In the literature there are at least two main formal structures to deal with situations of interactive epistemology: Kripke models and type spaces. As shown in many papers :149–225, 1999; Battigalli and Siniscalchi in J Econ Theory 106:356–391, 2002; Klein and Pacuit in Stud Log 102:297–319, 2014; Lorini in J Philos Log 42:863–904, 2013), both these frameworks can be used to express epistemic conditions for solution concepts in game theory. The main result of this paper is (...) a formal comparison between the two and a statement of semantic equivalence with respect to two different logical systems: a doxastic logic for belief and an epistemic–doxastic logic for belief and knowledge. Moreover, a sound and complete axiomatization of these logics with respect to the two equivalent Kripke semantics and type spaces semantics is provided. Finally, a probabilistic extension of the result is also presented. A further result of the paper is a study of the relationship between the epistemic–doxastic logic for belief and knowledge and the logic STIT by Belnap and colleagues. (shrink)

The Brandenburger–Keisler paradox is a self-referential paradox in epistemic game theory which can be viewed as a two-person version of Russell’s Paradox. Yablo’s Paradox, according to its author, is a non-self referential paradox, which created a significant impact. This paper gives a Yabloesque, non-self-referential paradox for infinitary players within the context of epistemic game theory. The new paradox advances both the Brandenburger–Keisler and Yablo results. Additionally, the paper constructs a paraconsistent model satisfying the paradoxical (...) statement. (shrink)

The paper argues that the Nash Equilibrium Refinement Programme was less successful than its competitor, the Epistemic Programme. The prime criterion of success is the extent to which the programmes were able to reach the key objective guiding non-cooperative game theory for much of the twentieth century, namely, to develop a complete characterisation of the strategic rationality of economic agents in the form of the ultimate solution concept for any normal form and extensive game. The paper (...) explains this in terms of unjustified degrees of mathematisation in Nash Equilibrium Refinement Programme. While this programme’s mathematical models were often inspired by purely mathematical concerns rather than the economic phenomena they were intended to model, the Epistemic Programme’s models were developed with a keen eye to the role beliefs and desires play in strategic interaction between rational economic agents playing games; that is, their interactive epistemology. The Epistemic Programme succeeded in developing mathematical models formalising aspects of strategic interaction that remained implicit in the Nash Equilibrium Refinement Programme owing to an unjustified degree of mathematisation. As a result, the Epistemic Programme is the more successful theory.Keywords: Epistemic Programme; Game theory; Interactive epistemology; Mathematisation; Nash equilibrium. (shrink)

Contents. Introduction. 1. Preliminaries. 2. Normal Form Games. 3. Extensive Games. 4. Applications of Game Theory. 5. The Methodology of Game Theory. Conclusion. Appendix. Bibliography. Index. Does game theory—the mathematical theory of strategic interaction—provide genuine explanations of human behaviour? Can game theory be used in economic consultancy or other normative contexts? Explaining Games: The Epistemic Programme in Game Theory—the first monograph on the philosophy of game theory—is (...) an attempt to combine insights from epistemic logic and the philosophy of science to investigate the applicability of game theory in such fields as economics, philosophy and strategic consultancy. I prove new mathematical theorems about the beliefs, desires and rationality principles of individual human beings, and explore in detail the logical form of game theory as it is used in explanatory and normative contexts. I argue that game theory reduces to rational choice theory if used as an explanatory device, and that game theory is nonsensical if used as a normative device. A provocative account of the history of game theory reveals that this is not bad news for all of game theory, though. Two central research programmes in game theory tried to find the ultimate characterisation of strategic interaction between rational agents. Yet, while the Nash Equilibrium Refinement Programme has done badly thanks to such research habits as overmathematisation, model-tinkering and introversion, the Epistemic Programme, I argue, has been rather successful in achieving this aim. "The 'epistemic' approach to game theory has emerged over the past twenty-five years. What is this approach? How does it differ from the conventional equilibrium-based approach to game theory? What have been its strengths and weaknesses to date? To find out, read this comprehensive and excellently written account". Adam Brandenburger, J. P. Valles Professor of Business Economics and Strategy, Stern School of Business, New York University "Reading Boudewijn de Bruin's book should be rewarding both for game theorists interested in the conceptual foundations of their discipline and for philosophers who want to learn more about formal analysis of strategic interaction. It provides an in-depth logical study of the currently dominant epistemic approaches to non-cooperative games, with an eye both to the attractions and to the serious challenges facing the Epistemic Programme". Wlodek Rabinowicz, Professor of Practical Philosophy, Department of Philosophy, Lund University . (shrink)

