Paul Ormerod is what you might call a heterodox economist. But his approach is one that mainstream economists ought to take very seriously. He uses the mathematics of complexity theory, which looks at non-linear relationships over time. Economics has tended to use linear relationships, because they’re easy to solve. This is a new kind of maths that dates back to the 70s, and has been used in the physical sciences and biology, and is now being adopted in economics.