The following considerations concern modelling Belief Dynamics (BD) not just in the sense of a formalization, but rather in the sense of building a computational model and implementing the corresponding data structures and algorithms of recomputing beliefs. The purpose of such a project is to illustrate some ideas about belief changes in a Web of Beliefs (WoB) to explore and deepen one's understanding of belief changes by trying to implement or improve corresponding algorithms.

We propose a dynamic hyperintensional logic of belief revision for non-omniscient agents, reducing the logical omniscience phenomena affecting standard doxastic/epistemic logic as well as AGM belief revision theory. Our agents don’t know all a priori truths; their belief states are not closed under classical logical consequence; and their belief update policies are such that logically or necessarily equivalent contents can lead to different revisions. We model both plain and conditional belief, then focus on (...) class='Hi'>dynamic belief revision. The key idea we exploit to achieve non-omniscience focuses on topic- or subject matter-sensitivity: a feature of belief states which is gaining growing attention in the recent literature. (shrink)

Conditionalization is one of the central norms of Bayesian epistemology. But there are a number of competing formulations, and a number of arguments that purport to establish it. In this paper, I explore which formulations of the norm are supported by which arguments. In their standard formulations, each of the arguments I consider here depends on the same assumption, which I call Deterministic Updating. I will investigate whether it is possible to amend these arguments so that they no longer depend (...) on it. As I show, whether this is possible depends on the formulation of the norm under consideration. (shrink)

The field of iterated belief change has focused mainly on revision, with the other main operator of AGM belief change theory, i.e. contraction, receiving relatively little attention. In this paper we extend the Harper Identity from single-step change to define iterated contraction in terms of iterated revision. Specifically, just as the Harper Identity provides a recipe for defining the belief set resulting from contracting A in terms of (i) the initial belief set and (ii) (...) the belief set resulting from revision by ¬A, we look at ways to define the plausibility ordering over worlds resulting from contracting A in terms of (iii) the initial plausibility ordering, and (iv) the plausibility ordering resulting from revision by ¬A. After noting that the most straightforward such extension leads to a trivialisation of the space of permissible orderings, we provide a family of operators for combining plausibility orderings that avoid such a result. These operators are characterised in our domain of interest by a pair of intuitively compelling properties, which turn out to enable the derivation of a number of iterated contraction postulates from postulates for iterated revision. We finish by observing that a salient member of this family allows for the derivation of counterparts for contraction of some well known iterated revision operators, as well as for defining new iterated contraction operators. (shrink)

We present a theory of truth in fiction that improves on Lewis's [1978] ‘Analysis 2’ in two ways. First, we expand Lewis's possible worlds apparatus by adding non-normal or impossible worlds. Second, we model truth in fiction as belief revision via ideas from dynamic epistemic logic. We explain the major objections raised against Lewis's original view and show that our theory overcomes them.

Despite its central role in our cognitive lives, rational belief revision has received relatively little attention from epistemologists. This dissertation begins to fill that absence. In particular, we explore the phenomenon of defeasible epistemic justification, i.e., justification that can be lost as well as gained by epistemic agents. We begin by considering extant theories of defeat, according to which defeaters are whatever cause a loss of justification or things that somehow neutralize one's reasons for belief. Both of these (...) theories are both extensionally and explanatorily inadequate and, so, are rejected. We proceed to develop a novel theory of defeat according to which defeaters are reasons against belief. According to this theory, the dynamics of justification are explained by the competition between reasons for and reasons against belief. We find that this theory not only handles the counter-examples that felled the previous theories but also does a fair job in explaining the various aspects of the phenomenon of defeat. Furthermore, this theory accomplishes this without positing any novel entities or mechanisms; according to this theory, defeaters are epistemic reasons against belief, the mirror image of our epistemic reasons for belief, rather than sui generis entities. (shrink)

In this article, we address a major outstanding question of probabilistic Bayesian epistemology: how should a rational Bayesian agent update their beliefs upon learning an indicative conditional? A number of authors have recently contended that this question is fundamentally underdetermined by Bayesian norms, and hence that there is no single update procedure that rational agents are obliged to follow upon learning an indicative conditional. Here we resist this trend and argue that a core set of widely accepted Bayesian norms is (...) sufficient to identify a normatively privileged updating procedure for this kind of learning. Along the way, we justify a privileged formalization of the notion of ‘epistemic conservativity’, offer a new analysis of the Judy Benjamin problem, and emphasize the distinction between interpreting the content of new evidence and updating one’s beliefs on the basis of that content. (shrink)

The thesis that agents should calibrate their beliefs in the face of higher-order evidence—i.e., should adjust their first-order beliefs in response to evidence suggesting that the reasoning underlying those beliefs is faulty—is sometimes thought to be in tension with Bayesian approaches to belief update: in order to obey Bayesian norms, it’s claimed, agents must remain steadfast in the face of higher-order evidence. But I argue that this claim is incorrect. In particular, I motivate a minimal constraint on a reasonable (...) treatment of the evolution of self-locating beliefs over time and show that calibrationism is compatible with any generalized Bayesian approach that respects this constraint. I then use this result to argue that remaining steadfast isn’t the response to higher-order evidence that maximizes expected accuracy. (shrink)

A fictional text is commonly viewed as constituting an invitation to play a certain game of make-believe, with the individual sentences written by the author providing the propositions we are to imagine and/or accept as true within the fiction. However, we can’t always take the text at face value. What narratologists call ‘unreliable narrators’ may present a confused or misleading picture of the fictional world. Meanwhile there has been a debate in philosophy about so-called ‘imaginative resistance’ in which we are (...) inclined to resist imagining (or even accepting as true in the fiction) what’s explicitly stated in the text. But if we can’t take the text’s word for it, how do we determine what’s true in a fiction? We propose an account of fiction interpretation in a dynamic setting (a version of DRT with a mechanism for opening, updating, and closing temporary ‘workspaces’) and combine this framework with belief revision logic. With these tools in hand we turn to modelling imaginative resistance and unreliable narrators. (shrink)