An introduction to the special issue on epistemic logic and the foundations of game theory edited by Michael Bacharach and Philippe Mongin. Contributors are Michael Bacharach, Robert Stalnaker, Salvatore Modica and Aldo Rustichini, Luc Lismont and Philippe Mongin, and Hyun-Song Shin and Timothy Williamson.

Game theory is the systematic study of interdependent rational choice. It should be distinguished from decision theory, the systematic study of individual (practical and epistemic) choice in parametric contexts (i.e., where the agent is choosing or deliberating independently of other agents). Decision theory has several applications to ethics (see Dreier 2004; Mele and Rawlings 2004). Game theory may be used to explain, to predict, and to evaluate human behavior in contexts where the outcome (...) of action depends on what several agents choose to do and where their choices depend on what others choose to do. (See the entry on game theory) Game theory consequently is relevant to ethics, and it is used in moral and political philosophy in a variety of ways. We shall concentrate on the influence and use of game theory in ethics and those parts of political theory involving norms or principles of justice, ignoring questions about political and legal institutions on the one hand and questions about issues dealing with moral virtues on the other. (shrink)

Rational choice theory enjoys unprecedented popularity and influence in the behavioral and social sciences, but it generates intractable problems when applied to socially interactive decisions. In individual decisions, instrumental rationality is defined in terms of expected utility maximization. This becomes problematic in interactive decisions, when individuals have only partial control over the outcomes, because expected utility maximization is undefined in the absence of assumptions about how the other participants will behave. Game theory therefore incorporates not only rationality (...) but also common knowledge assumptions, enabling players to anticipate their co-players' strategies. Under these assumptions, disparate anomalies emerge. Instrumental rationality, conventionally interpreted, fails to explain intuitively obvious features of human interaction, yields predictions starkly at variance with experimental findings, and breaks down completely in certain cases. In particular, focal point selection in pure coordination games is inexplicable, though it is easily achieved in practice; the intuitively compelling payoff-dominance principle lacks rational justification; rationality in social dilemmas is self-defeating; a key solution concept for cooperative coalition games is frequently inapplicable; and rational choice in certain sequential games generates contradictions. In experiments, human players behave more cooperatively and receive higher payoffs than strict rationality would permit. Orthodox conceptions of rationality are evidently internally deficient and inadequate for explaining human interaction. Psychological game theory, based on nonstandard assumptions, is required to solve these problems, and some suggestions along these lines have already been put forward. Key Words: backward induction; Centipede game; common knowledge; cooperation; epistemic reasoning; game theory; payoff dominance; pure coordination game; rational choice theory; social dilemma. (shrink)

This article proposes two interpretations of the concept of belief hierarchies in Bayesian game theory: the behaviorist interpretation and the mentalist interpretation. On the former, belief hierarchies are derived from the players’ preferences over acts. On the latter, they are causal mechanisms that are responsible for the players’ choices and preferences over acts. The claim is that the epistemic program in game theory is potentially confronted with a dilemma regarding which interpretation should be adopted. If (...) the behaviorist interpretation of belief hierarchies is retained, then Bayesian game theory cannot account for the players’ reasoning that leads to the generation of specific belief hierarchies and thus to the implementation of a specific strategy profile in a game. If the mentalist interpretation is retained, then belief hierarchies appear to be unnecessarily and unrealistically complex objects and that as a result they fail to provide reasonable epistemic foundations for various solution concepts. In other words, neither interpretation seems to allow the epistemic program to fulfill all its aims. I suggest however that the mentalist interpretation can be arranged to escape this dilemma. (shrink)

