Ricardo Silvestre

Induction, conceived as the class of rational non-truth preserving inferences, has been a perennial problem in philosophy. Aside from the problem of justification of induction, a less debated issue is the problem of properly describing inductive inferences. The purpose of this book is to conceptually investigate this descriptive problem of induction from the standpoint of the nonmonotonic logical tradition raised inside the field of Artificial Intelligence in the last thirty years. As we try to show, an essential part of this enterprise involves the analysis of a pragmatically oriented notion of probability, called by us inductive plausibility. This in turn is made from the viewpoint of paraconsistency ? which according to some is the unavoidable companion of nonmonotonicity ? and modal logic. We therefore put forward a nonmonotonic, paraconsistent and modal approach to induction and plausibility. The book shall be useful to philosophers, logicians and computer scientists interested in the problem of induction in general and in the logical analysis of induction and plausibility in particular.

O propósito desse artigo é fornecer um tratamento formal para um tipo de ação até o momento negligenciada nas lógicas modais filosóficas da ação: ação em plano. Ao fazer isso nós seguimos a abordagem padrão nas lógicas modais da ação exemplificados pelos trabalhos de Belnap, Chellas and Pörn. Como nós acreditamos que existe uma relação forte entre plano, tempo e indeterminismo, nós usamos a teoria do tempo ramificado para investigar as características básicas da ação em plano. Além de introduzir uma semântica do tempo ramificado, nós também apresentamos um cálculo correto e completo com relação a essa semântica. DOI:10.5007/1808-1711.2010v14n3p421

  This paper is an effort to realize and explore the connections that exist between nonmonotonic logic and confirmation theory. We pick up one of the most wide-spread nonmonotonic formalisms – default logic – and analyze to what extent and under what adjustments it could work as a logic of induction in the philosophical sense. By making use of this analysis, we extend default logic so as to make it able to minimally perform the task of a logic of induction, having as a result a system which we believe has interesting properties from the standpoint of theory of confirmation. It is for instance able to represent chains of inductive rules as well as to reason paraconsistently on the conclusions obtained from them. We then use this logic to represent some traditional ideas concerning confirmation theory, in particular the ones proposed by Carl Hempel in his classical paper "Studies in the Logic of Confirmation" of 1945 and the ones incorporated in the so-called abductive and hy-pothetico-deductive models

Sáo dois os propósitos deste artigo. Primeiro desejamos examinar porque o projeto de Carnap de construir uma lógica indutiva náo foi bem sucedido. De forma a realizar isso, nos apoiaremos na distinçáo entre o problema da justificaçáo da induçáo e o problema da descriçáo da induçáo. Tentaremos mostrar que a principal razáo pela qual o projeto de Carnap falhou foi sua relaçáo com o problema da justificaçáo da induçáo. Nosso segundo objetivo é propor algumas idéias de como seria um lógica da induçáo que propositadamente evite o problema da justificaçáo e possa consequentemente ser chamada de uma lógica puramente descritiva da induçáo. Utilizaremos para isso um conceito de probabilidade presente no Logical Foudations of Probability de Carnap chamada por ele de probabilidade pragmática

Our purpose in this paper is to contribute to the project of meta-theodicy, understood here as the elucidation of the concept of theodicy through the analysis of its adequacy. In our case, the analysis shall be made inside a framework including a taxonomical view of the theodical adequacy conditions which allows for a rigorously acceptable description of them as well as for a natural appraisal of the role, importance and intra-logical relations holding between them. The result of the analysis shall be used to introduce definitions minimally precise of the notions of theodicy, satisfactory theodicy, plausible theodicy, ideal theodicy, and the like.

O objetivo geral deste artigo é o de fazer algumas considerações teoréticas sobre o aspecto inferencial da Lógica dos Diálogos Inteligentes dentro do quadro conceitual fornecido pelas lógicas do senso comum desenvolvidas dentro da Inteligência Artificial. Mais especificamente, tentarei mostrar aqui que, para bem cumprir o seu papel, a LDI deve possuir uma maneira de representar as inferências não-monotônicas. Como argumento principal, defenderei a tese de que a não-monotonicidade é uma característica intrínseca à compreensão e uso da linguagem. O principal fenômeno relacionado com a linguagem natural utilizado como evidência para essa tese será o fenômeno do uso não literal da linguagem.