One of the leading exponents of W's ideas on the language games of inner and outer (the `Two Selves' operation of our personality or intentionality or EP etc.) is the prolific Daniel Hutto (DH). His approach is called `Radical Enactivism' and is well explained in numerous recent books and papers (see my review of Radicalizing Enactivism) and a new one is appearing as I write (Evolving Enactivism). It is a development of or version of the Embodied Mind ideas now current (...) and, cleansed of its jargon, it is a straightforward extension of W's 2nd and 3rd period writings (though Hutto seems only intermittently aware of this). -/- Unfortunately, in 2006 Hutto had not yet arrived at his Radical Enactivism, so much time is wasted on McDowell and Brandom and of course none of them to this day have totally digested the later W and his prescient analysis of automatic behavior and the two systems of thought - so fully in tune with contemporary research. Nor is there any discussion of Searle's groundbreaking and completely Wittgensteinian (unwittingly) disquisitions on the Construction of Social Reality. Thus, his chapters 5 and 6 on Realism and Idealism etc., though superb for 2002, need a complete rewrite from a modern two systems viewpoint and I provide a start on that in my review. Much time is wasted on Davidson and Williams, etc. but one can endure them for Hutto's brilliant analyses and the frequent quotes from W. The last chapter gives his critic Rupert Read the counterblast he deserves and permits a slight update to 2006. Overall a lovely book and I eagerly await the third edition which I hope will ensue. -/- Those wishing a comprehensive up to date framework for human behavior from the modern two systems view may consult my book ‘The Logical Structure of Philosophy, Psychology, Mind and Language in Ludwig Wittgenstein and John Searle’ 2nd ed (2019). Those interested in more of my writings may see ‘Talking Monkeys--Philosophy, Psychology, Science, Religion and Politics on a Doomed Planet--Articles and Reviews 2006-2019 3rd ed (2019) and Suicidal Utopian Delusions in the 21st Century 4th ed (2019). (shrink)

This chapter critically analyzes evolutionary epistemology as a theoretical framework for the study of science as a historical and cultural phenomenon. As spelled out by Campbell in the 1970s, evolutionary epistemology has an ambitious goal: it aims at understanding the complex relations between bio- logical evolution, especially the biological evolution of human cognition, and the cultural evolution of scientific knowledge. It eventually aims at forming an integrated causal theory of the evolution of science, starting with the evo- lution of human (...) cognition. In this chapter, the author considers Campbell’s project and specifies why it is still today a worthwhile project for explain- ing the evolution of science as a specific case of cultural evolution. But he also criticizes Campbell’s evolutionary epistemology for assuming that blind variation and selective retention are the processes through which science evolves. This assumption, the author argues, is at odds with much of what we know about scientific cognition and the history of science. He advocates (1) dropping the methodological constraint of looking for processes of blind variation and selective retention at the expense of other constructive processes and mechanisms of knowledge production; but (2) retaining the integrative point of evolutionary epistemology, which implies taking seriously the results of evolutionary psychology; and (3) retaining the populational framework for explaining the history of science, which means questioning why some scientific beliefs and practices eventually spread and stabilize in a scientific community. We end up with an updated research program for evolutionary epistemology, which faces new challenges. (shrink)

Context: Philosophical and - more recently - empirical approaches to the study of mind have recognized the research of lived experience as crucial for the understanding of their subject matter. Such research is faced with self-referentiality: every attempt at examining the experience seems to change the experience in question. This so-called “excavation fallacy” has been taken by many to undermine the possibility of first-person inquiry as a form of scientific practice. Problem: What is the epistemic character and value of reflectively (...) acquired phenomenological data? Can the study of experience, despite the excavation fallacy, rely on the act of reflection on lived experience and make sense and use of its results? Method: Through a philosophical discourse, informed by empirical first-person inquiry, we explore the experiential structure of the act of reflection and the formation of the corresponding belief about past experience. Results: We present a provisional first-person model of the experiential dynamics of retrospective reflection, in which the reflective act is characterized as enaction of belief about past experience that co-determines - rather than distorts - its results. From a constructivist perspective on the inevitable interdependence between the act of observing and the observed, the excavation “fallacy” is recognized as an intrinsic characteristic of reflection. Reflection is described as an iterative, self-referential process, guided by a context- and subject-specific horizon of expectations. Implications: Knowing the characteristics of the formation of beliefs about experience is essential for understanding first-person data and for the possibility of their acquisition and use in scientific practice, particularly in the context of second-person approaches to the study of experience. Constructivist content: We relate the proposed understanding of reflection to constructivist epistemology and argue that constructivism provides an epistemological foundation for the empirical study of experience more suitable than the traditional epistemological objectivism of cognitive science. We suggest that the constructive nature of the process of reflection calls for a collaboration between the fields of constructivism, phenomenology, and first-person research, and points towards the potential for their mutual enrichment. (shrink)

