In part 3 we looked at how we know the world through our categories, and in part 4, we looked at some of the limitations our senses put on that knowledge.

Today I'm going to give you a little exercise in perception, designed to help you experience what we've talked about so far, and perhaps take it to a new level.

The experience can be done, for it's fullest effect, sometime when you're out driving around, or walking. But it's still quite effective in your imagination, while you're sitting in front of a computer. Besides, once you do it in front of the computer, you'll be able to reproduce it anywhere, in a matter of seconds.

If you are sitting near a window, you can look at the view when you get to step three; if not, just use your imagination.

The Experience:

1. Take five slow, deep breaths, counting them as you take them. This is just to get you focused, and to clear your mind.
   


2. Look around you. What do you see? What do you hear? Start close at hand: your hands, the computer screen in front of you, the weight of your body on the chair, if you're sitting down. The furniture in the room, the walls, the ceiling. Pay attention to the solidness, the realness of things, the complexity and variety of the sounds—listen for the ones you usually don't hear. What odors are in the room? Is it warm? Cold? Can you feel the air on your skin?
   
   Do this on your own until you are ready for for the next step. Take your time.
   


3. Now move outside, either look out the window, or use your memory and imagination. If you're working from memory pick a time when you were really out in the open, and had a clear view for miles. Notice the plants, the buildings, the grass, whatever there is too see. Feel the air on your skin. Listen to the breeze in the leaves of the trees, the song of birds, whatever is actually there. Smell the air, the grass, the sea—whatever your particular experience brings: a sunrise, a summer day, snowfall on a quiet night, a sunset: whatever it is.
   
   Again, take your time. When you are ready, move to the next step.
   


4. Look at the sky. (Even if you already have.) Notice any clouds, jet trails, birds, planes. Notice how they move. Try to get a sense of just how big it is, how far away. If it's night, notice the stars or the moon. Imagine how incredibly far away they are—how immense, how complex the universe really is.
   


5. Now become completely aware of the fact that everything you have just experienced is your inside world—it exists completely inside your head: your creation, out of your categories, formed from the limited and distorted information your senses provide.
   
   Of course that's true, if you are just imagining, but it is just as true of the computer screen and your hands, or of a sunset that you really are looking at.
   
   You can become more clear on this by comparing what you experienced to a scientific description:
   
   Did the ground feel still beneath your feet? There's no such thing as standing still. The earth is rotating constantly, and hurtling though space in its orbit around the sun, which in turn is moving in relation to all the other stars.
   
   Did you see the sun rise? It was the earth, and you, spinning.
   
   Was the sky blue? Blueness is just the internal experience you assign to certain signals from your eyes—which give those signals when light of a certain wavelength excites them.
   
   Did that distant tree appear smaller? It was a function of the way your eyes work.
   
   Did objects seem solid? They are actually made up mostly of space, and the stuff that isn't space is not really solid—in the sense you mean it, anyway—either.
   
   Was the air warm? Warmth is a function of your inside world, a comparison of your temperature to some other. But those "temperatures" are not measures of heat as you experience it, but of kinetic energy, the vibrations and movement of molecules within that air. "Jiggliness," not "warmth".
   
   When you get this idea firmly rooted in your mind, that your entire world of experience, everything you take to be "outside" of you, is really in your head, if you can completely understand that nothing you have ever experienced is anything like the world that science tells us is out there, you are ready for the next step.
   


6. Ready? Now become completely aware of the fact that this whole, strange, enormously complicated world which science describes is also part of the inside world. Insofar as you can imagine it, it is part of your inside world. Insofar as a scientist can imagine it, it is part of hers.
   
   Scientists do not "get out" of their heads anymore than anyone else. That's not a slight on science, by the way, but just a fact of the limits of human perception.
   
   Everything in the scientific description of the world is also a product of the human mind, formed out of human categories and the information which comes through human senses. It correlates with the world out there in different ways than your everyday worldview, even in better ways, for scientific purposes, but it still is an "inside" world.
   


7. If you want to get a real sense of mystery, take those two, very different, pictures of the world, hold them in your head at the same time, and try to get a sense of what kind of wild and mysterious universe could be simultaneously seen through both those lenses, and still be, in itself, something even more different from each of them as they are from each other.
   
   Stick with it until you really have it.
   
   Got it?
   
   Good. That sense of the utterly unknowable, and yet somehow disclosable world, which can be caught-but-not-at-all-caught by two such completely different world-views and experiences, that sense of a reality beyond anything we know, is still just inside your head.
   
   There is no way to perceive the world as it is, even by focusing on the problem.
   
   That fact, when you come up against it with no escape, is the closest we can come to the mystery which is reality.

What else is there to say?

Quite a lot, actually. Stay tuned.