Ricardo Sousa Silvestre

Logic and Religion

We first start by describing the happening of the 1st World Congress on Logic and Religion. We then explain the motivation for developing the interaction between logic and religion. In a third part we discuss some papers presented at this event published in the present special issue.

Karma Theory, Determinism, Fatalism and Freedom of Will

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.

Paranormal modal logic – Part I. The system K? and the foundations of the logic of skeptical and credulous plausibility

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.

Paranormal modal logic – Part II: K?, K and Classical Logic and other paranormal modal systems

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.

On the logical formalization of theory change and scientific anomalies

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.

God, evil and the metaphysics of freedom

Este artigo e uma traducao, para o portugues, do nono capitulo do livro The Nature of Necessity de Alvin Plantinga, de 1974. Neste, esta exposta, na sua forma mais completa, a famosa defesa do livre arbitrio para o problema do mal. Utilizando-se da teoria dos mundos possiveis desenvolvida nos capitulos anteriores do livro, Plantinga concretiza, reconhecidamente, uma bem-sucedida tentativa de mostrar que a existencia do mal nao e inconsistente com a existencia de um ser onipotente, onibenevolente e onisciente. Alem da traducao, o artigo contem uma breve introducao a defesa do livre arbitrio de Plantinga e ao debate acerca de Deus e o mal na filosofia analitica da religiao. Palavras-chave: problema do mal, defesa do livre-arbitrio, mundos possiveis, filosofia analitica da religiao.