Malinowski and Suszko on many-valued logics: on the reduction of many-valuedness to two-valuedness

Abstract

We first describe the main features of Malinowski's book Many-Valued Logics: its orientation and its contents. The rest of our paper is devoted to the discussion of its original point, the presentation of Suszko's thesis, and questions directly related to it: What is many-valuedness? Are there only two truth-values?

We analyse and discuss the characterization of many-valuedness and the reduction of many-valuedness to two-valuedness presented by Malinowski. Then we argue against Suszko's thesis, taking examples of paraconsistent logic and of Malinowski's inferential many-valuedness. However, we also present some arguments to reject supplementary truth-values in the case of two topics discussed by Malinowski: modality and partiality.