This article contributes to the growing scholarship on the topic of assurance services for sustainability reports. We first synthetically illustrate the main international standards for the implementation of assurance services regarding the subject documents. The second part of our article is an empirical analysis of reports drawn up on the basis of the current Global Reporting Initiative 2006 guidelines, and looks at how effectively these standards have been implemented, analyzing the different typologies of assurance statement.
The main purpose of this exploratory analysis is to understand whether, based on evidence gathered from international best practices selected among corporations which adopt the Global Reporting Initiative guidelines in sustainability reporting (SR), stakeholders are significantly consulted and involved—as international literature would indicate—by assurance providers, during assurance processes of SR. We aim at verifying if this practice—known as stakeholder assurance—is in fact widespread in SR assurance by carrying out empirical research, through content analysis, into a sample of 161 assurance statements (...) of international corporations, in order to test characteristics of any stakeholder assurance implemented. (shrink)
In this paper we show that it is possible to eliminate the converse operator from the propositional dynamic logic CPDL (Converse PDL), without compromising the soundness and completeness of inference for it. Specifically we present an encoding of CPDL formulae into PDL that eliminates the converse programs from a CPDL formula, but adds enough information so as not to destroy its original meaning with respect to satisfiability, validity, and logical implication. Notably, the resulting PDL formula is polynomially related to the (...) original one. This fact allows one to build inference procedures for CPDL, by encoding CPDL formulae into PDL, and then running an inference procedure for PDL. (shrink)
An important part of Aristotelianism has revolved around the different interpretations given to the famous fifth chapter of Aristotle’s De Anima lll. The brevity with which he spoke about an intellectual agent principle described as divine and everlasting has led to a lengthy debate between those who argue that this principle is part of the individual soul and those who think that it must be placed outside the individual intellectual powers. Among the latter, the interpretation of the Renaissance Aristotelian (...) class='Hi'>Giacomo Zabarella (1533-1589), a great expert on classical Greek and Aristotle’s works, is still one of the most influential. (shrink)
In introducing his argument - which resumes and develops the philosophical analysis of the phenomenon of globalisation advanced in his book Westward Passage (forthcoming from Verso, London-New York) - Giacomo Marramao takes the film Babel, by the Mexican director Alejandro Gonzáles Iñárritu, as the point of departure for his discussion: the film depicts the globalised world as a complex space at once interdependent and differentiated in character, constituted like a mosaic, composed of a multiplicity of "asynchronic" ways and forms (...) of life which are brought together by the manifold flux of events that traverse them. This cinematographic depiction perfectly captures the disconcerting bi-logic of globalisation: the logic through which the mix of the global market and of digital technologies operating in "real time" generates an increasing diaspora of identities. The Babel of our contemporary world thereby reveals itself as a kind of planetary extension of the world of Kakania described by Robert Musil: a cacophonous compendium of proliferating and mutually untranslatable languages. In order to conceptualise, and produce a suitably fluid and dynamic account, of this new "world picture," we must not only dissolve the spurious dilemma between universalism and relativism, but move beyond the current impasse encouraged by a normative political philosophy which tends to reify "cultural identities" and "struggles for recognition" by treating these as givens rather than as problems. The philosophical approach pursued in the following discussion attempts to liberate the concept of "the universal" - despite the etymology of the word - from the logic of the reductio ad unum, and apply it instead to the realm of multiplicity and difference. Developing a double phenomenology of the increasingly homogenising phenomenon of the market on the one hand and of the internally conflicted pandemic of identitarian and communitarian approaches on the other, the author indicates a variety of universalising tendencies whose potential can only fully be evaluated in the context of a new theory and practice of translation. Marramao's proposal for a universalism of difference is predicated on the failure of the two principal models of "democratic" inclusion that have previously been attempted in the West: the republican or assimilationist model (that of a Republique founded upon what could be called a universalism of indifference) and the "strong" multiculturalism model (the so-called Londonistan model that derives from a mosaic of differences that also provides fertile ground for the growth of fundamentalist ideas). But to advance beyond the antagonistic complicity generated by this dilemma calls for a re-enchantment of the political: the only way in which we may be able to read the prognostic signs of our present. (shrink)
Emotions and actions are powerfully contagious; when we see someone laugh, cry, show disgust, or experience pain, in some sense, we share that emotion. When we see someone in distress, we share that distress. When we see a great actor, musician or sportsperson perform at the peak of their abilities, it can feel like we are experiencing just something of what they are experiencing. Yet only recently, with the discover of mirror neurons, has it become clear just how this powerful (...) sharing of experience is realised within the human brain. This book provides, for the first time, a systematic overview of mirror neurons, written by the man who first discovered them. -/- In the early 1990's Giacomo Rizzolatti and his co-workers at the University of Parma discovered that some neurons had a surprising property. They responded not only when a subject performed a given action, but also when the subject oberved someone else performing that same action. These results had a deep impact on cognitive neuroscience, leading the neuroscientist VS Ramachandran to predict that 'mirror neurons would do for psychology what DNA did for biology'. The unexpected properties of these neurons have not only attracted the attention of neuroscientists. Many sociologists, anthropologists, and even artists have been fascinated by mirror neurons. The director and playwright Peter Brook stated that mirror neurons throw new light on the mysterious link that is created each time actors take the stage and face their audience - the sight of a great actor performing activates in the brain of the observer the very same areas that are active in the performer - including both their actions and their emotions. -/- Written in a highly accessible style, that conveys something of the excitement of this groundbreaking theory, Mirrors in the brain is the definitive account of one the major scientific discoveries of the past 50 years. (shrink)
Truthout, August 5, 2011 "It is a common theme" that the United States, which "only a few years ago was hailed to stride the world as a colossus with unparalleled power and unmatched appeal is in decline, ominously facing the prospect of its final decay," Giacomo Chiozza writes in the current Political Science Quarterly.
