Where does complexity come from?


Self-organizing complexity may emerge directly from the laws of physics and chemistry governing the dynamics of material components while other instances may require additional levels of 'feedback' or regulation to produce the behaviours we observe. Even the simplest cellular systems utilize dozens of molecular parts making it nontrivial to determine what behaviours arise as a consequence of one or the other. 


     Does complexity necessarily require complex rules? 

Conway's 'Game of Life' is a game played on a grid of tiles, each tile black or white (as depicted to the left). Black is alive, white is dead. Each turn, any living square that is surounded by less than two living neighbors dies or turns white. Any living cell with two or three living neighbors is safe for the next turn. Four or more living neighbors and the tile dies from overcrowding. But any dead cell with three living neighbors comes to life. These simple rules of black and white generate surprising complexity.

The glider above apears to glide across the tiles as if it has a life of its own. But other structures actually generate gliders, such as the glider gun pattern shown on the right. The Puffer below leaves behind an array of glider guns in its wake. While the simple rules govern each turn, the emergent behavior of movement and reproduction were not programmed explicitly into the rules. Complex behaviour can emerge from very simple principles.