Streszczenie
The aim of this paper is to present Kazimierz Ajdukiewicz’s views on the concept of world-view and rationality of religious beliefs. The following presentation is closely related to his “unity thesis”, formulated by Ajdukiewicz himself and claiming that there are close connections among the basic philosophical disciplines: epistemology, metaphysics and ethics. The unity thesis adds to the evidence for a great influence of Franz Brentano and Bernard Bolzano on Polish philosophy. Both thinkers renewed some classical ideas in the philosophy of the nineteenth century and one of the essential features thereof was a close connection of basic philosophical disciplines. Such a non-reductive approach to philosophy was rejected by the positivist movement and also by pragmatism and Marxism, which were anti-metaphysically and anti-philosophically oriented