El presente artículo describe la conexión entre los espacios culturales rurales de la cultura mapuche y aquellos recreados en centros urbanos y su vinculación con la construcción de la identidad étnica en adolescentes mapuches urbanos. El estudio es cualitativo descriptivo y los datos se abordan desde el enfoque de análisis del discurso de la psicología discursiva y el enfoque de identidades espaciales de Proshansky . La muestra corresponde a treinta adolescentes mapuches hombres y mujeres residentes en la ciudad de Santiago (...) y treinta de la ciudad de Temuco, quienes participaron en entrevistas conducidas por un entrevistador mapuche. Los resultados revelan que el rol de los espacios culturales recreados en contextos urbanos es desarrollar una función mediadora del cambio desde el lugar de origen a nuevos espacios lo que permite reforzar la identidad étnica de los adolescentes. This article describes the connection between Mapuche rural cultural spaces and those re-created in urban areas and their connection with the construction of ethnic identity in urban Mapuche adolescents. This is a qualitative and descriptive study and the data is analyzed through the approach of discourse analysis of discursive psychology and considers the notion of place identity by Proshansky . The research population were thirty Mapuche adolescents living in Santiago and thirty living in Temuco. These adolescents were interviewed by a Mapuche interviewer. The findings reveal that the re-created urban cultural spaces fulfill a mediating role in the change from original places to new ones , which allows these adolescents to reinforce their ethnic identity construction. (shrink)

This study aims to characterize the different types of certification in the Brazilian citriculture as well as analyze the major changes in the market. The paper also has the objective to discuss how social and environmental factors influence the demand for food certifications and the sustainability and ethics aspects in the field. Therefore, a literature review on the subject was carried out as well as a qualitative research using interviews with certifiers, governmental institutions, farmers, cooperatives and producer associations. The certification (...) is becoming mandatory for those working in foreign markets and for those working nationally; it can be a competitive differential. The organic certification in citriculture shows the highest number of growers. Companies with large areas of citrus and the orange juice processing industry are adhering to this certification in order to maintain themselves competitive in the market. There is an enormous potential of Brazilian citriculture certification, because the certified area is still less than 6 % of the total area. Certification reduces the asymmetry of information and consists of an important step towards sustainability although incapable of solely guaranteeing it. (shrink)

El trabajo analiza la participación de la mujer en el proceso migratorio desde mediados del siglo XIX hasta los inicios del siglo XX mediante la colectividad alemana establecida en Valparaíso. Nos detenemos específicamente en la actividad social, el quehacer laboral y la vida familiar de la comunidad germana, con lo que podremos acceder a un ámbito poco conocido del accionar femenino en la empresa migratoria europea, en donde se desarrollan valores y costumbres que constituyen parte importante de la identidad alemana. (...) Se utilizan principalmente como fuentes diarios de vida y testamentos realizados por mujeres. The paper analyzes the participation of women in the migration process, since the mid-nineteenth century to the early twentieth century, through the established German community in Valparaiso. We stop specifically in social activity, professional work and family life of the German community, which we can access a little known field of women in the European migration, where they develop values and customs that are an important part of German identity. We mainly use as sources diaries and wills made??by women. (shrink)

Se analiza la evolución del transporte urbano, a través de un siglo, en una de las ciudades que experimentan mayores transformaciones tecnológicas como consecuencia de su condición de puerto muy vinculado al comercio internacional. Tal posicionamiento facilita la incorporación de mayores adelantos tecnológicos los cuales son también parte de la infraestructura que la ciudad requiere para llevar a cabo su quehacer económico en su dimensión externa. Efectivamente, la incorporación de la energía eléctrica en el transporte urbano constituye una expresión de (...) un proceso de modernización impulsado por la incorporación de tal medio energético en la actividad urbana de Valparaíso. Al mismo tiempo se hace notar las diferencias geográficas y sociales que presentan la ciudad y su vinculación al acceso a los medios de transporte y por consiguiente al proceso de modernización. (shrink)

