Speakers offer testimony. They also hedge. This essay offers an account of how hedging makes a difference to testimony. Two components of testimony are considered: how testimony warrants a hearer's attitude, and how testimony changes a speaker's responsibilities. Starting with a norm-based approach to testimony where hearer's beliefs are prima facie warranted because of social norms and speakers acquire responsibility from these same norms, I argue that hedging alters both components simultaneously. It changes which attitudes a hearer is prima facie (...) warranted in forming in response to testimony, and reduces how much responsibility a speaker undertakes in testifying. A consequence of this account is that speakers who hedge for strategic purposes deprive their hearers of warrant for stronger doxastic attitudes. (shrink)

Epistemically immodest agents take their own epistemic standards to be among the most truth-conducive ones available to them. Many philosophers have argued that immodesty is epistemically required of agents, notably because being modest entails a problematic kind of incoherence or self-distrust. In this paper, I argue that modesty is epistemically permitted in some social contexts. I focus on social contexts where agents with limited cognitive capacities cooperate with each other (like juries).

Many philosophers have offered arguments in favor of the following three theses: A is epistemically permitted to believe P only if A is in a position to know that P, incoherent agents fail to satisfy the aforementioned knowledge norm of belief, and A’s apparent reasons are relevant to determining what A is blameworthy for believing. In this paper, I argue that the above three theses are jointly inconsistent. The main upshot of the paper is this: even if the knowledge norm (...) of belief is correct, it cannot explain some deontic requirements governing belief. (shrink)

Is epistemic inconsistency a mere symptom of having violated other requirements of rationality—notably, reasons-responsiveness requirements? Or is inconsistency irrational on its own? This question has important implications for the debate on the normativity of epistemic rationality. In this paper, I defend a new account of the explanatory role of the requirement of epistemic consistency. Roughly, I will argue that, in cases where an epistemically rational agent is permitted to believe P and also permitted to disbelieve P, the consistency requirement plays (...) a distinct explanatory role. I will also argue that such a type of permissiveness is a live possibility when it comes to rational epistemic standards. (shrink)

It seems that epistemically rational agents should avoid incoherent combinations of beliefs and should respond correctly to their epistemic reasons. However, some situations seem to indicate that such requirements cannot be simultaneously satisfied. In such contexts, assuming that there is no unsolvable dilemma of epistemic rationality, either (i) it could be rational that one’s higher-order attitudes do not align with one’s first-order attitudes or (ii) requirements such as responding correctly to epistemic reasons that agents have are not genuine rationality requirements. (...) This result doesn’t square well with plausible theoretical assumptions concerning epistemic rationality. So, how do we solve this puzzle? In this paper, I will suggest that an agent can always reason from infallible higher-order reasons. This provides a partial solution to the above puzzle. (shrink)

The Lockean Thesis says that you must believe p iff you’re sufficiently confident of it. On some versions, the 'must' asserts a metaphysical connection; on others, it asserts a normative one. On some versions, 'sufficiently confident' refers to a fixed threshold of credence; on others, it varies with proposition and context. Claim: the Lockean Thesis follows from epistemic utility theory—the view that rational requirements are constrained by the norm to promote accuracy. Different versions of this theory generate different versions of (...) Lockeanism; moreover, a plausible version of epistemic utility theory meshes with natural language considerations, yielding a new Lockean picture that helps to model and explain the role of beliefs in inquiry and conversation. Your beliefs are your best guesses in response to the epistemic priorities of your context. Upshot: we have a new approach to the epistemology and semantics of belief. And it has teeth. It implies that the role of beliefs is fundamentally different than many have thought, and in fact supports a metaphysical reduction of belief to credence. (shrink)

This chapter presents a new semantics for inductive empirical knowledge. The epistemic agent is represented concretely as a learner who processes new inputs through time and who forms new beliefs from those inputs by means of a concrete, computable learning program. The agent’s belief state is represented hyper-intensionally as a set of time-indexed sentences. Knowledge is interpreted as avoidance of error in the limit and as having converged to true belief from the present time onward. Familiar topics are re-examined within (...) the semantics, such as inductive skepticism, the logic of discovery, Duhem’s problem, the articulation of theories by auxiliary hypotheses, the role of serendipity in scientific knowledge, Fitch’s paradox, deductive closure of knowability, whether one can know inductively that one knows inductively, whether one can know inductively that one does not know inductively, and whether expert instruction can spread common inductive knowledge—as opposed to mere, true belief—through a community of gullible pupils. (shrink)

This paper addresses the ongoing debate over the relation between belief and credence. A proposal is made to reverse the currently predominant order of analysis, by taking belief as conceptually basic and credence as the phenomenon to be clarified. In brief, the proposal is to explicate an agent’s credence in a proposition P as the agent’s tendency toward believing P. Platitudinous as this reduction may seem, it runs counter to all of the major positions in the debate, including the Threshold (...) View, the Certainty View as conventionally understood, Dualism, Eliminativism, as well as Credence Primitivism. Section 1 gives an overview on the current state of the debate. Section 2 considers unsuccessful predecessors of the proposed belief-first approach to credence. Section 3 motivates and lays out the basics of a conceptual framework for thinking about doxastic states that characterizes such states in terms of two formally independent dimensions, one pertaining to the agent’s tendency toward believing P, the other to the level of resilience with which the agent manifests that tendency. Against this backdrop, it is argued in Sect. 4 that the present reduction satisfies a set of standard, theoretically neutral criteria of adequacy for theories of credence, at least once they are purged of a quite common conflation of tendency and resilience. Section 5 argues against all of the above competing accounts. (shrink)