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)
This paper investigates the epistemic assumptions that David Lewis makes in his account of social conventions. In particular, I focus on the assumption that the agents have common knowledge of the convention to which they are parties. While evolutionary analyses show that the common knowledge assumption is unnecessary in certain classes of games, Lewis’ original account (and, more recently, Cubitt and Sugden’s reconstruction) stresses the importance of including it in the definition of convention. I discuss arguments pro et contra to (...) argue that, although the assumption might be relevant to a descriptively adequate account of social convention, it is not required for its rational reconstruction. I then point out that Lewis’ account, properly speaking, is of common reason to believe, rather than of common knowledge, and argue that, in order to formalize aptly the distinction between reason to believe and belief, standard formal epistemic models need to be supplemented with so-called awareness structures. Finally, I stress that the notion of knowledge implicit in Lewis’ text involves interesting elements that cannot be captured in the standard propositional formalizations, but need the full expressive force of quantified epistemic logic. (shrink)
Theorizing in ecology and evolution often proceeds via the construction of multiple idealized models. To determine whether a theoretical result actually depends on core features of the models and is not an artifact of simplifying assumptions, theorists have developed the technique of robustness analysis, the examination of multiple models looking for common predictions. A striking example of robustness analysis in ecology is the discovery of the Volterra Principle, which describes the effect of general biocides in predator-prey systems. This paper details (...) the discovery of the Volterra Principle and the demonstration of its robustness. It considers the classical ecology literature on robustness and introduces two individual-based models of predation, which are used to further analyze the Volterra Principle. The paper also introduces a distinction between parameter robustness, structural robustness, and representational robustness, and demonstrates that the Volterra Principle exhibits all three kinds of robustness. *Received September 2006; revised May 2007. ‡Earlier versions of this paper were presented at the Australasian Association of Philosophy, the London School of Economics, and the University of Bristol. The authors wish to thank those audiences as well as Patrick Forber, Ken Waters, Deena Skolnick Weisberg, Uri Wilensky, and Bill Wimsatt for many helpful comments. Special thanks to Giacomo Sillari for his assistance in translating Volterra's original paper and his insightful thoughts about Volterra's aims and methods. Some of the research in this paper was supported by NSF grant SES-0620887 to MW. †To contact the authors, please write to: Michael Weisberg, Department of Philosophy, University of Pennsylvania, 433 Logan Hall, Philadelphia, PA 19104; e-mail: weisberg@phil.upenn.edu; Kenneth Reisman, Pluribo, Inc., 100 Park Avenue, Suite 1600, New York, NY 10017; e-mail: ken@pluribo.com. (shrink)
Spinoza speculated on how ethics could emerge from biology and psychology rather than disrupt them and recent evidence suggests he might have gotten it right. His radical deconstruction and reconstruction of ethics is supported by a number of avenues of research in the cognitive and neurosciences. This paper gathers together and presents a composite picture of recent research that supports Spinoza’s theory of the emotions and of the natural origins of ethics. It enumerates twelve naturalist claims of Spinoza that now (...) seem to be supported by substantial evidence from the neurosciences and recent cognitive science. I focus on the evidence provided by Lakoff and Johnson in their summary of recent cognitive science in Philosophy in the Flesh: The Embodied Mind and Its Challenge to Western Thought (1999); by Antonio Damasio in his assessment of the state of affective neuroscience in Descartes’ Error (1994) and in The Feeling of What Happens (1999) (with passing references to his recent Looking for Spinoza (2003); and by Giacomo Rizzolatti, Vittorio Gallese and their colleagues in the neural basis of emotional contagion and resonance, i.e., the neural basis of primitive sociality and intersubjectivity, that bear out Spinoza’s account of social psychology as rooted in the mechanism he called attention to and identified as affective imitation. (shrink)
The principle of belief persistence, or conservativity principle, states that ’\Nhen changing beliefs in response to new evidence, you should continue to believe as many of the old beliefs as possible' (Harman, 1986, p. 46). In particular, this means that if an individual gets new information, she has to accommodate it in her new belief set (the set of propositions she believes), and, if the new information is not inconsistent with the old belief set, then (1) the individual has to (...) maintain all the beliefs she previously had and (2) the change should be minimal in the sense that every proposition in the new belief set must be deducible from the union of the old belief set and the new information (see, e.g., Gardenfors, 1988; Stalnaker, 1984). We focus on this minimal notion of belief persistence and characterize it both semantically and syntactically. A ’possible world' semantic formalization of the principle easily comes to mind. The set of all the propositions that the individual believes corresponds to the set of states of the world that she considers possible and is a subset of the set of states that are not ruled out by the individual's information (or knowledge). It is required that, if the individual considers a state possible and her new information does not exclude this state, then she continue to consider it possible. Furthermore, if the individual regards a particular state as impossible, then she should continue to regard it as impossible unless her new information excludes all the states that she previously regarded as possible. This is closely related to the.. (shrink)