In this paper we distinguish between various kinds of doxastic theories. One distinction is between informal and formal doxastic theories. AGM-type theories of belief change are of the former kind, while Hintikka’s logic of knowledge and belief is of the latter. Then we distinguish between static theories that study the unchanging beliefs of a certain agent and dynamic theories that investigate not only the constraints that can reasonably be imposed on the doxastic states of a rational agent (...) but also rationality constraints on the changes of doxastic state that may occur in such agents. An additional distinction is that between non-introspective theories and introspective ones. Non-introspective theories investigate agents that have opinions about the external world but no higher-order opinions about their own doxasticnstates. Standard AGM-type theories as well as the currently existing versions of Segerberg’s dynamic doxastic logic (DDL) are non-introspective. Hintikka-style doxastic logic is of course introspective but it is a static theory. Thus, the challenge remains to devise doxastic theories that are both dynamic and introspective. We outline the semantics for truly introspective dynamic doxastic logic, i.e., a dynamic doxastic logic that allows us to describe agents who have both the ability to form higher-order beliefs and to reflect upon and change their minds about their own (higher-order) beliefs. This extension of DDL demands that we give up the Preservation condition on revision. We make some suggestions as to how such a non-preservative revision operation can be constructed. We also consider extending DDL with conditionals satisfying the Ramsey test and show that Gärdenfors’ well-known impossibility result applies to such a framework. Also in this case, Preservation has to be given up. (shrink)

This paper examines three accounts of the sleeping beauty case: an account proposed by Adam Elga, an account proposed by David Lewis, and a third account defended in this paper. It provides two reasons for preferring the third account. First, this account does a good job of capturing the temporal continuity of our beliefs, while the accounts favored by Elga and Lewis do not. Second, Elga’s and Lewis’ treatments of the sleeping beauty case lead to highly counterintuitive consequences. The proposed (...) account also leads to counterintuitive consequences, but they’re not as bad as those of Elga’s account, and no worse than those of Lewis’ account. (shrink)

In recent decades much literature has been produced on disagreement; the puzzling conclusion being that epistemic disagreement is, for the most part, either impossible (e.g. Aumann (Ann Stat 4(6):1236–1239, 1976)), or at least easily resolvable (e.g. Elga (Noûs 41(3):478–502, 2007)). In this paper I show that, under certain conditions, an equally puzzling result arises: that is, disagreement cannot be rationally resolved by belief updating. I suggest a solution to the puzzle which makes use of some of the principles of (...) Hintikka’s Socratic epistemology. (shrink)

In researching presuppositions dealing with logic and dynamic of belief we distinguish two related parts. The first part refers to presuppositions and logic, which is not necessarily involved with intentional operators. We are primarily concerned with classical, free and presuppositonal logic. Here, we practice a well known Strawson’s approach to the problem of presupposition in relation to classical logic. Further on in this work, free logic is used, especially Van Fraassen’s research of the role of presupposition in supervaluations (...) logical systems. At the end of the first part, presuppositional logic, advocated by S.K. Thomason, is taken into consideration. The second part refers to the presuppositions in relation to the logic of the dynamics of belief. Here the logic of belief change is taken into consideration and other epistemic notions with immanent mechanism for the presentation of the dynamics. Three representative and dominant approaches are evaluated. First, we deal with new, less classical, situation semantics. Besides Strawson’s theory, the second theory is the theory of the belief change, developed by Alchourron, Gärdenfors, and Makinson (AGM theory). At the end, the oldest, universal, and dominant approach is used, recognized as Hintikka’s approach to the analysis of epistemic notions. (shrink)

It has been an open question whether or not we can define a belief revision operation that is distinct from simple belief expansion using paraconsistent logic. In this paper, we investigate the possibility of meeting the challenge of defining a belief revision operation using the resources made available by the study of dynamic epistemic logic in the presence of paraconsistent logic. We will show that it is possible to define dynamic operations of belief revision (...) in a paraconsistent setting. (shrink)

Belief storage is often modeled as having the structure of a single, unified web. This model of belief storage is attractive and widely assumed because it appears to provide an explanation of the flexibility of cognition and the complicated dynamics of belief revision. However, when one scrutinizes human cognition, one finds strong evidence against a unified web of belief and for a fragmented model of belief storage. Using the best available evidence from cognitive science, we (...) develop this fragmented model into a nascent theory of the cognitive architecture of belief storage. (shrink)

A large body of work has demonstrated the utility of the Bayesian framework for capturing inference in both specialist and everyday contexts. However, the central tool of the framework, conditionalization via Bayes’ rule, does not apply directly to a common type of learning: the acquisition of conditional information. How should an agent change her beliefs on learning that “If A, then C”? This issue, which is central to both reasoning and argumentation, has recently prompted considerable research interest. In this paper, (...) we critique a prominent proposal and provide a new, alternative, answer. -/- . (shrink)

Two systems of belief change based on paraconsistent logics are introduced in this article by means of AGM-like postulates. The first one, AGMp, is defined over any paraconsistent logic which extends classical logic such that the law of excluded middle holds w.r.t. the paraconsistent negation. The second one, AGMo , is specifically designed for paraconsistent logics known as Logics of Formal Inconsistency (LFIs), which have a formal consistency operator that allows to recover all the classical inferences. Besides the three (...) usual operations over belief sets, namely expansion, contraction and revision (which is obtained from contraction by the Levi identity), the underlying paraconsistent logic allows us to define additional operations involving (non-explosive) contradictions. Thus, it is defined external revision (which is obtained from contraction by the reverse Levi identity), consolidation and semi-revision, all of them over belief sets. It is worth noting that the latter operations, introduced by S. Hansson, involve the temporary acceptance of contradictory beliefs, and so they were originally defined only for belief bases. Unlike to previous proposals in the literature, only defined for specific paraconsistent logics, the present approach can be applied to a general class of paraconsistent logics which are supraclassical, thus preserving the spirit of AGM. Moreover, representation theorems w.r.t. constructions based on selection functions are obtained for all the operations. (shrink)

