We investigate the semantics of messages, and argue that the meaning ofa message is naturally and usefully given in terms of how it affects theknowledge of the agents involved in the communication. We note thatthis semantics depends on the protocol used by the agents, and thus not only the message itself, but also the protocol appears as a parameter in the meaning. Understanding this dependence allows us to give formal explanations of a wide variety of notions including language dependence, implicature, (...) and the amount of information in a message. (shrink)

Influential neoclassical economist Lionel McKenzie has made major contributions to postwar economic thought in the fields of equilibrium, trade, and capital accumulation. This selection of his papers traces the development of his thinking in these three crucial areas.McKenzie's early academic life took him to Duke, Princeton, Oxford, the University of Chicago, and the Cowles Commission. In 1957, he went to the University of Rochester to head the economics department there, and he remains at Rochester, now Wilson Professor Emeritus of Economics. (...) McKenzie's most significant research was undertaken during a period that saw the development of the major themes of neoclassical economics and the use of fundamental mathematical methods to do so. McKenzie contributed to both aspects of this research program. He helped shape the direction of the field and, at Rochester, influenced generations of future scholars. In 2002, The MIT Press published McKenzie's Classical General Equilibrium Theory, a detailed summary of the model and methodology. This book, collecting his most important papers in the form in which they were originally published, can be seen as a companion to that one. The many state-of-the-art results achieved in McKenzie's original papers present sophisticated theoretical work that will continue to be important to future developments in the discipline. (shrink)

Communication and content presents a comprehensive and foundational account of meaning based on new versions of situation theory and game theory. The literal and implied meanings of an utterance are derived from first principles assuming little more than the partial rationality of interacting agents. New analyses of a number of diverse phenomena – a wide notion of ambiguity and content encompassing phonetics, syntax, semantics, pragmatics, and beyond, vagueness, convention and conventional meaning, indeterminacy, universality, the role of truth in communication, semantic (...) change, translation, Frege’s puzzle of informative identities – are developed. Communication, speaker meaning, and reference are defined. Frege’s context and compositional principles are generalized and reconciled in a fixed-point principle, and a detailed critique of Grice, several aspects of Lewis, and some aspects of the Romantic conception of meaning are offered. Connections with other branches of linguistics, especially psycholinguistics, sociolinguistics, historical linguistics, and natural language processing, are explored. -/- The book will be of interest to scholars in philosophy, linguistics, artificial intelligence, and cognitive science. It should also interest readers in related fields like literary and cultural theory and the social sciences. (shrink)

Both the Beth definability theorem and Craig's lemma (interpolation theorem from now on) deal with the issue of the entanglement of one language L1 with another language L2, that is to say, information transfer—or the lack of such transfer—between the two languages. The notion of splitting we study below looks into this issue. We briefly relate our own results in this area as well as the results of other researchers like Kourousias and Makinson, and Peppas, Chopra and Foo.Section 3 does (...) contain one apparently new theorem. (shrink)

One interpretation of the conditional If P then Q is as saying that the probability of Q given P is high. This is an interpretation suggested by Adams (1966) and pursued more recently by Edgington (1995). Of course, this probabilistic conditional is nonmonotonic, that is, if the probability of Q given P is high, and R implies P, it need not follow that the probability of Q given R is high. If we were confident of concluding Q from the fact (...) that we knew P, and we have stronger information R, we can no longer be confident of Q. We show nonetheless that usually we would still be justified in concluding Q from R. In other words, probabilistic conditionals are mostly monotonic. (shrink)

We propose a new relevance sensitive model for representing and revising belief structures, which relies on a notion of partial language splitting and tolerates some amount of inconsistency while retaining classical logic. The model preserves an agent's ability to answer queries in a coherent way using Belnap's four-valued logic. Axioms analogous to the AGM axioms hold for this new model. The distinction between implicit and explicit beliefs is represented and psychologically plausible, computationally tractable procedures for query answering and belief..