This article proposes two interpretations of the concept of belief hierarchies in Bayesian game theory: the behaviorist interpretation and the mentalist interpretation. On the former, belief hierarchies are derived from the players’ preferences over acts. On the latter, they are causal mechanisms that are responsible for the players’ choices and preferences over acts. The claim is that the epistemic program in game theory is potentially confronted with a dilemma regarding which interpretation should be adopted. If (...) the behaviorist interpretation of belief hierarchies is retained, then Bayesian game theory cannot account for the players’ reasoning that leads to the generation of specific belief hierarchies and thus to the implementation of a specific strategy profile in a game. If the mentalist interpretation is retained, then belief hierarchies appear to be unnecessarily and unrealistically complex objects and that as a result they fail to provide reasonable epistemic foundations for various solution concepts. In other words, neither interpretation seems to allow the epistemic program to fulfill all its aims. I suggest however that the mentalist interpretation can be arranged to escape this dilemma. (shrink)

This collection of papers in epistemic logic is oriented towards applications to game theory and individual decision theory. Most of these papers were presented at the inaugural conference of the LOFT (Logic for the Theory and Games and Decisions) conference series, which took place in 1994 in Marseille. Among the notions dealt with are those of common knowledge and common belief, infinite hierarchies of beliefs and belief spaces, logical omniscience, positive and negative introspection, backward induction (...) and rationalizable equilibria in game theory. (shrink)

Ideology critics believe that many bad social practices persist because of ideology, and that critiquing ideology is an effective way to promote social reform. Skeptics draw on game theory to argue that the persistence of such practices is better explained by collective action problems, and that ideology critique is causally inefficacious. In this paper, I reconcile these camps. I show that while game theory can help us identify contexts where ideology critique makes no difference, it also (...) reveals causal mechanisms by which ideology critique can have a significant effect. I then consider some objections and directions for further research. (shrink)

:Most game-theoretic accounts of institutions reduce institutions to behavioural patterns the players are incentivized to implement. An alternative account linking institutions to rule-following behaviour in a game-theoretic framework is developed on the basis of David Lewis’s and Ludwig Wittgenstein's respective accounts of conventions and language games. Institutions are formalized as epistemic games where the players share some forms of practical reasoning. An institution is a rule-governed game satisfying three conditions: common understanding, minimal awareness and minimal practical (...) rationality. Common understanding has a strong similarity with Ludwig Wittgenstein's concept of lebensform while minimal awareness and minimal practical rationality capture the idea that rule-following is community-based. (shrink)

Recent years have witnessed an increased number of game-theoretic approaches to social norms, which apparently share some common vocabulary and methods. We describe three major approaches of this kind (due to Binmore, Bicchieri and Gintis), before comparing them systematically on five crucial themes: generality of the solution, preference transformation, punishment, epistemic conditions and type of explanation. This allows us to show that these theories are, by and large, less compatible than they seem. We then argue that those three (...) theories struggle to account for three phenomena pertaining to social norms (namely context-dependence, conflicting norms and self-evidence), with which any complete game-theoretic account should in principle be able to deal. (shrink)

The mathematical tools of game theory are frequently used in the social sciences and economic consultancy. But how do they explain social phenomena and support prescriptive judgments? And is the use of game theory really necessary? I analyze the logical form of explanatory and prescriptive game theoretical statements, and argue for two claims: (1) explanatory game theory can and should be reduced to rational choice theory in all cases; and (2) prescriptive (...) class='Hi'>game theory gives bad advice in some cases, is reducible to rational choice theory in other cases, while it makes no sense in yet other cases. (shrink)

IntroductionA quick glance at the opening paragraphs in many of the classic logic textbooks reveals a common view: Logical methods highlight the reasoning patterns of a single agent engaged in some form of mathematical thinking.A sampling from my bookshelf: Shoenfield’s Mathematical Logic: “Logic is the study of reasoning; and mathematical logic is the study of the type of reasoning done by mathematicians”; Enderton’s A Mathematical Introduction of Logic: “Symbolic logic is a mathematical model of deductive thought”; and Chiswell and Hodges (...) Mathematical Logic: “In this course we shall study some ways of proving statements.” However, this traditional view of the “subject matter” of logic is expanding. There is a growing literature using phrases such as “rational interaction” or “information flow” to describe its subject matter while still employing traditional logical methods. The clearest example of this can be found in the work of Johan van Benthem and others on l .. (shrink)

