In this paper, we investigate the use of event models for automated planning. Event models are the action defining structures used to define a semantics for dynamic epistemic logic. Using event models, two issues in planning can be addressed: Partial observability of the environment and knowledge. In planning, partial observability gives rise to an uncertainty about the world. For single-agent domains, this uncertainty can come from incomplete knowledge of the starting situation and from the nondeterminism of actions. In multi-agent domains, (...) an additional uncertainty arises from the fact that other agents can act in the world, causing changes that are not instigated by the agent itself. For an agent to successfully construct and execute plans in an uncertain environment, the most widely used formalism in the literature on automated planning is “belief states”: sets of different alternatives for the current state of the world. Epistemic logic is a significantly more expressive and theoretically better founded method for representing knowledge and ignorance about the world. Further, epistemic logic allows for planning according to the knowledge (and iterated knowledge) of other agents, allowing the specification of a more complex class of planning domains, than those simply concerned with simple facts about the world. We show how to model multi-agent planning problems using Kripke-models for representing world states, and event models for representing actions. Our mechanism makes use of slight modifications to these concepts, in order to model the internal view of agents, rather than that of an external observer. We define a type of planning domain called epistemic planning domains, a generalisation of classical planning domains, and show how epistemic planning can successfully deal with partial observability, nondeterminism, knowledge and multiple agents. Finally, we show epistemic planning to be decidable in the single-agent case, but only semi-decidable in the multi-agent case. (shrink)

In this paper we show how to formalise false-belief tasks like the Sally-Anne task and the second-order chocolate task in Dynamic Epistemic Logic. False-belief tasks are used to test the strength of the Theory of Mind of humans, that is, a human’s ability to attribute mental states to other agents. Having a ToM is known to be essential to human social intelligence, and hence likely to be essential to social intelligence of artificial agents as well. It is therefore important to (...) find ways of implementing a ToM in artificial agents, and to show that such agents can then solve false-belief tasks. In this paper, the approach is to use DEL as a formal framework for representing ToM, and use reasoning in DEL to solve false-belief tasks. In addition to formalising several false-belief tasks in DEL, the paper introduces some extensions of DEL itself: edge-conditioned event models and observability propositions. These extensions are introduced to provide better formalisations of the false-belief tasks, but expected to have independent future interest. (shrink)

An anthology of previously unpublished essays from some of the most outstanding scholars working in philosophy, mathematics, and computer science today, _Self-Reference_ reexamines the latest theories of self-reference, including those that attempt to explain and resolve the semantic and set-theoretic paradoxes. With a thorough introduction that contextualizes the subject for students, this book will be important reading for anyone interested in the general area of self-reference and philosophy.

Plausibility models are Kripke models that agents use to reason about knowledge and belief, both of themselves and of each other. Such models are used to interpret the notions of conditional belief, degrees of belief, and safe belief. The logic of conditional belief contains that modality and also the knowledge modality, and similarly for the logic of degrees of belief and the logic of safe belief. With respect to these logics, plausibility models may contain too much information. A proper notion (...) of bisimulation is required that characterises them. We define that notion of bisimulation and prove the required characterisations: on the class of image-finite and preimage-finite models, two pointed Kripke models are modally equivalent in either of the three logics, if and only if they are bisimilar. As a result, the information content of such a model can be similarly expressed in the logic of conditional belief, or the logic of degrees of belief, or that of safe belief. This, we found a surprising result. Still, that does not mean that the logics are equally expressive: the logics of conditional and degrees of belief are incomparable, the logics of degrees of belief and safe belief are incomparable, while the logic of safe belief is more expressive than the logic of conditional belief. In view of the result on bisimulation characterisation, this is an equally surprising result. We hope our insights may contribute to the growing community of formal epistemology and on the relation between qualitative and quantitative modelling. (shrink)

