Monday, September 12, 2011

The map and the territory

There's a part of your brain that I want to talk about. Let's call it the "labeler". What does it do? Well, consider: your eyes are basically cameras, but when you look at something you see rocks, trees and flowers, not little blips of light. The labeler is the part of your brain that takes an image from your eyes and tell the rest of your brain, "there's a rock here, a tree there, that's a car..." In other words, it sees a rock-shaped and colored group of pixels and attaches the XML tag to the area.

The interesting thing (well, the one I want to talk about) is that the labeler works at different levels of abstraction. For example, if you see a hand, the labeler tells you, "There's a hand there!" But if you focus in on the hand, the labeler will tell you, "There's four fingers, a thumb, and a palm there!" If you focus in further, you'll see the outlines of veins and muscles, and perhaps some fingernails. So, depending on what you're paying attention to, the labeler will mark the same piece of reality (e.g., a hand) with different labels.

Before I say anything else, I want to note that this is a very useful thing for our brains to do for us. Humans only have working memory for around seven things at once. If we couldn't step back and abstract away details, we would be completely overwhelmed and wouldn't be able to do much of anything. Rocks pretty much all behave the same way, and it's very efficient for us to be able to think of a rock in terms of what we will do with it without thinking about what minerals it's composed of.

However. As useful as it is to think about reality in conveniently labeled chunks, it is important to remember that reality itself does not have multiple layers of abstraction. We see some colored stuff which our brain labels a "hand"; in reality, the hand is made of cells made of molecules made of atoms made of protons and neutrons made of quarks. We see the same stuff, this time labeled "fingers and thumb" because we're focusing on it; the reality is the same cells made of molecules made of atoms made of protons and neutrons made of quarks.

So, the labels our brain uses can be at various levels of abstraction; they can be more concrete, or "zoomed in" (cells) or more abstract, or "zoomed out" (hands). But reality has only one level.

It is not as if there is one set of physical laws that govern fingers, and another that governs hands. There is only one set of physical laws, and they operate on quarks. It is not as if Newton governs bullets and Einstein governs spaceships. We see an airplane, and the wings are labelled "wings"; but the labels are in our heads, conveniently placed there by our brain; not on the actual molecules that compose the wings.

And now I can define the terms. Map refers to the labels your brain places on reality; territory refers to the universe itself. The map is built of multiple layers of abstraction. The territory has only a single, vast layer, where the basic building blocks of the universe follow the physical laws.

Another disclaimer. I am not saying that there is no such thing as a hand. Yes, the label "hand" is in your head, written down on your internal map by your brain, and the universe itself does not have a basic particle of "hand" or separate laws that govern hands. But this does not imply that there is no such thing as a hand! The concept "hand" is in your head, but that doesn't mean it's not real. Yes, we could explain a hand in terms of quarks, but that would be less useful to people trying to figure out how to use their hands. The meaning is in your (and my) head, yes, but that doesn't make it less real or meaningful. And anyway, there's no other place it could be.

Finally: The map is NOT the territory.

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