Invented by scientists at the nearby Los Alamos National Laboratory in the 1980s, complexity science is a gumbo of insights drawn from fields as diverse as biology, physics, and economics. At its core is the belief that any seemingly complex and utterly random system or phenomenon–from natural selection to the stock market–emerges from the simple behavior of thousands or millions of individuals. Using computer algorithms to stand in for those individual “agents,” scientists discovered they could build fantastically powerful and detailed models of these systems if only they could nail down the right set of rules.

When Brown arrived in town in the late 1990s, many of the scientists-in-residence at the Santa Fe Institute–the serene think tank dedicated to the contemplation of complexity–were rushing to commercialize their favorite research topics. The Prediction Co. was profitably gaming Wall Street by spotting and exploiting small pockets of predictability in capital flows. An outfit called Complexica was working on a simulator that could basically model the entire insurance industry, acting as a giant virtual brain to foresee the implications of any disaster. And the BiosGroup was perfecting agent-based models that today would fall under the heading of “artificial life.”