[A semantically closed language is one which includes] its expressions, also the names of these … language, [and the equivalences of the form (T) X is true if, and only if, p.] … [p. 53] [Because of the Liar's paradox] we decide not to use any … [p. 54] we have to use two different languages … field of semantics. … We shall refer to the first language as … the symbol 'p' in (T) [X is true if, and only if, p] stands for … [p. 55: For a satisfactory definition of truth, the metalanguage only needs to be essentially richer than the object language]
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