In this paper, we consider recent attempts to metaphysically explain agentive modality in terms of conditionals. We suggest that the best recent accounts face counterexamples, and more worryingly, they take some agentive modality for granted. In particular, the ability to perform basic actions features as a primitive in these theories. While it is perfectly acceptable for a semantics of agentive modal claims to take some modality for granted in getting the extension of action claims correct, a metaphysical (...) explanation of agentive modality cannot, at least not in the way that conditional approaches to agentive modality do. We argue that this problem was present even in the classical conditional analysis. By a pessimistic induction, we suggest that, probably, no conditional approach to agentive modality will succeed. (shrink)

This essay proposes a new theory of agentive modals: ability modals and their duals, compulsion modals. After criticizing existing approaches—the existential quantificational analysis, the universal quantificational analysis, and the conditional analysis—it presents a new account that builds on both the existential and conditional analyses. On this account, the act conditional analysis, a sentence like ‘John can swim across the river’ says that there is some practically available action that is such that if John tries to do (...) it, he swims across the river. The essay argues that the act conditional analysis avoids the problems faced by existing accounts of agentive modality and shows how the act conditional analysis can be extended to an account of generic agentive modal claims. The upshot is a new vantage point on the role of agentive modal ascriptions in practical discourse: ability ascriptions serve as a kind of hypothetical guarantee, and compulsion ascriptions as a kind of nonhypothetical guarantee. (shrink)

A number of philosophical projects require a proper understanding of the modal aspects of agency, or of what I call ‘the agentive modalities.’ I propose a general account of the agentive modalities, one which takes as its primitive the decision-theoretic notion of an option. I relate this account to the standard semantics for ‘can’ and to the viability of some positions in the free will debates.

This thesis develops a theory about the structure of modal judgment and knowledge. Arguing in favour of pluralism about the source of modal knowledge, it focuses on the questions of the varieties of modal judgment and their relations, the function of modal judgment and the scope of modal knowledge. It offers a hypothesis about the development of the framework of modal knowledge, grounding it on the capacity to evaluate temporal judgments, from which the capacity to evaluate alternatives comes from, and (...) it suggests that the most basic framework of modal judgments consists in that of agentive modality, and in particular, about what one can do, and how. Then, it is argued that the rest of the framework of modal judgment can be developed on this basis, although this imposes certain restrictions about the scope of modal knowledge. Additionally, the thesis provides analyses of various agentive modal notions, such as imaginability, what is a way to do something, and discusses how to understand counterfactuals with impossible antecedents. (shrink)

A proper understanding of agentive modals promises to clarify issues to do with free will, know how, and other philosophically interesting topics. In this paper I identify one constraint on, and one structural feature of, trying-based versions of the conditional analysis of the agentive modals. I suggest that the constraint and structural feature together provide a novel account of why the famous Lehrer-Chisholm objection to conditional analyses of ability modals is so powerful. I argue that (...) Mandelkern et al.’s ‘Agentive Modals’ (Philosophical Review,126/3, 301–343, 2017) conditional analysis of the agentive modals fails to avoid this problem. I also identify two further problems for their account. I close by summarising a number of criteria which any successful semantic analysis of the agentive modals should satisfy. (shrink)

This article introduces Agentive Cognitive Construction Grammar, an emerging field that seeks to connect the linguistic system with speaker-meaning. The stated purpose is thus to tackle a pervasive disconnect in both cognitive linguistics and construction grammar, whereby the linguistic system and speaker selections are separated in the belief that language is essentially a mental process associated with the brain, and hence, separated from bodily experience. I contend this view by introducing a triadic model of construction in which form and (...) function are inextricably bound up with agency. This is possible because language is tethered to senses of movement and balance that connect experiences with the physical world with the mental. A major insight of the paper is that argument structure constructions partake of both linguistic and non-linguistic signs, which provides speakers with a means to verbalize their thoughts and distribute agency in specific events. (shrink)

There are two alternative approaches to accommodating an agent-centered restriction against, say, φ-ing. One approach is to prohibit agents from ever φ-ing. For instance, there could be an absolute prohibition against breaking a promise. The other approach is to require agents both to adopt an end that can be achieved only by their not φ-ing and to give this end priority over that of minimizing overall instances of φ-ing. For instance, each agent could be required both to adopt the end (...) of minimizing their own promise-breakings and to give this end priority over that of minimizing promise-breakings overall. The former is what I’ll call the side-constraint approach, and the latter is what I’ll call the teleological approach. In this chapter, I argue that, when it comes to accommodating restrictions, we should (1) favor the teleological approach over the side-constraint approach, (2) favor an act-consequentialist approach over a non-consequentialist, teleological approach (such as Rossian pluralism), and (3) favor a Kantsequentialist approach over other act-consequentialist approaches, where Kantsequentialism is a version of act-consequentialism that holds that persons are ends-in-themselves who are inherently and unconditionally valuable and are, thus, owed our respect. (shrink)