Plausibility models are Kripke models that agents use to reason about knowledge and belief, both of themselves and of each other. Such models are used to interpret the notions of conditional belief, degrees of belief, and safe belief. The logic of conditional belief contains that modality and also the knowledge modality, and similarly for the logic of degrees of belief and the logic of safe belief. With respect to these logics, plausibility models may contain too much information. A proper notion (...) of bisimulation is required that characterises them. We define that notion of bisimulation and prove the required characterisations: on the class of image-finite and preimage-finite models, two pointed Kripke models are modally equivalent in either of the three logics, if and only if they are bisimilar. As a result, the information content of such a model can be similarly expressed in the logic of conditional belief, or the logic of degrees of belief, or that of safe belief. This, we found a surprising result. Still, that does not mean that the logics are equally expressive: the logics of conditional and degrees of belief are incomparable, the logics of degrees of belief and safe belief are incomparable, while the logic of safe belief is more expressive than the logic of conditional belief. In view of the result on bisimulation characterisation, this is an equally surprising result. We hope our insights may contribute to the growing community of formal epistemology and on the relation between qualitative and quantitative modelling. (shrink)

An anthology of previously unpublished essays from some of the most outstanding scholars working in philosophy, mathematics, and computer science today, _Self-Reference_ reexamines the latest theories of self-reference, including those that attempt to explain and resolve the semantic and set-theoretic paradoxes. With a thorough introduction that contextualizes the subject for students, this book will be important reading for anyone interested in the general area of self-reference and philosophy.

We present a logic which we call Hybrid Duration Calculus. HDC is obtained by adding the following hybrid logical machinery to the Restricted Duration Calculus : nominals, satisfaction operators, down-arrow binder, and the global modality. RDC is known to be decidable, and in this paper we show that decidability is retained when adding the hybrid logical machinery. Decidability of HDC is shown by reducing the satisfiability problem to satisfiability of Monadic Second-Order Theory of Order. We illustrate the increased expressive power (...) obtained in hybridizing RDC by showing that HDC, in contrast to RDC, can express all of the 13 possible relations between intervals. (shrink)

In this paper we define a family of many-valued semantics for hybrid logic, where each semantics is based on a finite Heyting algebra of truth-values. We provide sound and complete tableau systems for these semantics. Moreover, we show how the tableau systems can be made terminating and thereby give rise to decision procedures for the logics in question. Our many-valued hybrid logics turn out to be "intermediate" logics between intuitionistic hybrid logic and classical hybrid logic in a specific sense explained (...) in the paper. Our results show that many-valued hybrid logic is indeed a natural enterprise. (shrink)

In this paper we define a family of many-valued semantics for hybrid logic, where each semantics is based on a finite Heyting algebra of truth-values. We provide sound and complete tableau systems for these semantics. Moreover, we show how the tableau systems can be made terminating and thereby give rise to decision procedures for the logics in question. Our many-valued hybrid logics turn out to be "intermediate" logics between intuitionistic hybrid logic and classical hybrid logic in a specific sense explained (...) in the paper. Our results show that many-valued hybrid logic is indeed a natural enterprise. (shrink)

The context in which Thomas Aquinas reflects on teaching is discussed, as are the texts in which he does so. We learn how he understands teaching from two other considerations, how he went about the task, and the pedagogical concerns that persist through his writing career. The most important source for his convictions about pedagogy is the Bible, and Jesus is ‘the most excellent of teachers’. His account of teaching is ultimately theological, then, in line with his concerns in (...) Summa theologiae, such that creation may be understood as teaching and redemption as learning. (shrink)

When making decisions, humans can observe many kinds of information about others' activities, but their effects on performance are not well understood. We investigated social learning strategies using a simple problem-solving task in which participants search a complex space, and each can view and imitate others' solutions. Results showed that participants combined multiple sources of information to guide learning, including payoffs of peers' solutions, popularity of solution elements among peers, similarity of peers' solutions to their own, and relative payoffs from (...) individual exploration. Furthermore, performance was positively associated with imitation rates at both the individual and group levels. When peers' payoffs were hidden, popularity and similarity biases reversed, participants searched more broadly and randomly, and both quality and equity of exploration suffered. We conclude that when peers' solutions can be effectively compared, imitation does not simply permit scrounging, but it can also facilitate propagation of good solutions for further cumulative exploration. (shrink)