A Computable Universe is a collection of papers discussing computation in nature and the nature of computation, a compilation of the views of the pioneers in the contemporary area of intellectual inquiry focused on computational and informational theories of the world. This volume is the definitive source of informational/computational views of the world, and of cutting-edge models of the universe, both digital and quantum, discussed from a philosophical perspective as well as in the greatest technical detail. The book discusses the (...) foundations of computation in relation to nature. It focuses on two main questions: What is computation? How does nature compute? The contributors are world-renowned experts who have helped shape a cutting-edge computational understanding of the universe. They discuss computation in the world from a variety of perspectives, ranging from foundational concepts to pragmatic models to ontological conceptions and their philosophical implications. The volume provides a state-of-the-art collection of technical papers and non-technical essays representing a field that takes information and computation to be key to understanding and explaining the basic structure underpinning physical reality. It also includes a new edition of Konrad Zuse's "Calculating Space", and a panel discussion transcription on the topic, featuring worldwide experts (including a Nobel prize) in quantum mechanics, physics, cognition, computation and algorithmic complexity.A Computable Universe is a collection of papers discussing computation in nature and the nature of computation, a compilation of the views of the pioneers in the contemporary area of intellectual inquiry focused on computational and informational theories of the world. This volume is the definitive source of informational/computational views of the world, and of cutting-edge models of the universe, both digital and quantum, discussed from a philosophical perspective as well as in the greatest technical detail. The book discusses the foundations of computation in relation to nature. It focuses on two main questions: What is computation? How does nature compute? The contributors are world-renowned experts who have helped shape a cutting-edge computational understanding of the universe. They discuss computation in the world from a variety of perspectives, ranging from foundational concepts to pragmatic models to ontological conceptions and their philosophical implications. The volume provides a state-of-the-art collection of technical papers and non-technical essays representing a field that takes information and computation to be key to understanding and explaining the basic structure underpinning physical reality. It also includes a new edition of Konrad Zuse's "Calculating Space", and a panel discussion transcription on the topic, featuring worldwide experts (including a Nobel prize) in quantum mechanics, physics, cognition, computation and algorithmic complexity. (shrink)

Building on a model first proposed by Gary Johnson, it is hypothesized that religious institutions demanding celibacy and other forms of altruism from members take advantage of human predispositions to favor genetic relatives in order to maintain and reinforce these desired behaviors in non-kin settings. This is accomplished through the institutionalization of practices to manipulate cues through which such relatives are regularly identified. These cues are association, phenotypic similarity, and the use of kin terms. In addition, the age of recruits (...) and their contact with actual kin are factors that relate to kinship recognition and that are similarly manipulated by institutions in order to reinforce altruistic behavior directed toward non-kin. Support for this set of predictions is presented from historical and ethnographic sources on monastic life in Buddhism, Christianity, and Hinduism, as well as Islamic dervish groups, the Essenes, Shakers, and others. Potential implications of the model for understanding the development of religious institutions are preliminarily explored by reviewing Joachim Wach's model of religious developmental stages as well as some of the literature on the relationship between individualism and communalism in incipient religious organizations, in light of the kin-cue manipulation model. (shrink)

This study explores the efficacy of a specific tool – the articulation of the ideal self – in job engagement, psychological well-being, and organizational citizenship behavior. We hypothesized that employees who can visualize their jobs as part of their ideal self – in particular how it helps in its development and realization – would feel higher levels of engagement and fulfillment in their lives, as well as engage in greater amounts of helping and voice OCB. A total of 239 full (...) time employees from five companies in Costa Rica filled out the ideal self questionnaire, the job engagement, and psychological well-being surveys, and were evaluated by their peers on task behavior and helping and voice OCB. Results of the SEM model showed that the ideal self was positively related to job engagement, psychological well-being and helping and voice. These findings contribute to the research on the impact and importance for organizations to help employees find meaningfulness in their work. (shrink)

The paper presents an exploration of conceptual issues that have arisen in the course of investigating speed-up and slowdown phenomena in small Turing machines, in particular results of a test that may spur experimental approaches to the notion of computational irreducibility. The test involves a systematic attempt to outrun the computation of a large number of small Turing machines (3 and 4 state, 2 symbol) by means of integer sequence prediction using a specialized function for that purpose. The experiment prompts (...) an investigation into rates of convergence of decision procedures and the decidability of sets in addition to a discussion of the (un)predictability of deterministic computing systems in practice. We think this investigation constitutes a novel approach to the discussion of an epistemological question in the context of a computer simulation, and thus represents an interesting exploration at the boundary between philosophical concerns and computational experiments. (shrink)

We have now provided an overall simple theoretical account of the structure of perceptual experience proto-philosophically examined in Part I. The next task is to find the proper logical machinery to formulatte those accounts rigorously.