This book concerns the foundations of epistemic modality and hyperintensionality and their applications to the philosophy of mathematics. I examine the nature of epistemic modality, when the modal operator is interpreted as concerning both apriority and conceivability, as well as states of knowledge and belief. The book demonstrates how epistemic modality and hyperintensionality relate to the computational theory of mind; metaphysical modality and hyperintensionality; the types of mathematical modality and hyperintensionality; to the epistemic status of large cardinal axioms, undecidable propositions, (...) and abstraction principles in the philosophy of mathematics; to the modal and hyperintensional profiles of the logic of rational intuition; and to the types of intention, when the latter is interpreted as a hyperintensional mental state. Chapter 2 argues for a novel type of expressivism based on the duality between the categories of coalgebras and algebras, and argues that the duality permits of the reconciliation between modal cognitivism and modal expressivism. I also develop a novel topic-sensitive truthmaker semantics for dynamic epistemic logic, and develop a novel dynamic epistemic two-dimensional hyperintensional semantics. Chapter 3 provides an abstraction principle for epistemic (hyper-)intensions. Chapter 4 advances a topic-sensitive two-dimensional truthmaker semantics, and provides three novel interpretations of the framework along with the epistemic and metasemantic. Chapter 5 applies the fixed points of the modal μ-calculus in order to account for the iteration of epistemic states in a single agent, by contrast to availing of modal axiom 4 (i.e. the KK principle). The fixed point operators in the modal μ-calculus are rendered hyperintensional, which yields the first hyperintensional construal of the modal μ-calculus in the literature and the first application of the calculus to the iteration of epistemic states in a single agent instead of the common knowledge of a group of agents. Chapter 6 advances a solution to the Julius Caesar problem based on Fine's `criterial' identity conditions which incorporate conditions on essentiality and grounding. Chapter 7 provides a ground-theoretic regimentation of the proposals in the metaphysics of consciousness and examines its bearing on the two-dimensional conceivability argument against physicalism. The topic-sensitive epistemic two-dimensional truthmaker semantics developed in chapters 2 and 4 are availed of in order for epistemic states to be a guide to metaphysical states in the hyperintensional setting. Chapters 8-12 provide cases demonstrating how the two-dimensional hyperintensions of hyperintensional, i.e. topic-sensitive epistemic two-dimensional truthmaker, semantics, solve the access problem in the epistemology of mathematics. Chapter 8 examines the interaction between my hyperintensional semantics and the axioms of epistemic set theory, large cardinal axioms, the Epistemic Church-Turing Thesis, the modal axioms governing the modal profile of Ω-logic, Orey sentences such as the Generalized Continuum Hypothesis, and absolute decidability. These results yield inter alia the first hyperintensional Epistemic Church-Turing Thesis and hyperintensional epistemic set theories in the literature. Chapter 9 examines the modal and hyperintensional commitments of abstractionism, in particular necessitism, and epistemic hyperintensionality, epistemic utility theory, and the epistemology of abstraction. I countenance a hyperintensional semantics for novel epistemic abstractionist modalities. I suggest, too, that observational type theory can be applied to first-order abstraction principles in order to make first-order abstraction principles recursively enumerable, i.e. Turing machine computable, and that the truth of the first-order abstraction principle for hyperintensions is grounded in its being possibly recursively enumerable and the machine being physically implementable. Chapter 10 examines the philosophical significance of hyperintensional Ω-logic in set theory and discusses the hyperintensionality of metamathematics. Chapter 11 provides a modal logic for rational intuition and provides a hyperintensional semantics. Chapter 12 avails of modal coalgebras to interpret the defining properties of indefinite extensibility, and avails of hyperintensional epistemic two-dimensional semantics in order to account for the interaction between the interpretational and objective modalities and truthmakers thereof. This yields the first hyperintensional category theory in the literature. I invent a new mathematical trick in which first order structures are treated as categories, and Vopenka's principle can be satisfied because of the elementary embeddings between the categories and generate Vopenka cardinals while bypassing the category of Set in category theory. Chapter 13 examines modal responses to the alethic paradoxes. Chapter 14 examines, finally, the modal and hyperintensional semantics for the different types of intention and the relation of the latter to evidential decision theory. (shrink)

In recent work, Robert Brandom has articulated important connections between the deontic normative statuses of entitlement and commitment and the alethic modal statuses of possibility and necessity. In this paper, I articulate an until now unexplored connection between Brandom’s core normative statuses of entitlement and commitment and the agentive modal statuses of ability and compulsion. These modals have application not only in action, but also in perception and inference, and, in both of these cases, there is a direct (...) mapping between the normative statuses that one bears towards various claims, articulated from the perspective of the attributor of commitments and entitlements, and the agentive modal statuses that one bears towards various judgments, articulated from the perspective of the undertaker of commitments. I will highlight this correspondence, focusing on the case of perception, and show how it sheds light on the account of mindedness that emerges from Brandom’s theory of discursive practice. (shrink)

This paper proposes a semantic description of the linear step-like temporal multi-agent logic with the universal modality \(\mathcal{LTK}.sl_U\) based on the idea of non-reflexive non-transitive nature of time. We proved a finite model property and projective unification for this logic.