This book illustrates the program of Logical-Informational Dynamics. Rational agents exploit the information available in the world in delicate ways, adopt a wide range of epistemic attitudes, and in that process, constantly change the world itself. Logical-Informational Dynamics is about logical systems putting such activities at center stage, focusing on the events by which we acquire information and change attitudes. Its contributions show many current logics of information and change at work, often in multi-agent settings where social behavior is essential, (...) and often stressing Johan van Benthem's pioneering work in establishing this program. However, this is not a Festschrift, but a rich tapestry for a field with a wealth of strands of its own. The reader will see the state of the art in such topics as information update, belief change, preference, learning over time, and strategic interaction in games. Moreover, no tight boundary has been enforced, and some chapters add more general mathematical or philosophical foundations or links to current trends in computer science. The theme of this book lies at the interface of many disciplines. Logic is the main methodology, but the various chapters cross easily between mathematics, computer science, philosophy, linguistics, cognitive and social sciences, while also ranging from pure theory to empirical work. Accordingly, the authors of this book represent a wide variety of original thinkers from different research communities. And their interconnected themes challenge at the same time how we think of logic, philosophy and computation. Thus, very much in line with van Benthem's work over many decades, the volume shows how all these disciplines form a natural unity in the perspective of dynamic logicians (broadly conceived) exploring their new themes today. And at the same time, in doing so, it offers a broader conception of logic with a certain grandeur, moving its horizons beyond the traditional study of consequence relations. (shrink)

This paper studies Aumann’s agreeing to disagree theorem from the perspective of dynamic epistemic logic. This was first done by Dégremont and Roy (J Phil Log 41:735–764, 2012) in the qualitative framework of plausibility models. The current paper uses a probabilistic framework, and thus stays closer to Aumann’s original formulation. The paper first introduces enriched probabilistic Kripke frames and models, and various ways of updating them. This framework is then used to prove several agreement theorems, which are natural formalizations of (...) Aumann’s original result. Furthermore, a sound and complete axiomatization of a dynamic agreement logic is provided, in which one of these agreement theorems can be derived syntactically. These technical results are used to show the importance of explicitly representing the dynamics behind the agreement theorem, and lead to a clarification of some conceptual issues surrounding the agreement theorem, in particular concerning the role of common knowledge. The formalization of the agreement theorem thus constitutes a concrete example of the so-called dynamic turn in logic. (shrink)

Pretense imagination is imagination understood as the ability to recreate rational belief revision. This kind of imagination is used in pretend-play, risk-assessment, etc. Some even claim that this kind of hypothetical belief revision can be grounds to justify new beliefs in conditionals, in particular conditionals that play a foundational role in the epistemology of modality. In this paper, I will argue that it cannot. I will first provide a very general theory of pretense imagination, which I formalise using tools from (...) dynamic epistemic logic. As a result, we can clearly see that pretense imagination episodes are build up out of two kinds of imaginative stages, so I will present an argument by cases. This argument shows that pretense imagination might indeed provide us with justification for believing certain conditionals. Despite this, I will argue that these arenotthe kind of conditionals that allow pretense imagination to play a foundational role in the epistemology of modality. (shrink)

Pretense imagination is imagination understood as the ability to recreate rational belief revision. This kind of imagination is used in pretend-play, risk-assessment, etc. Some even claim that this kind of hypothetical belief revision can be grounds to justify new beliefs in conditionals, in particular conditionals that play a foundational role in the epistemology of modality. In this paper, I will argue that it cannot. I will first provide a very general theory of pretense imagination, which I formalise using tools from (...) dynamic epistemic logic. As a result, we can clearly see that pretense imagination episodes are build up out of two kinds of imaginative stages, so I will present an argument by cases. This argument shows that pretense imagination might indeed provide us with justification for believing certain conditionals. Despite this, I will argue that these are not the kind of conditionals that allow pretense imagination to play a foundational role in the epistemology of modality. (shrink)

The paper gives a formal analysis of public lies, explains how public lying is related to public announcement, and describes the process of recoveries from false beliefs engendered by public lying. The framework treats two kinds of public lies: simple lying update and two-step lying, which consists of suggesting that the lie may be true followed by announcing the lie. It turns out that agents’ convictions of what is true are immune to the first kind, but can be shattered by (...) the second kind. Next, recovery from public lying is analyzed. Public lies that are accepted by an audience cannot be undone simply by announcing their negation. The paper proposes a recovery process that works well for restoring beliefs about facts but cannot be extended to beliefs about beliefs. The formal machinery of the paper consists of KD45 models and conditional neighbourhood models, with various update procedures on them. Completeness proofs for a number of reasoning systems (converse belief logic, public lies logic, lying and recovery logic, conditional neighbourhood logic, plus its dynamic version) are included. (shrink)