 Carnap had moved to Prague in late 1931, where he became a full professor at the German University, and wrote both drafts of the Logical Syntax of Language. The published book had tried to fuse the three major ideas of 1931–2. First, in January 1931, had come the rejection of Wittgenstein’s picture theory of meaning and its replacement by Hilbert’s sharp distinction between a language (a calculus, a purely formal symbol system) and its interpretation, with the requirement that a language be entirely specified by explicit rules. Closely bound up with this was the second idea, the insistence on the “formal mode of speech” and the avoidance of talk of meaning in the metalanguage. And third, late in 1932, had come the principle of tolerance: no language is definitive or “correct”, there is no logical “reality” for a language to “correspond to”. But within a year of the book’s publication, the second idea had been dropped; Carnap incorporated Tarski’s new semantical accounts of designation and truth, and extended his view of language accordingly. The first and third ideas, however, survived for the rest of Carnap’s career. What did not survive was the overreaction against “meaning” that accompanied the original insight of January 1931—the exclusive emphasis on the “formal mode of speech” in meta-discourse. In distinguishing between a language and its interpretation, Carnap’s first response had been to restrict extra-linguistic interpretation to the object language (and there to one particular—physicalistic—interpretation) and dispense with it entirely in the “elucidatory” metalanguage. But this restriction was loosened when Tarski convinced him in 1935 that interpretation could be completely specified by explicit rules governing satisfaction, designation, and truth. 