Big Ideas for Little Kids includes everything a teacher, a parent, or a college student needs to teach philosophy to elementary school children from picture books. Written in a clear and accessible style, the book explains why it is important to allow young children access to philosophy during primary-school education. Wartenberg also gives advice on how to construct a "learner-centered" classroom, in which children discuss philosophical issues with one another as they respond to open-ended questions by saying whether they agree (...) or disagree with what others have said. (shrink)

The newly updated Right and Wrong 2nd Edition is an accessible introduction to the major traditions in western philosophical ethics, written in a lively and engaging style. It is designed for entry-level ethics courses and includes real-life ethical scenarios chosen to appeal directly to students. Greatly expanded and improved, this successful text introduces students to the major ethical traditions, and provides a simple methodology for resolving ethical dilemmas Treats teleological and deontological approaches to ethics as the two most important traditions, (...) but now includes chapters on virtue ethics and the ethics of care The very accessible writing style speaks directly to students’ own experience Draws examples from three types of real-life ethical scenarios submitted by students: academic dishonesty, partying, and personal relationships Provides a concise treatment of this notoriously complex subject, perfect for entry-level ethics and applied ethics courses. (shrink)

v. 1. Editorial introduction -- v. 2. The English and Latin texts (i) -- v. 3. The English and Latin texts (ii).

Some theories of goodness are descriptively rich: they have much to say about what makes things good. Neo-Aristotelian accounts, for instance, detail the various features that make a human being, a dog, a bee good relative to facts about those forms of life. Famously, such theories of relative goodness tend to be comparatively poor: they have little or nothing to say about what makes one kind of being better than another kind. Other theories of goodness—those that take there to be (...) absolute goodness—are comparatively rich: they offer grounds for judging some types of things better than others because they have more absolute goodness. Moorean accounts, for example, can tell us that humans and human experiences are superior to bees and blades of grass. But such theories tend to be descriptively poor: they struggle to tell us in virtue of what this is so. In this essay we motivate and flesh out a view that splits the difference between accounts of goodness as relative and accounts of goodness as absolute. Such a view holds promise only if the mechanics of this kind of metaphysics of goodness can be worked out. Here we present a view on which the paradigm for absolute goodness is God and the paradigm for each kind of relative goodness is a divine idea. (shrink)

Although Foucault was clearly a critical thinker, his approach also provides for the possibility of a genealogy of critique. Such an approach problematizes critique, and I trace the emergent problematization of critique in Foucault’s later works, and briefly in Latour and Boltanski. From this I move on to the ‘critical problematic’, that is, how critique operates as a form of power/knowledge, as a discourse that creates subjects through a critical regime of truth and critical truth-games. Specifically, I argue that critique (...) is a discourse which transforms and unmasks other ‘truth-claims’, replacing them with a starker vision of reality, which in the end is also a specific cultural vision. To elaborate this view, I return to Foucault’s discussion of Kant, his late lectures on Cynicism and also on ordo-liberalism. The wider circulation of critical discourses is demonstrated through an analysis of ‘cool’ or critical consumerism. In conclusion, the relationship between critique, crisis and modernity is considered. (shrink)

Roughly speaking all economists can be divided into two groups--those who agree with Milton Friedman and those who do not. Both groups, however, espouse the view that science is a series of approximations to a demonstrated accord with reality. Methodological controversy in economics is now merely a Conventionalist argument over which comes first--simplicity or generality. Furthermore, this controversy in its current form is not compatible with one important new and up and coming economic (welfare) theory called "the theory of the (...) Second Best." In this paper I offer a Second Best meta-theory that says that (1) any compromise between simplicity and generality must yield a theory which is "third best" by these Conventionalist criteria; and (2) there exists a better way than a compromise. (shrink)

Proceedings of a conference held in Apr. 2008 in Washington, D.C.

