I argue that trust is epistemically important because it is the foundation of social practices that confer significant epistemic benefits on scientific communities. I begin by showing the limitations of the dominant rational choice account of trust, which maintains that trust is rational when the truster has good reason to believe that it is in the trusted's self-interest to act trustworthily. These limitations motivate my alternative account of trust, which recognizes non-self-interested motivations for acting trustworthily, such as having a sense of duty. The first part of the account captures the cognitive aspect of trust. When we trust, we take a particular cognitive attitude towards the claim that the trusted will do what we expect her to do; I argue that this cognitive attitude can be either belief or acceptance, in the sense outlined by Michael Bratman. The second part of my account captures the emotional and moral aspects of trust by providing a framework to understand the connection between trust and betrayal—the feeling that usually results from being let down by a person one trusts. I provide an account of betrayal as a reactive emotion that connects it to beliefs about relational obligations. Thus when we trust, we depend on the trusted because we believe that our relationship with the trusted morally obliges her to act as expected. Using this account of trust, I argue that scientific communities can garner significant epistemic benefits when scientists are trustworthy and when they trust each other. Applying a framework adapted from Alvin Goldman's work on social epistemology, I argue that trust fosters epistemically beneficial sharing between scientists. These arguments are supported by a case study of the role that trust played in the achievements made by the community of early 20th Century Drosophilists. Finally, using recent examples of scientific fraud in cloning research and public policy responses to much-publicized 'crises in trust', I argue that the epistemic success of science results, in part, from science's ability to balance competition and cooperation, trust and distrust, self-interest and other-interest