If updating with E has the same result across all epistemically possible worlds, then the agent has no uncertainty as to the behavior of the update, and we may call it a transparent update. If an agent is uncertain about the behavior of an update, we may call it opaque. In order to model the uncertainty an agent has about the result of an update, the same update must behave differently across different possible worlds. In this paper, I study opaque (...) updates using a simple system of dynamic epistemic logic suitably modified for that purpose. The paper highlights the connection between opaque updates and the dynamic-epistemic principles Perfect-Recall and No-Miracles. I argue that opaque updates are central to contemporary discussions in epistemology, in particular to externalist theories of knowledge and to the related problem of epistemic bootstrapping, or easy knowledge. Opaque updates allow us to explicitly investigate a dynamic form of uncertainty, using simple and precise logical tools. (shrink)

Many view cancellation as a method for holding influential personalities accountable for bad behavior, while others think cancelling amounts to censorship and bullying. I hold that neither of these accounts are worth pursuing, especially if the aim is social progress. In this paper, I offer a situated account of cancellation and cancel culture, locating the phenomenon in our exclusionary history while examining the social dynamics of belief. When we situate cancel culture, we can see how problematic instances of cancelling (...) are embedded in ignorance. While combatting ignorance appears to call for a remedy rooted in feminist standpoint epistemology, there are risks in adopting naive practices of deference. Applying criticisms of epistemic injustice and adopting Táíwò’s elite capture framework, I explain how well-intentioned cancelling can work against social movements. Since epistemic trust mechanisms discourage self-reflection and belief revision, the relevant tactics for enacting social change—coalition politics and education—seem out of reach. I conclude by sketching cancel culture as a diagnostic tool: cancellation can be used appropriately in marginalized communities, but when it comes to combatting ignorance among privileged folks, we should view cancel culture as a method for determining where our social institutions are failing us. (shrink)

This is the latest draft of chapter 1 of _A New Theory of Reasons for Belief: Pragmatic Foundations and Pluralistic Reasons_ (Under Contract with OUP). It outlines the view that is the focus of the book: Welfarist Pluralism. Welfarist pluralism is the view that all normative reasons for belief are grounded in wellbeing and that being in a positive epistemic state is one of the components of wellbeing. This chapter explains how one can develop a principled version of (...) non-derivative pluralism about normative reasons for belief while still accepting that theoretical reason has a single, unified pragmatic foundation. Updated 25 January 2023. (shrink)

After a number of decades of research into the dynamics of rational belief, the belief revision theory community remains split on the appropriate handling of sequences of changes in view, the issue of so-called iterated revision. It has long been suggested that the matter is at least partly settled by facts pertaining to the results of various single revisions of one’s initial state of belief. Recent work has pushed this thesis further, offering various strong principles that ultimately (...) result in a wholesale reduction of iterated to one-shot revision. The present paper offers grounds to hold that these principles should be significantly weakened and that the reductionist thesis should ultimately be rejected. Furthermore, the considerations provided suggest a close connection between the logic of iterated belief change and the logic of evidential relevance. (shrink)

Judgment-aggregation theory has always focused on the attainment of rational collective judgments. But so far, rationality has been understood in static terms: as coherence of judgments at a given time, defined as consistency, completeness, and/or deductive closure. This paper asks whether collective judgments can be dynamically rational, so that they change rationally in response to new information. Formally, a judgment aggregation rule is dynamically rational with respect to a given revision operator if, whenever all individuals revise their judgments in light (...) of some information (a learnt proposition), then the new aggregate judgments are the old ones revised in light of this information, i.e., aggregation and revision commute. We prove an impossibility theorem: if the propositions on the agenda are non-trivially connected, no judgment aggregation rule with standard properties is dynamically rational with respect to any revision operator satisfying some basic conditions on revision. Our theorem is the dynamic-rationality counterpart of some well-known impossibility theorems for static rationality. We also explore how dynamic rationality might be achieved by relaxing some of the conditions on the aggregation rule and/or the revision operator. Notably, premise-based aggregation rules are dynamically rational with respect to so-called premise-based revision operators. (shrink)

Article Summary. The epistemology of disagreement studies the epistemically relevant aspects of the interaction between parties who hold diverging opinions about a given subject matter. The central question that the epistemology of disagreement purports to answer is how the involved parties should resolve an instance of disagreement. Answers to this central question largely depend on the epistemic position of each party before disagreement occurs. Two parties are equally positioned from an epistemic standpoint—namely, they are epistemic peers—to the extent that they (...) have roughly equal access to the evidence and comparable intellectual resources. When one party is epistemically better positioned than the other—that is, when one is an epistemic superior—it is widely agreed that this party should retain their belief while the other party—the epistemic inferior—should revise their opinion in the direction of what the epistemic superior believes. Addressing the central question is a complex task when the disagreeing parties are epistemic peers. Three main answers can be distinguished. Conciliatory answers mandate that both parties revise—i.e. lower their confidence in—their beliefs upon the occurrence of peer disagreement. Steadfast answers allow both parties to retain their respective beliefs, thereby committing them to demote the epistemic position of the interlocutor. The third group of answers suggests that the solution to peer disagreement depends on whether either party is highly justified in holding their belief. If either party is highly justified, then it is rational that this party retains its view. If neither party is highly justified, both should revise. The epistemology of disagreement addresses further important questions such as: whether the occurrence of disagreement opens the doors to skepticism and/or relativism; what the consequences of epistemic disagreement on intellectual character are; what laypeople should do when experts disagree with each other; and whether disagreement among groups can be treated in the same way as disagreement among individuals. (shrink)