Father Williams explains how the conscience is formed through our training and experiences and informed by the Holy Spirit, making it an essential tool for daily living. He uses familiar and surprising characters to illustrate the positive choices conscience can direct--and the disaster that results when a conscience is undeveloped or ignored. Questions he tackles include "Is it more important to be smart or good?""Is there a morally right thing to do in every situation?" and "Is the Christian moral life (...) an exciting adventure, or a necessary burden?" Rich, provocative, and practical for everyday decision making, KNOWING RIGHT FROM WRONG is a must-read for all who hunger for personal holiness. (shrink)

This article considers `critique' as performative, being on the one hand a reiterative performance, that enacts the `critic' through the act of critique, and on the other hand reflecting the constitution of the subject. While this approach takes on the conceptual framework of Judith Butler's work, it differs by refusing critique — or its correlates; parody, subversion or similar — any special status. Like any other performance critique is taken here as a cultural practice, as a Foucauldian `technique of self', (...) though the complex genealogy of such a technique lies outside the scope of this article. In order to illustrate this argument I interpret a number of Butler's prefaces, interviews and digressions which diverge from her own theoretical framework, and argue that these `fictions' arise from critical `disavowals': that is, a `self-transformative' turn against power. The subjective `crisis' that prompts critique is then elaborated by comparison to Girard's work on imitation and sacrifice. (shrink)

Nancy Cartwright claims that "Causality is a hot topic today both in philosophy and economics." She may be right about philosophers, but not when it comes to economists. Cartwright talks about "economics" but nothing she says about it corresponds to what is taught in economics classes. Today, economics is dominated by model builders—but not all models involve econometrics. While all model builders do respect an endogenous-exogenous distinction between variables, this distinction will not be on the basis of which type of (...) variable "causes" which, but on which variables are "determined" (and hence explained) by the model and those which are not. (shrink)

While Latour criticises the tautologies of the ‘sociologists of the social’ as an intellectual shortcut, here sociology in the broadest sense is reconsidered as informed by unrecognised theological ideas, inter alia. Durkheim’s classic account of religion, wherein ‘society is God’ is taken as a starting point to explore the intersection of sociology and theology. Thereafter the article examines three social theorists, Elias, Giddens and Boltanski, each of whom attempt a re-casting of sociology, yet rearticulate theological models. In particular, this includes (...) an ontological conception of society, structure or system in terms of over-arching and invisible forces which is derived – inter alia – from religious models of divine will and providential order, which incorporates human choice – or agency in contemporary parlance. Accompanying this ontology is an epistemology of deciphering ‘deeper’ or ‘structural’ or ‘transcendent’ aspects of society by observing trends, cases or culture, akin to divining the providential will by observing its manifestations, which can be conducted in a more critical or forgiving manner. By examining these theological strands which persist in sociology, this aim is not to critically repudiate them, but to recognise the productive contribution of these models of thinking to imagining the ‘social’. (shrink)

It is somewhat misleading to think of the Franciscans as forming a “school” in ethics, since there was a fair bit of diversity among Franciscans. Nonetheless, one can identify certain characteristic tendencies of Franciscan moral thought, and certain “celebrity” Franciscans whose views in ethics and moral psychology are particularly noteworthy. I shall first offer an overview of the general character of Franciscan moral thought in the late thirteenth and early fourteenth centuries and then turn to a more detailed examination of (...) the thought of John Duns Scotus (1265/66-1308) and William Ockham (c. 1288-1347) on three central matters of debate: the nature of the virtues, the relationship between intellect and will, and the relationship between moral requirements and the divine will. (shrink)

In this book Thomas Wren uncovers and assesses the largely hidden philosophical assumptions about human motivation that have shaped contemporary psychological ...

THE NATURE OF ART is a collection of 29 seminal, historically-organized readings that are focused on a basic philosophical question: What is Art? Including writings from the Western tradition'both Continental and Analytic traditions'as well as non-Western, minority, and feminist writings, this volume provides students with a rich set of resources to explore this matter both broadly and deeply. Introductions to each reading situate the selection amidst each respective thinker's body of work and the greater philosophical context in which the remarks (...) arose. Reading questions accompany each selection, drawing students' attention to key points to be encountered. Hailed by reviewers and adopters for its clarity and rigor, Wartenberg's THE NATURE OF ART offers a lively and engaging introduction to the philosophy of art. (shrink)