Ru Ye

According to a widely held norm of rationality, one should not change prior credences without new evidence. An important argument for this norm appeals to accuracy considerations, which says that changing priors doesn't maximize expected accuracy. This is because accuracy measures are strictly proper, and thus any probabilistically coherent person regards her own priors as uniquely maximizing expected accuracy compared with other priors. This paper attempts to resist the accuracy argument against changing priors. We argue that even if rational epistemic decisions maximize expected accuracy according to strictly proper accuracy measures, it can still be rational to change priors sometimes. The core idea of our argument is that changing priors can be rational if one wants to maximize not just one's current, short-term accuracy but also future, long-term accuracy. Our argument, if successful, shows that considering long-term accuracy has significant ramifications for the accuracy-first project.

Impurism says that practical factors encroach on knowledge. An important version of impurism is called 'Threshold-Impurism,' which says that practical factors encroach on the threshold that rational credence must pass in order for one to have knowledge. A prominent kind of argument for Threshold-Impurism is the so-called 'principle-based argument,' which relies on a principle of fallibilism and a knowledge-action principle. This paper offers a new challenge against Threshold-Impurism. I attempt to show that the two principles Threshold-Impurists are committed to-KJ and Fallibilism-are jointly in tension with a widely-held principle of credence that's called 'Truth-Directedness,' in the sense that the former two principles cannot both apply to those who know the third. This tension constitutes a serious challenge to Threshold-Impurists, because it leaves them two options, both of which are undesirable: denying Truth-Directedness, or accepting Truth-Directedness and accepting that whether KJ and Fallibilism apply to a person depends on whether she knows Truth-Directedness.

Epistemic permissivism says that sometimes there are multiple rational responses to the same body of evidence. A recent argument against permissivism says that this view is incompatible with a plausible understanding of the accuracy-conduciveness of rationality, according to which rationality is accuracy-conducive because rational credence is more expectedly accurate than irrational credence. This is called ‘the value problem for permissivism.’ In this paper, I propose a new response to this problem. I defend a convergence- theoretic epistemology: Rationality is accuracy-conducive not because rational credence is more expectedly accurate than irrational credence, but because rational credence performs better with regard to convergence to truth. Drawing on recent developments in formal learning theory, I argue that this ‘convergence-to-truth’ understanding of the accuracy-conduciveness of rationality has many attractive features, and I argue that the convergence understanding is compatible with and even favors permissivism.

The debate between Uniqueness and Permissivism concerns whether a body of evidence sometimes allows multiple doxastic attitudes towards a proposition. An important motivation for Uniqueness is the so-called ‘arbitrariness argument,’ which says that Permissivism leads to some
unacceptable arbitrariness with regard to one’s beliefs. An influential response to the argument says that the arbitrariness in beliefs can be avoided by invoking epistemic standards. In this paper, I argue that such a response to the arbitrariness argument is unsuccessful. Then I defend a new response: contrary to common conception, the arbitrariness resulted by Permissivism is acceptable. The basic idea is that the arbitrariness resulted by Permissivism is analogous to the arbitrariness in permissive actions and the latter arbitrariness is intuitively acceptable. I answer three possible objections against this analogy, which are all motivated by the thought that beliefs aim at the truth. In addressing the last objection, I draw inspiration from the recent debate on transformative experience.

It's widely accepted that higher-order defeaters, i.e., evidence that one's belief is formed in an epistemically defective way, can defeat doxastic justification. However, it's yet unclear how exactly such kind of defeat happens. Given that many theories of doxastic justification can be understood as fitting the schema of proper basing on propositional justifiers, we might attempt to explain the defeat either by arguing that a higher-order defeater defeats propositional justification or by arguing that it defeats proper basing. It has been argued that the first attempt is unpromising because a variety of prominent theories of propositional justification don't imply that we lose propositional justification when gaining higher-order defeaters. This leads some scholars to take the second attempt. In this paper, I criticize this second attempt, and I defend the first attempt by arguing that a theory of propositional justification that requires intellectual responsibility can nicely account for higher-order defeat. My proposal is that we lose doxastic justification when we gain higher-order defeaters because there is no intellectually responsible way for us to maintain our original beliefs due to the defeaters.

Richard Foley has presented a puzzle purporting to show that all attempts in trying to find a sufficient condition of rationality are doomed. The puzzle rests on two plausible assumptions. The first is a level-connecting principle: if one rationally believes that one’s belief p is irrational, then one’s belief p is irrational. The second is a claim about a structural feature shared by all promising sufficient conditions of rationality: for any such condition, it is possible that one’s belief satisfies it and yet one rationally believes that it doesn’t. With the two assumptions, Foley argues that a sufficient condition of rationality is impossible. I explain how exactly the puzzle goes and try to offer a solution. If my solution works, all theorists of rationality who accept certain level-connecting principles will need to add an extra condition to their favorite rationality-making condition.

According to the Dogmatism Puzzle presented by Gilbert Harman, knowledge induces dogmatism because, if one knows a proposition that p, one knows that any evidence against p is misleading and therefore one can ignore it when gaining the evidence in the future. I try to offer a new solution to the puzzle by explaining why the principle is false that evidence known to be misleading can be ignored. I argue that knowing that some evidence is misleading doesn't always damage the credential of the evidence, and therefore it doesn't always entitle one to ignore it. I also explain in what kind of cases and to what degree such knowledge allows one to ignore evidence. Hopefully, through the discussion, we can not only understand better where the dogmatism puzzle goes wrong, but also understand better in what sense rational believers should rely on their evidence and when they can ignore it.

The higher-order evidence debate concerns how higher-order evidence affects the rationality of our first-order beliefs. This Element has two parts. The first part (Sections 1 and 2) provides a critical overview of the literature, aiming to explain why the higher-order evidence debate is interesting and important. The second part (Sections 3 to 6) defends calibrationism, the view that we should respond to higher-order evidence by aligning our credences
to our reliability degree. The author first discusses the traditional version of calibrationism and explains its main difficulties, before proposing a new version of calibrationism called ‘Evidence-Discounting Calibrationism.’ The Element argues that this new version is independently plausible and that it can avoid the difficulties faced by the traditional version.