Abstract

The terms: ‘diachronic logic’ and ‘non-Fregean logic’ we owe to Roman Suszko. He called ‘diachronic logic’ an application of classical logic to study of the development of knowledge. But Non-Fregean logic is a logical calculus obtained from the classical logic by adding identity connective and axioms for it. The main goal of the paper is to proof that the non-Fregean logic is a continuation of diachronic logic. The article is divided into following parts: 1. Diachronic logic, 2. Non-Fregan logic, which contain 2.1. Introduction, 2.2. Axiomatic form of non-Fregean Logic, 2.3. Properties of non-Fregean logic, and Bibliography.