This paper introduces the special issue on Logic and Philosophy of Religion of the journal Sophia: International Journal of Philosophy and Traditions (Springer). The issue contains the following articles: Logic and Philosophy of Religion, by Ricardo Sousa Silvestre and Jean-Yvez Béziau; The End of Eternity, by Jamie Carlin Watson; The Vagueness of the Muse—The Logic of Peirce’s Humble Argument for the Reality of God, by Cassiano Terra Rodrigues; Misunderstanding the Talk(s) of the Divine: Theodicy in the Wittgensteinian Tradition, by Ondřej Beran; On the Concept of Theodicy, by Ricardo Sousa Silvestre; The Logical Problem of the Trinity and the Strong Theory of Relative Identity, by Daniel Molto; Thomas Aquinas on Logic, Being, and Power, and Contemporary Problems for Divine Omnipotence, by Errin D. Clark.

The so-called theory of karma is one of the distinguishing aspects of Hinduism and other non-Hindu south-Asian traditions. At the same time that the theory can be seen as closely connected with the freedom of will and action that we humans supposedly have, it has many times been said to be determinist and fatalist. The purpose of this paper is to analyze in some deepness the relations that are between the theory of karma on one side and determinism, fatalism and free-will on the other side. In order to do that, I shall use what has been described as the best formal approach we have to indeterminism: branching time theory. More specifically, I shall introduce a branching time semantic framework in which, among other things, statements such as “state of affairs e is a karmic effect of agent a”, “a wills it to be the case that e” and “e is inevitable” could be properly represented.

The purpose of this paper is twofold. First, it aims at introducing the ontological argument through the analysis of five historical developments: Anselm’s argument found in the second chapter of his Proslogion, Gaunilo’s criticism of it, Descartes’ version of the ontological argument found in his Meditations on First Philosophy, Leibniz’s contribution to the debate on the ontological argument and his demonstration of the possibility of God, and Kant’s famous criticisms against the (cartesian) ontological argument. Second, it intends to critically examine the enterprise of formally analyzing philosophical arguments and, as such, contribute in a small degree to the debate on the role of formalization in philosophy. My focus will be mainly on the drawbacks and limitations of such enterprise; as a guideline, I shall refer to a Carnapian, or Carnapian-like theory of argument analysis.

In this two-parts paper we present paranormal modal logic: a modal logic which is both paraconsistent and paracomplete. Besides using a general framework in which a wide range of logics  including normal modal logics, paranormal modal logics and classical logic can be defined and proving some key theorems about paranormal modal logic (including that it is inferentially equivalent to classical normal modal logic), we also provide a philosophical justification for the view that paranormal modal logic is a formalization of the notions of skeptical and credulous plausibility

An investigation of what might be called the logical formalization of the process of theory change due to anomalies is presented. By anomaly, we mean an observed fact falling into the explanatory scope of a theory that does not agree with the theory prevision. A classical approach to restore the explicative power of a theory faced with an anomaly is to propose new, tentative auxiliary hypotheses which, along with part of the old set of auxiliary hypotheses, are able to solve the anomaly. After laying down some conclusions about the structure of such process, we propose a multi-modal and non-monotonic logical framework able to represent some key aspects of this important facet of the dynamics of scientific theories. Due to the necessity of accommodating incompatible tentative hypotheses, this framework incorporates a weak form of paraconsistency. As a case study, we analyze the anomalous behaviour of the planet Uranus that threatened the Newtonian celestial mechanics for more than half a century and gave rise to the discovery of Neptune

In this two-part paper we present paranormal modal logic: a modal logic which is both paraconsistent and paracomplete. Besides using a general framework in which a wide range of logics – including normal modal logics, paranormal modal logics and classical logic – can be defined and proving some key theorems about paranormal modal logic (including that it is inferentially equivalent to classical normal modal logic), we also provide a philosophical justification for the view that paranormal modal logic is a formalization of the notions of skeptical and credulous plausibility

