Semi-contraction is a withdrawal operation defined by Fermé in "On the logic of theory change: Contraction without recovery." In this paper we propose: (1) an axiomatic characterization of semi-contraction; (2) an alternative construction for semi-contraction based on semi-saturatable sets, inspired by Levi's saturatable sets; (3) a special kind of semi-contraction that satisfies the Lindström and Rabinowicz interpolation thesis.

This book explains how the logic of theory change employs formal models in the investigation of changes in belief states and databases. The topics covered include equivalent characterizations of AGM operations, extended representations of the belief states, change operators not included in the original framework, iterated change, applications of the model, its connections with other formal frameworks, and criticism of the model.

The 1985 paper by Carlos Alchourrón (1931–1996), Peter Gärdenfors, and David Makinson (AGM), "On the Logic of Theory Change: Partial Meet Contraction and Revision Functions" was the starting-point of a large and rapidly growing literature that employs formal models in the investigation of changes in belief states and databases. In this review, the first twentyfive years of this development are summarized. The topics covered include equivalent characterizations of AGM operations, extended representations of the belief states, change operators not included in (...) the original framework, iterated change, applications of the model, its connections with other formal frameworks, computatibility of AGM operations, and criticism of the model. (shrink)

The 1985 paper by Carlos Alchourrón, Peter Gärdenfors, and David Makinson, “On the Logic of Theory Change: Partial Meet Contraction and Revision Functions” was the starting-point of a large and rapidly growing literature that employs formal models in the investigation of changes in belief states and databases. In this review, the first twenty-five years of this development are summarized. The topics covered include equivalent characterizations of AGM operations, extended representations of the belief states, change operators not included in the original (...) framework, iterated change, applications of the model, its connections with other formal frameworks, computatibility of AGM operations, and criticism of the model. (shrink)

We introduce a constructive model of selective belief revision in which it is possible to accept only a part of the input information. A selective revision operator ο is defined by the equality K ο α = K * f(α), where * is an AGM revision operator and f a function, typically with the property ⊢ α → f(α). Axiomatic characterizations are provided for three variants of selective revision.

We propose a new class of multiple contraction operations — the system of spheres-based multiple contractions — which are a generalization of Grove’s system of spheres-based (singleton) contractions to the case of contractions by (possibly non-singleton) sets of sentences. Furthermore, we show that this new class of functions is a subclass of the class of the partial meet multiple contractions.

Since the early 1980s, logical theories of belief revision have offered formal methods for the transformation of knowledge bases or “corpora” of data and beliefs. Early models have dealt with unconditional acceptance and integration of potentially belief-contravening pieces of information into the existing corpus. More recently, models of “non-prioritized” revision were proposed that allow the agent rationally to refuse to accept the new information. This paper introduces a refined method for changing beliefs by specifying constraints on the relative plausibility of (...) propositions. Like the earlier belief revision models, the method proposed is a qualitative one, in the sense that no numbers are needed in order to specify the posterior plausibility of the new information. We use reference beliefs in order to determine the degree of entrenchment of the newly accepted piece of information. We provide two kinds of semantics for this idea, give a logical characterization of the new model, study its relation with other operations of belief revision and contraction, and discuss its intuitive strengths and weaknesses. (shrink)

This paper focuses on the extension of AGM that allows change for a belief base by a set of sentences instead of a single sentence. In [FH94], Fuhrmann and Hansson presented an axiomatic for Multiple Contraction and a construction based on the AGM Partial Meet Contraction. We propose for their model another way to construct functions: Multiple Kernel Contraction, that is a modification of Kernel Contraction, proposed by Hansson [Han94] to construct classical AGM contractions and belief base contractions. This construction (...) works out the unsolved problem pointed out by Hansson in [Han99, pp. 369]. (shrink)