Thinking, Language, and Experience was first published in 1989.Hector-Neri Castañeda's intricate and provocative essays have been widely influential, especially his work in epistemology and ethics, and his theory on the relation of thought to action. The fourteen essays in Thinking, Language, and Experience -- half of them written expressly for this volume -- demonstrate the breadth and richness of his recent work on the unitary structure of human experience.A comprehensive, unified study of phenomena at the intersection between experience, thinking, language, (...) and reality, this book focuses on singular reference -- that is, reference to individuals insofar as they are thought of as individuals: indicators, quasi-indicators, proper names, singular descriptions. Castañeda establishes a large number of new facts -- linguistic, semantic, psychological, and sociological -- about the workings of language in human experience, and from them develops a network of new theories, all grounded in his comprehensive Guise Theory.These theories offer a systematic account for: the structure of human experience and the world at large; the mental powers required to think of the world and to undergo experiences; self-consciousness; the language for thinking of other minds; perception and the interaction between indexical reference and perceptual fields; and the role of subjectivity in perception and intentional action. (shrink)

Inter-organizational models are both a well-documented phenomena and a well-established domain in management and business ethics. Those models rest on collaborative capabilities. However, mainstream theories and practices aimed at developing these capabilities are based on a narrow set of assumptions and ethical principles about human nature and relationships, which constrain the very development of capabilities sought by them. This article presents an Aristotelic–Thomistic approach to collaborative entrepreneurship within and across communities of firms operating in complementary markets. Adopting a scholarship of (...) integration approach and evaluating the six studies of communities of organizations, we contribute an inter-organizational network model based on the assumptions about human motives and choice offered by Aristotle. We argue that the sustainability of inter-organizational communities depends on how rich is the set of assumptions about human nature upon which they are based. In order to develop and sustain collaborative capabilities in inter-organizational communities, a set of assumptions that takes both self-regarding and others’-regarding preferences as ends is required to avoid any kind of instrumentalization of collaboration, which is an end in itself. Implications for theory and practice are discussed. (shrink)

Main description: Verbreitet ist die Auffassung, dass es vernünftig ist, moralisch zu handeln, weil es unvernünftig ist, gegen moralische Normen zu verstoßen. Gegen diese Ansicht vertritt der Autor die These, dass es immer vernünftigerweise erlaubt ist, moralisch zu handeln, dass aber im Falle eines Konflikts zwischen Klugheitsgründen und moralischen Normen sowohl die moralische als auch die unmoralische Handlungsweise vernünftigerweise erlaubt sind.

