José Gusmão

Resumo Nas secções que se seguem, primeiro explorarei várias questões conceptuais e de enquadramento teórico, como o que se entende por relativismo e como o relativismo acerca da verdade se distingue de outros tipos de relativismo, uma elucidação da ideia de verdade relativa e, finalmente, em que sentidos se pode dizer que uma dada tese é auto-refutante e como se classificam os vários argumentos designados para provar que o relativismo se refuta a si mesmo nesses tipos de auto-refutação. Nas últimas, e mais importantes, duas ultimas secções; avaliarei primeiro duas tentativas, uma devido a Hales e outra de Ressler,1 de desenvolver lógicas relativistas a partir das quais se pode ajuizar se o relativista é culpado de um dos tipos identificados de auto-refutação; o sistema de Ressler análogo a lógicas modais não-normais é considerado promissor. Outras variedades de argumentos de auto-refutação: transcendentais, semânticos e pragmáticos, também são considerados e rejeitados. Palavras-chave : auto-refutação, lógica filosófica, relativismo, verdade In the following sections, I will try to answer several conceptual questions and clarify the vocabulary pertaining to the theoretical framework in which I am going to work. Examples being: what is relativism? How is truth-relativism is to be distinguished from other kinds of relativism? What is relative truth? In which senses can a certain thesis be self-refuting? And, finally, among the classical arguments laid out in the literature for the conclusion that relativism refutes itself, how are they to be classified among the several senses of self-refutation found? In the last, and most important two sessions: First, I will evaluate two attempts, one by Steven Hales and other by Mark Ressler, to construct formal systems of relative logic in which it can be properly be ascertained whether global forms truth-relativism are self-refuting. The system developed by Mark Ressler, analogous to non-normal modal logics, is considered promising in this regard. Arguments purporting to show that relativism falls prey to other varieties of self-refutation are also considered and then rejected. Keywords : philosophical logic, relativism, self-refutation, truth

This article aims to review the standard objections to dualism and to argue that will either fail to convince someone committed to dualism or are flawed on independent grounds. I begin by presenting the taxonomy of metaphysical positions on concrete particulars as they relate to the dispute between materialists and dualists, and in particular substance dualism is defined. In the first section, several kinds of substance dualism are distinguished and the relevant varieties of this kind of dualism are selected. The remaining sections are analyses of the standard objections to substance dualism : It is uninformative, has troubles accounting for soul individuation, causal pairing and interaction, violates laws of physics, is made implausible by the development of neuroscience and it postulates entities beyond necessity. I conclude that none of these objections is successful.