We look at two fundamental logical processes, often intertwined in planning and problem solving: inference and update. Inference is an internal process with which we uncover what is implicit in the information we already have. Update, on the other hand, is produced by external communication, usually in the form of announcements and in general in the form of observations, giving us information that might not have been available (even implicitly) before. Both processes have received attention from the logic community, usually (...) separately. In this work, we develop a logical language that allows us to describe them together. We present syntax, semantics and a complete axiom system; we discuss similarities and differences with other approaches and mention how the work can be extended. (shrink)

Classical epistemic logic describes implicit knowledge of agents about facts and knowledge of other agents based on semantic information. The latter is produced by acts of observation or communication that are described well by dynamic epistemic logics. What these logics do not describe, however, is how significant information is also produced by acts of inference— and key axioms of the system merely postulate "deductive closure". In this paper, we take the view that all information is produced by acts, and hence (...) we also need a dynamic logic of inference steps showing what effort on the part of the agent makes a conclusion explicit knowledge. Strong omniscience properties of agents should be seen not as static idealizations, but as the result of dynamic processes that agents engage in. This raises two questions: (a) how to define suitable information states of agents and matching notions of explicit knowledge, (b) how to define natural processes over these states that generate new explicit knowledge. To this end, we use a static base from the existing awareness literature, extending it into a dynamic system that includes traditional acts of observation, but also adding and dropping formulas from the current ' awareness' set. We give a completeness theorem, and we show how this dynamics updates explicit knowledge. Then we extend our approach to multi-agent scenarios where awareness changes may happen privately. Finally, we mention further directions and related approaches. Our contribution can be seen as a ' dynamification' of existing awareness logics. (shrink)

Epistemic logic with its possible worlds semantic model is a powerful framework that allows us to represent an agent’s information not only about propositional facts, but also about her own information. Nevertheless, agents represented in this framework are logically omniscient: their information is closed under logical consequence. This property, useful in some applications, is an unrealistic idealisation in some others. Many proposals to solve this problem focus on weakening the properties of the agent’s information, but some authors have argued that (...) solutions of this kind are not completely adequate because they do not look at the heart of the matter: the actions that allow the agent to reach such omniscient state. Recent works have explored how acts of observation, inference, consideration and forgetting affect an agent’s implicit and explicit knowledge; the present work focuses on acts that affect an agent’s implicit and explicit beliefs. It starts by proposing a framework in which these two notions can be represented, and then it looks into their dynamics, first by reviewing the existing notion of belief revision, and then by introducing a rich framework for representing diverse forms of inference that involve both knowledge and beliefs. (shrink)

This work proposes an understanding of deductive, default and abductive reasoning as different instances of the same phenomenon: epistemic dynamics. It discusses the main intuitions behind each one of these reasoning processes, and suggest how they can be understood as different epistemic actions that modify an agent’s knowledge and/or beliefs in a different way, making formal the discussion with the use of the dynamic epistemic logic framework. The ideas in this paper put the studied processes under the same umbrella, thus (...) highlighting their relationship and allowing a better understanding of how they interact together. (shrink)

As a new type of epistemic logics, the logics of knowing how capture the high-level epistemic reasoning about the knowledge of various plans to achieve certain goals. Existing work on these logics focuses on axiomatizations; this paper makes the first study of their model theoretical properties. It does so by introducing suitable notions of bisimulation for a family of five knowing how logics based on different notions of plans. As an application, we study and compare the expressive power of these (...) logics. (shrink)

In this paper, we explore the relation between an agent’s doxastic attitude and her arguments in support of a given claim. Our main contribution is the design of a logical setting that allows us reason about binary arguments which are either in favour or against a certain claim. This is a setting in which arguments and propositions are the basic building blocks so that the concept of argument-based belief emerges in a straightforward way. We work against the background of Dung’s (...) abstract argumentation framework, extending it to a new setting in which we can study the formal properties of binary arguments as well as the larger structures they establish. This paper introduces a formal ‘two-dimensional’ language to talk about propositions and arguments, for which a sound and complete axiom system is provided. (shrink)