Liberados el romanticismo y el idealismo del lastre secular de su vínculo imaginario con la “catástrofe alemana” deviene una vez más posible recurrir a ellos para repensar los problemas teóricos y prácticos del presente y localizar nuevos instrumentos conceptuales para su solución. En este contexto recobran interés numerosos temas que fueron objetos privilegiados de reflexión por parte de los pensadores románticos e idealistas. El romanticismo exaltó la Revolución Francesa como un acontecimiento epocal de reivindicación de los derechos de los individuos (...) contra la opresión de las formas anquilosadas de la religión y la organización estatal. Los pensadores románticos se rebelaron contra el orden burgués en todas sus formas, contra la pauta ubicua de la razón económico-instrumental. Para Kant, lo que es útil e intercambiable no posee dignidad, sino precio. El rechazo romántico de la exhaustiva reducción del mundo a mercancía conduce a la recuperación del valor infinito de la naturaleza, en esa medida, a su “reencantamiento”. En una misma línea, el romanticismo preconiza tendencialmente todos los fenómenos no cuantificables, aquéllos que no permiten ser calculados en términos mercantiles: la corporeidad, el erotismo, la pasión, la imaginación y la fantasía, el arte y la poesía, lo telúrico, la diversidad individual y cultural. El idealismo, por su parte, busca una síntesis entre la concepción ilustrada del mundo material y la visión pre-moderna del mismo. El resultado de esa mediación es la explicitación de las estructuras del propio espíritu humano presentes en su comprensión del mundo, toda vez que para el idealismo el mundo es siempre la teoría de la mente humana sobre el mundo. El pensamiento ilustrado pudo por ello confundir la filosofía de la naturaleza de los idealistas con una visión de lo material viciada de antropomorfismo, más próxima a la mística y a los bestiarios medievales que a las ciencias naturales de la Edad Moderna. El idealismo, por el contrario, encuentra en esta suerte de principio antrópico de toda teoría un factor de liberación moral y política. La toma de conciencia de que es el sujeto el que crea sistemas de sentido y que, por tanto, éstos deben reflejar en sí mismos su origen humano, implica el corolario de que con las teorías –sea cual sea el ámbito de la realidad que ellas busquen explicar– se trata en verdad de dispositivos de ordenamiento para el conocimiento y la acción construidas por la propia subjetividad humana; en esta medida, en su origen no se encuentran datos brutos de un supuesto orden natural que debe, por tanto, ser respetado sacralmente, sino la propia comunidad de sujetos vivientes. Aunque haya dejado tras de sí y olvidado el proceso de mediaciones que le dio origen, aunque se presente, pues, como replegado sobre sí mismo y, en esa medida, como la suma de re-presentaciones de un orden encontrado en el mundo, cada sistema de ideas contiene el conjunto de prácticas subjetivas inferenciales que lo constituyeron y que fueron realizadas por múltiples sujetos en plexos históricos concretos. El idealismo consiste en explicitar a la subjetividad actuando en el objeto y, con ello, en conminar el peligro de la mutación de las teorías en ideologías. El fundamento último de la libertad descansa para el idealismo menos en el orden determinado que funciona como condición de posibilidad del ejercicio de la libertad que en el modo de autoconcepción de la propia subjetividad. A partir del mundo de las autoconcepciones del sujeto –para Hegel se trata del ámbito específico del sujeto que ha devenido por ello mismo absoluto– derivan luego, como sus corolarios prácticos, las formas concretas de ordenamiento social y político. Si bien asume en sí numerosos motivos románticos, el idealismo aspira también a una mediación de esos elementos con las contribuciones teóricas de la Ilustración, con la que guarda entonces una relación menos crítica que el romanticismo. Fruto de este espíritu más ecuménico y menos orientado a la ruptura, defiende una concepción más pacífica de la racionalidad capitalista y el mundo burgués. Hegel reivindica así el rol positivo del mercado con su división social del trabajo y una concepción menos revolucionaria y más reformista de la vida política. El neoliberalismo contemporáneo se concibe a sí mismo como el sistema que resulta naturalmente del principio de la libertad negativa. Una tesis central del idealismo alemán es que para que sea posible el ejercicio de la capacidad de decidirse autónomamente por diferentes metas es necesario el marco efectivo de la libertad positiva. Sin la presencia de un orden racional con poder coercitivo sobre los miembros de la sociedad para regular su conducta, la libertad negativa de esos miembros, a primera vista disminuida y parcialmente cercenada por aquel orden, no es en la práctica posible. (shrink)

En este trabajo se estudia la primera concepción escotista sobre las categorías y sobre el objeto del tratado aristotélico de las Categorías. El artículo se concentra sobre las tres primeras cuestiones del comentario de Duns Escoto al texto de Aristóteles. Una de las novedades del texto es su tematización del concepto mismo de categoría, entendido como concepto lógico y como objeto propio del tratado aristotélico. Esta aproximación permite a Escoto distinguir el orden lógico y el orden metafísico en el tratamiento (...) de las categorías. En el primero, la lógica se ocupa del concepto de categoría y, en el segundo, la metafísica se ocupa de la diversidad categorial y de su referencia a la categoría de la substancia. (shrink)

In this paper we analyze two recent conditional interpretations of defaults, one based on probabilities, and the other, on models. We study what makes them equivalent, explore their limitations and develop suitable extensions. The resulting framework ties together a number of important notions in default reasoning, like high-probabilities and model-preference, default priorities and argument systems, and independence assumptions and minimality considerations.

