Complexity theory involves the study of complex systems which are characterized by nonlinear interactions between many elements. It reveals how such interactions can bring about qualitatively new structures and how the whole is related to and different from its individual components. This contrasts to the traditional view between cause and effect, where simple rules imply simple behaviours and, therefore, complicated behaviour must arise from complicated rules. When applied to sustainable development, it centres on the notion that such processes are holistic and that development is not a series of individual successes, but a property of a system as a whole.
(Retrieved from Kirit Patel’s article “Embracing complexity in the UN Development System: Facilitating Middle-income Countries to break the Middle-income Trap”, prepared for the UN Reflection Series)