This article stems from the contradictions that may be observed between the current demand for sustainability and the current functioning of our financial system. Beginning with a discussion of the epistemological assumptions underlying financial theory, it seeks to reveal the ways in which it may be viewed as an Ideology supporting the financialization of economies and societies. In order to counterbalance this ideology, we use the Ricœurian notion of the cultural imaginary to develop a Utopia, which is referred to as Finance as a Common. The reflexivity enabled by this Utopia reveals the mental structures in which financial actors are embedded, while opening up possible pathways for the reconstruction of the financial system and the renewal of financial knowledge.