Recent events have led many commentators to suggest that we live in a post-truth world. Beliefs seem decreasingly sensitive to evidence: instead, we believe what we want to believe. Using the tools of philosophy and deeply informed by cognitive science, this project aims to investigate and illuminate the processes underlying belief formation. By developing a deeper understanding of the nature of belief and of the mechanisms that cause belief change, it aims to develop concrete proposals for making beliefs more responsive to evidence, and to assess the ethical permissibility of utilising these proposals. As well as deepening our understanding of belief, it aims to develop tools that allow for better informed decision-making .