This thesis consists in six articles and a comprehensive summary. • The pourpose of the summary is to introduce the AGM theory of belief change and to exemplify the diversity and significance of the research that has been inspired by the AGM article in the last 25 years. The research areas associated with AGM was divided in three parts: criticisms, where we discussed some of the more common criticisms of AGM. Extensions where the most common extensions and variations of AGM (...) are presented and applications where we provided an overview of applications and connections with other areas of research. • Article I elaborates on the connection between partial meet contractions [AGM85] and kernel contractions [Han94a] in belief change theory. Also both functions are equivalent in belief sets, there are notequivalent in belief bases. A way to define incision functions from selection functions and vice versa is presented. It is explained under which conditions there are exact correspondences between selection and incision functions so that the same contraction operations can be obtained by using either of them. • Article II proposes an axiomatic characterization for ensconcement-based contraction functions, belief base functions proposed byWilliams and relates this function with other kinds of base contraction functions. • Article III adapts the Fermé and Hansson model of Shielded Contraction [FH01] as well as Hansson et all Credibility-Limited Revision [HFCF01] for belief bases, to join two of the many variations of the AGM model [AGM85], i.e. those in which knowledge is represented through belief bases instead of logic theories, and those in which the object of the epistemic change does not get the priority over the existing information as it is the case in the AGM model. • Article IV introduces revision by comparison a refined method for changing beliefs by specifying constraints on the relative plausibility of propositions. Like the earlier belief revision models, the method proposed is a qualitative one, in the sense that no numbers are needed in order to specify the posterior plausibility of the new information. The method uses reference beliefs in order to determine the degree of entrenchment of the newly accepted piece of information. Two kinds of semantics for this idea are proposed and a logical characterization of the new model is given. • Article V focuses on the extension of AGM that allows change for a belief base by a set of sentences instead of a single sentence. In [FH94], Fuhrmann and Hansson presented an axiomatic for Multiple Contraction and a construction based on the AGM Partial Meet Contraction. This essay proposes for their model another way to construct functions: Multiple Kernel Contraction, that is a modification of Kernel Contraction,proposed by Hansson [Han94a] to construct classical AGM contractions and belief base contractions. • Article VI relates AGM model with the DFT model proposed by Carlos Alchourrón [Alc93]. Alchourrón devoted his last years to the analysis of the notion of defeasible conditionalization. His definition of the defeasible conditional is given in terms of strict implication operator and a modal operator f which is interpreted as a revision function at the language level. This essay points out that this underlying revision function is more general than AGM revision. In addition, a complete characterization of that more general kind of revision that permits to unify models of revision given by other authors is given. (shrink)

Revision operation is the consistent expansion of a theory by a new belief-representing sentence. We consider that in a paraconsistent setting this desideratum can be accomplished in at least three distinct ways: the output of a revision operation should be either non-trivial or non-contradictory (in general or relative to the new belief). In this paper those distinctions will be explored in the constructive level by showing how the remainder sets could be refined, capturing the key concepts of paraconsistency in a (...) dynamical scenario. These are preliminaries results of a wider project on Paraconsistent Belief Change conduced by the authors. (shrink)

In this article we present a new class of multiple contraction functionswhich are a generalization of the epistemic entrenchment-based contractions (Grdenfors & Makinson, 1988) to the case of contractions by (possibly nonsingleton) sets of sentences and provide an axiomatic characterization for that class of functions. Moreover, we show that the class of epistemic entrenchment-based multiple contractions coincides with the class of system of spheres-based multiple contractions introduced in Fermé & Reis (2012).

Alchourrón devoted his last years to the analysis of the notion of defeasible conditionalization. He developed a formal system capturing the essentials of this notion. His definition of the defeasible conditional is given in terms of strict implication operator and a modal operator f which is interpreted as a revision function at the language level. In this paper, we will point out that this underlying revision function is more general than the well known AGM revision [4]. In addition, we will (...) give a complete characterization of that more general kind of revision and will show how permits to unify models of revision given by other authors. Alchourrón dedicó sus últimos años al análisis de la noción de condicionalización derrotable. Desarrolló un sistema formal que captura los aspectos esenciales de esta noción. Su definición de condicional revisable está dada en términos del operador de implicación estricta y un operador modal f el cual es interpretado en el nivel del lenguaje como una función de revisión. En este trabajo señalamos que la función de revisión subyacente es más general que la bien conocida función de revisión de AGM. Además, presentaremos una caracterización completa de una clase de revisión más general y mostraremos cómo nuestro modelo permite unificar los modelos de revisión propuestos por otros autores. (shrink)

