Popper’s Theory of Deductive Logic

We present Popper’s theory of deductive logic as exhibited in his articles published between 1947 and 1949. After an introduction to inferentialist approach idea “inferential definitions” logical constants, we discuss more formal detail general the deducibility relation (which, using Gentzen’s terminology, might be called “structural” theory), well special constants. put emphasis on inferential notion duality, which includes analysis “anti-conditional” (today “co-implication”), systematic study various forms negation including classical, intuitionistic weaker negations, system bi-intuitionistic logic, quantification identity. also touch treatment modal operators, is based Carnap’s Meaning Necessity.