This contribution is a gentle introduction to so-called dynamic epistemic logics, that can describe how agents change their knowledge and beliefs. We start with a concise introduction to epistemic logic, through the example of one, two and finally three players holding cards; and, mainly for the purpose of motivating the dynamics, we also very summarily introduce the concepts of general and common knowledge. We then pay ample attention to the logic of public announcements, wherein agents change their knowledge as the (...) result of public announcements. One crucial topic in that setting is that of unsuccessful updates: formulas that become false when announced. The Moore-sentences that were already extensively discussed at the conception of epistemic logic in Hintikka’s ‘Knowledge and Belief’ give rise to such unsuccessful updates. After that, we present a few examples of more complex epistemic updates. Our closing observations are on recent developments that link the ‘standard’ topic of belief revision, as in ‘On the Logic of Theory Change: partial meet contraction and revision functions’, by Alchourron et al. , to the dynamic epistemic logics introduced here. (shrink)

FoLLI-LNCS is the publication platform for the Association of Logic, Language and Information. The Association was founded in 1991 to advance research and education on the interface between logic, linguistics, computer science, and cognitive science. The FoLLI Publications on Logic, Language and Information aim to disseminate results of cutting-edge research and tutorial materials in these interdisciplinary areas. This LNCS volume is part of FoLLi book serie and contains the papers presented at the 5th International Workshop on Logic, Rationality and Interaction/, (...) held in October 2015 in Taipei, Taiwan. The topics covered in this program well represent the span and depth that hasby now become a trademark of the LORI workshop series, where logic interfaceswith disciplines as diverse as game theory and decision theory, philosophyand epistemology, linguistics, computer science and artificial intelligence. (shrink)

Choices confront us with questions. How we act depends on our answers to those questions. So the way our beliefs guide our choices is not just a function of their informational content, but also depends systematically on the questions those beliefs address. This paper gives a precise account of the interplay between choices, questions and beliefs, and harnesses this account to obtain a principled approach to the problem of deduction. The result is a novel theory of belief-guided action that explains (...) and predicts the decisions of agents who, like ourselves, fail to be logically omniscient: that is, of agents whose beliefs may not be deductively closed, or even consistent. (Winner of the 2021 Isaac Levi Prize.). (shrink)

This paper proposes a new account of bounded or minimal doxastic rationality (in the sense of Cherniak 1986), based on the notion that beliefs are answers to questions (à la Yalcin 2018). The core idea is that minimally rational beliefs are linked through thematic connections, rather than entailment relations. Consequently, such beliefs are not deductively closed, but they are closed under parthood (where a part is an entailment that answers a smaller question). And instead of avoiding all inconsistency, minimally rational (...) believers only avoid blatant inconsistencies (where some beliefs are blatantly inconsistent when they contradict one another on a particular question). Rather than cohering into a single overall world view, beliefs are more loosely connected in what is best described as a web of questions. This view of minimally rational belief naturally gives rise to an account of deductive inquiry on which deductive reasoning is a matter of posing new questions. (shrink)

Conversational exculpature is a pragmatic process whereby information is subtracted from, rather than added to, what the speaker literally says. This pragmatic content subtraction explains why we can say “Rob is six feet tall” without implying that Rob is between 5'0.99" and 6'0.01" tall, and why we can say “Ellen has a hat like the one Sherlock Holmes always wears” without implying Holmes exists or has a hat. This article presents a simple formalism for understanding this pragmatic mechanism, specifying how, (...) in context, the result of such subtractions is determined. And it shows how the resulting theory of conversational exculpature accounts for a varied range of linguistic phenomena. A distinctive feature of the approach is the crucial role played by the question under discussion in determining the result of a given exculpature. (shrink)