The design and development of appropriate regulatory mechanisms have attracted renewed attention in recent years. In particular, a shift towards voluntary self-regulatory mechanisms has been witnessed within many industries, such as the Australian mining and petroleum industries which have developed voluntary codes of conduct. This paper analyses the development of different regulatory forms and provides a brief comparative analysis of the two main voluntary codes of conduct used by the Australian mining and petroleum industries. In particular, the study focuses on (...) the integration of social sustainability elements within these frameworks that help contribute to solving issues such as coverage of human rights, approaches to employee and community relations, systems of stakeholder engagement, community consultation and public reporting. The study concludes that stakeholders have an important role to play in driving the introduction of voluntary regulation. This phenomenon can be traced back to how a company’s need to maintain its legitimacy, or social licence to operate, often motivates it to go beyond compliance. By providing a fuller understanding of factors driving the evolution of different regulatory mechanisms, this study has important implications for policy makers and practitioners interested in developing effective regulation. (shrink)

Subset Spaces were introduced by L. Moss and R. Parikh in [8]. These spaces model the reasoning about knowledge of changing states.In [2] a kind of subset space called intersection space was considered and the question about the existence of a set of axioms that is complete for the logic of intersection spaces was addressed. In [9] the first author introduced the class of directed spaces and proved that any set of axioms for directed frames also characterizes intersection spaces.We (...) give here a complete axiomatization for directed spaces. We also show that it is not possible to reduce this set of axioms to a finite set. (shrink)

In Language and Equilibrium, Prashant Parikh offers a new account of meaning for natural language. He argues that equilibrium, or balance among multiple interacting forces, is a key attribute of language and meaning and shows how to derive the meaning of an utterance from first principles by modeling it as a system of interdependent games.His account results in a novel view of semantics and pragmatics and describes how both may be integrated with syntax. It considers many aspects of meaning--including (...) literal meaning and implicature--and advances a detailed theory of definite descriptions as an application of the framework.Language and Equilibrium is intended for a wide readership in the cognitive sciences, including philosophers, linguists, and artificial intelligence researchers as well as neuroscientists, psychologists, and economists interested in language and communication. (shrink)

We consider fixed and asking price strategies in the context of selling an asset with Bernoullian updating of the seller’s subjective probability of sale at a given price. The determination of optimal fixed, asking and endogenous reservation prices is discussed under risk-neutrality and expected utility maximisation. With risk-neutrality, the optimal asking price exceeds the optimal fixed price when the expected gain is a strictly concave function. The seller’s choice between the fixed and the asking price strategies depends on several factors: (...) the expected cost of haggling, price competition and the seller’s attitude towards risk. (shrink)

Journal of Philosophical Logic 34, 97-119, 2005.

We suggest that the issue of constructing andverifying social procedures, which we suggestively call socialsoftware, be pursued as systematically as computer software is pursued by computer scientists. Certain complications do arise withsocial software which do not arise with computer software, but thesimilarities are nonetheless strong, and tools already exist which wouldenable us to start work on this important project. We give a variety ofsuggestive examples and indicate some theoretical work which alreadyexists.