This is chapter 5 of the book project _The true and the good: a new theory of theoretical reason_, in which I explore the claim that both alethic and pragmatic reasons for belief are basic, but that they share a pragmatic foundation in a pluralist theory of wellbeing in which being in a positive epistemic state is a non-derivative component of wellbeing. This chapter argues that all three of fittingness first, reasons first, and value first views are false. It (...) does so by showing that fittingness and reasons both have unalike variance conditions with respect to value, i.e. that sometimes the value of something can switch from good to bad or bad to good without there being any change in whether it is fitting to favour it or whether there are reason to favour it. This is a form of an argument from under-generation following on earlier work by Krister Bykvist and Andrew Reisner, respectively. It is also more tentatively that reasons cannot be analysed in terms of correctness. Because the the arguments in this paper concern the extensional adequacy of the various bi-conditionals linking fittingness, reasons, and value, they suffice for rejecting even modest versions of '-first' views that do not purport to provide analyses, but rather only sets of correctness conditions for, e.g., reasons and value in terms of fittingness, or any two in terms of the third. (Updated 10 May 2022). (shrink)

Coherence and correspondence are classical contenders as theories of truth. In this paper we examine them instead as interacting factors in the dynamics of belief across epistemic networks. We construct an agent-based model of network contact in which agents are characterized not in terms of single beliefs but in terms of internal belief suites. Individuals update elements of their belief suites on input from other agents in order both to maximize internal belief coherence and to incorporate (...) ‘trickled in’ elements of truth as correspondence. Results, though often intuitive, prove more complex than in simpler models (Hegselmann & Krause 2002, 2006; Grim, Singer, Reade & Fisher 2015). The optimistic finding is that pressures toward internal coherence can exploit and expand on small elements of truth as correspondence is introduced into epistemic networks. Less optimistic results show that pressures for coherence can also work directly against the incorporation of truth, particularly when coherence is established first and new data is introduced later. (shrink)

“Probably Peirce’s best-known works are the first two articles in a series of six that originally were collectively entitled Illustrations of the Logic of Science and published in Popular Science Monthly from November 1877 through August 1878. The first is entitled ‘The Fixation of Belief’ and the second is entitled ‘How to Make Our Ideas Clear.’ In the first of these papers Peirce defended, in a manner consistent with not accepting naive realism, the superiority of the scientific method over (...) other methods of overcoming doubt and ‘fixing belief.’” — Robert Burch, “Charles Sanders Peirce,” entry in the Stanford Encyclopedia of Philosophy (2021 revision) -/- “Pragmatist epistemologies often explore how we can carry out inquiries in a self-controlled and fruitful way. (Where much analytic epistemology centres around the concept of knowledge, considered as an idealised end-point of human thought, pragmatist epistemology centres around the concept of inquiry, considered as the process of knowledge-seeking and how we can improve it.) So pragmatists often provide rich accounts of the capacities or virtues that we must possess in order to inquire well, and the rules or guiding principles that we should adopt. A canonical account is Peirce’s classic early paper ‘The Fixation of Belief‘. Here Peirce states that inquiry is a struggle to replace doubt with “settled belief“, and that the only method of inquiry that can make sense of the fact that at least some of us are disturbed by inconsistent beliefs, and will subsequently reflect upon which methods of fixing belief are correct is the Method of Science, which draws on the Pragmatic Maxim described above. This contrasts with three other methods of fixing belief: i) refusing to consider evidence contrary to one’s favored beliefs (the Method of Tenacity), ii) accepting an institution’s dictates (the Method of Authority), iii) developing the most rationally coherent or elegant-seeming belief-set (the A Priori Method).“ — Catherine Legg, “Pragmatism,” entry in the Stanford Encyclopedia of Philosophy (2021 revision). (shrink)

Duncan Pritchard’s Epistemic Angst promises a novel solution to the closure-based sceptical problem that, unlike more traditional solutions, does not entail revising our fundamental epistemological commitments. In order to do this, it appeals to a Wittgensteinian account of rational evaluation, the overarching theme of which is that it neither makes sense to doubt nor to believe in our anti-sceptical hinge commitments. The purpose of this paper is to show that the argument for the claim that there can be no rational (...) basis to believe our anti-sceptical hinge commitments relies upon an implicit assumption about rational support that I label The Pritchensteinian Rational Grounds Principle. I argue that, insofar as this principle is intended to apply to closure-style inferences, it leads to irrational doxastic attitudes. I consider a seemingly plausible modification of the principle that would avoid this result but show that this modified principle faces serious problems of its own. -/- . (shrink)

In this dissertation we present proof systems for several modal logics. These proof systems are based on analytic (or semantic) tableaux. -/- Modal logics are logics for reasoning about possibility, knowledge, beliefs, preferences, and other modalities. Their semantics are almost always based on Saul Kripke’s possible world semantics. In Kripke semantics, models are represented by relational structures or, equivalently, labeled graphs. Syntactic formulas that express statements about knowledge and other modalities are evaluated in terms of such models. -/- This dissertation (...) focuses on modal logics with dynamic operators for public announcements, belief revision, preference upgrades, and so on. These operators are defined in terms of mathematical operations on Kripke models. Thus, for example, a belief revision operator in the syntax would correspond to a belief revision operation on models. -/- The ‘dynamic’ semantics of dynamic modal logics are a clever way of extending languages without compromising on intuitiveness. We present ‘dynamic’ tableau proof systems for these dynamic semantics, with the express aim to make them conceptually simple, easy to use, modular, and extensible. This we do by reflecting the semantics as closely as possible in the components of our tableau system. For instance, dynamic operations on Kripke models have counterpart dynamic relations between tableaux. -/- Soundness, completeness, and decidability are three of the most important properties that a proof system may have. A proof system is sound if and only if any formula for which a proof exists, is true in every model. A proof system is complete if and only if for any formula that is true in all models, a proof exists. A proof system is decidable if and only if any formula can be proved to be a theorem or not a theorem in a finite number of steps. All proof systems in this dissertation are sound, complete, and decidable. -/- Part of our strategy to create modular tableau systems is to delay concerns over decidability until after soundness and completeness have been established. Decidability is attained through the operations of folding and through operations on ‘tableau cascades’, which are graphs of tableaux. -/- Finally, we provide a proof-of-concept implementation of our dynamic tableau system for public announcement logic in the Clojure programming language. (shrink)