This paper presents and defends an argument that the continuum hypothesis is false, based on considerations about objective chance and an old theorem due to Banach and Kuratowski. More specifically, I argue that the probabilistic inductive methods standardly used in science presuppose that every proposition about the outcome of a chancy process has a certain chance between 0 and 1. I also argue in favour of the standard view that chances are countably additive. Since it is possible to randomly pick (...) out a point on a continuum, for instance using a roulette wheel or by flipping a countable infinity of fair coins, it follows, given the axioms of ZFC, that there are many different cardinalities between countable infinity and the cardinality of the continuum. (shrink)

Newton’s First Law of Motion is typically understood to govern only the motion of force-free bodies. This paper argues on textual and conceptual grounds that it is in fact a stronger, more general principle. The First Law limits the extent to which any body can change its state of motion –– even if that body is subject to impressed forces. The misunderstanding can be traced back to an error in the first English translation of Newton’s Principia, which was published a (...) few years after Newton’s death. (shrink)

Branching-time temporal logics have proved to be an extraordinarily successful tool in the formal specification and verification of distributed systems. Much of their success stems from the tractability of the model checking problem for the branching time logic CTL, which has made it possible to implement tools that allow designers to automatically verify that systems satisfy requirements expressed in CTL. Recently, CTL was generalised by Alur, Henzinger, and Kupferman in a logic known as "Alternating-time Temporal Logic". The key insight in (...) ATL is that the path quantifiers of CTL could be replaced by "cooperation modalities", of the form $\langle \langle \Gamma \rangle \rangle $, where Γ is a set of agents. The intended interpretation of an ATL formula $\langle \langle \Gamma \rangle \rangle \varphi $ is that the agents Γ can cooperate to ensure that φ holds. In this paper, we extend ATL with knowledge modalities, of the kind made popular in the work of Fagin, Halpern, Moses, Vardi and colleagues. Combining these knowledge modalities with ATL, it becomes possible to express such properties as "group Γ can cooperate to bring about φ iff it is common knowledge in Γ that ψ". The resulting logic -- Alternating-time Temporal Epistemic Logic -- shares the tractability of model checking with its ATL parent, and is a succinct and expressive language for reasoning about game-like multiagent systems. (shrink)

Although the change of beliefs in the face of new information has been widely studied with some success, the revision of other mental states has received little attention from the theoretical perspective. In particular, intentions are widely recognised as being a key attitude for rational agents, and while several formal theories of intention have been proposed in the literature, the logic of intention revision has been hardly considered. There are several reasons for this: perhaps most importantly, intentions are very closely (...) connected with other mental states—in particular, beliefs about the future and the abilities of the agent. So, we cannot study them in isolation. We must consider the interplay between intention revision and the revision of other mental states, which complicates the picture considerably. In this paper, we present some first steps towards a theory of intention revision. We develop a simple model of an agent’s mental states, and define intention revision operators. Using this model, we develop a logic of intention dynamics, and then investigate some of its properties. (shrink)

This book explores aesthetic forms of the left to negotiate the political frontiers of post-colonial, post-partition South Asia. Spanning India, Sri Lanka, Pakistan and Bangladesh, the contributors study art, film and literature to illuminate interconnections across regions and countries, and discuss the shifting political contours of the region during the latter half of the 20th century. With a clear focus and conceptualization this volume raises two key questions; how left-wing art generated cultural and social formations, and how aesthetic forms held (...) political value across the region. Reframing political aesthetics within a postcolonial and decolonised framework, it traces the trajectories and nuances the left-wing cultural movement took during decolonization, and focuses on connections and continuities across post-1947 India, Pakistan and Bangladesh. Following the evolution of progressive culture in the 1950s and 60s, networks of leftist filmmakers and theatre activists in postcolonial Pakistan, and the changing fate of left cultural politics in Sri Lanka and India during the 1970s, this book looks to reinvigorate the entangled histories of the left cultural movement in post-partition South Asia. (shrink)