Triviality results threaten plausible principles governing our credence in epistemic modal claims. This paper develops a new account of modal credence which avoids triviality. On the resulting theory, probabilities are assigned not to sets of worlds, but rather to sets of information state-world pairs. The theory avoids triviality by giving up the principle that rational credence is closed under conditionalization. A rational agent can become irrational by conditionalizing on new evidence. In place of conditionalization, the paper develops a new account (...) of updating: conditionalization with normalization. (shrink)

There are three primary aims of the book. The first, set out in the book's introduction, is to explain how two fairly recent developments in philosophy, externalism and modalism, provide the basis for a promising account of knowledge - an account that achieves anti-skeptical results and avoids Gettier-style counterexamples that are based on an agent having warranted beliefs that are merely luckily true. Epistemological externalism is the thesis that not all the factors that make a true belief a case of (...) knowledge need to be cognitively accessible or "internal" to the agent. Modalism, as the author construes it, is the use of possible worlds talk in clarifying what would or might be the case and what is necessarily so." "The second objective is to work through the different modalized epistemologies extant in the literature, assessing their strengths and weaknesses, with a view toward constructing a working theory. Finally, the author proposes the theory that knowledge is reliably formed, sensitive true belief, and defends the theory against objections."--Jacket. (shrink)

My topic is moderate modal skepticism in the spirit of Peter van Inwagen. Here understood, this is a conservative version of modal empiricism that severely limits the extent to which an ordinary agent can reasonably believe “exotic” possibility claims. I offer a novel argument in support of this brand of skepticism: modal skepticism grounds an attractive (and novel) reply to Humean skepticism. Thus, I propose that modal skepticism be accepted on the basis of its theoretical utility as a tool for (...) dissolving philosophical paradox. (shrink)

According to a naïve view sometimes apparent in the writings of moral philosophers, ‘ought’ often expresses a relation between agents and actions – the relation that obtains between an agent and an action when that action is what that agent ought to do. It is not part of this naïve view that ‘ought’ always expresses this relation – on the contrary, adherents of the naïve view are happy to allow that ‘ought’ also has an epistemic sense, on which it means, (...) roughly, that some proposition is likely to be the case, and adherents of the naïve view are also typically happy to allow that ‘ought’ also has an evaluative sense, on which it means, roughly, that were things ideal, some proposition would be the case.1 What is important to the naïve view is not that these other senses of ‘ought’ do not exist, but rather that they are not exhaustive – for what they leave out, is the important deliberative sense of ‘ought’, which is the central subject of moral inquiry about what we ought to do and why – and it is this deliberative sense of ‘ought’ which the naïve view understands to express a relation between agents and actions.2 In contrast, logically and linguistically sophisticated philosophers – with a few notable exceptions3 – have rejected this naïve view. According to a dominant perspective in the interpretation of deontic logic and in linguistic semantics, for example, articulated by Roderick Chisholm (1964) and Bernard Williams (1981) in philosophy and in the dominant paradigm in linguistic semantics as articulated in particular by.. (shrink)

In a recent paper I argued that agent causation theorists should be compatibilists. In this paper, I argue that compatibilists should be agent causation theorists. I consider six of the main problems facing compatibilism: (i) the powerful intuition that one can't be responsible for actions that were somehow determined before one was born; (ii) Peter van Inwagen's modal argument, involving the inference rule (β); (iii) the objection to compatibilism that is based on claiming that the ability to do otherwise is (...) a necessary condition for freedom; (iv) "manipulation arguments," involving cases in which an agent is manipulated by some powerful being into doing something that he or she would not normally do, but in such a way that the compatibilist's favorite conditions for a free action are satisfied; (v) the problem of constitutive luck; and (vi) the claim that it is not fair to blame someone for an action if that person was determined by forces outside of his or her control to perform that action. And in the case of each of these problems, I argue that the compatibilist has a much more plausible response to that problem if she endorses the theory of agent causation than she does otherwise. (shrink)

The modal collapse objection to classical theism has received significant attention among philosophers as of late. My aim in this paper is to advance this blossoming debate. First, I briefly survey the modal collapse literature and argue that classical theists avoid modal collapse if and only if they embrace an indeterministic link between God and his effects. Second, I argue that this indeterminism poses two challenges to classical theism. The first challenge is that it collapses God’s status as an intentional (...) agent who knows and intends what he is bringing about in advance. The second challenge is that it collapses God’s providential control over which creation obtains. (shrink)

A growing consensus in the literature on agentive modals has it that ability modals like ‘can’ or ‘able to’ have a _dual_, i.e. interpretations of ‘must’ or ‘cannot but’ which stand to _necessity_ as ability stands to _possibility_. We argue that this thesis (which we call ‘Agentive Duality’) is much more controversial than meets the eye. While Agentive Duality follows from the orthodox possibility analysis of ability given natural assumptions, it sits uneasily with a wide (...) range of alternative proposals which are unified by the idea that ability requires _control_. In particular, we show that against the background of a control requirement on ability, Agentive Duality can be used to derive absurd predictions featuring this dual. Far from being a purely definitional thesis, Agentive Duality thus affords a new lens through which to assess the long-standing debate between possibility analyses of ability and their discontents. (shrink)