The orthodox view in epistemology is that belief is constitutively evidence-responsive. I offer a novel argument for a version of this view, one that appeals to capacities to rationally respond to evidence. I do so by developing the Sellarsian idea that the concept of belief functions to mark the space of reasons in a non-intellectualist and naturalistic direction. The resulting view does justice to the role of belief in social interactions, joint deliberation, and rational persuasion, while including (...) evidence-resistant beliefs and animal beliefs as genuine beliefs. It has a range of further benefits: it helps us account for epistemic normativity, paves the way for better psychological models of belief revision, distinguishes beliefs from imaginings and mere acceptances, and helps us avoid noxious simplistic takes on human irrationality. (shrink)

As I head home from work, I’m not sure whether my daughter’s new bike is green, and I’m also not sure whether I’m on drugs that distort my color perception. One thing that I am sure about is that my attitudes towards those possibilities are evidentially independent of one another, in the sense that changing my confidence in one shouldn’t affect my confidence in the other. When I get home and see the bike it looks green, so I increase my (...) confidence that it is green. But something else has changed: now an increase in my confidence that I’m on color-drugs would undermine my confidence that the bike is green. Jonathan Weisberg and Jim Pryor argue that the preceding story is problematic for standard Bayesian accounts of perceptual learning. Due to the ‘rigidity’ of Conditionalization, a negative probabilistic correlation between two propositions cannot be introduced by updating on one of them. Hence if my beliefs about my own color-sobriety start out independent of my beliefs about the color of the bike, then they must remain independent after I have my perceptual experience and update accordingly. Weisberg takes this to be a reason to reject Conditionalization. I argue that this conclusion is too pessimistic: Conditionalization is only part of the Bayesian story of perceptual learning, and the other part needn’t preserve independence. Hence Bayesian accounts of perceptual learning are perfectly consistent with potential underminers for perceptual beliefs. (shrink)

The traditional conception of knowledge is justified, true belief. If one looks at a modern textbook on epistemology, the great bulk of questions with which it deals are to do with personal knowledge, as embodied in beliefs and the proper experiences that someone ought to have had in order to have the right (or justification) to know. I intend to argue that due to the explosive growth of knowledge whose domain is “outside the head”, this conception has outlived its (...) relevance. -/- On the other hand, Karl Popper’s (1934) Falsificationism, with its emphasis on the objective character of knowledge, is not only a sounder, but also a more appropriate theory of knowledge for understanding the nature and growth of civilization. Later, Popper (1945) generalized this approach to obtain critical rationalism, in which all claims to knowledge, whether scientific or otherwise, are understood as objective solutions to objective problems and can be evaluated by other non-observational - types of criticism. I will first argue that Popper’s methodology is quite suited to the view that knowledge is an objective autonomous product and then adduce his theory of world 3, an ontology that neatly wraps up various considerations. World 3 is the domain of abstract products of the human mind that now have a life of their own, outside of human heads: theories, arguments, problems, plans, etc. I then adduce some other arguments for the autonomous quality of knowledge. (shrink)

Traditionally, consistency is the only criterion for the quality of a theory in logic-based approaches to reasoning about actions. This work goes beyond that and contributes to the meta-theory of actions by investigating what other properties a good domain de- scription should satisfy. Having Propositional Dynamic Logic (PDL) as background, we state some meta-theoretical postulates concerning this sore spot. When all pos- tulates are satisfied, we call the action theory modular. We point out the problems that arise when the (...) postulates about modularity are violated, and propose algorith- mic checks that can help the designer of an action theory to overcome them. Besides being easier to understand and more elaboration tolerant in McCarthy’s sense, mod- ular theories have interesting computational properties. Moreover, we also propose a framework for updating domain descriptions and show the importance modularity has in action theory change. (shrink)

There has been considerable philosophical debate in recent years over a thesis called epistemic permissivism. According to the permissivist, it is possible for two agents to have the exact same total body of evidence and yet differ in their belief attitudes towards some proposition, without either being irrational. However, I argue, not enough attention has been paid to the distinction between different ways in which permissivism might be true. In this paper, I present a taxonomy of forms of epistemic (...) permissivism framed as the upshot of different ways one might respond to a basic argument against the view from Roger White. I then introduce a new type of permissive view which the contemporary debate has completely ignored and which is made available when we reject a widespread and largely unexamined background commitment to static rational norms connecting beliefs and evidence in favor of dynamic norms governing processes of consideration. I show how the dynamic strategy of rejecting static norms on belief opens the door to a new kind of permissivism which is both independently attractive and especially well-placed to answer worries that have been raised against traditional permissivist views. (shrink)

In this paper, I consider how, given mutual knowledge of the information codified in a compositional semantic theory, an assertion of a sentence serves to update the shared information in a conversation. There is a standard account, due to Stalnaker, of how such conversational updating occurs. While this account has much to recommend it, in this paper I argue that it needs to be revised in light of certain patterns of updating that result from certain natural discourses. Having argued for (...) this, I present a new account of conversational updating that can be seen as a natural generalization of the standard account, and show how it can predict these patterns in a simple and principled manner. (shrink)

