Resumo

SANCHEZ HERNANDEZ, Juan Carlos. Tableaux for an alethic-epistemic logic and its conditional versions. Sig. Fil [online]. 2022, vol.24, n.48, pp.114-151.  Epub 02-Jun-2023. ISSN 1665-1324.

Although modal logic has significantly developed since the possible worlds semantics invention, today, it is recognized that a modal logic that uses only one type of modality is very restricted. In this article, I aim to provide the semantics and tableaux systems for some alethic-epistemic-doxastic logics. The basic system (T/T/KD*) is used to discuss the validity of some principles and some of Spinoza’s ideas on modal thinking, for he believed that the possibility and contingency ideas are defects of our cognition. Next, the system’s extensions based on are used to discuss the validity of the doxastic, epistemic, and alethic closure principles by means of the distinction between absolute and relative knowledge. Finally, the system is extended to develop a pair of conditional epistemic-doxastic logics to evaluate some skeptical statements.

Palavras-chave : actualism; knowledge analysis; contingency; skepticism; multimodal logic; Spinoza.