Deflationary Truth Is a Logical Notion

The thesis that truth is a logical notion has been stated repeatedly by deflationists in philosophical discussions on the nature of truth. However, to prove the point, one would need to show that the truth predicate does classify as logical according to some reasonable criterion of logicality. Following Tarski, invariance criteria have been considered to provide an adequate rendering of the generality and formality of logic. In this article, we show how the deflationist can use invariance criteria in support of her claim that deflationary truth is a logical notion.