The empirical study of belief is emerging at a rapid clip, uniting work from all corners of cognitive science. Reliance on belief in understanding and predicting behavior is widespread. Examples can be found, inter alia, in the placebo, attribution theory, theory of mind, and comparative psychological literatures. Research on belief also provides evidence for robust generalizations, including about how we fix, store, and change our beliefs. Evidence supports the existence of a Spinozan system of belief fixation: (...) one that is automatic and independent of belief rejection. Independent research supports the existence of a system of fragmented belief storage: one that relies on large numbers of causally isolated, context-sensitive stores of belief in memory. Finally, empirical and observational data support at least two systems of belief change. One system adheres, mostly, to epistemological norms of updating; the other, the psychological immune system, functions to guard our most centrally held beliefs from potential inconsistency with newly formed beliefs. Refining our under- standing of these systems can shed light on pressing real-world issues, such as how fake news, propaganda, and brainwashing exploit our psychology of belief, and how best to construct our modern informational world. (shrink)

This paper considers a problem for Bayesian epistemology and proposes a solution to it. On the traditional Bayesian framework, an agent updates her beliefs by Bayesian conditioning, a rule that tells her how to revise her beliefs whenever she gets evidence that she holds with certainty. In order to extend the framework to a wider range of cases, Jeffrey (1965) proposed a more liberal version of this rule that has Bayesian conditioning as a special case. Jeffrey conditioning is a rule (...) that tells the agent how to revise her beliefs whenever she gets evidence that she holds with any degree of confidence. The problem? While Bayesian conditioning has a foundationalist structure, this foundationalism disappears once we move to Jeffrey conditioning. If Bayesian conditioning is a special case of Jeffrey conditioning, then they should have the same normative structure. The solution? To reinterpret Bayesian updating as a form of diachronic coherentism. (shrink)

Several philosophers and psychologists have characterized belief in conspiracy theories as a product of irrational reasoning. Proponents of conspiracy theories apparently resist revising their beliefs given disconfirming evidence and tend to believe in more than one conspiracy, even when the relevant beliefs are mutually inconsistent. In this paper, we bring leading views on conspiracy theoretic beliefs closer together by exploring their rationality under a probabilistic framework. We question the claim that the irrationality of conspiracy theoretic beliefs stems from an (...) inadequate response to disconfirming evidence and internal incoherence. Drawing analogies to Lakatosian research programs, we argue that maintaining a core conspiracy belief can be Bayes-rational when it is embedded in a network of auxiliary beliefs, which can be revised to protect the more central belief from disconfirmation. We propose that the irrationality associated with conspiracy belief lies not in a flawed updating method, but in a failure to converge toward wellconfirmed, stable belief networks in the long run. This approach not only reconciles previously disjointed views, but also points toward more specific descriptions of why agents may be prone to adopting beliefs in conspiracy theories. (shrink)

As I hope to show in this paper, Fichte’s rejection of traditional social contractarian accounts of human social relations is related to his rejection of the search for a criterion, or external standard, by which we might measure our knowledge in epistemology. More specifically, Fichte’s account of the impossibility of a normative social contract (as traditionally construed) is related to his account of the impossibility of our knowing things as they might be “in themselves,” separate from and independent of our (...) own activity in knowing them. Addressing the question of whether we finite human knowers can ever transcend the limits of our own consciousness, Fichte argues that Hume was not sufficiently critical: “…the Humean system holds open the possibility that we might someday be able to go beyond the boundary of the human mind, whereas the Critical system proves that such progress is absolutely impossible, and it shows that the thought of a thing possessing existence and specific properties in itself and apart from any faculty of representation is a piece of whimsy, a pipe dream, a nonthought.” In a very real sense, then, Fichte aims to “out-Hume” Hume on the question of whether we can ever know “things-in-themselves” or an external criterion for testing our knowledge. That is, Fichte goes beyond Hume and insists on the necessary – and not merely contingent – character of our ignorance of so-called things-in-themselves (i.e., things that supposedly exist antecedent to and independent of our consciousness of them). But unlike Hume, Fichte argues that radical skepticism regarding all possible knowledge of things-in-themselves does not undermine – but actually confirms and sustains – our belief in the emancipatory power of reason. (shrink)

This article is about the implications of a conciliatory view about the epistemology of peer disagreement for our moral beliefs. Many have endorsed a conciliatory view about the epistemology of peer disagreement according to which if we find ourselves in a disagreement about some matter with another whom we should judge to be our epistemic peer on that matter, we must revise our judgment about that matter. This article focuses on three issues about the implications of conciliationism for our moral (...) beliefs. The first is whether there is an asymmetry between the implications of conciliationism for the epistemic status of our moral beliefs and the implications of conciliationism for the epistemic status of our non-moral beliefs; for instance, some have argued that conciliationism leads to epistemological moral skepticism but not to epistemological nonmoral skepticism. The second is what the implications of conciliationism are for the epistemic status of particular moral beliefs. The third is whether conciliationism's impact on the epistemic status of our moral beliefs has practical implications. (shrink)

I argue that a standard formulation of hinge epistemology is host to epistemic relativism and show that two leading hinge approaches (Coliva’s acceptance account and Pritchard’s nondoxastic account) are vulnerable to a form of incommensurability that leads to relativism. Building on both accounts, I introduce a new, minimally epistemic conception of hinges that avoids epistemic relativism and rationally resolves hinge disagreements. According to my proposed account, putative cases of epistemic incommensurability are rationally resolvable: hinges are propositions that are the objects (...) of our belief-like attitudes and are rationally revisable in virtue of our overarching commitment to avoid systematic deception in our epistemic practices. (shrink)

Bayesianism is our leading theory of uncertainty. Epistemology is defined as the theory of knowledge. So “Bayesian Epistemology” may sound like an oxymoron. Bayesianism, after all, studies the properties and dynamics of degrees of belief, understood to be probabilities. Traditional epistemology, on the other hand, places the singularly non-probabilistic notion of knowledge at centre stage, and to the extent that it traffics in belief, that notion does not come in degrees. So how can there be a Bayesian epistemology?

