But Ruhl supports his position with complexity theory, a new science used to study everything from brain cells to bank loans. Complexity theory deals with systems in which lots of players do lots of things all at one time-and where everything affects everything else. It arose after advanced computers began allowing scientists to plot the paths of all those interactions. The first says that the whole acts differently from its individual parts, which makes prediction of future events impossible. And the third says that because one change touches off a host of others, an unwanted result can't be undone by taking back that first change.
Systems adapting to constant change on many fronts churn out increasingly complex responses.
These responses add more parts to the mix, which produces more surprises-and more problems. This sets off another set of even more complicated changes. Each set of changes takes more effort. Eventually, the costs of change outweigh the benefits that change produces, and the whole system becomes vulnerable. But we can see it at work in more than just economics.