Among the non-monotonic reasoning processes, abduction is one of the most important. Usually described as the process of looking for explanations, it has been recognized as one of the most commonly used in our daily activities. Still, the traditional definitions of an abductive problem and an abductive solution mention only theories and formulas, leaving agency out of the picture. Our work proposes a study of abductive reasoning from an epistemic and dynamic perspective. In the first part we explore syntactic definitions (...) of both an abductive problem in terms of an agent’s information and an abductive solution in terms of the actions that modify the agent’s information. We look at diverse kinds of agents, including not only omniscient ones but also those whose information is not closed under logical consequence and those whose reasoning abilities are not complete. In the second part, we look at an existing logical framework whose semantic model allows us to interpret the previously stated formulas, and we define two actions that represent forms of abductive reasoning. (shrink)

Classical epistemic logic describes implicit knowledge of agents about facts and knowledge of other agents based on semantic information. The latter is produced by acts of observation or communication that are described well by dynamic epistemic logics. What these logics do not describe, however, is how significant information is also produced by acts of inference—and key axioms of the system merely postulate “deductive closure”. In this paper, we take the view that all information is produced by acts, and hence we (...) also need a dynamic logic of inference steps showing what effort on the part of the agent makes a conclusion explicit knowledge. Strong omniscience properties of agents should be seen not as static idealizations, but as the result of dynamic processes that agents engage in. This raises two questions: (a) how to define suitable information states of agents and matching notions of explicit knowledge, (b) how to define natural processes over these states that generate new explicit knowledge. To this end, we use a static base from the existing awareness literature, extending it into a dynamic system that includes traditional acts of observation, but also adding and dropping formulas from the current ‘awareness’ set. We give a completeness theorem, and we show how this dynamics updates explicit knowledge. Then we extend our approach to multi-agent scenarios where awareness changes may happen privately. Finally, we mention further directions and related approaches. Our contribution can be seen as a ‘dynamification’ of existing awareness logics. (shrink)

This paper is part of an on-going programme on the study of the logical aspects of social network formation. It recalls the so-called social network model, discussing the properties of a notion of closeness between agents ; then introduces an extended social network model in which different agents might assign different values to different traits, discussing the properties of the notion of weighted closeness that arises. These notions are used to define social network creation operations by means of a threshold (...) strategy. The paper studies the properties of the social networks the updates create, providing sound and complete axiom systems for formal languages describing these updates’ effects. (shrink)

Theory of Mind (ToM), the cognitive capacity to attribute internal mental states to oneself and others, is a crucial component of social skills. Its formal study has become important, witness recent research on reasoning and information update by intelligent agents, and some proposals for its formal modelling have put forward settings based on Epistemic Logic (EL). Still, due to intrinsic idealisations, it is questionable whether EL can be used to model the high-order cognition of ‘real’ agents. This manuscript proposes a (...) framework that takes visibility, memory, perspective and communication as the main factors underpinning mental attributions. This is more in-line with findings in cognitive science and allows us to model well-known False-Belief Tasks that are typically used in testing people's ToM. We discuss some of the framework's technical features, arguing why it does justice to empirical observations. (shrink)

The paper develops an interface between syntax-based logical models of awareness and dynamic epistemic logic. The framework is shown to be able to accommodate a variety of notions of awareness and knowledge, as well as their dynamics. This, it is argued, offers a natural formal environment for the analysis of epistemic phenomena typical of multi-agent information exchange, such as how agents become aware of relevant details, how they perform inferences and how they share their information within a group. Technically, the (...) logics presented are all simple refinements of the logic of public announcements. (shrink)

This manuscript presents a topological argumentation framework for modelling notions of evidence-based (i.e., justified) belief. Our framework relies on so-called topological evidence models to represent the pieces of evidence that an agent has at her disposal, and it uses abstract argumentation theory to select the pieces of evidence that the agent will use to define her beliefs. The tools from abstract argumentation theory allow us to model agents who make decisions in the presence of contradictory information. Thanks to this, it (...) is possible to define two new notions of beliefs, grounded beliefs and fully grounded beliefs. These notions are discussed in this paper, analysed and compared with the existing notion of topological justified belief. This comparison revolves around three main issues: closure under conjunction introduction, the level of consistency and their logical strength. (shrink)