The theory of belief revision deals with (rational) changes in beliefs in response to new information. In the literature a distinction has been drawn between belief revision and belief update (see [6]). The former deals with situations where the objective facts describing the world do not change (so that only the beliefs of the agent change over time), while the letter allows for situations where both the facts and the doxastic state of the agent change over time. We focus on (...) belief revision and propose a temporal framework that allows for iterated revision. We model the notion of “minimal” or “conservative” belief revision by considering logics of increasing strength. We move from one logic to the next by adding one or more axioms and show that the corresponding logic captures more stringent notions of minimal belief revision. The strongest logic that we propose provides a full axiomatization of the well-known AGM theory of belief revision. (shrink)
Two views of game theory are discussed: (1) game theory as a description of the behavior of rational individuals who recognize each other’s rationality and reasoning abilities, and (2) game theory as an internally consistent recommendation to individuals on how to act in interactive situations. It is shown that the same mathematical tool, namely modal logic, can be used to explicitly model both views.
The issue of biotechnology has been chosen in the MIRRORS project in order to analyze the sometimes uneasy relationship between science and society. After analyzing the situation of biotechnology regarding the GMO debate in Spain, France and Italy during a previous MIRRORS Workshop (This MIRRORS Workshop is entitled European Policies and Knowledge Society , held in Catania on December 15th 2008, during the which the undersigned, Anna Benedetta Francese and Cinzia Rizza discussed three papers about this topic [see the MIRRORS (...) website www.mirrors-project.it ]), in this essay I have tried to tackle the relationship science–society , focalizing my attention on the epistemological and methodological problems behind the biotechnology debate that are often not clearly expressed, remaining mainly tacitly presupposed. I will take as a starting point some questions about the role of science in society and about the way science is used by policy makers in decision-making processes. These questions are fundamental in order to analyze (and possibly to propose salvation strategies) the existing problems of the relationship between science and society which has assumed, especially nowadays, more conflictual aspects. Our Research Team firmly holds that it is not possible to tackle this topic without an in-depth discussion of the most significant epistemological questions regarding research, discussions, and methods of biotechnology. (shrink)
We establish a correspondence between the rationalizability of choice studied in the revealed preference literature and the notion of minimal belief revision captured by the AGM postulates. A choice frame consists of a set of alternatives , a collection E of subsets of (representing possible choice sets) and a function f : E ! 2 (representing choices made). A choice frame is rationalizable if there exists a total pre-order R on..
Spinoza speculated on how ethics could emerge from biology and psychology rather than disrupt them and recent evidence suggests he might have gotten it right. His radical deconstruction and reconstruction of ethics is supported by a number of avenues of research in the cognitive and neurosciences. This paper gathers together and presents a composite picture of recent research that supports Spinoza’s theory of the emotions and of the natural origins of ethics. It enumerates twelve naturalist claims of Spinoza that now (...) seem to be supported by substantial evidence from the neurosciences and recent cognitive science. I focus on the evidence provided by Lakoff and Johnson in their summary of recent cognitive science in Philosophy in the Flesh: The Embodied Mind and Its Challenge to Western Thought (1999); by Antonio Damasio in his assessment of the state of affective neuroscience in Descartes’ Error (1994) and in The Feeling of What Happens (1999) (with passing references to his recent Looking for Spinoza (2003); and by Giacomo Rizzolatti, Vittorio Gallese and their colleagues in the neural basis of emotional contagion and resonance, i.e., the neural basis of primitive sociality and intersubjectivity, that bear out Spinoza’s account of social psychology as rooted in the mechanism he called attention to and identified as affective imitation. (shrink)
Two notions of memory are studied both syntactically and semantically: memory of past beliefs and memory of past actions. The analysis is carried out in a basic temporal logic framework enriched with beliefs and actions.
