Classical epistemic logic describes implicit knowledge of agents about facts and knowledge of other agents based on semantic information. The latter is produced by acts of observation or communication that are described well by dynamic epistemic logics. What these logics do not describe, however, is how significant information is also produced by acts of inference— and key axioms of the system merely postulate "deductive closure". In this paper, we take the view that all information is produced by acts, and hence (...) we also need a dynamic logic of inference steps showing what effort on the part of the agent makes a conclusion explicit knowledge. Strong omniscience properties of agents should be seen not as static idealizations, but as the result of dynamic processes that agents engage in. This raises two questions: (a) how to define suitable information states of agents and matching notions of explicit knowledge, (b) how to define natural processes over these states that generate new explicit knowledge. To this end, we use a static base from the existing awareness literature, extending it into a dynamic system that includes traditional acts of observation, but also adding and dropping formulas from the current ' awareness' set. We give a completeness theorem, and we show how this dynamics updates explicit knowledge. Then we extend our approach to multi-agent scenarios where awareness changes may happen privately. Finally, we mention further directions and related approaches. Our contribution can be seen as a ' dynamification' of existing awareness logics. (shrink)

We investigate dynamic operations acting over a knowing how logic. Our approach makes use of a recently introduced semantics for the knowing how operator, based on an indistinguishability relation between plans. This semantics is arguably closer to the standard presentation of knowing that modalities in classic epistemic logic. Here, we discuss how the semantics enables us to define dynamic modalities representing different ways in which an agent can learn how to achieve a goal. In this regard, we study two types (...) of updates: ontic updates (for which we provide axiomatizations over a particular class of models), and epistemic updates (for which we investigate some semantic properties). (shrink)

Epistemic logic with its possible worlds semantic model is a powerful framework that allows us to represent an agent’s information not only about propositional facts, but also about her own information. Nevertheless, agents represented in this framework are logically omniscient: their information is closed under logical consequence. This property, useful in some applications, is an unrealistic idealisation in some others. Many proposals to solve this problem focus on weakening the properties of the agent’s information, but some authors have argued that (...) solutions of this kind are not completely adequate because they do not look at the heart of the matter: the actions that allow the agent to reach such omniscient state. Recent works have explored how acts of observation, inference, consideration and forgetting affect an agent’s implicit and explicit knowledge; the present work focuses on acts that affect an agent’s implicit and explicit beliefs. It starts by proposing a framework in which these two notions can be represented, and then it looks into their dynamics, first by reviewing the existing notion of belief revision, and then by introducing a rich framework for representing diverse forms of inference that involve both knowledge and beliefs. (shrink)

This work proposes an understanding of deductive, default and abductive reasoning as different instances of the same phenomenon: epistemic dynamics. It discusses the main intuitions behind each one of these reasoning processes, and suggest how they can be understood as different epistemic actions that modify an agent’s knowledge and/or beliefs in a different way, making formal the discussion with the use of the dynamic epistemic logic framework. The ideas in this paper put the studied processes under the same umbrella, thus (...) highlighting their relationship and allowing a better understanding of how they interact together. (shrink)

As a new type of epistemic logics, the logics of knowing how capture the high-level epistemic reasoning about the knowledge of various plans to achieve certain goals. Existing work on these logics focuses on axiomatizations; this paper makes the first study of their model theoretical properties. It does so by introducing suitable notions of bisimulation for a family of five knowing how logics based on different notions of plans. As an application, we study and compare the expressive power of these (...) logics. (shrink)

The paper develops an interface between syntax-based logical models of awareness and dynamic epistemic logic. The framework is shown to be able to accommodate a variety of notions of awareness and knowledge, as well as their dynamics. This, it is argued, offers a natural formal environment for the analysis of epistemic phenomena typical of multi-agent information exchange, such as how agents become aware of relevant details, how they perform inferences and how they share their information within a group. Technically, the (...) logics presented are all simple refinements of the logic of public announcements. (shrink)

Among the non-monotonic reasoning processes, abduction is one of the most important. Usually described as the process of looking for explanations, it has been recognized as one of the most commonly used in our daily activities. Still, the traditional definitions of an abductive problem and an abductive solution mention only theories and formulas, leaving agency out of the picture. Our work proposes a study of abductive reasoning from an epistemic and dynamic perspective. In the first part we explore syntactic definitions (...) of both an abductive problem in terms of an agent’s information and an abductive solution in terms of the actions that modify the agent’s information. We look at diverse kinds of agents, including not only omniscient ones but also those whose information is not closed under logical consequence and those whose reasoning abilities are not complete. In the second part, we look at an existing logical framework whose semantic model allows us to interpret the previously stated formulas, and we define two actions that represent forms of abductive reasoning. (shrink)

