## Conceptual models from complexity theory

Using arcane mathematical theories to design a Web site might strike many Web site designers as total nonsense. It may well be, if we were only designing a Web site, but we're not: we are designing a system: where the Web site is simply a functional component. As such, the Web site cannot have a static design: it must be capable of continuous change - a dynamic design.

To get this idea into perspective, think about an ant colony - the model upon which the concept of stigmergy is based (see the tutorial "Harnessing the power of stigmergy"). The ants you see running around have evolved over the course of millions of years. The genes they use, to read and write their pheromone trails, have become a permanent feature of the ant design and there is no evolutionary pressure for the queen ant to change these genes. This equates to the queen ant having created a Web site that works and there being no need to change it.

In designing a stigmergic system, we are not in the fortunate position of being able to start with a model that has already evolved to perform efficiently. We have to set up a system to make this happen.

This requires a very big paradigm shift, because the design of a stigmergic system is not simply about copying the activities of the ants when they lay pheromone trails to food sources. That is too simplistic.

We have to think about copying the system that brought about the behavior of the ants: the evolutionary processes that resulted in the queen ant providing the worker ants with the right kinds of genes that allow them to read and write the pheromone trails that allow them to tell each other where to find sources of food.

In other words, we have to go beyond the design of the ants, even beyond the design of the queen: we need to be able to create the equivalent of a queen that can continually evolve until it is providing ants with the right kind of genes that allow them to work efficiently.

This is a very difficult design concept to work with, because it isn't about creating a pre-planned design. It is about creating a system where the design emerges.

In practice, this means we have to have a stigmergic system program that will be able to continuously experiment with different Web site designs until the Web site is functioning efficiently. To do this, using a conventional approach to Web site design, would be prohibitively time consuming and expensive - so, we need to have a completely new conceptual model to work with.

Here we have to venture into strange and exotic fields at the cutting edge of technology: evolutionary strategies, molecular biology and the physics of complexity and chaos. We don't need to have a full knowledge of these subject areas, we just need to borrow some of the conceptual models that are used. This will allow us to copy some of the innovative strategies employed by biological organisms - which are understandable only in terms of the concepts that have emerged over the last twenty years from the theory of complex dynamic systems.

Central to the theory of complex dynamic systems is the idea of 'attractor basins'. This concept will enable us make incremental changes to a system design in a controlled and progressive direction. Attractors hold the key to the use of stigmergy in producing systems that will allow people to help each other find information efficiently.