The evolutionary continuity between the prespeech functions of premotor cortex and its new linguistic functions, the main thesis of MacNeilage's target article, is confirmed by the recent discovery of “mirror” neurons in monkeys and a corresponding action-observation/action-execution matching system in humans. Physiological data (and other considerations) appear to indicate, however, that brachiomanual gestures played a greater role in language evolution than MacNeilage would like to admit.
Recent attempts to define and support realism in semantics seem to acknowledge, as the only defence from skeptical attacks to the notion of meaning, a flat acceptance of the existence of representational relations between language and things in the world. In this paper I reconsider part of the mistrust about the normative character of meaning, in order to show that some of the worries urging the realists to cling to representationalism actually rest on misconceptions. To the contrary, I suggest that (...) normativity is the main strength of a stable realist stance in semantics. Support to this suggestion comes from the reanalysis of some oft-ignored Sellarsian themes. (shrink)
We propose a modal logic based on three operators, representing intial beliefs, information and revised beliefs. Three simple axioms are used to provide a sound and complete axiomatization of the qualitative part of Bayes’ rule. Some theorems of this logic are derived concerning the interaction between current beliefs and future beliefs. Information flows and iterated revision are also discussed.
The logic of common belief does not always re‡ect that of individual beliefs. In particular, even when the individual belief operators satisfy the KD45 logic, the common belief operator may fail to satisfy axiom 5. That is, it can happen that neither is A commonly believed nor is it common belief that A is not commonly believed. We identify the intersubjective restrictions on individual beliefs that are incorporated in axiom 5 for common belief.
The notion of perfect recall in extensive games was introduced by Kuhn (1953), who interpreted it as "equivalent to the assertion that each player is allowed by the rules of the game to remember everything he knew at previous moves and all of his choices at those moves''. We provide a characterization and axiomatization of perfect recall based on two notions of memory: (1) memory of past knowledge and (2) memory of past actions.
In the present article we discuss the relevance of the mirror mechanism for our sense of self and our sense of others. We argue that, by providing us with an understanding from the inside of actions, the mirror mechanism radically challenges the traditional view of the self and of the others. Indeed, this mechanism not only reveals the common ground on the basis of which we become aware of ourselves as selves distinct from other selves, but also sheds new light (...) on the content of our self and other experience, showing that we primarily experience ourselves and the others in terms of our own and of their motor possibilities respectively. -/- . (shrink)
We consider strategic-form games with ordinal payoffs and provide a syntactic analysis of common belief/knowledge of rationality, which we define axiomatically. Two axioms are considered. The first says that a player is irrational if she chooses a particular strategy while believing that another strategy is better. We show that common belief of this weak notion of rationality characterizes the iterated deletion of pure strategies that are strictly dominated by pure strategies. The second axiom says that a player is irrational if (...) she chooses a particular strategy while believing that a different strategy is at least as good and she considers it possible that this alternative strategy is actually better than the chosen one. We show that common knowledge of this stronger notion of rationality characterizes the restriction to pure strategies of the iterated deletion procedure introduced by Stalnaker (1994). Frame characterization results are also provided. (shrink)
In her book Rationality and coordination (Cambridge University Press, 1994) Cristina Bicchieri brings together (and adds to) her own contributions to game theory and the philosophy of economics published in various journals in the period 1987-1992. The book, however, is not a collection of separate articles but rather a homogeneous unit organized around some central themes in the foundations of non-cooperative game theory. Bicchieri’s exposition is admirably clear and well organized. Somebody with a good knowledge of game theory would probably (...) benefit mainly from reading the second part of Chapter 3 (from Section 3.6 onward) and Chapter 4. On the other hand, those who have had little exposure to game theory, would certainly benefit from reading the entire book. I shall begin with an overview of the content of the book and then offer some critical comments on what I consider to be the most important part of it. (shrink)
The Common Prior Assumption (CPA) is central to the economics of information and the foundations of game theory. Recent contributions (Dekel and Gul, 1997, Gul, 1996, Lipman, 1995) have questioned its meaningfulness in situations of incomplete information where there is no ex ante stage and the primitives of the model are the individuals’ belief hierarchies. We address this conceptual issue by providing characterizations of two local versions of the CPA which are in terms of the primitives and, therefore, do not (...) involve a counterfactual and problematic ex ante stage. The characterizations involve three notions: Comprehensive Agreement, no error of beliefs and common belief in no error. Comprehensive Agreement is defined as the absence of “agreement to disagree” about any aspect of beliefs; it is a generalization of Aumann’s (1976) notion of agreement. The entire analysis is carried out locally, that is, with reference to the “true state” (which represents the actual profile of belief hierarchies) and does not rely on the Truth Axiom for individual beliefs. (shrink)
Two questions are examined within a model of vertical differentiation. The first is whether cost-reducing innovations are more likely to be observed in regimes of more intense or less intense competition. Following Delbono and Denicolo (1990) and Bester and Petrakis (1993) we compare two identical industries that differ only in the regime of competition: Bertrand versus Cournot. Since Cournot competition leads to lower output and higher prices, it can be thought of as a regime of less intense competition. We find (...) that the increase in profits associated with any given cost reduction is higher in the case of Cournot competition than in the case of Bertrand competition. Thus there are cost-reducing innovations that would be pursued under Cournot competition but not under Bertrand competition. (shrink)
A poetic for histories -- Sharks that walk on the land -- The face of battle : Valparaiso, 1814 -- The theatricality of history making and the paradoxes of acting -- Possessing Tahiti -- Hollywood makes history -- Inventing others -- Songlines and seaways -- Anzac day -- School at war -- Soliloquy in San Giacomo.
