## Thursday, July 8, 2010

### Emergent Complexity

It is understandable why when people see complexity they imagine their needs to be some designer behind all of it. Consider the computer. The computer is very complex with all of its components. The computer had a designer behind it, a mind, that knew exactly what it was doing to put all the pieces of a computer together. Or consider an orchestra. All those instruments come together to produce complex music. There is a designer behind all of it, namely the conductor. The conductor gives instructions to the orchestra and they follow through thereby producing music. It therefore makes sense to us when we see something which is complex we imagine that there needs to be some designer behind all of it. This kind of complexity is known as "top-down complexity". There is someone on top who transmits the information down below, the one on top is the designer, the one who created the complexity.

Now consider Conway's "Game of Life". The Game of Life is a computer simulation developed by the mathematician Conway, still living. It is a very simple game. It consists of a grid with each square either on or off. It follows very basic rules. If a square is isolated by itself, lonely, it will sadly die out (turn off), if a square is near another square, they will have sex and reproduce another square (turn on). If there are too many squares next to one another, they have an overpopulation problem, and some will die out (turn off). These are not the specific rules but just enough to tell you the idea of this game. What is interesting is that certain arrangement of squares will produce some very complex patterns. Sometimes it creates simulations as if their is a living organism, for example see this this. The Game of Life is an example of "bottom-up complexity". There is no designer in the Game of Life. There is no programmer who is making this simulation run. It runs by itself. The squares follow a few basic rules of life and when these squares get together they creates a complex pattern.