Five types of constructions are introduced for non-prioritized belief revision, i.e., belief revision in which the input sentence is not always accepted. These constructions include generalizations of entrenchment-based and sphere-based revision. Axiomatic characterizations are provided, and close interconnections are shown to hold between the different constructions.

This paper focuses on the extension of AGM that allows change for a belief base by a set of sentences instead of a single sentence. In [FH94], Fuhrmann and Hansson presented an axiomatic for Multiple Contraction and a construction based on the AGM Partial Meet Contraction. We propose for their model another way to construct functions: Multiple Kernel Contraction, that is a modification of Kernel Contraction, proposed by Hansson [Han94] to construct classical AGM contractions and belief base contractions. This construction (...) works out the unsolved problem pointed out by Hansson in [Han99, pp. 369]. (shrink)

The postulate of Recovery, among the six postulates for theory contraction, formulated and studied by Alchourrón, Gärdenfors and Makinson is the one that has provoked most controversy. In this article we construct withdrawal functions that do not satisfy Recovery, but try to preserve minimal change, and relate these withdrawal functions with the AGM contraction functions.

Five types of constructions are introduced for non-prioritized belief revision, i.e., belief revision in which the input sentence is not always accepted. These constructions include generalizations of entrenchment-based and sphere-based revision. Axiomatic characterizations are provided, and close interconnections are shown to hold between the different constructions.

This paper aims at comparing and relating belief revision and argumentation as approaches to model reasoning processes. Referring to some prominent literature references in both fields, we will discuss their (implicit or explicit) assumptions on the modeled processes and hence commonalities and differences in the forms of reasoning they are suitable to deal with. The intended contribution is on one hand assessing the (not fully explored yet) relationships between two lively research fields in the broad area of defeasible reasoning and (...) on the other hand pointing out open issues and potential directions for future research. (shrink)

In the logic of theory change, the standard model is AGM, proposed by Alchourrón et al. (J Symb Log 50:510–530, 1985 ). This paper focuses on the extension of AGM that accounts for contractions of a theory by a set of sentences instead of only by a single sentence. Hansson (Theoria 55:114–132, 1989 ), Fuhrmann and Hansson (J Logic Lang Inf 3:39–74, 1994 ) generalized Partial Meet Contraction to the case of contractions by (possibly non-singleton) sets of sentences. In this (...) paper we present the possible worlds semantics for partial meet multiple contractions. (shrink)

This chapter contains sections titled: Belief Revision in Latin America: The Legacy of Carlos Alchourrón The AGM Approach The Logic of Theory Change and Epistemology What Is an Epistemic State? Departures from AGM References.

Eduardo Arroyo, Armelle Auris, François Boissonnet, Paul HENRY, Pierre-Jean LABARRIERE, MATIEU, Gilles AILLAUD, Gérad THALMANN, Nicole MATHIEU, Jacques VIMARD, Michel QUAREZ, Leonardo CREMONINI, L'atelier d'Eduardo Arryo: Le carré blanc du ring, Rue Descartes, No. 7, Logiques de l'éthique (Juin 1993), pp. 149-168.

Entrevista com o Prof. Eduardo Jardim, Revisor técnico da edição brasileira de "Pensar sem corrimão", mais recente livro de Hannah Arendt no Brasil.

