O problema frege-geach e a solução expressivista híbrida de Michael Ridge

Abstract

This work has as its general objective the analysis of the solution for the Frege- Geach problem offered by the hybrid expressivist Michael Ridge (2006, 2007a e 2014). More than that, the present work has as its specific objectives analysing the solutions for the Frege-Geach problem offered by pure (classical and sophisticated) expressivist approaches. However, the expressivist proposals do not properly solve the Frege-Geach problem. First, the classical pure expressivist approach, as shown in Alfred Ayer’s (1952) and Daniel Stoljar’s (1993) work, cannot clarify the meanings of the moral sentences which occur in nonincorporated contexts. Besides that, it can only explain the validity of the moral argument in a formal way. Therefore, the classical pure expressivist approach does not overcome Geach’s challenge. In other words, it does not accordingly solve the Frege-Geach problem. Secondly, the sophisticated pure expressivist approach, represented by Simon Blackburn’s work (1973, 1984 e 1988), cannot overcome Geach’s challenge either. The sophisticated expressivist approach poses more refined answers than the classical expressivist approach, nevertheless there are strong objections directed to these answers, such as the set of objections named impediment for an expressivist logic, the mixed contexts problem and the negation problem. At the end, there will be proved that the hybrid expressivist approach from Michael Ridge, even not having the same issues as the pure expressivist theories, and being able to replicate the more substantial objections directed at his metaethics, cannot solve the Frege-Geach problem in a definite way, because the foundations of his “semantic machinery” need detailed explanations for demonstrating its truthfulness.