The temporal updating of an agent’s beliefs in response to a flow of information is modeled in a simple modal logic that, for every date t, contains a normal belief operator B t and a non-normal information operator I t which is analogous to the ‘only knowing’ operator discussed in the computer science literature. Soundness and completeness of the logic are proved and the relationship between the proposed logic, the AGM theory of belief revision and the notion of plausibility is (...) discussed. (shrink)
Since Lewis’s (1969) and Aumann’s (1976) pioneering contributions, the concepts of common knowledge and common belief have been discussed extensively in the literature, both syntactically and semantically1. At the individual level the difference between knowledge and belief is usually identified with the presence or absence of the Truth Axiom ( iA → A), which is interpreted as ”if individual i believes that A, then A is true”. In such a case the individual is often said to know that A (thus (...) it is possible for an individual to believe a false proposition but she cannot know a false proposition). Going to the interpersonal level, the literature then distinguishes between common knowledge and common belief on the basis of whether or not the Truth Axiom is postulated at the individual level. However, while at the individual level the Truth Axiom captures merely a relationship between the individuals’ beliefs and the external world, at the interpersonal level it has very strong implications. For example, the following is a consequence of the Truth Axiom: i jA → iA, that is, if individual i believes that individual j believes that A, then individual i herself believes that A. Thus, in contrast to other axioms, the Truth Axiom does not merely reflect individual agents’ “logic of belief”. (The reason why the Truth Axiom is much stronger in an interpersonal context than appears at first glance is that it amounts to assuming that agreement of any individual’s belief with the truth is common knowledge). Given its logical force, it is not surprising to find that it has strong implications for the logic of common knowledge. In particular, if each individual’s beliefs satisfy the strongest logic of knowledge (namely S5 or KT5), the associated common knowledge operator satisfies this logic too. Such is not the case for belief: bereft of the Truth Axiom, even the strongest logic for individual belief (KD45) is insufficient to ensure the satisfaction of the “Negative Introspection” axiom for common belief: ¬ ∗A → ∗¬ ∗A (where ∗ denotes the common belief operator).. (shrink)
The logical foundations of game-theoretic solution concepts have so far been explored within the con¯nes of epistemic logic. In this paper we turn to a di®erent branch of modal logic, namely temporal logic, and propose to view the solution of a game as a complete prediction about future play. The branching time framework is extended by adding agents and by de¯ning the notion of prediction. A syntactic characterization of backward induction in terms of the property of internal consistency of prediction (...) is given. (shrink)
An information completion of an extensive game is obtained by extending the information partition of every player from the set of her decision nodes to the set of all nodes. The extended partition satisfies Memory of Past Knowledge (MPK) if at any node a player remembers what she knew at earlier nodes. It is shown that MPK can be satisfied in a game if and only if the game is von Neumann (vN) and satisfies memory at decision nodes (the restriction (...) of MPK to a player's own decision nodes). A game is vN if any two decision nodes that belong to the same information set of a player have the same number of predecessors. By providing an axiom for MPK we also obtain a syntactic characterization of the said class of vN games. (shrink)
Introducing Applied Ethics Edited by Brenda Almond, Blackwell, 1995. Pp. 375. ISBN 0-631-19389-8. 45.00 (hbk), 14.99 (pbk). Environmental Ethics Edited by Robert Elliot, Oxford University Press, 1995. Pp. 255. ISBN 9-19-875144-3. 9.95 (pbk) Medicine and Moral Reasoning Edited by K.W.M. Fulford, Grant Gillett and Janet Martin Soskice Cambridge University Press, 1994. Pp. 207. ISBN 0-521-45325-9 37.50 (hbk), 12.95 (pbk). Enlightenment and Religion. Rational Dissent in Eighteenth-century Britain Edited by Knud Haakonssen, Cambridge University Press, 1996. Pp. xii + 348. ISBN 0-521-56060-8. (...) 40.00. Dialettica, Arte e Societ : Saggio su Theodor W. Adorno By Giacomo Rinaldi, Quattroventi, Urbino, 1994. Pp. 205. L. 30,000. Relevance: Communication and Cognition, new revised edition, By Dan Sperber and Deirdre Wilson, Blackwell, 1995. Pp. 326. ISBN 0-631-19878-4. 15.99. Autobiographical Reflections By Eric Voegelin (Edited, with Introduction, by Ellis Sandoz), Louisiana State University Press, 1996. Pp. 131. ISBN 0807120766 $10.95. (shrink)
Within the context of extensive-form (or dynamic) games, we use choice frames to represent the initial beliefs of a player as well as her disposition to change those beliefs when she learns that an information set of hers has been reached. As shown in [5], in order for the revision operation to be consistent with the AGM postulates [1], the player’s choice frame must be rationalizable in terms of a total pre-order on the set of histories. We consider four properties (...) of choice frames and show that, together with the hypothesis of a common prior, are necessary and sufficient for the existence of a plausibility order that rationalizes the epistemic state (that is, initial beliefs and disposition to revise those beliefs) of all the players. The plausibility order satisfies the properties introduced in [6] as part of a new definition of perfect Bayesian equilibrium for dynamic games. Thus the present paper provides epistemic foundations for that solution concept. (shrink)
