 To see an argument for (a), consider a Gödel sentence, \(G\), formulated within the language of Peano Arithmetic (henceforth, \(PA)\). \(G\) is not a theorem of PA if PA is consistent (cf. the entry on  Gödel’s incompleteness theorems).  But \(G\) becomes a theorem when PA is expanded by adding certain plausible principles that appear to govern a truth predicate. Thus, the resultant theory of arithmetical truth is strong enough to prove G and appears therefore to be non-conservative over arithmetic. If, as has been argued by a number of theorists, any adequate account of truth will be non-conservative over a base theory, then deflationists appear to be in trouble.