Science writer John Horgan cautions against putting too much faith in complexity science because, he writes, a general theory might not be achievable. 

Read Horgan's article in Scientific American (December 10, 2012)

In the article, he calls SFI "a hotbed of research on complex systems," and offers six reasons to be wary of high expectations for complex systems science: 1) there is no working definition of complex systems, 2) past boom cycles for complex systems science have waned as limits have emerged, 3) complex systems are inherently unpredictable, 4) complex social systems are especially difficult to model, 5) computing power has not realized expectations, 6) innovations tend to create more problems than they solve.

He closes with this: "Engineers and scientists have demonstrated their ability to invent and manage extraordinarily complex systems, which provide us with energy, transportation, food and water, health care, entertainment, communication, shelter, security. We must, and will, find ways to further minimize the downside and maximize the upside of civilization. But given the history of complexity research, our can-do optimism should always be tempered by skepticism and caution."