We study belief change in the branching-time structures introduced in Bonanno (Artif Intell 171:144–160, 2007 ). First, we identify a property of branching-time frames that is equivalent (when the set of states is finite) to AGM-consistency, which is defined as follows. A frame is AGM-consistent if the partial belief revision function associated with an arbitrary state-instant pair and an arbitrary model based on that frame can be extended to a full belief revision function that satisfies the AGM postulates. Second, we (...) provide a set of modal axioms that characterize the class of AGM-consistent frames within the modal logic introduced in Bonanno (Artif Intell 171:144–160, 2007 ). Third, we introduce a generalization of AGM belief revision functions that allows a clear statement of principles of iterated belief revision and discuss iterated revision both semantically and syntactically. (shrink)
Making a prediction is essentially expressing a belief about the future. It is therefore natural to interpret later predictions as revisions of earlier ones and to investigate the notion of belief revision in this context. We study, both semantically and syntactically, the following principle of minimum revision of prediction: “as long as there are no surprises, that is, as long as what actually occurs had been predicted to occur, then everything which was predicted in the past, if still possible, should (...) continue to be predicted, and no new predictions should be added.”. (shrink)
The Common Prior Assumption (CPA) plays an important role in game theory and the economics of information. It is the basic assumption behind decision-theoretic justifications of equilibrium reasoning in games (Aumann, 1987, Aumann and Brandenburger, 1995) and no-trade results with asymmetric information (Milgrom and Stokey, 1982). Recently several authors (Dekel and Gul, 1997, Gul, 1996, Lipman, 1995) have questioned whether the CPA is meaningful in situations of incomplete information, where there is no ex ante stage and where the primitives of (...) the model are the individuals' beliefs about the external world (their first-order beliefs), their beliefs about the other individuals' beliefs (second-order beliefs), etc., i.e. their hierarchies of beliefs. In this context, the CPA is a mathematical property whose conceptual content is not clear. The main results of this paper (Theorems 1 and 2) provide a characterization of Harsanyi consistency in terms of properties of the belief hierarchies that are entirely unrelated to the idea of an ex ante stage. (shrink)
This paper presents the results of an experiment on mutual versus common knowledge of advice in a two-player weak-link game with random matching. Our experimental subjects play in pairs for thirteen rounds. After a brief learning phase common to all treatments, we vary the knowledge levels associated with external advice given in the form of a suggestion to pick the strategy supporting the payoff-dominant equilibrium. Our results are somewhat surprising and can be summarized as follows: in all our treatments both (...) the choice of the efficiency-inducing action and the percentage of efficient equilibrium play are higher with respect to the control treatment, revealing that even a condition as weak as mutual knowledge of level 1 is sufficient to significantly increase the salience of the efficient equilibrium with respect to the absence of advice. Furthermore, and contrary to our hypothesis, mutual knowledge of level 2 induces, under suitable conditions, successful coordination more frequently than common knowledge. (shrink)
Counterexamples to two results by Stalnaker (Theory and Decision, 1994) are given and a corrected version of one of the two results is proved. Stalnaker's proposed results are: (1) if at the true state of an epistemic model of a perfect information game there is common belief in the rationality of every player and common belief that no player has false beliefs (he calls this joint condition âstrong rationalizabilityâ), then the true (or actual) strategy profile is path equivalent to a (...) Nash equilibrium; (2) in a normal-form game a strategy profile is strongly rationalizable if and only if it belongs to C8 , the set of profiles that survive the iterative deletion of inferior profiles. (shrink)
This paper suggests a way of formalizing the amount of information that can be conveyed to each player along every possible play of an extensive game. The information given to each player i when the play of the game reaches node x is expressed as a subset of the set of terminal nodes. Two definitions are put forward, one expressing the minimum amount of information and the other the maximum amount of information that can be conveyed without violating the constraint (...) represented by the information sets. Our definitions provide intuitive characterizations of such notions as perfect recall, perfect information and simultanetty. (shrink)