The aim of this paper is to propose an alternative behavioural definition of computation (and of a computer) based simply on whether a system is capable of reacting to the environment—the input—as reflected in a measure of programmability. This definition is intended to have relevance beyond the realm of digital computers, particularly vis-à-vis natural systems. This will be done by using an extension of a phase transition coefficient previously defined in an attempt to characterise the dynamical behaviour of cellular automata (...) and other systems. The transition coefficient measures the sensitivity of a system to external stimuli and will be used to define the susceptibility of a system to be (efficiently) programmed. (shrink)

Ao analisar a teoria da memória mecânica de Hegel, a maioria dos intérpretes considerou apenas dois aspectos da memorização mecânica: o desaparecimento do significado nas palavras mecânicamente memorizadas ou a internalização totalmente abstrata da mente que as memoriza. No primeiro caso, a interpretação concentrou-se na relação entre o significante e o significado das palavras; no segundo caso, concentrou-se na relação entre o signo linguístico como um todo e a mente. Entretanto, a posição específica da memória mecânica na sistematização das atividades (...) cognitivas de Hegel não se baseia nessas duas relações, mas na relação entre o significado de cada palavra e o significado das outras palavras. Ao memorizar de cor fileiras de palavras que não estão conectadas umas às outras por seus significados, mas apenas pela força da mente que decide memorizá-las juntas, a mente se liberta de qualquer conteúdo dado externamente e sublima a referência linear do conteúdo representacional de cada significado à intuição em sua origem. A atualização do poder da mente de interconectar conteúdos de acordo com as próprias regras lógicas da mente realiza, para Hegel, a transição para o pensamento propriamente dito. (shrink)

La exterioridad de una cosa o de un estado de cosas configurados por el ser humano no implica para Hegel que esa cosa o ese estado de cosas deban ya por ello ser considerados como formas del espíritu objetivo, mientras que en contrapartida las formas del espíritu absoluto estarían entonces conformadas por contenidos ideales del pensamiento. La diferencia entre espíritu objetivo y espíritu absoluto no radica en la diferencia entre lo que el espíritu humano “hace” y lo que “conoce”. En (...) efecto, las obras de arte, es decir, configuraciones exteriores hechas por el ser humano utilizando, por ejemplo, piedras, metales, colores o sonidos, son para Hegel instancias del espíritu absoluto, mientras que, por su parte, realidades que en cuanto tales no son intuibles, como, por ejemplo, los contratos o la organización estatal, son instancias del espíritu objetivo. Que Hegel considere al arte como una forma del espíritu absoluto pone de manifiesto que, a sus ojos, las cosas que intuimos en el universo son, en rigor, productos del propio sujeto que las conoce. Espontáneamente el sujeto cognoscente piensa que lo que intuye es algo que recibe desde un mundo externo; sostener que el arte es una forma de conocimiento es justamente el modo como Hegel está expresando que lo intuido es en todos los casos un contenido producido por el propio espíritu, que es, por así decirlo, una obra de arte humano. En el arte mismo, sin embargo, la producción de la cosa intuible es insuficiente, dado que el material que el espíritu utiliza para sus configuraciones conserva en mayor o menor medida, según el caso, una determinidad propia que resiste a la determinidad que el espíritu busca conferirle. Por esta razón, las obras de arte se presentan inicialmente como productos arbitrarios. Recién cuando integra sus intuiciones en la actividad de comprensión -actividad cognitiva con la que opera la filosofía- y media con ello completamente la determinidad de los contenidos intuidos, el espíritu configura finalmente un universo que le es propio y específico. El objetivo de mi ponencia es reconstruir desde el marco teórico recién expuesto el sentido y función que Hegel le atribuye al arte en su teoría del conocimiento. (shrink)

This is a presentation about joint work between Hector Zenil and Jean-Paul Delahaye. Zenil presents Experimental Algorithmic Theory as Algorithmic Information Theory and NKS, put together in a mixer. Algorithmic Complexity Theory defines the algorithmic complexity k(s) as the length of the shortest program that produces s. But since finding this short program is in general an undecidable question, the only way to approach k(s) is to use compression algorithms. He shows how to use the Compress function in Mathematica to (...) give an idea about the compressibility of various sequences. However, the idea of applying a compression algorithm breaks down for very short sequences. This is true not only for the Compress function, but also for any other compression algorithm. Zenil's approach is to construct a metric of algorithmic complexity for short sequences from scratch. He defines the algorithmic probability as the probability that an arbitrary program produces a sequence. The basic idea is to run a whole class of computational devices such as Turing Machines or Cellular Automata, and compute the distributions of the sequences they generate. Zenil presents a comparison of frequency distributions of sequences generated by 2-state 3-color Turing Machines and 2-color radius 1 Cellular Automata. He also compared these distributions to distributions found in data from the real world, and found that not only there is correlation across different systems, but also that the distributions are rather stable, and the difference between the distributions in abstract systems and real-world data can be attributed to noise. In his paper Zenil elaborates on the nature of the noise he has encountered. Zenil conjectures that the correlation distances between different systems decreases with a larger number of steps, and converge in the infinite limit case. (shrink)