Economic theories of team reasoning build on the assumption that agents can sometimes behave according to beliefs or preferences attributed to a group or a team. In this paper, I propose a different framework to introduce collective intentionality into game theory. I build on John Searle’s account, which makes collective intentionality constitutive of institutional facts. I show that as soon as one accepts that institutions are required to solve indetermination problems in a game, it is necessary to (...) assume a form of collective intentionality that comes from what I call a common understanding of the situation among the players. This common understanding embodies the epistemic requirements for an institution to be a correlated equilibrium in a game. As a consequence, I question recent claims made by some economists according to which game-theoretic accounts of institutions do not need to assume collective intentionality. (shrink)

Traditionally, epistemologists have distinguished between epistemic and pragmatic goals. In so doing, they presume that much of game theory is irrelevant to epistemic enterprises. I will show that this is a mistake. Even if we restrict attention to purely epistemic motivations, members of epistemic groups will face a multitude of strategic choices. I illustrate several contexts where individuals who are concerned solely with the discovery of truth will nonetheless face difficult game theoretic problems. (...) Examples of purely epistemic coordination problems and social dilemmas will be presented. These show that there is a far deeper connection between economics and epistemology than previous appreciated. (shrink)

A combination of epistemic logic and dynamic logic of programs is presented. Although rich enough to formalize some simple game-theoretic scenarios, its axiomatization is problematic as it leads to the paradoxical conclusion that agents are omniscient. A cut-free labelled Gentzen-style proof system is then introduced where knowledge and action, as well as their combinations, are formulated as rules of inference, rather than axioms. This provides a logical framework for reasoning about games in a modular and systematic way, and (...) to give a step-by-step reconstruction of agents omniscience. In particular, its semantic assumptions are made explicit and a possible solution can be found in weakening the properties of the knowledge operator. (shrink)

Open peer commentary on the article “Consciousness as Self-Description in Differences” by Diana Gasparyan. Upshot: The aim of my commentary is to support some of Gasparyan’s ideas and to reformulate them in a more constructive way in terms of both formalized hermeneutical procedures and networks and in the light of game-theory approaches.

is used to give a formalization of Artemov’s knowledge based reasoning approach to game theory, (KBR), [ 4 , 5 ]. Epistemic states of players are represented explicitly and reasoned about formally. We give a detailed analysis of the Centipede game using both proof theoretic and semantic machinery. This helps make the case that PDL + E can be a useful basis for the logical investigation of game theory.

Mathematical game theory has been embraced by a variety of scholars: social scientists, biologists, linguists, and now, increasingly, logicians. This volume illustrates the recent advances of game theory in the field. Logicians benefit from things like game theory's ability to explain informational independence between connectives; meanwhile, game theorists have even begun to benefit from logical epistemic analyses of game states. In concert with such pioneering work, this volume also present surprising developments (...) in classical fields, including first-order logic and set theory. (shrink)

This paper proposes a logical framework for representing static and dynamic properties of different kinds of individual and collective attitudes. A complete axiomatization as well as a decidability result for the logic are given. The logic is applied to game theory by providing a formal analysis of the epistemic conditions of iterated deletion of weakly dominated strategies (IDWDS), or iterated weak dominance for short. The main difference between the analysis of the epistemic conditions of iterated weak (...) dominance given in this paper and other analysis is that we use a semi-qualitative approach to uncertainty based on the notion of plausibility first introduced by Spohn, whereas other analysis are based on a quantitative representation of uncertainty in terms of probabilities. (shrink)

Game theoretic pragmatics is a small but growing part of formal pragmatics, the linguistic subfield studying language use. The general logic of a game theoretic explanation of a pragmatic phenomenon is this: the conversational context is modelled as a game between speaker and hearer; an adequate solution concept then selects the to‐be‐explained behavior in the game model. For such an explanation to be convincing, both components, game model and solution concept, should be formulated and scrutinized (...) as explicitly as possible. The article demonstrates this by a concise overview of both evolutionary and non‐evolutionary approaches to game theoretic pragmatics, arguing for the use of agent‐based micro‐dynamics within evolutionary, and for the use of epistemic game theory within non‐evolutionary approaches. (shrink)