Deontic Logic goes back to Ernst Mally’s 1926 work, Grundgesetze des Sollens: Elemente der Logik des Willens [Mally. E.: 1926, Grundgesetze des Sollens: Elemente der Logik des Willens, Leuschner & Lubensky, Graz], where he presented axioms for the notion ‘p ought to be the case’. Some difficulties were found in Mally’s axioms, and the field has much developed. Logic of Knowledge goes back to Hintikka’s work Knowledge and Belief [Hintikka, J.: 1962, Knowledge and Belief: An Introduction to the Logic of (...) the Two Notions, Cornell University Press] in which he proposed formal logics of knowledge and belief. This field has also developed quite a great deal and is now the subject of the TARK conferences. However, there has been relatively little work combining the two notions of knowledge (belief) with the notion of obligation. (See, however, [Lomuscio, A. and Sergot, M.: 2003, Studia Logica 75 63–92; Moore, R. C.: 1990, In J. F. Allen, J. Hendler and A. Tate (eds.), Readings in Planning, Morgan Kaufmann Publishers, San Mateo, CA]) In this paper we point out that an agent’s obligations are often dependent on what the agent knows, and indeed one cannot reasonably be expected to respond to a problem if one is not aware of its existence. For instance, a doctor cannot be expected to treat a patient unless she is aware of the fact that he is sick, and this creates a secondary obligation on the patient or someone else to inform the doctor of his situation. In other words, many obligations are situation dependent, and only apply in the presence of the relevant information. Thus a case for combining Deontic Logic with the Logic of Knowledge is clear. We introduce the notion of knowledge based obligation and offer an S5, history based Kripke semantics to express this notion, as this semantics enables us to represent how information is transmitted among agents and how knowledge changes over time as a result of communications. We consider both the case of an absolute obligation (although dependent on information) as well as the (defeasible) notion of an obligation which may be over-ridden by more relevant information. For instance a physician who is about to inject a patient with drug d may find out that the patient is allergic to d and that she should use d′ instead. Dealing with the second kind of case requires a resort to non-monotonic reasoning and the notion of justified belief which is stronger than plain belief, but weaker than absolute knowledge in that it can be over-ridden. This notion of justified belief also creates a derived notion of default obligation where an agent has, as far as the agent knows, an obligation to do some action a. A dramatic application of this notion is our analysis of the Kitty Genovese case where, in 1964, a young woman was stabbed to death while 38 neighbours watched from their windows but did nothing. The reason was not indifference, but none of the neighbours had even a default obligation to act, even though, as a group, they did have an obligation to take some action to protect Kitty. (shrink)

We offer a probabilistic model of rational consequence relations (Lehmann and Magidor, 1990) by appealing to the extension of the classical Ramsey-Adams test proposed by Vann McGee in (McGee, 1994). Previous and influential models of nonmonotonic consequence relations have been produced in terms of the dynamics of expectations (Gärdenfors and Makinson, 1994; Gärdenfors, 1993).'Expectation' is a term of art in these models, which should not be confused with the notion of expected utility. The expectations of an agent are some form (...) of belief weaker than absolute certainty. Our model offers a modified and extended version of an account of qualitative belief in terms of conditional probability, first presented in (van Fraassen, 1995). We use this model to relate probabilistic and qualitative models of non-monotonic relations in terms of expectations. In doing so we propose a probabilistic model of the notion of expectation. We provide characterization results both for logically finite languages and for logically infinite, but countable, languages. The latter case shows the relevance of the axiom of countable additivity for our probability functions. We show that a rational logic defined over a logically infinite language can only be fully characterized in terms of finitely additive conditional probability. (shrink)

We present a method for relevance sensitive non-monotonic inference from belief sequences which incorporates insights pertaining to prioritized inference and relevance sensitive, inconsistency tolerant belief revision. Our model uses a finite, logically open sequence of propositional formulas as a representation for beliefs and defines a notion of inference from maxiconsistent subsets of formulas guided by two orderings: a temporal sequencing and an ordering based on relevance relations between the putative conclusion and formulas in the sequence. The relevance relations are ternary (...) (using context as a parameter) as opposed to standard binary axiomatizations. The inference operation thus defined easily handles iterated revision by maintaining a revision history, blocks the derivation of inconsistent answers from a possibly inconsistent sequence and maintains the distinction between explicit and implicit beliefs. In doing so, it provides a finitely presented formalism and a plausible model of reasoning for automated agents. (shrink)

We propose a model for belief which is free of presuppositions. Current models for belief suffer from two difficulties. One is the well known problem of logical omniscience which tends to follow from most models. But a more important one is the fact that most models do not even attempt to answer the question what it means for someone to believe something, and just what it is that is believed. We provide a flexible model which allows us to give meaning (...) to beliefs in general contexts, including the context of animal belief , and of human belief which is expressed in language. (shrink)