O objetivo desse artigo é realizar o que podemos chamar de uma análise conceitual da noção de indução, tomando como ponto de partida o problema das ambigüidades indutivas. Tentaremos mostrar que existe não apenas uma, mas duas maneiras igualmente autênticas de lidar com o problema das ambigüidades indutivas, e que quando certos aspec-tos lógicos dos dois conceitos de plausibilidade oriundos dessas duas abor-dagens da indução são considerados, muito da controvérsia a respeito das ambigüidades indutivas é dissolvido. Dentre tais aspectos está uma su-posta relação entre essas duas noções indutivas de plausibilidade e os conceitos de paraconsistência e paracompletude. Nossa análise é materializada, por assim dizer, em uma lógica modal paraconsistente e paracompleta capaz de dar conta dos aspectos mais básicos dessas duas abordagens da indução bem como dos dois conceitos de plausibilidade delas oriundos. Na exemplificação do tipo de controvérsia o qual estamos nos referindo, bem como a solução que estamos propondo, nos detalharemos sobre uma das mais ilustres instâncias do problema das inconsistências induti-vas: o paradoxo da loteria.The purpose of this paper is to undertake a conceptual analysis of the notion of induction, taking as starting-point the problem of induc-tive ambiguities. We shall try to show that there is not only one, but two equally authentic ways of dealing with the problem of inductive ambigui-ties, and that when certain logical aspects of the two plausibility concepts that arise from these two approaches to induction are considered, much of the controversy about the inductive ambiguities disappears. Among such aspects is a relation that supposedly exists between these two no-tions of inductive plausibility and the concepts of paraconsistency and paracompleteness. Our analysis is materialized, so to speak, in a paracon-sistent and paracomplete modal logic able to deal with the most basic as-pects of these two approaches to induction. In exemplifying the kind of controversy we are talking about, as well as the solution we are propos-ing, we shall focus on one of the noblest instances of the problem of in-ductive inconsistencies: the lottery paradox

My purpose in this paper is to clarify or explicate the concept of theodicy. More specifically, I shall provide an account of the concept that takes its logical aspects seriously into consideration as well as satisfies the basic intuitions philosophers of religions have had about it. This shall be done by systematically analysing the several theodical conditions found in the literature. As it shall be seen, these conditions are logically related to one another; collectively, they point not to one, but to several concepts of theodicy. Thus, as by-product of this explicatory endeavour, I shall provide a logically guided, I may say, analysis of such conditions as well as a systematization of the theodical concepts arising from them. I shall follow what might be termed a semiformal approach; despite not developing a full logical theory, I use the standard notation and some important results from the field of formal logic.

The purpose of this paper is twofold. First we want to extent a specific paranormal modal logic in such a way as obtain a paraconsistent and paracomplete multimodal logic able to formalize the notions of plausibility and certainty. With this logic at hand, and this is our second purpose, we shall use a modified version of Reiter‘s default logic to build a sort of inductive logic of plausibility and certainty able to represent some basic principles of epistemic inductive reasoning, such as a negative autoepistemic principle, an `error-prone feature of induction' principle and a confirmation by enumeration principle

This paper introduces the special issue on Logic and Religion of the journal Logica Universalis (Springer). The issue contains the following articles: Logic and Religion, by Jean-Yves Beziau and Ricardo Silvestre; Thinking Negation in Early Hinduism and Classical Indian Philosophy, by Purushottama Bilimoria; Karma Theory, Determinism, Fatalism and Freedom of Will, by Ricardo Sousa Silvestre; From Logic in Islam to Islamic Logic, by Musa Akrami; Leibniz’s Ontological Proof of the Existence of God and the Problem of Impossible Objects, by Wolfgang Lenzen; A Logical Analysis of the Anselm’s Unum Argumentum (from Proslogion), by Jean-Pierre Desclés; Monotonic and Non-monotonic Embeddings of Anselm’s Proof, by Jacob Archambault; Computer-Assisted Analysis of the Anderson–Hájek Ontological Controversy, by C. Benzmüller, L. Weber and B. Woltzenlogel Paleo.