An alternative to reductionism consists of studying economic systems with a complexity approach. The complexity approach ́s point of departure is that the behavior of the whole is much more complex than the behavior of the parts.

Complexity economics has focused on economic phenomena like business cycle, crises and other out of equilibrium behavior. Its use of non-linear models offers the advantage that the same model allows us to describe stable as well as unstable and even chaotic behaviors.

The use of non-linear models in finance as well as the possibility of finding chaotic behavior in economics are discussed. Models of interacting agents in economics and finance are mentioned as another promising line of research in complexity applied to economics. Finally, whether the complexity approach is another twist of orthodoxy or constitutes a heterodox paradigm is another issue discussed in the paper.