 The former book was translated into English as The Logical Syntax of Language in 1937. In it, Carnap argued that the correct method in philosophy is to engage in conceptual analysis conceived of as ‘logical syntax’, roughly speaking syntax proper and proof theory. To address philosophical differences, one proposes regimenting the disputed positions in formal languages or ‘frameworks’ which include a system of axioms and rules of proof; given these, some sentences are ‘determinate’, are provable or refutable. These are the analytic, and contradictory, sentences, relative to that framework. How do we choose which system to adopt? Carnap’s Principle of Tolerance (1934 [1937], p. 52) allows us to adopt any system we wish: