Abstract

The present paper proposes a comparative analysis of two standpoints on the existence and nature of universals hold by Stanisław Leśniewski and Bolesław Sobociński. We consider first the nominalistic argumentation of Leśniewski formalized by Sobocińki and described in the correspondence with J. M. Bocheński in 1956. Sobociński’s formalization revealed a fundamental pragmatic weakness of the reconstructed argumentation which was also mentioned by Sobociński. He himself was aware of the difficulties connected with an adequate interpretation of the crucial axiom, whose acceptance Leśniewski imputed to supporters of all theories of universals. Finally, the problem of the existence and nature of universals was elaborated by Sobociński also in a separate typescript “Uwagi w sprawie powszechników”. The view formulated by Sobociński comes from a combination of the methodology of deductive systems and the conceptualist standpoint. From the philosophical perspective Sobociński’s idea is both interesting and original, but it remained unknown to philosophers and logicians in general. For these reason we describe it and compare it with Leśniewski’s approach. We use in this description epistemological notions of R. Suszko. Our analysis enables to speak about universals in sense of Leśniewski, which are described by some universal in sense of Sobociński.