The Epistemology of Testimonal Trust

According to a strong assurance view of testimonial trust, a speaker's assurance that p grounds a reason for the hearer to believe p. While the strong view offers a genuinely inter-personal account of testimony, it faces a problem about bootstrapping: how can trust generate epistemic reasons when trust can obtain between unreliable speakers and hearers? In contrast, a weaker assurance view holds that a speaker's assurance that p grounds a reason for the hearer to believe p only if the speaker is reliable. While the weaker view offers an epistemic account of testimony, it faces a problem about redundancy: how can trust play any epistemic role when the speaker's reliability seems to pre-empt any contribution that trust may make towards such epistemic reason? This paper argues that neither horn of this dilemma is convincing once proponents of assurance views avail themselves of an epistemic distinction between reasons of rationality as a guide to reasonable belief and reasons of justification as a guide to true belief. Whereas testimonial assurance grounds rational reasons, which need not make probable the beliefs they make reasonable, testimonial reliability grounds justificatory reasons, which need not make reasonable the beliefs they make probable.