Humans communicate with different modalities. We offer an account of multi-modal meaning coordination, taking speech-gesture meaning coordination as a prototypical case. We argue that temporal synchrony (plus prosody) does not determine how to coordinate speech meaning and gesture meaning. Challenging cases are asynchrony and broadcasting cases, which are illustrated with empirical data. We propose that a process algebra account satisfies the desiderata. It models gesture and speech as independent but concurrent processes that can communicate flexibly with each other and exchange (...) the same information more than once. The account utilizes the ψ-calculus, allowing for agents, input-output-channels, concurrent processes, and data transport of typed λ-terms. A multi-modal meaning is produced integrating speech meaning and gesture meaning into one semantic package. Two cases of meaning coordination are handled in some detail: the asynchrony between gesture and speech, and the broadcasting of gesture meaning across several dialogue contributions. This account can be generalized to other cases of multi-modal meaning. (shrink)

I argue against the Standard View of ignorance, according to which ignorance is defined as equivalent to lack of knowledge, that cases of environmental epistemic luck, though entailing lack of knowledge, do not necessarily entail ignorance. In support of my argument, I contend that in cases of environmental luck an agent retains what I call epistemic access to the relevant fact by successfully exercising her epistemic agency and that ignorance and non-ignorance, contrary to what the Standard View predicts, are not (...) modal in the sense that knowledge is. After responding to objections, I conclude by sketching an alternative account of ignorance centered on the notions of epistemic access and epistemic agency. (shrink)

Modal epistemologies aim to explicate the necessary link between belief and truth that constitutes knowledge. This strain of epistemological theorizing is typically externalist; hence, it does not require that the agent know or understand the nature of the knowledge-constituting link. A central concern of modal epistemology is to articulate conditions on knowing such that no merely lucky true belief counts as knowledge. In the effort to eliminate luck, epistemic principles are often cast modally, requiring that an agent’s belief is true (...) not only in the actual world but also in relevant possible worlds, indicating that the link between truth and belief is more than an actual world lucky coincidence. (Note, then, that this entry is not about the epistemology of modals—statements involving modal operators such as “necessarily,” “possibly,” and the like—but about the use of modal principles in characterizing the nature of knowledge in general. For purposes of disambiguation and in deference to the other topic, perhaps “modalized epistemologies” would be a better term, though it is not typically used here.) Modal epistemologies typically have antiskeptical consequences, but the strengths of the antiskeptical results vary significantly, especially between the two best-known modal principles, sensitivity and safety. (shrink)

Perceptual modalities have been traditionally considered the product of dedicated biological systems producing information for higher cognitive processing. Psychological and neuropsychological evidence is offered which undermines this point of view and an alternative account of modality from the enactive approach to understanding cognition is suggested. Under this view, a perceptual modality is a stable form of perception which is structured not just by the biological sensitivities of the agent, but by their goals and the set of skills or expertise which (...) they are deploying at a given time. Such a view suggests that there is no such thing as an experience that is purely visual, auditory, or otherwise modal and that our attempts to understand consciousness and the mind must be conducted within a framework that provides an account of embodied, goal-directed adaptive coping with the world. (shrink)

In this paper, I argue that the conscious awareness one has of oneself as acting, i.e., agentive awareness, is not a type of sensory awareness. After providing some set up in Sect. 1, I move on in Sect. 2 to sketch a profile of sensory agentive experiences as representational states with sensory qualities by which we come to be aware of ourselves as performing actions. In Sect. 3, I critique two leading arguments in favor of positing such sensory (...) experiences: the argument from pathology and the argument from cognitive impenetrability. Since neither of these arguments succeeds, the case for positing SAEs is dealt a significant blow. I proceed in Sect. 4 to advance my positive argument against SAEs. The argument runs as follows: If SAEs exist, then they must exist in some sensory modality or set of sensory modalities. Either the relevant sensory modalities are ones that we already recognize, or they are novel sensory modalities. I will argue that neither of these options is workable, and so we have nowhere to locate SAEs. Agentive awareness is not sensory awareness. (shrink)