This paper introduces and studies a notion of cautious distributed belief. Different from the standard distributed belief, the cautious distributed belief of a group is inconsistent only when all group members are individually inconsistent. The paper presents basic results about cautious distributed belief, investigates whether it preserves properties of individual belief, and compares it with standard distributed belief. Although both notions are equivalent in the class of reflexive models, this is not the case in general. While we argue that an (...) understanding of the concept of cautious distributed belief from first principles is important, cautious distributed belief can be expressed using standard distrbuted belief and we show that the propositional language extended only with cautious distributed belief is in fact strictly less expressive than the propositional language extended only with standard distributed belief. We, finally, identify a small extension of the language making the former as expressive as the latter. (shrink)

Communication within groups of agents has been lately the focus of research in dynamic epistemic logic. This paper studies a recently introduced form of partial (more precisely, topic-based) communication. This type of communication allows for modelling scenarios of multi-agent collaboration and negotiation, and it is particularly well-suited for situations in which sharing all information is not feasible/advisable. The paper can be divided into two parts. In the first part, we present results on invariance and complexity of model checking. Moreover, we (...) compare partial communication with the public announcement and arrow update settings in terms of both language-expressivity and update-expressivity. Regarding the former, the three settings are equivalent, their languages being equally expressive. Regarding the latter, all three modes of communication are incomparable in terms of update-expressivity. In the second part, we shift our attention to strategic topic-based communication. We do so by extending the language with a modality that quantifies over the topics the agents can ‘talk about’, thus allowing a form of arbitrary partial communication. For this new framework, we provide a complete axiomatisation, showing also that the new language’s model checking problem is PSPACE-complete. Finally, we argue that, in terms of expressivity, this new language of arbitrary partial communication is incomparable to that of arbitrary public announcements and also to that of arbitrary arrow updates. (shrink)

The paper focuses on a recent challenge brought forward against the interventionist approach to the meaning of counterfactual conditionals. According to this objection, interventionism cannot account for the interpretation of right-nested counterfactuals, the problem being its strict interventionism. We will report on the results of an empirical study supporting the objection. Furthermore, we will extend the well-known logic of intervention with a new operator expressing an alternative notion of intervention that does away with strict interventionism. This new notion of intervention (...) operates on the valuation of the variables in a causal model, and not on their functional dependencies. (shrink)

Belief revision is concerned with belief change fired by incoming information. Despite the variety of frameworks representing it, most revision policies share one crucial feature: incoming information outweighs current information and hence, in case of conflict, incoming information will prevail. However, if one is interested in representing the way actual humans revise their beliefs, one might not always want for the agent to blindly believe everything they are told. This manuscript presents a semantic approach to non-prioritized belief revision. It uses (...) plausibility models for depicting an agent’s beliefs, and model operations for displaying the way beliefs change. The first proposal, semantically-based screened revision, compares the current model with the one the revision would yield, accepting or rejecting the incoming information depending on whether the ‘differences’ between these models go beyond a given threshold. The second proposal, semantically-based gradual revision, turns the binary decision of acceptance or rejection into a more general setting in which a revision always occurs, with the threshold used rather to choose ‘the right revision’ for the given input and model. (shrink)

The paper proposes a logical framework representing the notion of explicit knowledge as the combination of awareness of and awareness that. The setting, semantically combining neighbourhood models with ideas from awareness logic, separates the mere fact of entertaining some information (being aware of $\varphi$) from the acknowledgement that the information is indeed the case (being aware that $\varphi$ holds). The text discusses not only the main properties these concepts obtain under the given representation, but also several of the epistemic actions (...) that can be defined, and the way they affect the agent’s awareness (and thus her knowledge). (shrink)

