This article defends the Fixed Point Thesis: that it is always a rational mistake to have false beliefs about the requirements of rationality. The Fixed Point Thesis is inspired by logical omniscience requirements in formal epistemology. It argues to the Fixed Point Thesis from the Akratic Principle: that rationality forbids having an attitude while believing that attitude is rationally forbidden. It then draws out surprising consequences of the Fixed Point Thesis, for instance that certain kinds of a priori justification are (...) indefeasible and that misleading all-things-considered evidence about rational requirements is impossible. Finally, the Fixed Point Thesis is applied to defend the Right Reasons position on peer disagreement, according to which an agent who has drawn the correct conclusion from her evidence should retain belief in that conclusion even in the face of disagreeing peers. (shrink)

The Uniqueness Thesis holds, roughly speaking, that there is a unique rational response to any particular body of evidence. We first sketch some varieties of Uniqueness that appear in the literature. We then discuss some popular views that conflict with Uniqueness and others that require Uniqueness to be true. We then examine some arguments that have been presented in its favor and discuss why permissivists find them unconvincing. Last, we present some purported counterexamples that have been raised against Uniqueness and (...) discuss some possible reasons why proponents of Uniqueness might find these similarly unconvincing. (shrink)

Michael G. Titelbaum presents a new Bayesian framework for modeling rational degrees of belief—the first of its kind to represent rational requirements on agents who undergo certainty loss.

'Fundamentals of Bayesian Epistemology' provides an accessible introduction to the key concepts and principles of the Bayesian formalism. This volume introduces degrees of belief as a concept in epistemology and the rules for updating degrees of belief derived from Bayesian principles.--.

Different people reason differently, which means that sometimes they reach different conclusions from the same evidence. We maintain that this is not only natural, but rational. In this essay we explore the epistemology of that state of affairs. First we will canvass arguments for and against the claim that rational methods of reasoning must always reach the same conclusions from the same evidence. Then we will consider whether the acknowledgment that people have divergent rational reasoning methods should undermine one’s confidence (...) in one’s own reasoning. Finally we will explore how agents who employ distinct yet equally rational methods of reasoning should respond to interactions with the products of each others’ reasoning. We find that the epistemology of multiple reasoning methods has been misunderstood by a number of authors writing on epistemic permissiveness and peer disagreement. (shrink)

There are many kinds of epistemic experts to which we might wish to defer in setting our credences. These include: highly rational agents, objective chances, our own future credences, our own current credences, and evidential probabilities. But exactly what constraint does a deference requirement place on an agent's credences? In this paper we consider three answers, inspired by three principles that have been proposed for deference to objective chances. We consider how these options fare when applied to the other kinds (...) of epistemic experts mentioned above. Of the three deference principles we consider, we argue that two of the options face insuperable difficulties. The third, on the other hand, fares well|at least when it is applied in a particular way. (shrink)

'Fundamentals of Bayesian Epistemology' provides an accessible introduction to the key concepts and principles of the Bayesian formalism. Volume 2 introduces applications of Bayesianism to confirmation and decision theory, then gives a critical survey of arguments for and challenges to Bayesian epistemology.--.

Begins by explaining then proving a generalized language dependence result similar to Goodman's "grue" problem. I then use this result to cast doubt on the existence of an objective evidential favoring relation (such as "the evidence confirms one hypothesis over another," "the evidence provides more reason to believe one hypothesis over the other," "the evidence justifies one hypothesis over the other," etc.). Once we understand what language dependence tells us about evidential favoring, our options are an implausibly strong conception of (...) the a priori, a hard externalism on which agents are unable to determine what their evidence favors, or a subjectivist view that makes evidential favoring relative to features of the agent. (shrink)

Can self-locating beliefs be relevant to non-self-locating claims? Traditional Bayesian modeling techniques have trouble answering this question because their updating rule fails when applied to situations involving contextsensitivity. This essay develops a fully general framework for modeling stories involving context-sensitive claims. The key innovations are a revised conditionalization rule and a principle relating models of the same story with different modeling languages. The essay then applies the modeling framework to the Sleeping Beauty Problem, showing that when Beauty awakens her degree (...) of belief in heads should be one-third. This demonstrates that it can be rational for an agent who gains only self-locating beliefs between two times to alter her degree of belief in a non-self-locating claim. (shrink)

The Sleeping Beauty Problem attracts so much attention because it connects to a wide variety of unresolved issues in formal epistemology, decision theory, and the philosophy of science. The problem raises unanswered questions concerning relative frequencies, objective chances, the relation between self-locating and non-self-locating information, the relation between self-location and updating, Dutch Books, accuracy arguments, memory loss, indifference principles, the existence of multiple universes, and many-worlds interpretations of quantum mechanics. After stating the problem, this article surveys its connections to all (...) of these areas. (shrink)

Abstract. Richard Feldman’s Uniqueness Thesis holds that “a body of evidence justifies at most one proposition out of a competing set of proposi- tions”. The opposing position, permissivism, allows distinct rational agents to adopt differing attitudes towards a proposition given the same body of evidence. We assess various motivations that have been offered for Uniqueness, including: concerns about achieving consensus, a strong form of evidentialism, worries about epistemically arbitrary influences on belief, a focus on truth-conduciveness, and consequences for peer disagreement. (...) We argue that each of these motivations either misunderstands the commitments of permissivism or is question-begging. Better understanding permissivism makes it a much more plausible position. (shrink)