Using Riemann’s Rearrangement Theorem, Øystein Linnebo (2020) argues that, if it were possible to apply an infinite positive weight and an infinite negative weight to a working scale, the resulting net weight could end up being any real number, depending on the procedure by which these weights are applied. Appealing to the First Postulate of Archimedes’ treatise on balance, I argue instead that the scale would always read 0 kg. Along the way, we stop to consider an infinitely jittery flea, (...) an infinitely protracted border conflict, and an infinitely electric glass rod. (shrink)

Since it was first proposed by Moses, Shoham, and Tennenholtz, the social laws paradigm has proved to be one of the most compelling approaches to the offline coordination of multiagent systems. In this paper, we make four key contributions to the theory and practice of social laws in multiagent systems. First, we show that the Alternating-time Temporal Logic (atl) of Alur, Henzinger, and Kupferman provides an elegant and powerful framework within which to express and understand social laws for multiagent systems. (...) Second, we show that the effectiveness, feasibility, and synthesis problems for social laws may naturally be framed as atl model checking problems, and that as a consequence, existing atl model checkers may be applied to these problems. Third, we show that the complexity of the feasibility problem in our framework is no more complex in the general case than that of the corresponding problem in the Shoham–Tennenholtz framework (it is np-complete). Finally, we show how our basic framework can easily be extended to permit social laws in which constraints on the legality or otherwise of some action may be explicitly required. We illustrate the concepts and techniques developed by means of a running example. (shrink)

Terence Irwin's edition of the Nicomachean Ethics offers more aids to the reader than are found in any modern English translation. It includes an Introduction, headings to help the reader follow the argument, explanatory notes on difficult or important passages, and a full glossary explaining Aristotle's technical terms. The Third Edition offers additional revisions of the translation as well as revised and expanded versions of the notes, glossary, and Introduction. Also new is an appendix featuring translated selections from related texts (...) of Aristotle. (shrink)

Although normative systems, or social laws, have proved to be a highly influential approach to coordination in multi-agent systems, the issue of compliance to such normative systems remains problematic. In all real systems, it is possible that some members of an agent population will not comply with the rules of a normative system, even if it is in their interests to do so. It is therefore important to consider the extent to which a normative system is robust, i.e., the extent (...) to which it remains effective even if some agents do not comply with it. We formalise and investigate three different notions of robustness and related decision problems. We begin by considering sets of agents whose compliance is necessary and/or sufficient to guarantee the effectiveness of a normative system; we then consider quantitative approaches to robustness, where we try to identify the proportion of an agent population that must comply in order to ensure success; and finally, we consider a more general approach, where we characterise the compliance conditions required for success as a logical formula. We furthermore introduce a logic for specifying properties of norm compliance in general and norm robustness in particular. (shrink)

Tim French, Wiebe van der Hoek, Petar Iliev and Barteld Kooi. Succinctness of Epistemic Languages. In: T. Walsh (editor). Proceedings of the Twenty-Second International Joint Conference on Artificial Intelligence (IJCAI-11), pp. 881-886, AAAI Press, Menlo Park.

We study several modal languages in which some (sets of) generalized quantifiers can be represented; the main language we consider is suitable for defining any first order definable quantifier, but we also consider a sublanguage thereof, as well as a language for dealing with the modal counterparts of some higher order quantifiers. These languages are studied both from a modal logic perspective and from a quantifier perspective. Thus the issues addressed include normal forms, expressive power, completeness both of modal systems (...) and of systems in the quantifier tradition, complexity as well as syntactic characterizations of special semantic constraints. Throughout the paper several techniques current in the theory of generalized quantifiers are used to obtain results in modal logic, and conversely. (shrink)