Restricting attention to the class of extensive games defined by von Neumann and Morgenstern with the added assumption of perfect recall, we specify the information of each player at each node of the game-tree in a way which is coherent with the original information structure of the extensive form. We show that this approach provides a framework for a formal and rigorous treatment of questions of knowledge and common knowledge at every node of the tree. We construct a particular information (...) partition for each player and show that it captures the notion of maximum information in the sense that it is the finest within the class of information partitions that satisfy four natural properties. Using this notion of “maximum information” we are able to provide an alternative characterization of the meet of the information partitions. (shrink)
I first outline the arguments by which Hegel upholds the validity of his ‘rationalistic’ ideal of an ‘absolute knowing’, and then attempt to state precisely the sense in which such a Hegelian conception can be rightfully styled ‘idealistic’, and the reasons why it turns out to be preferable to the opposite empirical-realistic outlook. Thirdly, I examine his critique of ‘finite knowing’. Finally, I enumerate the fundamental features of that ‘speculative (i.e., strictly philosophical) knowing’ which, as the Absolute Idea, Hegel sets (...) against ‘finite knowing’ as the higher category in which the peculiar deficiencies and contradictions of the latter are integrated and reconciled. (shrink)
Adapting a definition introduced by Milgrom (1981) we say that a signal about the environment is good news relative to some initial beliefs if the posterior beliefs dominate the initial beliefs in the sense of first-order stochastic dominance (the assumption being that higher values of the parameter representing the environment mean better environments). We give an example where good news leads to the adoption of a more pessimistic course of action (we say that action a, reveals greater pessimism than action (...) aâ if it gives higher payoff in bad environments and lower payoff in good environments). We then give sufficient conditions for a signal not to induce a more pessimistic choice of action. (shrink)
If today a decidedly analytical interpretation of Wittgenstein’s thought seems to be dominant in many ways, there are, in my opinion, countless reasons that lead instead to reintroduce the possibility, and even the opportunity, of a different reading: a proper philosophical-aesthetic reading – where “philosophical” is equivalent to “transcendental” in the Kantian sense – which certainly seems to me more productive in theoretical terms.
The New Economic Windows Series, derived from Massimo Salzano's ideas and work, incorporates material from textbooks, monographs and conference proceedings that deals with both the theoretical and applied aspects of various sub-disciplines ...
What makes casanova the prototype of the seducer? This is the question that many have tried to answer, such as Hermann Kesten, in his study dedicated to this character, whose name has become a common proper noun in almost all European languages. Was the incredible force of Casanova’s seduction made possible by a certain technique or, better, an art with rules that everyone can master? As he says in The Story of My Life, “The chief business of my life has (...) always been to indulge my senses.” Is it possible that this was the nucleus that radiated such a mysterious force? Did he discover something extraordinary, Kesten asked, that escaped the knowledge of the rest of the people?1 Yes, indeed, Giacomo Casanova .. (shrink)
In the following article I present a basic proposal that is intended to provide the ground for a broader program in which I attempt to explain and characterize the foundations of the normativity generally regarded as implicit in the notion of a "person." I intend to argue that these foundations are natural in the sense that they are derived from basic behavioral and cognitive patterns which are particularly characteristic of human beings especially during their infancy. Among these basic patterns I (...) take that known as dyadic engagement to be merely the foundational stage at which embryonic personhood emerges. Dyadic engagement is a very primitive and special form of social competence which has been identified by some cognitive developmentalists and comparative psychologists as a particular kind of sensitivity for contingencies which are experienced from the very beginning in the various processes of communicative interaction. (shrink)
The notion of Nash equilibrium in static oligopoly games is based on the assumption that each firm knows its entire demand curve (and, therefore, its entire profit function). It is much more likely, however, that firms only have some idea of the outcome of small price variations within some relatively small interval of prices. This is because firms can only learn their demand functions through price experiments and if they are risk-averse and/or have a low discount factor, they will be (...) unwilling to engage in extensive price experiments involving large variations in price. We can therefore expect firms to experiment through small price variations and stop when they reach a price such that no small deviation.. (shrink)
behaviour from the rival manufacturer. We consider the case where franchise fees can be used to extract retailers' surplus. We show that vertical separation is in the collective, as well as individual, interest of manufacturers, and hence facilitates some collusion in the simple setting..
