An analysis of Grigoriev and Zaitsev's four-valued logic CNL2^4 that applies Haack's classicist strategy — reading its connectives, truth values, and consequence relation in classical terms — and relates the system to those of Ruet and Kamide. It shows the same proof system admits at least four incompatible classical readings, sharpening Carnap's problem: the deductive apparatus underdetermines the intended semantics, so two people reasoning identically in the system can mean radically different things by its symbols.
This note examines Grigoriev and Zaitsev's four-valued logic CNL2^4 and clarifies its connection to related systems of Ruet and Kamide. Applying Haack's classicist strategy — reading the connectives,…