A mathematical theory of truth and an application to the regress problem

Abstract

In this paper a class of languages which are formal enough for mathematical reasoning are introduced. First-order formal languages containing natural numbers and numerals belong to that class. Its languages are called mathematically agreeable (shortly MA). Languages containing a given MA language L, and being sublanguages of L augmented by a monadic predicate, are constructed. A mathematical theory of truth (shortly MTT) is formulated for some of these languages. MTT makes them MA languages which posses their own truth predicates. MTT is shown to conform well with the eight norme presented for theories of truth in the paper 'What Theories of Truth Should be Like (but Cannot br)' by Hannes Leitgeb. MTT is also free from infinite regress, providing a proper framework to study the regress problem. Main tools in proofs are Zermelo-Fraenkel (ZF) set theory and classical logic.