We investigate dynamic operations acting over a knowing how logic. Our approach makes use of a recently introduced semantics for the knowing how operator, based on an indistinguishability relation between plans. This semantics is arguably closer to the standard presentation of knowing that modalities in classic epistemic logic. Here, we discuss how the semantics enables us to define dynamic modalities representing different ways in which an agent can learn how to achieve a goal. In this regard, we study two types (...) of updates: ontic updates (for which we provide axiomatizations over a particular class of models), and epistemic updates (for which we investigate some semantic properties). (shrink)

Abductive problems and their solutions are presented by means of justification logic. We introduce additional meta-constructions in order to generate and compare different solutions to the same abductive problem. Our approach has three advantages: (i) it makes structurally explicit the solution to an abductive problem (as it has a syntactic nature); (ii) it gives a precise meaning to the notion of evidence; (iii) it provides clear definitions and procedures for the comparison of solutions that can be adapted to different needs.

Tras la llegada de los conquistadores españoles y durante los dos siglos del reinado de su monopolio, no se permitió el ingreso de extranjeros y la población permaneció distribuida en las regiones, en proporciones casi inversas a las actuales. Con la caída del régimen español y los avances del monopolio inglés, comenzó a desplazarse el centro territorial argentino desde el Noroeste hacia el Litoral y a producirse variaciones en la dinámica demográfica. El establecimiento del modelo agroexportador produjo una afluencia excepcional (...) de inmigrantes de ultramar, que generaron cambios vertiginosos en la estructura de la población. Asimismo, el fin del modelo agroexportador que provocó la abrupta interrupción del flujo inmigratorio de ultramar, generó nuevamente otro intenso cambio demográfico que incidió en la estructura poblacional hasta la actualidad. Este artículo se centra en el movimiento migratorio que produjo el modelo agroexportador, con el objetivo de analizar sus efectos en el ritmo de crecimiento de la población, en la distribución de las variables demográficas básicas —sexo y edad—, y en los cambios en la distribución espacial, siendo su fuente principal los censos nacionales de población realizados hasta la actualidad. (shrink)

La presente obra reúne los temas imprescindibles de un curso de filosofía política, dirigido tanto a estudiantes como a lectores interesados en la historia, los fundamentos y las implicaciones actuales de esta disciplina. La primera parte trata de la tradición liberal, los socialismos, las dimensiones del nacionalismo, el feminismo como proyecto filosófico-político y la institución de la democracia. La segunda parte aborda en profundidad un amplio abanico de cuestiones, desde la globalización o los problemas de legitimación del poder, pasando por (...) las relaciones entre Estado y nación, los derechos humanos como legado de la Modernidad o la actualidad y perspectivas de la ciudadanía, hasta la multiculturalidad y la inmigración, los movimientos sociales, la ecología o la justicia social. (shrink)

Ao desenvolver a ciência biológica, o ser humano logrou obter novas variedades de animais e de plantas, a partir das silvestres. Quando as técnicas de engenharia genética se aplicaram a êstes organismos, obtiveram-se êxitos que se traduziram em dezenas de animais e de plantas com modificações genéticas agora hereditárias. Segundo o artigo, da análise bioética dos organismos modificados geneticamente e da sua utilizaçéo surgem várias propostas: 1) o direito do consumidor a ser informado em termos que possa entender acerca da (...) natureza das mudanças genéticas realizadas nos alimentos, 2) o direito do consumidor a decidir livremente se os quer consumir ou não e, 3) os deveres morais e científicos dos cientistas e das indústrias agro-alimentares para demonstrar a inocuidade destes animais e plantas transgénicos para o ser humano, o meio ambiente e a biodiversidade. /// Through the development of biological science, humankind was able to obtain new varieties of animals and plants in a process beginning with the wild species. When genetic engineering techniques were applied to these organisms, several dozens of transgenic organisms were obtained including plants and animals with specific inheritable changes, which are now transgenic foods. From the bioethical analysis of genetically modified organisms the article argues in favor of the right of the consumer to be informed in terms he or she can understand on the nature of genetic changes induced in foods, as well as in favor of the right of consumers to choose between standard or modified food. Finally, the article also argues in favor of the moral and scientific duties of scientists and food industries to demonstrate that genetically modified foods are not dangerous to human beings or noxious to the environment or biota. (shrink)

