The Edge of Chaos

We have seen that life requires a dynamic balance of order and chaos. If life were totally ordered everything would be the same and follow the same rules without any errors. It would leave no room for anything new to occur. If, on the other hand, everything were in total disorder and nothing could be predicted from one moment to the next, everything would be constantly new and nothing could have any sense of permanence.

Life could not exist in a totally ordered world or a totally chaotic world. We live in a world where there is a mix of both. There is enough structure that there is a sense of permanence and continuity in our lives. We can reasonably predict much of what will happen in our lives. We form a generally stable sense of personal identity which enables us to interact with the people around us. The patterns of the seasons and the heavens, the laws of physics, and even our own human laws give our lives enough structure and predictability to avoid becoming overwhelmed.

At the same time there is enough diversity and unpredictability in life so that new and unknown things regularly appear in our world, things we can make use of to improve and grow. That unpredictability is generally not so large that we are overwhelmed by change. Life exists at a balance point between order and chaos.

Consider people running. They want to get to their goal as quickly as possible. Some runners will choose to be slow, careful and ordered in their running to make sure they do not fall over and perhaps not even finish the race. While the risk of total failure is low, they take too long to reach the goal. Some runners will put all their efforts into going as fast as possible, using all their energy, running in a more chaotic fashion. They will indeed advance more quickly, but the danger of falling and injuring themselves would be much increased. Neither approach is effective in the long term. Being too ordered takes too long, while being too chaotic is too dangerous. What is needed is the best balance point where the runner reaches the goal in a shortest reasonable time and the risk of injury is sufficiently reduced, so that overall the running is optimally effective. If it is too ordered it needs to become more chaotic, and if too chaotic, to become more ordered.

The most effective balance point called the Edge of Chaos, turns out to be just before the runner lapses into chaos. The risk of falling into chaos and being injured is still real and catastrophes can and do occur in Edge of Chaos systems, but overall, it is the most effective place to be.

The Edge of Chaos is not a stable balance point. The balance point is a dynamic balance point where effort must be constantly made to maintain stability. The runner similarly needs to slow down a bit when the terrain becomes steeper or more difficult to traverse and speed up when it becomes more even. A tight rope walker is also an example of a dynamic balance point. The walker does not just set the balance and then forget it. The balance point is constantly being reset and by maintaining that dynamic balance, the walker can traverse the rope.

The Edge of Chaos is more than just a balance point. It is a point of emergence. When the Edge of Chaos is reached, whole new behaviours can emerge that could not have been previously predicted before. Emergent behaviour occurs in many complex systems, where a system spontaneously develops new system wide properties and new levels of complexity that is not at all apparent, if we only view the individual agents. Looking an in individual ant gives us no clue as to the complex co-ordination that is evident in an entire ant colony.

There is a chemical example of the Edge of Chaos system called the Belousov - Zhabotinsky reaction where two chemicals are mixed and spun around between two cylinders. At the critical point of the Edge of Chaos, the whole mixture changes rhythmically from one colour to another rather than just a mix of the two colours. That change could not have been predicted just by looking at the original chemicals. 

The Edge of Chaos is found very often in nature; throughout ecosystems, in human dynamics, and in many other places in the world about us.

Per Bak is particularly known for his work developing the concept of self-organised criticality. It says that large complex systems such as those found in nature tend to move towards the Edge of Chaos. If they are too ordered they self-adjust to become more chaotic and if they are too chaotic they self adjust to become more ordered. When complex systems do move to the Edge of Chaos they tend to self-organise to be scale free and exhibit power law distributions (to be discussed later). Novel emergent properties can develop from this critical state. Self-organised criticality has also been proposed to apply to economics, traffic jams, forest fires and even the brain. Self organised criticality is also used in the theory of Punctuated Equilibria, which proposes that evolution has not occurred as a slow incremental process, but rather by long periods of time with relatively little change taking place, punctuated by times of intense change, triggered by some critical states in the eco-system.

While it appears logical that the Edge of Chaos would be the most effect state for complex systems, there is a great deal of debate as to whether natural systems automatically move towards the Edge of Chaos.

Measuring real life systems moving towards self-organised criticality at the Edge of Chaos proves more difficult that it would first appear. It is likely that in real life staying at the Edge of Chaos is just too stressful to maintain. Instead, organisms may move to the Edge of Chaos for short periods, where they receive a boost, but are not able to maintain that state. They then drop back until they have integrated the changes before once again approaching the Edge of Chaos.

Rene Thom developed Catastrophe Theory and looked at systems at the Edge of Chaos identified critical points where a complex system was more likely to lapse.