Pace Carabelli and Dow, There is No Common Discourse Language Logic in Keynes’s A Treatise on Probability

Abstract

For 45 years, both A. Carabelli and S. Dow have been arguing that Keynes’s non demonstrative logic in the A Treatise on Probability is a common discourse logic (rhetoric). They provide no textual evidence anywhere in Keynes’s A Treatiseon Probability to support this claim. They have never supported, through the citation of specific pages or paragraphs in Keynes’s book, their claims that Keynes’s logic is NOT a formal logic. What is in the A Treatise on Probability is a version of Boole’s relational, propositional logic that Keynes combined with a first order (predicate) logic. These are mathematical, formal, symbolic logics. They have nothing to do with common discourse logics using the English language. A simultaneous reading of chapters I and II of Keynes’s book and chapters I, XI, and XII of Boole’s The Laws of Thought lead to one, and only one, conclusion- Keynes’s logic is a formal logic derived from G. Boole. The only conclusion that follows from Keynes’s application of Boolean logics is that Carabelli and Dow have been severely confused for 45 years in what a formal logic is and what a common discourse logic is.