[A revised and updated version of an earlier article 'Understanding Creativity: Affect Decision and Inference' (unpublished), posted at PhilArchive in 2021.] -/- This book looks at the creative process in the human mind. -/- Creativity involves a major restructuring of the conceptual space where a sustained inferential process eventually links remote conceptual domains, thereby opening up the possibility of a large number of new correlations between remote concepts by a cascading process. Since the process of inductive inference depends crucially on (...) decisions at critical junctures of the inferential chain, it becomes necessary to examine the basic mechanism underlying the making of decisions. In the framework that we attempt to build up for the understanding of scientific creativity, this role of decision making in the inferential process assumes central relevance. -/- Referring to the process of inferential exploration of the conceptual space that generates the possibility of correlations being established between remote conceptual domains, such exploration is guided and steered at every stage by the affect system, -/- While the affect system plays a guiding role in the exploration of the conceptual space, the process of exploration itself consists of the establishment of correlations between concepts by means of beliefs and heuristics, the self-linked ones among the latter having a special role in making possible the inferential journey along alternative routes whenever the shared rules of inference become inadequate. -/- Representing the conceptual space in the form of a complex network, the overall process can be likened to one of self-organised criticality commonly observed in the dynamical evolution of complex systems. An instance of self-organised criticality is found in the avalanche set up in a slowly growing sand-pile. (shrink)

To what extent do our beliefs, and how strongly we hold them, depend upon how they matter to us, on what we take to be at stake on them? The idea that beliefs are sometimes stake-sensitive (Armendt 2008, 2013) is further explored here, with a focus on whether beliefs may be stake-sensitive and rational. In contexts of extended deliberation about what to do, beliefs and assessments of options interact. In some deliberations, a belief about what you will do may (...) rationally influence your estimate of the value of doing it; deliberation dynamics provides a framework for modeling such interactions. A distinction is drawn between sensitivity to the magnitude of the stakes, and sensitivity to the shape of the stakes. Contexts of extended deliberation are settings in which some beliefs that p rationally depend on the shape of the stakes on p. The dependence is either rational stake-sensitivity or an outcome of rational learning; empirical evidence concerning contexts of deliberation may lead us to model rational beliefs in one way or the other. (shrink)

According to an increasingly popular epistemological view, people need outright beliefs in addition to credences to simplify their reasoning. Outright beliefs simplify reasoning by allowing thinkers to ignore small error probabilities. What is outright believed can change between contexts. It has been claimed that thinkers manage shifts in their outright beliefs and credences across contexts by an updating procedure resembling conditionalization, which I call pseudo-conditionalization (PC). But conditionalization is notoriously complicated. The claim that thinkers manage their beliefs via PC is (...) thus in tension with the view that the function of beliefs is to simplify our reasoning. I propose to resolve this puzzle by rejecting the view that thinkers employ PC. Based on this solution, I furthermore argue for a descriptive and a normative claim. The descriptive claim is that the available strategies for managing beliefs and credences across contexts that are compatible with the simplifying function of outright beliefs can generate synchronic and diachronic incoherence in a thinker’s attitudes. Moreover, I argue that the view of outright belief as a simplifying heuristic is incompatible with the view that there are ideal norms of coherence or consistency governing outright beliefs that are too complicated for human thinkers to comply with. (shrink)

This dissertation is a contribution to formal and computational philosophy. -/- In the first part, we show that by exploiting the parallels between large, yet finite lotteries on the one hand and countably infinite lotteries on the other, we gain insights in the foundations of probability theory as well as in epistemology. Case 1: Infinite lotteries. We discuss how the concept of a fair finite lottery can best be extended to denumerably infinite lotteries. The solution boils down to the introduction (...) of infinitesimal probability values, which can be achieved using non-standard analysis. Our solution can be generalized to uncountable sample spaces, giving rise to a Non-Archimedean Probability (NAP) theory. Case 2: Large but finite lotteries. We propose application of the language of relative analysis (a type of non-standard analysis) to formulate a new model for rational belief, called Stratified Belief. This contextualist model seems well-suited to deal with a concept of beliefs based on probabilities ‘sufficiently close to unity’. -/- The second part presents a case study in social epistemology. We model a group of agents who update their opinions by averaging the opinions of other agents. Our main goal is to calculate the probability for an agent to end up in an inconsistent belief state due to updating. To that end, an analytical expression is given and evaluated numerically, both exactly and using statistical sampling. The probability of ending up in an inconsistent belief state turns out to be always smaller than 2%. (shrink)

This paper is an original attempt to understand the foundations of economic reasoning. It endeavors to rigorously define the relationship between subjective interpretations and objective valuations of such interpretations in the context of theoretical economics. This analysis is substantially expanded through a dynamic approach, where the truth of a valuation results in an updated interpretation or changes in the agent's subjective belief regarding the effectiveness of the selected action as well as the objective reality of the effectiveness of (...) all other possible actions (i.e. consequence realization). Complications arise when the economic agent is presented with a set of actions that render ambiguous preference, or when the effectiveness of an action cannot be perceived upon its selection, thereby necessitating a different theory of choice and consequence realization. (shrink)