 Much of the recent discussion surrounding the Syntax, especially the principle of tolerance, was inspired by Gödel’s critique of Carnap, unpublished until 1995, that was originally intended for the Schilpp (1963) volume on Carnap in the Library of Living Philosophers. Gödel withdrew his paper, but six successive drafts of it were found in his Nachlass, of which several have now been published (Gödel 1995). It appears, from its title (“Is Mathematics Syntax of Language?”) and much of the exposition, to focus specifically on the “syntax” thesis, or more generally on the “linguistic” accounts of the foundations of mathematics deriving from Wittgenstein’s Tractatus (Goldfarb 1995: 325). However, Gödel himself understood that Carnap had meanwhile left behind that view (in its Logical Syntax form), and recent commentary has focused on the principle of tolerance (see section 1 of the supplement  Tolerance, Metaphysics, and Meta-Ontology  for the details of Gödel’s criticism). 