Abstract

This book focuses on mathematical logic that was a prominent philosophical method in the Lvov-Warsaw School. Kazimierz Twardowski, who was the founder of the Lvov-Warsaw School, favoured psychology as a philosophical method. However, his pupil Jan Łukasiewicz opposed to him and claimed that the proper method is mathematical logic. Łukasiewicz’s work attracted many other members of the Lvov-Warsaw School and soon became one of its most important subjects of interest. The results of its members in the field of mathematical logic have achieved world fame, but they have not yet been presented thoroughly and systematically in the Czech philosophical literature. The aim of this work is to partially fill this gap. The first chapter is a historical introduction to the issue. The subsequent three chapters deal directly with the logical systems created and developed by the logicians of the Lvov-Warsaw School: propositional calculus, multivalued logics, and Leśniewski’s system of logic and the foundations of mathematics. The last three chapters focus on the philosophical theories that have been influenced by mathematical logic: theories of truth, problems of deduction, induction, and methodology of science, as well as the original approach to the history of logic introduced by Łukasiewicz.