Nous partageons, au sujet de la nature du temps, l’intuition fondamentale selon laquelle le futur est ouvert tandis que le passé est fermé. Par exemple, alors que nous pensons pouvoir influencer le cours du futur, nous savons qu’aucune de nos actions ne peut influencer le cours du passé. Cependant, bien que cette intuition soit largement partagée, identifier la nature de l’asymétrie qu’elle reflète n’est pas chose aisée. Dans cet article, j’explore différentes manières de caractériser l’asymétrie entre le ‘futur ouvert’ et (...) le ‘passé fermé’ dans le but de rendre justice à notre intuition. En particulier, je discute la question de savoir si cette asymétrie doit être caractérisée de façon sémantique, épistémique, métaphysique ou ontologique. Je conclus que, bien que plusieurs de ces caractérisations contribuent à une compréhension globale du phénomène, une caractérisation ontologique de l’asymétrie doit être préférée, car elle s’avère supérieure en termes de pouvoir explicatif, d’intelligibilité, ainsi que dans sa capacité à inclure différents sens que l’on peut prêter au concept d’ouverture. (shrink)

_The Power of Religion in the Public Sphere_, co-edited by Eduardo Mendieta and Jonathan VanAntwerpen, represents a rare opportunity to experience a diverse group of preeminent philosophers confronting one pervasive contemporary concern: what role does, or should, religion play in our public lives? Reflecting on her recent work concerning state violence in Israel-Palestine, Judith Butler explores the potential of religious perspectives for renewing cultural and political criticism, while Jürgen Habermas, best known for his seminal conception of the public sphere, (...) thinks through the ambiguous legacy of the concept of "the political" in contemporary theory. Charles Taylor argues for a radical redefinition of secularism, and Cornel West defends civil disobedience and emancipatory theology. Eduardo Mendieta and Jonathan VanAntwerpen detail the immense contribution of these philosophers to contemporary social and political theory, and an afterword by Craig Calhoun places these attempts to reconceive the significance of both religion and the secular in the context of contemporary national and international politics. (shrink)

Se postula en este artículo que existe a lo largo de la historia del pensamiento una fascinación por la capacidad creativa, considerándosela una facultad distintiva a través de la cual los individuos y las sociedades pueden expandir sus posibilidades más allá de lo existente, y se desarrolla la hipótesis de tres niveles ascendentes de creatividad que contienen a su vez tres “metodologías” para su desarrollo. Estos niveles son: las técnicas de aprendizaje creativo, el cambio de paradigma y el viaje al (...) interior de uno mismo. (shrink)

Este texto recoge la propuesta de algunas tradiciones espirituales sobre la existencia de un arte objetivo, vinculado al estado de meditación y a la posibilidad del ser humano de adquirir una conciencia objetiva, señalándose lo lejana que está esta propuesta de la cultura de la modernidad y la postmodernidad. Pese a ello, sostiene que existiría un puente entre este arte objetivo y el arte crítico que devela el ocultamiento ideológico permitiendo mirar con los propios ojos, a través de sostener que (...) tienen en común la búsqueda de comprensión de la realidad, pero diferenciándose en cómo la comprenden. (shrink)

El libro de Oriana Zorrilla es un texto de investigación periodística importante, que instala en el debate nacional un tema que coloca la experiencia existencial del maltrato en el escenario democrático, retratando una realidad desconocida de acoso laboral a los empleados públicos, constituyéndose en un tema político sobre la calidad y profundidad de nuestra democracia. Ya en el prólogo Armando Uribe señala que el libro “es la denuncia bien fundada en la historia personal y colectiva, y tiene..

El autor plantea que si Dios ha regresado, es porque en realidad nunca se fue; aunque debió refugiarse en la gruta de los místicos. Si ha vuelto es porque las grandes tradiciones espirituales de todos los tiempos: sufismo, hinduismo, budismo, cristianismo, y también las tradiciones chamánicas del mundo latino y norteamericano previo a la invasión europea, han vuelto a hacer oír su voz profunda en el territorio de la modernidad occidental. Y lo han hecho con su misma enseñanza profunda presentada (...) bajo nuevas formas. Pero también su Dios regresó es porque la cultura hegemónica occidental está y las personas han vuelto a tener oídos para Dios. Ilustra este proceso el autor con la presentación de algunos maestros espirituales contemporáneos y sus fuentes, a la vez que con una breve historia de su influencia en Chile. (shrink)