Conciliation, Uniqueness and Rational Toxicity1

Conciliationism holds that disagreement of apparent epistemic peers often substantially undermines rational confidence in our opinions. Uniqueness principles say that there is at most one maximally rational doxastic response to any given batch of total evidence. The two views are often thought to be tightly connected. This paper distinguishes two ways of motivating conciliationism, and two ways that conciliationism may be undermined by permissive accounts of rationality (those that deny uniqueness). It shows how conciliationism can flourish under certain strongly permissive accounts of rationality. This occurs when the motivation for conciliationism does not come (as is sometimes supposed) from taking disagreement as evidence of one's own rational failings. However, divorcing the motive for conciliating from worries about rationality does not remove a feature of conciliationism that some find troubling: that conciliationism can lead to cases of rational toxicity, in which the most rational response to one's evidence involves violating some rational ideal.