This chapter contains sections titled: Acosta, José de (1539–1600) Alberdi, Juan Bautista (1810–84) Bello, Andrés (1781–1865) Bilbao, Francisco (1823–65) Bolkvar, Simón (1783–1830) Casas, Bartolomé de las (1484–1566) Caso, Antonio (1883–1946) Cruz, Sor Juana Inés de la (1651–95) da Costa, Newton Carneiro Affonso (b. 1929) Dussel, Enrique (b. 1934) Frondizi, Risieri (1910–83) Gaos, José (1900–69) González Prada, Manuel (1848–1918) Gracia, Jorge J. E. (b. 1942) Haya de la Torre, Victor Raúl (1895–1979) Hostos, Eugenio Marka de (1839–1903) Ingenieros, José (1877–1925) Korn, Alejandro (...) (1860–1936) Lastarria, José Victorino (1817–88) Lemos, Miguel (1854–1917) Mariátegui, José Carlos (1895–1930) Martk, José (1853–95) Méndez Sierra, Justo (1848–1912) Mora, José Maria Luis (1794–1850) Miró Quesada, Francisco (b. 1918) Rabossi, Eduardo (1930–2005) Ramos, Samuel (1897–1959) Rodó, José Enrique (1872–1917) Romero, Francisco (1891–1962) Sahagún, Fray Bernardino de (1499–1590) Salazar Bondy, Augusto (1925–74) Sarmiento, Domingo Faustino (1811–88) Ofelia Schutte (b. 1945) Sepslveda, Juan Ginés de (ca. 1494–1573) Torretti, Roberto (b. 1930) Vasconcelos, José (1882–1959) Vaz Ferreira, Carlos (1872–1958) Villoro, Luis (b. 1922) Vitoria, Francisco de (ca. 1483–1546) Zea Aguilar, Leopoldo (1912–2004) Acknowledgment Further Reading. (shrink)

This special issue on Formal Models of Awareness contains five papers that concentrate on different approaches to the notion of awareness. They include syntactic and semantic approaches to modelling awareness and an alternative view from the multi-agent systems perspective where awareness is identified as the ability to perceive and understand actions of other agents.Velázquez-Quesada studies a logic of plausibility acknowledgement models used to interpret the notions of implicit and explicit beliefs. The models use the notion of a formula (...) being acknowledged as true that is similar to syntactic awareness in that the set of formulas acknowledged as true by an agent is not assumed to be closed under logical consequence. However it has a different meaning . A dynamic epistemic logic over such models is cons .. (shrink)

In Frege’s logicism, numbers are logical objects in the sense that they are extensions of certain concepts. Frege’s logical system is inconsistent, but Richard Heck showed that its restriction to predicative quantification is consistent. This predicative fragment is, nevertheless, too weak to develop arithmetic. In this paper, I will consider an extension of Heck’s system with impredicative quantifiers. In this extended system, both predicative and impredicative quantifiers co-exist but it is only permissible to take extensions of concepts formulated in the (...) predicative fragment of the language. This system is consistent. Moreover, it proves the principle of reducibility applied to concepts true of only finitely many objects. With the aid of this form of reducibility, it is possible to develop arithmetic in a thoroughly Fregean way. (shrink)

When, on December 7, 2000, the European Parliament, the Council and the Commission proclaimed solemnly in Nice the Charter of Fundamental Rights of the European Union, many thought that European integration was practically guaranteed and that the Charter would soon be made into a binding legal text. Since then, the two attempts to enact a European consitution - the Constitutional Treaty for the European Union of 2004 and the arguably less ambitious Treaty of Lisbon of 2007 - both failed. Further (...) efforts at unification have stagnated, in part due to the 2008 economic crisis and the European Union’s inability to coordinate responses to issues as serious as immigration, the refugee crisis, and terrorism. In this paper, I examine a theoretical counterpoint to that bleak perspective for European unification, to wit, Jürgen Habermas’ eurofederalist proposal of the postnational democracy and European constitutional patriotism. (shrink)

