With theory, we can separate fundamental characteristics from fascinating idiosyncrasies and incidental features. Theory supplies landmarks and guideposts, and we begin to know what to observe and where to act.

This use of building blocks to generate internal models is a pervasive feature of complex adaptive systems.

The recycling of resource by the aggregate behavior of a diverse array of agents is much more than the sum of the individual actions.

Unwrapping occurs when the "solution" is explicitly built into the program from the start.

If there is to be a competition, there must be some basis for resolving it. It is also clear that the competition should be experienced based.

Model building is the art of selecting those aspects of a process that are relevant to the question being asked. As with any art, this selection is guided by taste, elegance, and metaphor; it is a matter of induction, rather than deduction. High science depends on this art.

Holland's and Kauffman's work, together with Dawkins' simulations of evolution and Varela's models of autopoietic systems, provide essential inspiration for the new discipline of artificial life, This approach, initiated by Chris Langton (1989, 1992), tries to develop technological systems (computer programs and autonomous robots) that exhibit lifelike properties, such as reproduction, sexuality, swarming, and co-evolution.