BackgroundThis article is part of a study to gain insight into the decision-making process by looking at the views of the relatives of potential brain dead donors. Alongside a literature review, focus interviews were held with healthcare professionals about their role in the request and decision-making process when post-mortal donation is at stake. This article describes the perspectives of the relatives.MethodsA content-analysis of 22 semi-structured in-depth interviews with relatives involved in an organ donation decision.ResultsThree themes were identified: ‘conditions’, ‘ethical considerations’ (...) and ‘look back’. Conditions were: ‘sense of urgency’, ‘incompetence to decide’ and ‘agreement between relatives’. Ethical considerations result in a dilemma for non-donor families: aiding people or protecting the deceased’s body, especially when they do not know his/her preference. Donor families respect the deceased’s last will, generally confirmed in the National Donor Register. Looking back, the majority of non-donor families resolved their dilemma by justifying their decision with external arguments. Some non-donor families would like to be supported during decision-making.DiscussionThe discrepancy between general willingness to donate and the actual refusal of a donation request can be explained by multiple factors, with a cumulative effect. Firstly, half of the participants stated that they felt that they were not competent to decide in such a crisis and they seem to struggle with utilitarian considerations against their wish to protect the body. Secondly, non-donor families refused telling that they did not know the deceased’s wishes or contesting posthumous autonomy of the eligible. Thirdly, the findings emphasise the importance of Donor Registration, because it seems to prevent dilemmas in decision-making, at least for donor families.ConclusionDiscrepancies between willingness to consent to donate and refusal at the bedside can be attributed to an unresolved dilemma: aiding people or protect the body of the deceased. Non-donor families felt incompetent to decide. They refused consent for donation, since their deceased had not given any directive. When ethical considerations do not lead to an unambiguous answer, situational factors were pivotal. Relatives of unregistered eligible donors are more prone to unstable decisions. To overcome ambivalence, coaching during decision-making is worth investigation. (shrink)

I present a new pragmatic theory of loose talk, focussing on the loose use of numbers and measurement expressions. The account explains loose readings as arising from a pragmatic mechanism aimed at restoring relevance to the question under discussion (QUD), appealing to Krifka's notion of a measurement scale. The core motivating observation is that the loose reading of a claim need not be weaker than its literal content, as almost all pragmatic treatments of loose talk have assumed (e.g. Lasersohn). The (...) loosening mechanism described here can be applied to a range of other linguistic phenomena as well. (shrink)

Models of collective deliberation often assume that the chief aim of a deliberative exchange is the sharing of information. In this paper, we argue that an equally important role of deliberation is to draw participants’ attention to pertinent questions, which can aid the assembly and processing of distributed information by drawing deliberators’ attention to new issues. The assumption of logical omniscience renders classical models of agents’ informational states unsuitable for modelling this role of deliberation. Building on recent insights from psychology, (...) linguistics and philosophy about the role of questions in speech and thought, we propose a different model in which beliefs are treated as answers directed at specific questions. Here, questions are formally represented as partitions of the space of possibilities and individuals’ information states as sets of questions and corresponding partial answers to them. The state of conversation is then characterised by individuals’ information together with the questions under discussion, which can be steered by various deliberative inputs. Using this model, deliberation is then shown to shape collective decisions in ways that classical models cannot capture, allowing for novel explanations of how group consensus is achieved. (shrink)

Qualitative Coalitional Games are a variant of coalitional games in which an agent's desires are represented as goals that are either satisfied or unsatisfied, and each choice available to a coalition is a set of goals, which would be jointly satisfied if the coalition made that choice. A coalition in a QCG will typically form in order to bring about a set of goals that will satisfy all members of the coalition. Our goal in this paper is to develop and (...) study logics for reasoning about QCGs. We begin by introducing a logic for reasoning about “static” QCGs, where participants play a single game, and we then introduce and study Temporal QCGs , i.e., games in which a sequence of QCGs is played. In order to represent and reason about such games, we introduce a linear time temporal logic of QCGs, called ℒ. We give a complete axiomatisation of ℒ, use it to investigate the properties of TQCGs, identify its expressive power, establish its complexity, characterise classes of TQGCs with formulas from our logical language, and use it to formulate several solution concepts for TQCGs. (shrink)

