23 research outputs found
A Four-Valued Logical Framework for Reasoning About Fiction
In view of the limitations of classical, free, and modal logics to deal with fictional names, we develop in this paper a four-valued logical framework that we see as a promising strategy for modeling contexts of reasoning in which those names occur. Specifically, we propose to evaluate statements in terms of factual and fictional truth values in such a way that, say, declaring ‘Socrates is a man’ to be true does not come down to the same thing as declaring ‘Sherlock Holmes is a man’ to be so. As a result, our framework is capable of representing reasoning involving fictional characters that avoids evaluating statements according to the same semantic standards. The framework encompasses two logics that differ according to alternative ways one may interpret the relationships among the factual and fictional truth values
Logics of Deontic inconsistency
Orientador: Marcelo Esteban ConiglioDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Filosofia e Ciencias HumanasResumo: Esse trabalho expõe brevemente o que são as Lógicas da Inconsistência Formal ¿Observação: O resumo, na Ãntegra poderá ser visualizado no texto completo da tese digital.Abstract: This work expose briefly what are the Logics of Formal Inconsistency ...Note: The complete abstract is available with the full electronic digital thesis or dissertations.MestradoFilosofiaMestre em Filosofi
Modal logic with non-deterministic semantics: Part I—Propositional case
Dugundji proved in 1940 that most parts of standard modal systems cannot be characterized by a single finite deterministic matrix. In the eighties, Ivlev proposed a semantics of four-valued non-deterministic matrices (which he called quasi-matrices), in order to characterize a hierarchy of weak modal logics without the necessitation rule. In a previous paper, we extended some systems of Ivlev’s hierarchy, also proposing weaker six-valued systems in which the (T) axiom was replaced by the deontic (D) axiom. In this paper, we propose even weaker systems, by eliminating both axioms, which are characterized by eight-valued non-deterministic matrices. In addition, we prove completeness for those new systems. It is natural to ask if a characterization by finite ordinary (deterministic) logical matrices would be possible for all those Ivlev-like systems. We will show that finite deterministic matrices do not characterize any of them
Modal (in)completeness by finite Nmatrices
Orientador: Marcelo Esteban ConiglioTese (doutorado) - Universidade Estadual de Campinas, Instituto de Filosofia e Ciências HumanasResumo: Esse é um estudo sobre a viabilidade de matrizes finitas como semântica para lógica modal. Separamos nossa análise em dois casos: matrizes determinÃsticas e não-determinÃsticas. No primeiro caso, generalizamos o Teorema de Incompletude de Dugundji, garantindo que uma vasta famÃlia de lógicas modais não pode ser caracterizada por matrizes determinÃsticas finitas. No segundo caso, ampliamos a semântica de matrizes não- determinÃsticas para lógica modal proposta independentemente por Kearns e Ivlev. Essa ampliação engloba sistemas modais que, de acordo com nossa generalização, não podem ser caracterizados por matrizes determinÃsticas finitasAbstract: This is a study on the feasibility of finite matrices as semantics for modal logics. We separate our analysis into two cases: deterministic and non-deterministic matrices. In the first case, we generalize Dugundji's Incompleteness Theorem, ensuring that a wide family of modal logic cannot be characterized by deterministic finite matrices. In the second, we extend the non-deterministic matrices semantics to modal logics proposed independently by Kearns and Ivlev. This extension embraces modal systems that, according to our generalization, cannot be characterized by finite deterministic matricesDoutoradoFilosofiaDoutor em Filosofi
A Paraconsistentist Approach to Chisholm's Paradox
As Lógicas da (In)Consistência Deôntica (LDI’s) podem ser consideradas como sendo a contraparte deôntica das lógicas paraconsistentes chamadas de Lógicas da (In)Consistência Formal. Neste artigo são introduz das e estudadas novas LDI’s e outras lógicas deônticas paraconsistentes satisfazendo diferentes propriedades: sistemas tolerantes a obrigações contraditórias; sistemas em que as obrigações contraditórias produzem trivialização; e uma lógica deôntica paraconsistente bimodal que combina as caracterÃsticas de sistemas previamente introduzidos. Estas lógicas são utilizadas para analisar o conhecido paradoxo de Chisholm aproveitando-se do fato de que, além que as obrigações contraditórias não trivializam nas LDI’s, varias das dependências lógicas da lógica clássica são bloqueadas no contexto das LDI’s, permitindo assim dissolver o paradoxo