The paper focuses on a recent challenge brought forward against the interventionist approach to the meaning of counterfactual conditionals. According to this objection, interventionism cannot account for the interpretation of right-nested counterfactuals, the problem being its strict interventionism. We will report on the results of an empirical study supporting the objection. Furthermore, we will extend the well-known logic of intervention with a new operator expressing an alternative notion of intervention that does away with strict interventionism. This new notion of intervention (...) operates on the valuation of the variables in a causal model, and not on their functional dependencies. (shrink)

This paper introduces and studies a notion of cautious distributed belief. Different from the standard distributed belief, the cautious distributed belief of a group is inconsistent only when all group members are individually inconsistent. The paper presents basic results about cautious distributed belief, investigates whether it preserves properties of individual belief, and compares it with standard distributed belief. Although both notions are equivalent in the class of reflexive models, this is not the case in general. While we argue that an (...) understanding of the concept of cautious distributed belief from first principles is important, cautious distributed belief can be expressed using standard distrbuted belief and we show that the propositional language extended only with cautious distributed belief is in fact strictly less expressive than the propositional language extended only with standard distributed belief. We, finally, identify a small extension of the language making the former as expressive as the latter. (shrink)

In this paper, we explore the relation between an agent’s doxastic attitude and her arguments in support of a given claim. Our main contribution is the design of a logical setting that allows us reason about binary arguments which are either in favour or against a certain claim. This is a setting in which arguments and propositions are the basic building blocks so that the concept of argument-based belief emerges in a straightforward way. We work against the background of Dung’s (...) abstract argumentation framework, extending it to a new setting in which we can study the formal properties of binary arguments as well as the larger structures they establish. This paper introduces a formal ‘two-dimensional’ language to talk about propositions and arguments, for which a sound and complete axiom system is provided. (shrink)

This manuscript presents a topological argumentation framework for modelling notions of evidence-based (i.e., justified) belief. Our framework relies on so-called topological evidence models to represent the pieces of evidence that an agent has at her disposal, and it uses abstract argumentation theory to select the pieces of evidence that the agent will use to define her beliefs. The tools from abstract argumentation theory allow us to model agents who make decisions in the presence of contradictory information. Thanks to this, it (...) is possible to define two new notions of beliefs, grounded beliefs and fully grounded beliefs. These notions are discussed in this paper, analysed and compared with the existing notion of topological justified belief. This comparison revolves around three main issues: closure under conjunction introduction, the level of consistency and their logical strength. (shrink)

This paper is part of an on-going programme on the study of the logical aspects of social network formation. It recalls the so-called social network model, discussing the properties of a notion of closeness between agents ; then introduces an extended social network model in which different agents might assign different values to different traits, discussing the properties of the notion of weighted closeness that arises. These notions are used to define social network creation operations by means of a threshold (...) strategy. The paper studies the properties of the social networks the updates create, providing sound and complete axiom systems for formal languages describing these updates’ effects. (shrink)

Abductive problems and their solutions are presented by means of justification logic. We introduce additional meta-constructions in order to generate and compare different solutions to the same abductive problem. Our approach has three advantages: (i) it makes structurally explicit the solution to an abductive problem (as it has a syntactic nature); (ii) it gives a precise meaning to the notion of evidence; (iii) it provides clear definitions and procedures for the comparison of solutions that can be adapted to different needs.

We look at two fundamental logical processes, often intertwined in planning and problem solving: inference and update. Inference is an internal process with which we uncover what is implicit in the information we already have. Update, on the other hand, is produced by external communication, usually in the form of announcements and in general in the form of observations, giving us information that might not have been available (even implicitly) before. Both processes have received attention from the logic community, usually (...) separately. In this work, we develop a logical language that allows us to describe them together. We present syntax, semantics and a complete axiom system; we discuss similarities and differences with other approaches and mention how the work can be extended. (shrink)

Classical epistemic logic describes implicit knowledge of agents about facts and knowledge of other agents based on semantic information. The latter is produced by acts of observation or communication that are described well by dynamic epistemic logics. What these logics do not describe, however, is how significant information is also produced by acts of inference—and key axioms of the system merely postulate “deductive closure”. In this paper, we take the view that all information is produced by acts, and hence we (...) also need a dynamic logic of inference steps showing what effort on the part of the agent makes a conclusion explicit knowledge. Strong omniscience properties of agents should be seen not as static idealizations, but as the result of dynamic processes that agents engage in. This raises two questions: (a) how to define suitable information states of agents and matching notions of explicit knowledge, (b) how to define natural processes over these states that generate new explicit knowledge. To this end, we use a static base from the existing awareness literature, extending it into a dynamic system that includes traditional acts of observation, but also adding and dropping formulas from the current ‘awareness’ set. We give a completeness theorem, and we show how this dynamics updates explicit knowledge. Then we extend our approach to multi-agent scenarios where awareness changes may happen privately. Finally, we mention further directions and related approaches. Our contribution can be seen as a ‘dynamification’ of existing awareness logics. (shrink)

Taking as its point of departure a sharp critique of Rawls's influential A Theory of Justice, this book looks at politics from an aesthetic perspective.

