If we are to understand the interactions of a large number of agents, we must first be able to describe the capabilities of individual agents.

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.

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

From the point of view of physics, it is a miracle that [seven million New Yorkers are fed each day] without any control mechanism other than sheer capitalism.

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.

The measure of performance of any given agent is the amount of money it accumulates through its actions.

Evolution continually innovates, but at each level it conserves the elements that are recombined to yield the innovations.