Modal logics, originally conceived in philosophy, have recently found many applications in computer science, artificial intelligence, the foundations of mathematics, linguistics and other disciplines. Celebrated for their good computational behaviour, modal logics are used as effective formalisms for talking about time, space, knowledge, beliefs, actions, obligations, provability, etc. However, the nice computational properties can drastically change if we combine some of these formalisms into a many-dimensional system, say, to reason about knowledge bases developing in time or moving objects. To study (...) the computational behaviour of many-dimensional modal logics is the main aim of this book. On the one hand, it is concerned with providing a solid mathematical foundation for this discipline, while on the other hand, it shows that many seemingly different applied many-dimensional systems (e.g., multi-agent systems, description logics with epistemic, temporal and dynamic operators, spatio-temporal logics, etc.) fit in perfectly with this theoretical framework, and so their computational behaviour can be analyzed using the developed machinery. We start with concrete examples of applied one- and many-dimensional modal logics such as temporal, epistemic, dynamic, description, spatial logics, and various combinations of these. Then we develop a mathematical theory for handling a spectrum of 'abstract' combinations of modal logics - fusions and products of modal logics, fragments of first-order modal and temporal logics - focusing on three major problems: decidability, axiomatizability, and computational complexity. Besides the standard methods of modal logic, the technical toolkit includes the method of quasimodels, mosaics, tilings, reductions to monadic second-order logic, algebraic logic techniques. Finally, we apply the developed machinery and obtained results to three case studies from the field of knowledge representation and reasoning: temporal epistemic logics for reasoning about multi-agent systems, modalized description logics for dynamic ontologies, and spatio-temporal logics. The genre of the book can be defined as a research monograph. It brings the reader to the front line of current research in the field by showing both recent achievements and directions of future investigations (in particular, multiple open problems). On the other hand, well-known results from modal and first-order logic are formulated without proofs and supplied with references to accessible sources. The intended audience of this book is logicians as well as those researchers who use logic in computer science and artificial intelligence. More specific application areas are, e.g., knowledge representation and reasoning, in particular, terminological, temporal and spatial reasoning, or reasoning about agents. And we also believe that researchers from certain other disciplines, say, temporal and spatial databases or geographical information systems, will benefit from this book as well. Key Features: Integrated approach to modern modal and temporal logics and their applications in artificial intelligence and computer science Written by internationally leading researchers in the field of pure and applied logic Combines mathematical theory of modal logic and applications in artificial intelligence and computer science Numerous open problems for further research Well illustrated with pictures and tables. (shrink)

Accounts of ability in the philosophical literature have tended to be modal ones: claims about an agent’s abilities are understood in terms of what she does in certain non-actual scenarios. In contrast, a prominent account of ability ascriptions in the recent semantics literature appeals to genericity: claims about an agent’s abilities are understood in terms of what she generally manages to do. The latter account resolves some long-standing problems for modal accounts, but encounters problems of its own. I propose a (...) hybrid view, on which ability involves both a modal and a generic element. (shrink)

In Bayesian belief revision a Bayesian agent revises his prior belief by conditionalizing the prior on some evidence using Bayes’ rule. We define a hierarchy of modal logics that capture the logical features of Bayesian belief revision. Elements in the hierarchy are distinguished by the cardinality of the set of elementary propositions on which the agent’s prior is defined. Inclusions among the modal logics in the hierarchy are determined. By linking the modal logics in the hierarchy to the strongest modal (...) companion of Medvedev’s logic of finite problems it is shown that the modal logic of belief revision determined by probabilities on a finite set of elementary propositions is not finitely axiomatizable. (shrink)

This book concerns the foundations of epistemic modality and hyperintensionality and their applications to the philosophy of mathematics. I examine the nature of epistemic modality, when the modal operator is interpreted as concerning both apriority and conceivability, as well as states of knowledge and belief. The book demonstrates how epistemic modality and hyperintensionality relate to the computational theory of mind; metaphysical modality and hyperintensionality; the types of mathematical modality and hyperintensionality; to the epistemic status of large cardinal axioms, undecidable propositions, (...) and abstraction principles in the philosophy of mathematics; to the modal and hyperintensional profiles of the logic of rational intuition; and to the types of intention, when the latter is interpreted as a hyperintensional mental state. Chapter \textbf{2} argues for a novel type of expressivism based on the duality between the categories of coalgebras and algebras, and argues that the duality permits of the reconciliation between modal cognitivism and modal expressivism. I also develop a novel topic-sensitive truthmaker semantics for dynamic epistemic logic, and develop a novel dynamic two-dimensional semantics. Chapter \textbf{3} provides an abstraction principle for epistemic (hyper-)intensions. Chapter \textbf{4} advances a topic-sensitive two-dimensional truthmaker semantics, and provides three novel interpretations of the framework along with the epistemic and metasemantic. Chapter \textbf{5} applies the fixed points of the modal $\mu$-calculus in order to account for the iteration of epistemic states in a single agent, by contrast to availing of modal axiom 4 (i.e. the KK principle). The fixed point operators in the modal $\mu$-calculus are rendered hyperintensional, which yields the first hyperintensional construal of the modal $\mu$-calculus in the literature and the first application of the calculus to the iteration of epistemic states in a single agent instead of the common knowledge of a group of agents. Chapter \textbf{6} advances a solution to the Julius Caesar problem based on Fine's `criterial' identity conditions which incorporate conditions on essentiality and grounding. Chapter \textbf{7} provides a ground-theoretic regimentation of the proposals in the metaphysics of consciousness and examines its bearing on the two-dimensional conceivability argument against physicalism. The topic-sensitive epistemic two-dimensional truthmaker semantics developed in chapters \textbf{2} and \textbf{4} are availed of in order for epistemic states to be a guide to metaphysical states in the hyperintensional setting. -/- Chapters \textbf{8-12} provide cases demonstrating how the two-dimensional hyperintensions of hyperintensional, i.e. topic-sensitive epistemic two-dimensional truthmaker, semantics, solve the access problem in the epistemology of mathematics. Chapter \textbf{8} examines the interaction between my hyperintensional semantics and the axioms of epistemic set theory, large cardinal axioms, the Epistemic Church-Turing Thesis, the modal axioms governing the modal profile of $\Omega$-logic, Orey sentences such as the Generalized Continuum Hypothesis, and absolute decidability. These results yield inter alia the first hyperintensional Epistemic Church-Turing Thesis and hyperintensional epistemic set theories in the literature. Chapter \textbf{9} examines the modal and hyperintensional commitments of abstractionism, in particular necessitism, and epistemic hyperintensionality, epistemic utility theory, and the epistemology of abstraction. I countenance a hyperintensional semantics for novel epistemic abstractionist modalities. I suggest, too, that observational type theory can be applied to first-order abstraction principles in order to make first-order abstraction principles recursively enumerable, i.e. Turing machine computable, and that the truth of the first-order abstraction principle for hyperintensions is grounded in its being possibly recursively enumerable and the machine being physically implementable. Chapter \textbf{10} examines the philosophical significance of hyperintensional $\Omega$-logic in set theory and discusses the hyperintensionality of metamathematics. Chapter \textbf{11} provides a modal logic for rational intuition and provides a hyperintensional semantics. Chapter \textbf{12} avails of modal coalgebras to interpret the defining properties of indefinite extensibility, and avails of hyperintensional epistemic two-dimensional semantics in order to account for the interaction between the interpretational and objective modalities and truthmakers thereof. This yields the first hyperintensional category theory in the literature. I invent a new mathematical trick in which first order structures are treated as categories, and Vopenka's principle can be satisfied because of the elementary embeddings between the categories and generate Vopenka cardinals while bypassing the category of Set in category theory. Chapter \textbf{13} examines modal responses to the alethic paradoxes. Chapter \textbf{14} examines, finally, the modal and hyperintensional semantics for the different types of intention and the relation of the latter to evidential decision theory. (shrink)