Locke rejected anarchism. Locke defended the universal necessity of political governments on the grounds that the state of nature will occasionally generate the inconveniences of war. The standard interpretation of Locke identifies three main causes of war in the state of nature: the lack of a common judge, moral disagreement over the law of nature, and self-love. In this paper, I argue that the combination of these three factors does not guarantee that war will occur in every plausible scenarios of (...) Locke’s state of nature. Instead, in order for war to occur at least sometimes in every plausible scenario of Locke’s state of nature, there has to be some sort of epistemic deficit. In this paper, I show via the tools of modern game theory, how Locke’s state of nature may occasionally generate war by two kinds of epistemic problems implied by Locke’s own epistemology: disagreements in subjective probabilities, and uncertainty in other people’s moral motivation to use force to enforce the law of nature. The fact that war occurs primarily because of such epistemic problems suggests a role for a very limited form of government; namely, the ultra-ultra-minimal state, whose role is confined to solving such epistemic problems. (shrink)

Bluffing is essentially nothing more than a type of deception. But, despite its morally questionable foundation, it is not only permissible in certain contexts, but sometimes encouraged and/or required (e.g., playing poker). Yet, the question remains as to whether it is permissible to bluff in other contexts – particularly everyday situations. In this paper, I look at László Mérő’s argument – one based in game theory and Kantian ethics – to the end that bluffing is morally permissible in (...) everyday contexts. I argue that Mérő’s argument is mistaken on two grounds. First, it includes an epistemic feature (i.e., knowledge that bluffing is part of the game) that is lacking in everyday contexts. Second, even if we add a proviso to solve this epistemic problem, the resulting strategies fail to guarantee an equilibrium state. Thus, I hope to show that Mérő’s attempt to justify the use of bluffing in everyday contexts fails. (shrink)

I argue that game theoretic explanations of human actions make implausible epistemological assumptions. A logical analysis of game theoretic explanations shows that they do not conform to the belief-desire framework of action explanation. Epistemic characterization theorems (specifying sufficient conditions for game theoretic solution concepts to obtain) are argued to be the canonical way to make game theory conform to that framework. The belief formation practices implicit in epistemic characterization theorems, however, disregard all information (...) about players except what can be found in the game itself. And such a practice of belief formation is, I show, implausible. (shrink)

The ancient puzzle of the Liar was shown by Tarski to be a genuine paradox or antinomy. I show, analogously, that certain puzzles of contemporary game theory are genuinely paradoxical, i.e., certain very plausible principles of rationality, which are in fact presupposed by game theorists, are inconsistent as naively formulated. ;I use Godel theory to construct three versions of this new paradox, in which the role of 'true' in the Liar paradox is played, respectively, by 'provable', (...) 'self-evident', and 'justifiable'. I also construct in modal operator logic a paradox involving reflexive empirical reasoning. Unlike the paradox of the Liar, the paradox of reflexive reasoning does not depend on self-reference. ;I consider various solutions to the Liar paradox and evaluate how well these solutions cope with the paradox of reflexive reasoning. I then formalize the solution to the paradoxes which I favor: the indexical-hierarchical approach, first sketched out by Charles Parsons and Tyler Burge. In this solution, occurrences of the predicate 'true' in sentence-tokens are contextually relativized to levels of a hierarchy. Drawing also on some brief remarks of Bertrand Russell and Charles Parsons, I develop an account of the kind of schematic generality needed for this theory to be statable. ;Finally, I demonstrate that the principles shown to be paradoxical are in fact presupposed by contemporary game theorists in their reliance on the notion of common knowledge or, more precisely, mutual belief. I create novel analyses of and corresponding solutions to several recalcitrant puzzles within game theory, including the "chain-store paradox". (shrink)

I examine how particular social arrangements and incentive structures encourage the honest reporting of experimental results and minimize fraudulent scientific work. In particular I investigate how epistemic communities can achieve this goal by promoting members to police the community. Using some basic tools from game theory, I explore a simple model in which scientists both conduct research and have the option of investigating the findings of their peers. I find that this system of peer policing can in (...) many cases ensure high levels of honesty. (shrink)

