History lessons: what can we learn about history?

What can we learn from the past? This paper examines the nature of the past and discusses the extent to which historical outcomes are robust over different starting conditions, using primarily the example of the origin of the Great War. It reviews the mathematical and psychological literature on complexity theory, and considers the idea that history can indeed in some circumstances be robust across initial conditions. I introduce the notion of a dynamic historical attractor to account for the way in which the past unfolds over time, and relate dynamic attractors to post-modern approaches to historical interpretation.