Recent discussion of Vogel-style “bootstrapping” scenarios suggests that they provide counterexamples to a wide variety of epistemological theories. Yet it remains unclear why it’s bad for a theory to permit bootstrapping, or even exactly what counts as a bootstrapping case. Going back to Vogel's original bootstrapping example, I note that an agent who could gain justification through the method Vogel describes would have available a “no-lose investigation”: an investigation that can justify a proposition but has no possibility of undermining it. (...) The main suggestion of this article is that an epistemological theory should not permit no-lose investigations. I identify necessary and sufficient conditions for such investigations, then explore epistemological theories that rule them out. If we want to avoid both skepticism and no-lose investigations, we must eschew either Closure or epistemic externalism. (shrink)

Roger White argued for a principle of indifference. Hart and Titelbaum showed that White’s argument relied on an intuition about conditioning on biconditionals that, while widely shared, is incorrect. Hawthorne, Landes, Wallmann, and Williamson argue for a principle of indifference. Remarkably, their argument relies on the same faulty intuition. We explain their intuition, explain why it’s faulty, and show how it generates their principle of indifference. 1Introduction 2El Caminos and Indifference 2.1Overview 2.2Fins and antennas 2.3HLWW in the example 2.4The restrictiveness (...) of Condition 2 2.5Summary 3The Specifics of HLWW s Argument 3.1Mapping their conditions to our equations 3.2HLWW’s responses to objections. (shrink)

I argue that given standard deontic logic, wide-scope rational requirements entail narrow-scope rational requirements. In particular, the widely-embraced Enkratic Principle entails that if a particular combination of attitudes is rationally forbidden, it is also rationally forbidden to believe that that combination of attitudes is required.

A plea: If you're going to propose a Bayesian framework for updating self-locating degrees of belief, please read this piece first. I've tried to survey all the extant formalisms, group them by their general approach, then describe challenges faced by every formalism employing a given approach. Hopefully this survey will prevent further instances of authors' re-inventing updating rules already proposed elsewhere in the literature.

Metaethicists have recently devoted a great deal of attention to questions about when a fact counts as a reason for or against a particular conclusion, and how such reasons interact. Chapter 9 asks a broader question: When a set of facts counts in favor of some conclusion, is that always because at least one of those facts is a reason for that conclusion? Examples are offered in which a set supports a conclusion without any fact in that set’s being a (...) reason for. The chapter then assesses the significance of such examples for philosophical methodology, the ‘reasons-first’ program, and metanormative realism. (shrink)

“Double-halfers” think that throughout the Sleeping Beauty Problem, Beauty should keep her credence that a fair coin flip came up heads equal to 1/2. I introduce a new wrinkle to the problem that shows even double-halfers can't keep Beauty's credences equal to the objective chances for all coin-flip propositions. This leaves no way to deny that self-locating information generates an unexpected kind of inadmissible evidence.

What goes wrong, from a rational point of view, when an agent’s beliefs change while her evidence remains constant? I canvass a number of answers to this question suggested by recent literature, then identify some desiderata I would like any potential answer to meet. Finally, I suggest that the rational problem results from the undermining of reasoning processes that are necessarily extended in time.

A response to G.A. Cohen's argument that a prevailing "ethos" of justice would prevent a Rawlsian just society from having any income inequalities. I suggest that Cohen's argument fails because a Rawlsian ethos would involve correlates of both of Rawls' principles of justice.

Roger White objects to interval-valued credence theories because they produce a counterintuitive “dilation” effect in a story he calls the Coin Game. We respond that results in the Coin Game were bound to be counterintuitive anyway, because the story involves an agent who learns a biconditional. Biconditional updates produce surprising results whether the credences involved are ranged or precise, so White's story is no counterexample to ranged credence theories.

The Stability of Belief: How Rational Belief Coheres with Probability, by LeitgebHannes. Oxford: Oxford University Press, 2017. Pp. xiv + 365.

Responding to Cappelen and Dever’s claim that there is no distinctive role for perspectivality in epistemology, I argue that facts about the outcomes of one’s own reasoning processes may have a different evidential significance than facts about the outcomes of others’.

Starting from the premise that akrasia is irrational, I argue that it is always a rational mistake to have false beliefs about the requirements of rationality. Using that conclusion, I defend logical omniscience requirements, the claim that one can never have all-things-considered misleading evidence about what's rational, and the Right Reasons position concerning peer disagreement.

I begin by discussing a conundrum that arises when Bayesian models attempt to assess the relevance of one claim to another. I then explain how my formal modeling framework manages this conundrum. Finally, I apply my modeling methodology to respond to Namjoong Kim’s objection to my framework.

Bayesian modeling techniques have proven remarkably successful at representing rational constraints on agents’ degrees of belief. Yet Frank Arntzenius’s “Shangri-La” example shows that these techniques fail for stories involving forgetting. This paper presents a formalized, expanded Bayesian modeling framework that generates intuitive verdicts about agents’ degrees of belief after losing information. The framework’s key result, called Generalized Conditionalization, yields applications like a version of Bas van Fraassen’s Reflection Principle for forgetting. These applications lead to questions about why agents should coordinate (...) their doxastic states over time, and about the commitments an agent can make by assigning degrees of belief. (shrink)