Communication facilitates coordination, but coordination might fail if there's too much uncertainty. I discuss a scenario in which vagueness-driven uncertainty undermines the possibility of publicly sharing a belief. I then show that asserting an epistemic modal sentence, 'Might p', can reveal the speaker's uncertainty, and that this may improve the chances of coordination despite the lack of a common epistemic ground. This provides a game-theoretic rationale for epistemic modality. The account draws on a standard relational semantics (...) for epistemic modality, Stalnaker's theory of assertion as informative update, and a Bayesian framework for reasoning under uncertainty. (shrink)

It is plausible that there are epistemic reasons bearing on a distinctively epistemic standard of correctness for belief. It is also plausible that there are a range of practical reasons bearing on what to believe. These theses are often thought to be in tension with each other. Most significantly for our purposes, it is obscure how epistemic reasons and practical reasons might interact in the explanation of what one ought to believe. We draw an analogy with a (...) similar distinction between types of reasons for actions in the context of activities. The analogy motivates a two-level account of the structure of normativity that explains the interaction of correctness-based and other reasons. This account relies upon a distinction between normative reasons and authoritatively normative reasons. Only the latter play the reasons role in explaining what state one ought to be in. All and only practical reasons are authoritative reasons. Hence, in one important sense, all reasons for belief are practical reasons. But this account also preserves the autonomy and importance of epistemic reasons. Given the importance of having true beliefs about the world, our epistemic standard typically plays a key role in many cases in explaining what we ought to believe. In addition to reconciling (versions of) evidentialism and pragmatism, this two-level account has implications for a range of important debates in normative theory, including the interaction of right and wrong reasons for actions and other attitudes, the significance of reasons in understanding normativity and authoritative normativity, the distinction between ‘formal’ and ‘substantive’ normativity, and whether there is a unified source of authoritative normativity. (shrink)

We develop a logical system that captures two different interpretations of what extensive games model, and we apply this to a long-standing debate in game theory between those who defend the claim that common knowledge of rationality leads to backward induction or subgame perfect (Nash) equilibria and those who reject this claim. We show that a defense of the claim à la Aumann (1995) rests on a conception of extensive game playing as a one-shot event in combination (...) with a principle of rationality that is incompatible with it, while a rejection of the claim à la Reny (1988) assumes a temporally extended, many-moment interpretation of extensive games in combination with implausible belief revision policies. In addition, the logical system provides an original inductive and implicit axiomatization of rationality in extensive games based on relations of dominance rather than the usual direct axiomatization of rationality as maximization of expected utility. (shrink)

It seems an undisputed, fundamental principle that solid philosophical and scientific theories require sufficient reason to support them. Philosophically sufficient reasoning is impossible, however, if it is not backed with strong, undisputed, first principles. This seemingly obvious claim is, nevertheless, not without problems: First, what are the undisputed first principles? What are the basic---logical/epistemological/ontological---differences between undisputed first principles and other ones? What can ensure the special status of these first principles? ;Adequate and well-reasoned answers to these questions seem to be (...) essential to establish firm grounds for any philosophical/scientific investigation. But such adequate reasoning seems impossible, since reasoning itself is the object of our investigation. Alternatively, traditional logic cannot offer us any sufficient solution as logic itself relies on undisputed, first principles. ;The failure of traditional logic to justify its own first principles does not necessarily mean that logic itself requires a leap of faith. Instead of accepting our first principles without any dispute, we should find a way to dispute them and to select those which resist all well-founded objections. The central argument of my thesis is that a dialectical theory of philosophical games is able to offer us such a way. ;In the first chapter I present an epistemic meta-theory of philosophical games. I argue that games can replace formal arguments and their introduction into philosophical discourse enlarges and re-innovates our philosophical language with such new terms as winning and losing a game, game rules and movements, etc. Using these terms several basic concepts such as truth and falsity, presupposition, and the burden of proof can be creatively reinterpreted. ;The most fundamental epistemic principles are the topics of the first part. The second part considers circular arguments ; the third focuses on conceivability arguments and the last part discusses the famous skeptical argument involving the skeptic's scenario of brains in a vat. The final chapter summarizes the advantages and shortcomings of the game-theoretical approach. (shrink)

Since Hintikka’s epistemic logic, the logic of knowledge, has been a subject of research in philosophy, computer science, artificial intelligence and game theory. This paper presents a framework of dynamic epistemic logic capable of investigating interactive voting decisions in liquid democracy.