This article offers a general “immanent” critique of Derrida’s Deconstructionism, whose positive outcome is an argument for the continuing viability of a Hegel-oriented idealistic metaphysics. Derrida’s thought is construed as an unspokenly skeptical and nihilistic development of Heidegger’s existential ontology and of the sensu latiori “structuralist” trend of contemporary human sciences. The main difficulties pointed out hinge on (§ 1) the relationship deconstructionism establishes between thought and language, speech and writing, and phonetic and non-phonetic writing, (§ 2) its paradoxical concept (...) of “transcendental writing” as the “origin” of empirical writing and of the “trace” as more “original” than original reality; and, finally, (§ 3) its specification of the alleged “radical other” to metaphysical thought as writing, difference, and literature. (shrink)
In the fifth of his John Locke Lectures, Robert Brandom takes up the challenge to define a formal semantics for modelling conceptual contents according to his normative analysis of linguistic practices. The project is to exploit the notion of incompatibility in order to directly define a modally robust relation of entailment. Unfortunately, it can be proved that, in the original definition, the modal system represented by Incompatibility Semantics (IS) collapses into propositional calculus. In this paper I show how IS can (...) be technically amended so to overcome this failure: the required modifications are already known and consist in adapting and including the main notions of Kripke's standard framework of possible worlds. I also show that the modifications do not jeopardize Brandom's original project. (shrink)
In my 1992 paper in Economic Notes, I argued that the traditional heuristic interpretation of taxes in the pivotal mechanism (in terms of the utility loss imposed by the taxed individual on the rest of society) is not correct, since it takes into account only the effect that the individual has on the decision concerning the project and disregards the effect that the same individual has on the taxes paid by the other members of society. Campbell criticizes my observation on (...) two grounds. (shrink)
Circulation of ideas among philosophers is the core of Philosophy itself. The lack of this circulation can lead to obscurantism and cultural provincialism. The latter, for instance, afflicted Italy during the first half of the 20th century because of the close-minded neo-idealism of Croce and the mutual indifference of science and philosophy. Antonio Gramsci tried to overcome the problem of provincialism. In this essay, I explain how he attempted to overcome it. I focus on his conceptual categories like heg emony, (...) organic intellectual, national-popular and so on. (shrink)
While the sociality of software agents drives toward the definition of institutions for multi agent systems, their autonomy requires that such institutions are ruled by appropriate norm mechanisms. Computational institutions represent useful abstractions. In this paper we show how computational institutions can be built on top of the RoleX infrastructure, a role-based system with interesting features for our aim. We achieve a twofold goal: on the one hand, we give concreteness to the institution abstractions; on the other hand, we demonstrate (...) the flexibility of the RoleX infrastructure. (shrink)
The essays collected in this issue all stem from talks delivered at the International Conference, Aesthetic preferences, language games and forms of life: from Ludwig Wittgenstein, which was held on 23-25 January 2013 in the Aula Magna of the Faculty of Education at the University of Florence. Contributions are here published in the same order they were presented at the Conference. With fruitful variety of approach, the entire thematic spectrum of the relationship between Wittgenstein and aesthetics is covered: 1) the (...) question of the presence of specific aesthetic issues in Wittgenstein’s works: from aesthetic judgment to the concept of the beautiful (J.-P. Cometti, G. Tomasi, G. Matteucci); 2) the question of the aesthetic paradigm as the key to understanding Wittgenstein’s philosophical research as a whole as well as the philosopher’s unmistakable style (F. Desideri, S. Säätelä, S. Borutti, F. Valagussa); 3) the issue concerning the crucial difference between showing and saying and the thin boundaries between sense and nonsense (V. Sanfélix, L. Distaso, M. De Iaco); 4) the peculiar, but extremely relevant, question concerning the relationship between music and language (J. Schulte, A. Arbo); 5) the question of the expressive character of the work of art and of the linguistic nature of poetry, considered as a vantage point for the pursuit of the analysis of linguistic facts, as well as the issue of the literary form of Wittgenstein’s later philosophy, with its deeply romantic character (M.W. Rowe, G. Di Giacomo); 6) the controversial issue of "seeing-as" and of its role within theories of depiction and pictoriality (K. Stock, A. Voltolini, E. Caldarola, E. Terrone). (shrink)
