LoCa - 10 de julho - O conceito de verdade da lógica Fregeana - Dirk Greimann

[jean-yves beziau]

LoCa  - Seminário Interuniversitário de Lógica no Rio de Janeiro

"O conceito de verdade da lógica Fregeana"
Dirk Greimann

Departamento de Filosofia, Universidade Federal Fluminense, Niterói

Quarta-feira dia 10 de Julho de 2024 às 17h30
Sala Celso Lemos (308), IFCS/UFRJ

Largo São Francisco de Paula 1, Centro, Rio de Janeiro

[jean-yves beziau]

LoCa  - Seminário Interuniversitário de Lógica no Rio de Janeiro

"O condicional implicativo"

Gilberto Lourenco Gomes, Universidade Estadual do Norte Fluminense,  RJ, Brasil

Quarta-feira dia 17 de Julho de 2024 às 17h30

https://www.rio-logic.org/2024-1.html

[jean-yves beziau]

The Implicative Conditional

Eric Raidl & Gilberto Gomes 

https://link.springer.com/article/10.1007/s10992-023-09715-6

This paper investigates the implicative conditional, a connective intended to describe the logical behavior of an empirically defined class of natural language conditionals, also named implicative conditionals, which excludes concessive and some other conditionals. The implicative conditional strengthens the strict conditional with the possibility of the antecedent and of the contradictory of the consequent.p ⇒ q is thus defined as p ⇒ q as  ¬à (p ∧ ¬q)∧ à p∧à ¬q.

We explore the logical properties of this conditional in a reflexive normal Kripke semantics, provide an axiomatic system and prove it to be sound and complete for our semantics. The implicative conditional validates transitivity and contraposition, which we take to be integral parts of reasoning and communication. But it only validates restricted versions of strengthening the antecedent, right weakening, simplification, and rational monotonicity. Apparent counterexamples to some of these properties are explained as due to contextual factors. Finally, the implicative conditional avoids the paradoxes of material and strict implication, and validates some connexive principles such as Aristotle’s theses and weak Boethius’ thesis, as well as some highly entrenched principles of conditionals, such as conjunction of consequents, disjunction of antecedents, modus ponens, cautious monotonicity and cut.