Starting from the assumption that decision situations in economic contexts are characterized by fundamental uncertainty, this article argues that the decision-making of intentionally rational actors is anchored in fictions. “Fictionality” in economic action is the inhabitation in the mind of an imagined future state of the world and the beliefs in causal mechanisms leading to this future state. Actors are motivated in their actions by the imagined future and organize their activities based on these mental representations. Since these representations are (...) not confined to empirical reality, fictional expectations are also a source of creativity in the economy. Fictionality opens up a way to an understanding of the microfoundations of the dynamics of the economy. The article develops the notion of fictional expectations. It discusses the role of fictional expectations for the dynamics of the economy and addresses the question of how fictional expectations motivate action. The last part relates the notion of fiction to calculation and social macrostructures, especially institutions and cultural frames. The conclusion hints at the research program developing from the concept of fictional expectations. (shrink)