The objective of this study was to take a closer look at defense-related expenses for medical malpractice cases over time. We conducted a retrospective review of medical malpractice claims reported to the Physician Insurers Association of America's Data Sharing Project with a closing date between January 1, 1985 and December 31, 2008. On average a medical malpractice claim costs more than $27,000 to defend. Claims that go to trial are much more costly to defend than are those that are dropped, (...) withdrawn, or dismissed. However, since the overwhelming majority of claims are dropped, withdrawn, or dismissed, the total amount spent to defend them surpasses that spent on claims that go to trial. Defense attorney expenses account for the majority of defense-related expenses (74%), while expert witness expenses and other expenses split the remaining 26%. A strong association was also found between the average indemnity payment and the amount it costs to defend individual claims by specialty. Our study found that defense-related expenses for medical malpractice claims are not an insignificant cost. As state and federal governments debate how to repair the malpractice system, addressing the high cost of defending claims should not be ignored. (shrink)

Whenever health care reform is debated, the state of the medical professional liability system in the United States re-emerges as an issue of importance. What exactly is broken with the MPL system and what the implications are is a point of contention among different stakeholder groups. Recent data demonstrate that medical liability premiums have been improving in recent years and the majority of premiums remained flat in 2010. General agreement still exists, however, that medical professional liability insurance premiums have become (...) unaffordable for many physicians, and coverage has become less available, especially for certain medical specialties and in specific areas of the country.Multiple factors go into the determination of medical professional liability insurance premiums including return on investments, reinsurance costs, claims frequency, average amount paid out on malpractice claims, defense expenses, and administrative costs such as underwriting expense. (shrink)

In recent years, the number of foreign students studying at universities in Turkey has been increasing. Recent studies show that foreign students experience problems such as social exclusion and loneliness in city and university life. Loneliness is a concept that has a direct impact on psychosocial well-being. For this reason, it seems important to examine loneliness and religious coping skills in foreign students. The aim of this study is to reveal the loneliness and religious coping levels of foreign university students (...) in terms of socio-demographic variables. Correlational research method, one of the quantitative research designs, was used in the research. The sample of the study consists of 139 students, 121 of whom are Syrian nationals and 18 Africans. On the other hand, this research is important in that it is conducted in Kilis, one of the provinces where the Syrian population is the most dense, and mostly with Syrian university students. As a result of the research, it was determined that the positive religious coping levels of university students under the age of 20 were higher than those of students over the age of 20. It was found out that the prolongation of the residence period in Turkey positively increased the religious coping levels of the students, and the family types of the students (parents together, separate, loss of parents, etc.) did not have an effect on the levels of religious coping and loneliness. On the other hand, it was showed that there was no significant relationship between the number of siblings and religious coping and loneliness in foreign students, and lastly, the religious coping levels of the engineering faculty students were higher than the students studying in other departments. (shrink)

Con la investigación se constató que la adecuada relación médico-paciente depende en gran medida de la calidad del proceso diagnóstico. La Imagenología como especialidad médica en el marco de la Revolución Científico Técnica ilustra el complejo escenario en que se desenvuelve la relación médico-paciente al evidenciar nuevas expectativas, posibilidades y contradicciones. El trabajo tiene como objetivos destacar los rasgos distintivos de la relación médico-paciente en el ámbito de la Imagenología; contribuir a la formación ética de estos profesionales y significar la (...) responsabilidad social acorde con los principios más humanitarios en la atención de salud. (shrink)

Supercommentary, with commentaries on Praśastapādabhāṣya, a work on Kaṇāda's Vaiśeṣikasūtra, treatise on the Vaiśeṣika school in Hindu philosophy.