Why are we interested in history at all? Why do we feel the need to distinguish between past and present? In this book, the author argues that the past originates from an experience of rupture separating past and present. Think of the radical rupture with Europe's past that was effected by the French and the Industrial Revolutions. Sublime Historical Experience investigates how the notion of sublime historical experience complicates and challenges existing conceptions of language, truth, and knowledge. These experiences of (...) rupture are paradoxical since they involve both the separation of past and present and, at the same time, the effort to overcome this separation in terms of historical knowledge. The experience unites feelings of loss/pain with those of love/satisfaction, and thus is in agreement with how sublime experience is ordinarily defined. The experience is also precognitive since it precedes historical knowledge. As such it is a challenge to traditional conceptions of the relationship between experience and truth or language. It compels us to disconnect the notions of experience and truth. (shrink)

We no longer have any texts, any past, but just interpretations of them. The evident multi -interpretability of a text causes it gradually to lose its capacity to function as arbiter in the historical debate. It is necessary to define a new link with the past based on a complete and honest recognition of the position in which we now see ourselves placed as historians. In recent years, many people have observed our changed attitude towards the phenomenon of information. For (...) postmodernism, science and information are independent objects of study which obey their own laws. Language and art are not situated opposite reality but are themselves a pseudo-reality and are therefore situated within reality. Because of the relation between the historiographical view and the language used by the historian to express his view - a relation which nowhere intersects the domain of the past -historiography possesses the same opacity and intensional dimension as art. The essence of postmodernism is precisely that we should avoid pointing out essentialist patterns in the past. There is reason to assume that our relation to the past and our insight into it will in future be of a metaphorical nature rather than a literal one. (shrink)

There are no dictionary meanings or authoritative discussions of "presence" that fix the significance of this word in a way that ought to be accepted by anybody using it. So we are in the welcome possession of great freedom to maneuver when using the term. In fact, the only feasible requirement for its use is that it should maximally contribute to our understanding of the humanities. When trying to satisfy this requirement I shall relate "presence" to representation. Then I focus (...) on a variant of representation in which the past is allowed to travel to the present as a kind of "stowaway" , so that the past is literally "present" in historical representation. I appeal to Runia's notion of so-called "parallel processes" for an analysis of this variant of historical representation. (shrink)

This book is the 1906 second edition of the Hulsean Lectures delivered at the University of Cambridge between 1901 and 1902. In these four lectures, F. R. Tennant challenges conventional teachings on Original Sin and the story of the Fall, arguing that his contemporaries had misinterpreted the biblical presentation of sin and its manifestations. Tennant aims to redefine the sin of both the race and the individual, and in doing so engages with traducianism and the philosophies of Malebranche, Kant and (...) Hegel. He argues that action predates modern conceptions of right and wrong, and that transgression is only sin if the actor is aware of what is morally right. Of course, these theories were met with great opposition, an opposition which Tennant uses the preface of this second edition to confront. These fascinating lectures and their appendages will be of great interest to scholars of Christian theology and the fin de siècle alike. (shrink)

There are no dictionary meanings or authoritative discussions of "presence" that fix the significance of this word in a way that ought to be accepted by anybody using it. So we are in the welcome possession of great freedom to maneuver when using the term. In fact, the only feasible requirement for its use is that it should maximally contribute to our understanding of the humanities. When trying to satisfy this requirement I shall relate "presence" to representation. Then I focus (...) on a variant of representation in which the past is allowed to travel to the present as a kind of "stowaway", so that the past is literally "present" in historical representation. I appeal to Runia's notion of so-called "parallel processes" for an analysis of this variant of historical representation. (shrink)

"The chief business of twentieth-century philosophy” is “to reckon with twentieth-century history," claimed R. G. Collingwood. In this remarkable collection of essays, Frank Ankersmit demonstrates the prescience of that remark and goes a long way toward meeting its challenge. Responding to the work of Hayden White, Arthur Danto, and Hans-Georg Gadamer, he examines such issues as the difference between historical representation and artistic expression, the status of metaphor in historical description, and the relation of postmodernism to historicism. Ankersmit's fluent grasp (...) of European thought and his ability to incorporate concepts from literary theory, art history, the philosophy of science, and political thought into his analyses assure that this collection will interest readers throughout the humanities. (shrink)