Logic, Validity and Metainferential Validity

PAILOS, FEDERICO MATÍAS

Buenos AIres

Workshop; VII Workshop on Philosophical Logic; 2018

Buenos Aires Logic Group-S.A.D.A.F.

We have presented a hierarchy of logics that recovers increasingly more classical logic (e.g., more classically valid metainferences). This hierarchy shows exactly how ST is different from CL. We have also presented the precise way in which every logic in the hierarchy relates to LP. Does that makes every logic in the hierarchy the same logic? We don?t think so. It shows that they share a common structure. Nevertheless, they disagree extensionally?e.g., in their set of valid metainferences for some inferential level. We have defend the idea that a logic should not be defined by a single consequence relation, but by a sequence of consequence relations Does any arbitrary set of consequence relations for increasingly higher inferential levels specify a logic? Yes. Does any arbitrary set of metainferences specify an interesting logic? No. Are Tarskian logics the only interesting logics? Maybe. That depends on the applications of the logic.