Kazimierz Ajdukiewicz

Kazimierz Ajdukiewicz (12 December 1890 – 12 April 1963) was a Polish philosopher and logician, a prominent figure in the Lwów–Warsaw school of logic. He originated many novel ideas in semantics, including categorial grammar, a flexible framework for analyzing natural language syntax and semantics that significantly influences formal linguistics. Ajdukiewicz's fields of research also included model theory and the philosophy of science. He was born in Tarnopol, Austrian Galicia, Austria-Hungary, and studied at the University of Lwów, where he also lectured, as well as in Warsaw and Poznań. He earned his PhD for a thesis on Kant's philosophy of space. From 1948 to 1952, he served as the Rector of the University of Poznań. He was instrumental in founding the journal *Studia Logica* in its current form and edited it until his death. In his early work on epistemology, known as Radical Conventionalism, Ajdukiewicz proposed that language could be understood as a set of expressions governed by rules of meaning (Axiomatic, Deductive, and Empirical). He suggested that a conceptual apparatus, an untranslatable set of meanings, is necessary for language use, including scientific language, leading to a form of conventionalism. He later abandoned this theory. His bibliography includes significant works such as "O znaczeniu wyrażeń" (On the Meaning of Expressions) and "Epistemologia i semantyka" (Epistemology and Semantics).