The field of epistemic logic developed into an interdisciplinary area focused on explicating epistemic issues in, for example, artificial intelligence, computer security, game theory, economics, multiagent systems and the social sciences. Inspired, in part, by issues in these different ‘application’ areas, in this paper I propose an epistemic logic T for metadata extracted from scientific papers on COVID-19. More in details, I introduce a structure S to syntactically and semantically modelling metadata extracted with systems for (...) extracting structured metadata from scientific articles in a born-digital form. These systems will be considered, in the logical model created, as ‘Metadata extraction agents’. In this case MEA taken into consideration are CERMINE and TeamBeam. In an increasingly data-driven world, modelling data or metadata means to help systematise existing information and support the research community in building solutions to the COVID-19 pandemic. (shrink)

Scientificity is essentially methodology. The use of information technology as methodological instruments in science has been increasing for decades, this raises the question: Does this transform science? This question is the subject of the Special Issue in Minds and Machines “The epistemological significance of methods in computer simulation and machine learning”. We show that there is a technological change in this area that has three methodological and epistemic consequences: methodological opacity, reproducibility issues, and altered forms of justification.

In this paper I study intentions of the form, that is, intentions with a we-content, and their role in interpersonal coordination. I focus on the notion of epistemic support for such intentions. Using tools from epistemic game theory and epistemic logic, I cast doubt on whether such support guarantees the other agents' conditional mediation in the achievement of such intentions, something that appears important if intentions with a we-content are to count as genuine intentions. I (...) then formulate a stronger version of epistemic support, one that does indeed ensure the required mediation, but I then argue that it rests on excessively strong informational conditions. In view of this I provide an alternative set of conditions that are jointly sufficient for coordination in games, and I argue that these conditions constitute a plausible alternative to the proposed notion of epistemic support. (shrink)

In this paper we study substantive assumptions in social interaction. By substantive assumptions we mean contingent assumptions about what the players know and believe about each other’s choices and information. We first explain why substantive assumptions are fundamental for the analysis of games and, more generally, social interaction. Then we show that they can be compared formally, and that there exist contexts where no substantive assumptions are being made. Finally we show that the questions raised in this paper are related (...) to a number of issues concerning “large” structures in epistemic game theory. (shrink)

We propose strategic games wherein the strategies consist of players asking each other questions and answering those questions. We study simplifications of such games wherein two players simultaneously ask each other a question that the opponent is then obliged to answer. The motivation for our research is to model conversation including the dynamics of questions and answers, to provide new links between game theory and dynamic logics of information, and to exploit the dynamic/strategic structure that, we think, lies (...) implicitly inside epistemic models for epistemic languages, and to make that structure an explicit subject of logical study. Our main contributions are: the notion of a two-person question-answer game with information goals, the existence and computation of equilibria for these games, the correspondence with Bayesian games and their equilibria, and a connection between logic and game theory namely the existence of equilibria for positive goal formulae. (shrink)

We argue that a Bayesian explanation of strategic choices in games requires introducing a psychological theory of belief formation. We highlight that beliefs in epistemic game theory are derived from the actual choice of the players, and cannot therefore explain why Bayesian rational players should play the strategy they actually chose. We introduce the players’ capacity of mindreading in a game theoretical framework with the simulation theory, and characterise the beliefs that Bayes rational players (...) could endogenously form in games. We show in particular that those beliefs need not be ratifiable, and therefore that rational players can form action-dependent beliefs. (shrink)

Understanding the flow of knowledge in multi-agent protocols is essential when proving the correctness or security of such protocols. Current logical approaches, often based on model checking, are well suited for modeling knowledge in systems where agents do not act strategically. Things become more complicated in strategic settings. In this paper we show that such situations can be understood as a special type of game – a knowledge condition game – in which a coalition “wins” if it is (...) able to bring about some epistemic condition. This paper summarizes some results relating to these games. Two proofs are presented for the computational complexity of deciding whether a coalition can win a knowledge condition game with and without opponents (Σ2P-complete and NP-complete respectively). We also consider a variant of knowledge condition games in which agents do not know which strategies are played, and prove that under this assumption, the presence of opponents does not affect the complexity. The decision problem without opponents is still NP-complete, but requires a different proof. (shrink)