the source of all the confusion. The skull that you see and can feel with your hands is only a miniature image of the real skull, a fantastically simplified and abbreviated representation of a real skull that is so gigantic and complex that it contains within it all that you know and perceive. As long as you perceive the skull in your hand as your real skull, you will be unable to picture the outside world as an internal percept. As soon as you fully realize that what you know as your body is nothing but a perceptual marionette fashoned by your mind as a miniature copy of the real one, only then will you begin to see the true relation between yourself and the world.

Here is a little piece of evidence to shake your faith in your perceptual world. Close your eyes, and roll them over to the left. Now, with your right hand, touch your right eyeball through the closed eyelid as far to the right as you can reach into your eye socket, until you see a patch of activity appear in your visual field. This purplish blob of activity is caused by the pressure of your finger on your retina, which generates a signal as if stimulated by an image of light. Notice however that the visual stimulus is seen at the opposite side of your eye! In other words, although you touch the right side of your eye, the patch appears over to the left! You can even do the experiment carefully with your eye partially open, and you will simultaneously see your finger to the right, and the pressure of your finger to the left. This is analogous to the radar controller who sees a blip approaching the center of the screen from the left, but hears the engines of the plane approaching from the right, because there is a 180 degree disparity between the outside world and the internal copy of it on the radar screen. In other words, when you imagine the real outside world, i.e. the one that is beyond the surface of your real skull that surrounds everything in your perceptual world, you must remember that there is a 180 degree disparity between that outside world and your internal copy of it. The real floor is above the perceptual ceiling, and the real sky is below your perceptual floor.

So, you might ask, even if it is true that my perceptual world is within my head, what purpose does it serve to think of it that way? Why should I confuse myself with a dual notion of the world, one perceived and one real? What if I just accept the perceptual world, which after all is the only one I can see and feel, as a representative of the real world? What do I lose by thinking of it that way? In practical terms of course it is best to completely immerse oneself in the perceptual world, and not to give a thought to the real world, just as the air traffic controller works best by pulling the shades on the real sky and focusing his full attention on the model sky on his screen. For the perceptual scientist however, a full realization of the implications of the internal world hypothesis will generate a deep respect and appreciation for the full complexity of the task of perception.

When you look out at the world, like a child looking into a mirror, you are actually looking into yourself and observing the activity in your own brain.