(This is Part 6 of a series. Go back to Part 5.)
To understand the critical state better it's a good idea to look at how it forms. And it fact, it forms right at the borderline between order and chaos. Let's see how:
Imagine an ordinary bar of iron, a magnetized one. If we were to examine the atoms in this iron magnet, we'd find them to be like little arrows, trillions upon trillions of them, all pointing in the same direction. This is the land of order.
However, if we heat this iron magnet we'd find the atoms becoming more agitated. And at high temperatures, in the realm of chaos, the little arrows would be flipping around randomly, pointing in all different directions. This is the realm of "noise."
However, there's an inbetween stage, which in iron occurs at 770 degrees C. At this stage, which physicists call a
phase transition—a transition from one phase to another —the iron is poised right on the boundary between being magnetized and unmagnetized. This is the critical state.
In the critical state the iron atoms are forming shifting "alliances" of magnetized atoms, that is, atoms that are pointing in the same direction. And at the same time there are also shifting "alliances" of non-magnetized atoms, that is, atoms that are pointing in random directions.
These various alliances are constantly molting and shifting in size. This is shown most clearly in computer simulations of thousands of iron atoms. When such simulations are projected onto a computer or TV screen, they take on a striking appearance:
The chaotic state looks like the "noise" or "snow" that you see on a TV that is not connected to a channel. The iron atoms are flipping around randomly. On the other hand, in the "ordered" or magnetized state our TV would show a screen that was all black or all white, depending upon whether the atoms were lined up pointing north or south.
The interesting state is the one right between these two, the critical state. Here we would see shifting factions of white and black areas. Some of the white areas would be small, some would be medium and some would be large; similarly, some of the black areas would be small, some medium and some large.
But such a static description doesn't do justice to the critical state. To get an adequate picture, we have to imagine these white and black areas constantly shifting both in size and in their alliances with other white or black areas.
As we watched the screen of the critical state we'd see large areas of white or black punctuated from time to time by sudden "avalanches" of the opposite color propagating across the screen. This is the "punctuated equilibrium" that we've seen before in empires, earthquakes, scientific revolutions, sandpiles and the evolution of life.
Researchers now believe that the brain itself operates at the critical state. If it was in the subcritical state, where everything is static and ordered, the brain could never grow or move to something new.
If, on the other hand, the brain was in the chaotic state, the brain would resemble the "snow" on TV, a series of chaotic and meaningless impulses.
But at the critical state the brain is characterized by "punctuated equilibrium," where "avalanches" of all sizes can propagate through the system. And each of those "avalanches" we experience as a thought or a feeling.
In this model, a large avalanche is what we experience as a profound insight—a breakdown of the old way of seeing things and a new synthesis—or a profound feeling such as awe or terror or compassion.
To say that there are avalanches of all sizes propagating through the system is the same as saying that factions and alliances of neurons are constantly shifting and reforming. This is how our thoughts can shift from what Mary said to the weather to the state of politics.
This shifting sea of alliances in the brain is made possible by the critical state, because only at the critical state can such patterns or alliances easily and quickly form and then easily and quickly morph into something else.
It is very fortunate that life itself exists at the critical state. If life existed in the subcritical state then everything would be static and perfectly ordered; nothing would ever change. Conversely, If life existed in a chaotic state there would be so much change that life would be complete randomness and nothing could be depended upon.
At the critical state life has a certain stability to it and yet can accomodate changes and evolutions of all kinds. And it's worth remembering that life self-organized, just like the grains of sand in the sandpile, to this critical state—a state where it could evolve and grow from one perfection to the next one.
What a miracle is this thing we call life. What a miracle is this thing we call existence.
(This is the end of Part 6. Go to Part 7.)
—jim sloman, 2.22.04 for Nov 25
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