We develop an analysis of discourse anaphora—the relationship between a pronoun and an antecedent earlier in the discourse —using games of partial information. The analysis is extended to include information from a variety of different sources, including lexical semantics, contrastive stress, grammatical relations, and decision theoretic aspects of the context.

The standard theory for belief revision provides an elegant and powerful framework for reasoning about how a rational agent should change its beliefs when confronted with new information. However, the agents considered are extremely idealized. Some recent models attempt to tackle the problem of plausible belief revision by adding structure to the belief bases and using nonstandard inference operations. One of the key ideas is that not all of an agent's beliefs are relevant for an operation of belief change.In this (...) paper we incorporate the insights pertaining to local change and relevance sensitivity with the use of approximate inference relations. These approximate inference relations offer us partial solutions at any stage of the revision process. The quality of the approximations improves as we allow for more and more resources to be used. We are provided with upper and lower bounds to what would be obtained with the use of classical inference. (shrink)

Aversive autobiographical memories sometimes prompt maladaptive emotional responses and contribute to affective dysfunction in anxiety and depression. One way to regulate the impact of such memories is to create a downward counterfactual thought–a mental simulation of how the event could have been worse–to put what occurred in a more positive light. Despite its intuitive appeal, counterfactual thinking has not been systematically studied for its regulatory efficacy. In the current study, we compared the regulatory impact of downward counterfactual thinking, temporal distancing, (...) and memory rehearsal in 54 adult participants representing a spectrum of trait anxiety. Participants recalled regretful experiences and rated them on valence, arousal, regret, and episodic detail. Two to six days later, they created a downward counterfactual of the remembered event, thought of how they might feel about it 10 years from now, or simply rehearsed it. A day later, participants re-rated the phenomenological characteristics of the events. Across all participants, downward counterfactual thinking, temporal distancing, and memory rehearsal were equally effective at reducing negative affect associated with a memory. However, in individuals with higher trait anxiety, downward counterfactual thinking was more effective than rehearsal for reducing regret, and it was as effective as distancing in reducing arousal. We discuss these results in light of the functional theory of counterfactual thinking and suggest that they motivate further investigation into downward counterfactual thinking as a means to intentionally regulate emotional memories in affective disorders. (shrink)

The primary function of language is communication. We use the tools of situation theory and game theory to develop a definition and model of communication between rational agents using a shared situated language. ;A central thesis of this dissertation is that the key feature of situated communication that enables agents to derive content from meaning is a special type of logical inference called a strategic inference. ;The model we develop, called the Strategic Discourse Model, looks at a single strategic inference. (...) An essential element of a strategic inference is that the content depends on the sentence uttered and on the embedding circumstances. This includes the private and public information and beliefs of the agents, their goals and intentions, and crucially, the other sentences the speaker might have uttered but chose not to. A complete model of communication involves a system of simultaneous strategic inferences. ;When the strategic interaction between two agents is common knowledge between them, that is, when it is a game, the information transfer is a communication. The content communicated is given by the solution to the game. This analysis formalizes Grice's ideas on nonnatural meaning within a situation-theoretic framework. A consequence of our situated analysis is that agents do not need to have the complex and infinite set of nested intentions postulated by the Gricean approach. A simple intention to communicate is all that is required, the ambient game doing the rest of the work. ;This model has many applications. Problems like resolving ambiguity, determining reference, inferring implicatures and indirect speech acts fall within its scope. As one application, we outline a new theory of names and definite descriptions. This account builds upon Russell and Strawson, and Barwise and Perry. The basic idea is that names and descriptions can both be used in various ways circumscribed by an ontological and a communicative constraint. This offers a new solution to the puzzle of informative identity statements and clarifies the referential-attributive distinction. It suggests an approach to the concept of representation. ;An underlying theme is to synthesize situation theory and game theory. (shrink)

Counterfactual thinking, or simulating alternative versions of occurred events, is a common psychological strategy people use to process events in their lives. However, CFT is also a core com...