A definition of a property P is impredicative if it quantifies over a domain to which P belongs. Due to influential arguments by Ramsey and Gödel, impredicative mathematics is often thought to possess special metaphysical commitments. It seems that an impredicative definition of a property P does not have the intended meaning unless P already exists, suggesting that the existence of P cannot depend on its explicit definition. Carnap (1937 [1934], p. 164) argues, however, that accepting impredicative definitions amounts to (...) choosing a "form of language" and is free from metaphysical implications. This paper explains this view in its historical context. I discuss the development of Carnap’s thought on the foundations of mathematics from the mid-1920s to the mid-1930s, concluding with an account of Carnap’s (1937 [1934]) non-Platonistic defense of impredicativity. This discussion is also important for understanding Carnap’s influential views on ontology more generally, since Carnap’s (1937 [1934]) view, according to which accepting impredicative definitions amounts to choosing a "form of language", is an early precursor of the view Carnap presents in "Empiricism, Semantics and Ontology" (1956 [1950]), according to which referring to abstract entities amounts to accepting a "linguistic framework". (shrink)

W artykule omówione zostały główne publikacje Bertranda Russella z lat 1905-1921 jako stanowiące inspirację dla powstania teorii wielości rzeczywistości Leona Chwistka. W ten sposób ukazano tło historyczne, tj. wpływ podnoszonych przez Russella zagadnień na postawę badawczą Chwistka. Artykuł zawiera także zestawienie poglądów obu filozofów oraz ocenę podobieństw i różnic między nimi. ----------------------- Zgłoszono: 28/03/2022. Zrecenzowano: 03/05/2022. Zaakceptowano do publikacji: 11/06/2022.