Complexity science has attracted considerable attention in a number of disciplines. However, this perspective on scientific understanding remains ill defined. In this paper, ideas and approaches from complexity science are reviewed. It appears that complexity science fundamentally is driven by ontological decisions on the part of the investigator. This is a result of the epistemological approach fundamental to complexity as it is currently studied, which is based on the construction of computer simulation models of reality. This methodology requires that researchers decide what exists and is important enough to represent in a simulation, and also what to leave out. Although this points to serious difficulties with complexity science, it is argued that the approach nevertheless has much to offer human geography. Drawing on complexity science, renewed engagements between physical and human geography, and between both and geographical information science seem possible, based on clearly shared concerns with the representation of geographical phenomena. In conclusion, it is suggested that seeing models as a source of geographical narratives may be a useful way to promote constructive engagement between different perspectives in the discipline.