In Bayesian belief revision a Bayesian agent revises his prior belief by conditionalizing the prior on some evidence using Bayes’ rule. We define a hierarchy of modal logics that capture the logical features of Bayesian belief revision. Elements in the hierarchy are distinguished by the cardinality of the set of elementary propositions on which the agent’s prior is defined. Inclusions among the modal logics in the hierarchy are determined. By linking the modal logics in the hierarchy to the strongest modal (...) companion of Medvedev’s logic of finite problems it is shown that the modal logic of belief revision determined by probabilities on a finite set of elementary propositions is not finitely axiomatizable. (shrink)

This paper develops an information-sensitive theory of the semantics and probability of conditionals and statements involving epistemic modals. The theory validates a number of principles linking probability and modality, including the principle that the probability of a conditional If A, then C equals the probability of C, updated with A. The theory avoids so-called triviality results, which are standardly taken to show that principles of this sort cannot be validated. To achieve this, we deny that rational agents update their (...) credences via conditionalization. We offer a new rule of update, Hyperconditionalization, which agrees with Conditionalization whenever nonmodal statements are at stake but differs for modal and conditional sentences. (shrink)

We present the propositional logic LEC for the two epistemic modalities of current and stable knowledge used by an agent who system-atically enriches his language. A change in the linguistic resources of an agent as a result of certain cognitive processes is something that commonly happens. Our system is based on the logic LC intended to formalize the idea that the occurrence of changes induces the passage of time. Here, the primitive operator C read as: it changes that, defines the (...) temporal succession of states of the world. The notion of current knowledge concerns variable components of the world and it may change over time. We represent it by the primitive operator k read as: the agent currently knows that, and assume that it has S5 properties. The second type of knowledge, symbolized by the primitive operator K read as: the agent stably knows that, relates to constant components of the world and it does not change. As a result of the axiomatic entanglement of C, K and k we show that stable knowledge satisfies axioms of S4.3. K and k modalities are not mutually definable, stable knowledge implies the current one and if the latter never changes, then it comes to be stable. The combination of K and k with the idea of an expanding language allows questioning of the so-called perfect recall principle. It cannot be maintained for both types of knowledge just because of changes in the vocabulary of the agent and possibly the growing spectrum of possible states of the world. We interpret LEC in the semantics of histories of epistemic changes and show that it is complete. Finally, we compare our logic with selected epistemic logics based on the concept of linear discrete time. (shrink)

I propose a unified solution to two puzzles: Ross's puzzle and free choice permission. I begin with a pair of cases from the decision theory literature illustrating the phenomenon of act dependence, where what an agent ought to do depends on what she does. The notion of permissibility distilled from these cases forms the basis for my analysis of 'may' and 'ought'. This framework is then combined with a generalization of the classical semantics for disjunction — equivalent to Boolean disjunction (...) on the diagonal, but with a different two-dimensional character — that explains the puzzling facts in terms of semantic consequence. (shrink)

