Charles S. Peirce on Identity: The case of the Existential Graphs

JAVIER LEGRIS

SALVADOR, BA

Conferencia; 20th Brazilian Logic Conference (EBL); 2022

SOCIEDADE BRASILEIRA DE LOGICA

Charles S. Peirce achieved, by the line of identity, a rich and usefulanalysis of quantification in the Beta Graphs that can be easily translatedinto the standard existential quantifier of classical First Order Logic.In this presentation I claim that the way the line of identity expressesidentity relation does not correspond to the usual understanding in thestandard classical First Order Language with identity (FOL=).It will be argued that the line of identity cannot be used to expressequations as in FOL=, but it expresses individual identity (in an moreontological sense). Finally, I will argue, more generally, that in the turmoil of ideas at the origins of modern logic, identity was diversely understood.