Jakob Donskov

Beliefs can be more or less supported by evidence. When the evidence speaks in favour of some proposition p, you can rationally be confident that p. On the Bayesian interpretation of doxastic states, this amounts to a high credence in p. But this cannot be the full account of confidence. Gaining evidence that supports the credence you already have improves your epistemic situation. Here, your credence level should remain unchanged, but the credence should become more resistant to change. Doxastic resilience measures your disposition to change credence in the face of incoming evidence. The central claim of this thesis is that by thinking of confidence in terms of both the level and resilience of credences, we can make progress on several philosophical problems. After briefly introducing doxastic resilience in Chapter 1, I put the concept to use in four philosophical debates. Chapter 2 offers an evidential account of rational resistance to counterevidence which contrasts with views according to which knowledge plays a special role in safeguarding against counterevidence. Chapter 3 argues that loss of resilience can influence rational decision-making, which sheds light on the normative significance of certain kinds of higher-order defeat. This contrasts with imprecise probability views on which higher-order defeat increases the imprecision of credence. Chapter 4 argues that higher-order uncertainty calibrates first-order credences and constrains expected resilience. This explains both higher-order confirmation and defeat. Chapter 5 shows that resilience bears on the expected value of inquiry. When unresilient, one should expect new evidence to be valuable. This explains cases where seemingly identical decision-relevant credences and utilities should nevertheless make different decisions when inquiry is feasible.

When can you rationally resist misleading evidence? One influential answer appeals to the idea that knowledge can serve as a safeguarding instrument, which, if not allowing you to outright dismiss misleading evidence—as Kripke’s dogmatism paradox suggests—at least makes it more likely that your true beliefs rationally resist defeat (Williamson, 2000). I reject the idea, arguing that any such rational resistance is well accounted for by our beliefs, regardless of whether they amount to knowledge. By paying attention to how evidential strength influences the resilience of rational belief, I offer an evidential account of rational resistance. I use the account to evaluate Harman’s solution to Kripke’s dogmatism paradox, highlighting the limits of the knowledge-based approach.

In some cases of higher-order defeat, you rationally doubt whether your credence in p is rational without having evidence of how to improve your credence in p. According to the resilience framework proposed by Steglich-Petersen (Higher-order defeat and Doxastic Resilience), such cases require loss of doxastic resilience: retain your credence level but become more disposed to change your mind given future evidence. Henderson (Higher-Order Evidence and Losing One’s Conviction) responds that this allows for irrational decision-making and that we are better off understanding higher-order defeat in terms of imprecise probabilities. We argue first that Henderson’s imprecise probability framework models the wrong kind of thing. Credal imprecision is neither necessary nor sufficient for higher-order doubt. Second, we offer two ways of understanding the practical import of higher-order defeat given loss of doxastic resilience.