This paper provides a semantic analysis of the particles afinal (European Portuguese) and alla fine (Italian) in terms of the notion of truth unpersistence, which can be situated at the intersection of epistemic modality and discourse structure. In the analysis proposed, the particles are propositional operators and require that the truth of a proposition p* fail to persist through a temporal succession of epistemic states, this proposition being incompatible with the prejacent, and that the interlocutors share knowledge of a previous (...) epistemic attitude toward p*. We analyze two main cases (plan-related and non plan-related propositions) and also show that these particles are indexical to one (or more) epistemic agent(s) and allow for shifts in perspective. (shrink)

Discussions of free will have frequently centered on principles concerning ability, control, unavoidability and other practical modalities. Some assert the closure of the latter over various propositional operations and relations, for example, that the consequences of what is beyond one's control are themselves beyond one's control.1 This principle has been featured in the unavoidability argument for incompatibilism: if everything we do is determined by factors which are not under our control, then, by the principle, we are unable to act and (...) choose other than we actually did. A second family of principles concerns the fixity of the past and the laws of nature. If no one is able to alter the past or violate the laws it seems but a small step to conclude that no one can do anything such that if they did it then the past would be altered or the laws violated. Accordingly, if an agent's performing an act is necessitated by the past and laws, then the agent is unable to refrain from that act at that time. Generalizing, determinism precludes anyone from doing anything other than what he or she did.2. (shrink)

It is widely held that it is unhelpful to model our epistemic access to modal facts on the basis of perception, and postulate the existence of a bodily mechanism attuned to modal features of the world. In this paper I defend modalizing mechanisms. I present and discuss a decision-theoretic model in which agents with severely limited cognitive abilities, at the end of an evolutionary process, have states which encode substantial information about the probabilities with which the outcomes of a certain (...) Bernoulli process occur. Thus, in the model, a process driven by very simple, thoroughly naturalistic mechanisms eventuates in modal sensitivity. (shrink)

Many powerful logics exist today for reasoning about multi-agent systems, but in most of these it is hard to reason about an infinite or indeterminate number of agents. Also the naming schemes used in the logics often lack expressiveness to name agents in an intuitive way.To obtain a more expressive language for multi-agent reasoning and a better naming scheme for agents, we introduce a family of logics called term-modal logics. A main feature of our logics is the use of modal (...) operators indexed by the terms of the logics. Thus, one can quantify over variables occurring in modal operators. In term-modal logics agents can be represented by terms, and knowledge of agents is expressed with formulas within the scope of modal operators. (shrink)

In the standard theory of deontic modals, ‘ought’ is understood as expressing a propositional operator. However, this view has been called into question by Almotahari and Rabern’s puzzle about deontic ‘ought’, according to which the ethical principle that one ought to be wronged by another person rather than wrong them is intuitively coherent but the standard theory makes it incoherent. In this paper, I take up Almotahari and Rabern’s challenge and offer a refinement of the standard theory to handle (...) the puzzle. I propose that ‘ought’ is evaluated relative to contextual parameters (e.g., Kratzer’s conversational backgrounds, Finlay and Snedegar’s alternative sets) and those contextual parameters are sensitive to agents as well as possible worlds. (shrink)

We introduce a type of weighted modal logic with explicit weights both in the language and in the models. The framework has its applications in epistemic logic for reasoning about agents’ knowledge based on their capability, and in deontic logic for agents’ choices based on their deontic capability or utilities. We make use of weighted Kripke models with the weights understood epistemically as a similarity measure between states and deontically as a measure of expected utilities. We present sound and complete (...) axiomatizations for the logics, and discuss variants and possible extensions. (shrink)

This paper has two goals. The first is to develop a cross-linguistically valid model of modality and mood that captures the most important dimensions along which modal expressions vary. I posit a model with two such dimensions, one of volitivity, and one of event-orientation vs. speaker-orientation, mood being placed at the speaker-oriented end relative to modality proper. The second goal is to provide a new perspective on semantic change of modal expressions on the basis of the proposed model. I argue (...) that unidirectional change along the event-oriented / speaker-oriented dimension is the one overarching tendency of semantic change in modals. This stands in contrast to the widespread perception that change from deontic to epistemic is the dominant tendency. The directionality suggested in this new model is also more comprehensive than previously proposed tendencies of change, such as ‘‘from agent-oriented to epistemic’’, ‘‘from agent-oriented to speaker-oriented’’, and ‘‘from participant-internal to participant-external’’, as it better accounts for various kinds of change that have been previously neglected, including change from epistemic to deontic. (shrink)

What Daniel Hausman has called 'the simple criticism of economic theory' affirms that neoclassical microeconomic models include false statements, and therefore economists cannot rationally accept such models. Hausman considers, but rejects, the modal view of economic models as a defense of neoclassical theory against the simple criticism. I attempt to show that, on the contrary, the modal view can be used to defend neoclassical micro theory. The modal view distinguishes theoretical from applied economic models. Theoretical models afford true descriptions of (...) hypothetical economic agents, whereas applied models contain true or false statements about some real world situation. Relying on the modal view, I argue that the simple criticism is not well-founded, whether it concerns theoretical or applied models. (shrink)