En este texto abordamos la problemática de las fuentes existentes y sus metodologías de análisis para el estudio de las grandes revueltas de esclavos de la República romana. Nuestro objetivo consiste en dilucidar cuáles son los diferentes tipos de fuentes que disponemos y sus estados de conservación; señalar las dificultades y posibilidades heurísticas que presentan; y analizarlas desde un punto de vista historiográfico. Si bien la mayoría de ellas, y las literarias en su totalidad, provienen de la élite ciudadana, y, (...) en consecuencia, expresan el punto de vista de los vencedores, hostil a la revuelta servil, e implican parcialidad, distorsión y ocultamiento en el registro histórico, argumentamos que no conviene exagerar su sesgo como un factor limitante del conocimiento de los hechos. Pues, por una parte, resulta posible extraer de las fuentes narrativas información valiosa sobre los esclavos rebeldes; por otra, también se conservan algunas fuentes materiales elaboradas por estos últimos. Todo lo cual nos permite al menos vislumbrar la visión de los vencidos. (shrink)

We introduce a herbrandized functional interpretation of a first-order semi-intuitionistic extension of Heyting Arithmetic and study its main properties. We then extend the interpretation to a certain system of second-order arithmetic which includes a (classically false) formulation of the FAN principle and weak König's lemma. It is shown that any first-order formula provable in this system is classically true. It is perhaps worthy of note that, in our interpretation, second-order variables are interpreted by finite sets of natural numbers.

In "'Yes" and "No'" (2000), Ian Rumfitt proposed bilateralism--a use-based account of the logical words, according to which the sense of a sentence is determined by the conditions under which it is asserted and denied. One of Rumfitt's key claims is that bilateralism can provide a justification of classical logic. This paper raises a techical problem for Rumfitt's proposal, one that seems to undermine the bilateralist programme.

There is no systematic knowledge about how individuals with Locked-in Syndrome experience their situation. A phenomenology of LIS, in the sense of a description of subjective experience as lived by the ill persons themselves, does not yet exist as an organized endeavor. The present article takes a step in that direction by reviewing various materials and making some suggestions. First-person narratives provide the most important sources, but very few have been discussed. LIS barely appears in bioethics and neuroethics. Research on (...) Quality of Life provides relevant information, one questionnaire study explores the sense of personal continuity in LIS patients, and LIS has been used as a test case of theories in “embodied cognition” and to explore issues in the phenomenology of illness and communication. A systematic phenomenology of LIS would draw on these different areas: while some deal directly with subjective experience, others throw light on its psychological, sociocultural and materials conditions. Such an undertaking can contribute to the improvement of care and QOL, and help inform philosophical questions, such as those concerning the properties that define persons, the conditions of their identity and continuity, or the dynamics of embodiment and intersubjectivity. (shrink)

The control principle implies that people should not feel guilt for outcomes beyond their control. Yet, the so-called ‘agent and observer puzzles’ in philosophy demonstrate that people waver in their commitment to the control principle when reflecting on accidental outcomes. In the context of car accidents involving conventional or autonomous vehicles, Study 1 established that judgments of responsibility are most strongly associated with expressions of guilt–over and above other negative emotions, such as sadness, remorse or anger. Studies 2 and 3 (...) then confirmed that, while people generally endorse the control principle, and deny that occupants in an AV should feel guilt when involved in an accident, they nevertheless ascribe guilt to those same occupants. Study 3 also uncovered novel implications of the observer puzzle in the legal context: Passengers in an AV were seen as more legally liable than either passengers in a conventional vehicle, or even their drivers–especially when participants were prompted to reflect on the passengers’ affective experience of guilt. Our findings document an important conflict–in the context of AV accidents–between people’s prescriptive reasoning about responsibility and guilt on one hand, and their counter-normative experience of guilt on the other, with apparent implications for liability decisions. (shrink)