One of the central concepts in rabbinic Judaism is the notion of the Evil Inclination, which appears to be related to similar concepts in ancient Christianity and the wider late antique world. The precise origins and understanding of the idea, however, are unknown. This volume traces the development of this concept historically in Judaism and assesses its impact on emerging Christian thought concerning the origins of sin. The chapters, which cover a wide range of sources including the Bible, the Ancient (...) Versions, Qumran, Pseudepigrapha and Apocrypha, the Targums, and rabbinic and patristic literature, advance our understanding of the intellectual exchange between Jews and Christians in classical Antiquity, as well as the intercultural exchange between these communities and the societies in which they were situated. (shrink)

While it is legitimate to study ideas and concepts related to information in their broadest sense, that formal approaches properly belong in specific contexts is a fact that is too often ignored. That their use outside these contexts amounts to misuse or imprecise use cannot and should not be overlooked. This paper presents a framework based on algorithmic information theory for discussing concepts of relevance to information in philosophical contexts. Special attention will be paid to the intersection of syntactic and (...) semantic variants and connections. (shrink)

El propósito de este escrito es reflexionar sobre el significado y la vigencia de la filosofíade la liberación en el actual contexto de la globalización y en el marco de la crisis dela modernidad ilustrada. La razón, para el pensamiento postmoderno, es débil, complejay plural; la historia carece de desarrollo progresivo y lineal. Sin embargo, estacrítica posmoderna parece dejarnos desprovistos de criterios para adelantar una acciónresponsable y solidaria de cara precisamente a los grandes desafíos globales delpresente. Ante estas insuficiencias posmodernas, (...) parece recuperable de la modernidadsu crítica racional a lo existente y la transformación de la praxis desde y a través de loracionalmente sabido. En el fondo, sigue abierta la posibilidad de una filosofía críticay liberadora. Y es aquí donde el pensamiento de Ignacio Ellacuría ofrece aportes a laaltura de los requerimientos teóricos y prácticos de hoy, fundamentalmente los tressiguientes: su visión estructural de la totalidad, su concepción de la historicidad de larealidad y su perspectiva de la relación teoría-praxis. (shrink)

Job satisfaction is a core variable in the study and practice of organizational psychology because of its implications for desirable work outcomes. Knowledge of its antecedents is abundant and informative, but there are still psychological processes underlying job satisfaction that have not received complete attention. This is the case of employee emotion regulation. In this study, we argue that employees’ behaviors directed to manage their affective states participate in their level of job satisfaction and hypothesize that employee affect-improving and -worsening (...) emotion regulation behaviors increase and decrease, respectively, job satisfaction, through the experience of positive and negative affect. Using a diary study with a sample of professionals from diverse jobs and organizations, for the most part, the mediational hypotheses were supported by the results albeit a more complex relationship was found in the case of affect worsening emotion regulation. This study contributes to expanding the job satisfaction and emotion regulation literatures and informs practitioners in people management in organizations about another route to foster and sustain positive attitudes at work. (shrink)

This book describes in detail the relationship between symbolic representations of knowledge and abstract states of knowledge, exploring along the way the foundations of knowledge, knowledge bases, knowledge-based systems, and knowledge representation and reasoning. The idea of knowledge bases lies at the heart of symbolic, or "traditional," artificial intelligence. A knowledge-based system decides how to act by running formal reasoning procedures over a body of explicitly represented knowledge—a knowledge base. The system is not programmed for specific tasks; rather, it is (...) told what it needs to know and expected to infer the rest. This book is about the logic of such knowledge bases. It describes in detail the relationship between symbolic representations of knowledge and abstract states of knowledge, exploring along the way the foundations of knowledge, knowledge bases, knowledge-based systems, and knowledge representation and reasoning. Assuming some familiarity with first-order predicate logic, the book offers a new mathematical model of knowledge that is general and expressive yet more workable in practice than previous models. The book presents a style of semantic argument and formal analysis that would be cumbersome or completely impractical with other approaches. It also shows how to treat a knowledge base as an abstract data type, completely specified in an abstract way by the knowledge-level operations defined over it. (shrink)