This article is oriented toward the use of modality in artificial intelligence (AI). An agent must reason about what it or other agents know, believe, want, intend or owe. Referentially opaque modalities are needed and must be formalized correctly. Unfortunately, modal logics seem too limited for many important purposes. This article contains examples of uses of modality for which modal logic seems inadequate.I have no proof that modal logic is inadequate, so I hope modal logicians will take the examples as (...) challenges. (shrink)

This paper considers some questions related to the determination of epistemic modal domains. Specifically, given situations in which groups of agents have epistemic states that bear on a modal domain, how is the domain best restricted? This is a metasemantic project, in which I combine a standard semantics for epistemic modals, as developed by Kratzer, with a standard story about conversational dynamics, as developed by Stalnaker. I show how a standard framework for epistemic logic can model their interaction. I (...) contend that if groups have epistemic states that bear on the modal domain, as the data suggests, then careful attention must be paid to the method of combination selected for the epistemic states of the individuals within the group. Specifically, there should be some explanation of the flow of information in a group-deliberative setting. Through this study we find a novel explanation of modal disagreement and uptake. (shrink)

It has been argued that the attribution of intentional actions is sensitive to our moral judgment. I suggest an alternative, where the attribution of intentional actions depends on modal (and not moral) considerations. We judge a foreseen side-effect of an agent’s intentionally performed action to be intentional if the following modal claim is true: if she had not ignored considerations about the foreseen side-effect, her action might have been different (other things being equal). I go through the most important examples (...) of the asymmetry in the attribution of intentionality and point out that the modal account can cover all the problematic cases, whereas the moral account can’t. (shrink)

How do modal expressions determine which possibilities they range over? According to the Modal Anchor Hypothesis (Kratzer in _The language-cognition interface: Actes du 19_ _e_ _congrès international des linguistes_, Libraire Droz, Genève, 179–199, 2013 ), modal expressions determine their domain of quantification from particulars (events, situations, or individuals). This paper presents novel evidence for this hypothesis, focusing on a class of Spanish relative clauses that host verbs inflected in the subjunctive. Subjunctive in Romance is standardly taken to be licensed only (...) in a subset of intensional contexts. However, in our relative clauses, subjunctive is exceptionally licensed in extensional contexts. At the same time, the interpretation of these relative clauses still involves modality, a type of modality that targets the goals of the agent of the main event. We argue that the pattern displayed by these relative clauses follows straightforwardly if subjunctive is associated with a modal operator that, like modal indefinites (Alonso-Ovalle and Menéndez-Benito in _Journal of Semantics_ 35(1):1–41, 2017 ), can project its domain from a volitional event. Overall, our proposal supports the event-based analysis of mood (Kratzer in Evidential mood in attitude and speech reports. Talk delivered at the 1st Syncart Workshop, Siena, July 13, 2016 ; Portner and Rubinstein in _Natural Language Semantics_ 28:343–393, 2020 ) and extends its application beyond attitudinal and modal complements. (shrink)

We introduce quantificational modal operators as dynamic modalities with (extensions of) Henkin quantifiers as indices. The adoption of matrices of indices (with action identifiers, variables and/or quantified variables as entries) gives an expressive formalism which is here motivated with examples from the area of multi-agent systems. We study the formal properties of the resulting logic which, formally speaking, does not satisfy the normality condition. However, the logic admits a semantics in terms of (an extension of) Kripke structures. As a consequence, (...) standard techniques for normal modal logic become available. We apply these to prove completeness and decidability, and to extend some standard frame results to this logic. (shrink)

It is widely held that for an action to be free it must be the case that the agent can do otherwise. Compatibilists and incompatibilists disagree over what this ability amounts to. Two recent articles offer novel perspectives on the debate by employing Angelika Kratzer’s semantics of ‘can’. Alex Grzankowski proposes that Kratzer’s semantics favour incompatibilism because they make valid a version of the Consequence Argument. Christian List argues that Kratzer’s semantics favour a novel form of compatibilism. I argue that (...) List’s compatibilist application of Kratzer’s semantics faces problems not faced by Grzankowski’s incompatibilist employment of them. On the other hand I argue that Kratzer’s semantics make Grzankowski’s version of the Consequence Argument valid only at the cost of rendering it dialectically useless. Contrary to both views Kratzer’s semantics do not appear to add substantial weight to either side of the compatibilism/incompatibilism dispute. (shrink)

The well known AGM framework for belief revision has recently been extended to include a model of the research agenda of the agent, i.e. a set of questions to which the agent wishes to find answers (Olsson & Westlund in Erkenntnis , 65 , 165–183, 2006 ). The resulting model has later come to be called interrogative belief revision . While belief revision has been studied extensively from the point of view of modal logic, so far interrogative belief revision has (...) only been dealt with in the metalanguage approach in which AGM was originally presented. In this paper, I show how to model interrogative belief revision in a modal object language using a class of operators for questions. In particular, the solution I propose will be shown to capture the notion of K-truncation , a method for agenda update in the case of expansion constructed by Olsson & Westlund. Two case studies are conducted: first, an interrogative extension of Krister Segerberg’s system DDL, and then a similar extension of Giacomo Bonanno’s modal logic for belief revision. Sound and complete axioms will be provided for both of the resulting logics. (shrink)