Propositional Modalities

Abstract

This paper examines some problems concerning modalities as operators acting on sentential arguments. At first, formal dependencies between modalities are described. Then, the problem of translations of modalities as operators into modalities as predicates is discussed. The author shows that although some predicates satisfy laws of the logical square for modalities, they cannot be represented by sentences with modal operators in front. The explanation of this fact is proposed by using Czeżowski's idea of modi entis and the content of presentations.