We define a multi-modal version of Computation Tree Logic ( ctl ) by extending the language with path quantifiers E δ and A δ where δ denotes one of finitely many dimensions, interpreted over Kripke structures with one total relation for each dimension. As expected, the logic is axiomatised by taking a copy of a ctl axiomatisation for each dimension. Completeness is proved by employing the completeness result for ctl to obtain a model along each dimension in turn. We also (...) show that the logic is decidable and that its satisfiability problem is no harder than the corresponding problem for ctl. We then demonstrate how Normative Systems can be conceived as a natural interpretation of such a multi-dimensional ctl logic. (shrink)

In the Netherlands, consent from relatives is obligatory for post mortal donation. This study explored the perspectives of relatives regarding the request for consent for donation in cases without donor registration. A content analysis of narratives of 24 bereaved relatives of unregistered, eligible, brain-dead donors was performed. Relatives of unregistered, brain-dead patients usually refuse consent for donation, even if they harbour pro-donation attitudes themselves, or knew that the deceased favoured organ donation. Half of those who refused consent for donation mentioned (...) afterwards that it could have been an option. The decision not to consent to donation is attributed to contextual factors, such as feeling overwhelmed by the notification of death immediately followed by the request; not being accustomed to speaking about death; inadequate support from other relatives or healthcare professionals, and lengthy procedures. Healthcare professionals could provide better support to relatives prior to donation requests, address their informational needs and adapt their message to individual circumstances. It is anticipated that the number of consenting families could be enlarged by examining the experience of decoupling and offering the possibility of consent for donation after circulatory death if families refuse consent for donation after brain-death. (shrink)

Death determination has long been a topic of intensive technoscientific and medical involvement. Due to advances in twentieth-century medical technology, the distinction between life and death has become less evident. Ambiguities appear when we start to use life-support technologies in order to save lives, bringing about “tragic artifacts” such as brain death and persistent vegetative state. In this paper we ask how this technoscientific and medical involvement shapes our understanding of death. We provide an overview of medical literature that has (...) appeared on (brain) death determination, highlighting thereby the role that technologies played in its establishment. Subsequently, we develop three philosophical interpretations of technological death determination: With Agamben and Marcuse as the installation of political power; with Don Ihde as an existential choice for the inevitable; and with Jacques Derrida as an encounter with the ineradicable mystery of death. To conclude, we argue that technological death determination reveals an intrinsic, paradoxical connection between human’s technicity and its ignorance of death. (shrink)

Death determination has long been a topic of intensive technoscientific and medical involvement. Due to advances in twentieth-century medical technology, the distinction between life and death has become less evident. Ambiguities appear when we start to use life-support technologies in order to save lives, bringing about “tragic artifacts” such as brain death and persistent vegetative state. In this paper we ask how this technoscientific and medical involvement shapes our understanding of death. We provide an overview of medical literature that has (...) appeared on (brain) death determination, highlighting thereby the role that technologies played in its establishment. Subsequently, we develop three philosophical interpretations of technological death determination: With Agamben and Marcuse as the installation of political power; with Don Ihde as an existential choice for the inevitable; and with Jacques Derrida as an encounter with the ineradicable mystery of death. To conclude, we argue that technological death determination reveals an intrinsic, paradoxical connection between human’s technicity and its ignorance of death. (shrink)

Hans van Ditmarsch, Wiebe van der Hoek and Barteld Kooi (2011). Reasoning about local properties in modal logic. In K. Tumer and P. Yolum and L. Sonenberg and P. Stone (editors). Proceedings of the 10th International Conference on Autonomous Agents and Multiagent Systems (AAMAS 2011), pp. 711-718.

Philipp Koralus' "Reason and Inquiry" presents a questioning or erotetic theory of reasoning. This review connects ideas from the book to the broader philosophical literature on inquiry and questions, as well as providing a simplified overview of the theory.