'Why Did Keynes Have Such' … Great Confidence that They (Author’s Insert-Ramsey and Braithwaite) Are Wrong About His Logical Theory of Probability Contained in His a Treatise on Probability(1921): The Answer Is that Keynes Had Built His Theory on An Indestructible, Invincible and Impregnable Foundation of Boolean Logic and Algebra in Part Ii of the a Treatise on Probability

The foundations of Keynes’s logical theory of probability, as contained in his A Treatise on Probability, are unassailable. As pointed out by Francis Y Edgeworth, (1922)Theodore Hailperin (1986) and Edwin Bidwell Wilson (1934), for instance, Keynes had used Boole’s original logical theory of probability as the foundation upon which to erect a more advanced version. This unassailable foundation consists of an interval valued (upper and lower bounds) theory based on propositions about events or outcomes that will accommodate numerical probability if the lower and upper bounds are the same. It is in Part II of the A Treatise on Probability that Keynes (a) shows that additivity is a special case and (b) develops his own version of Boole’s original interval valued probability based on conditional probability assessments, given the existence of partial orders. The Ramsey and Braithwaite critique completely ignored these foundations in Part II, as well as the extensions made by Keynes in Parts III, IV and V of A Treatise on Probability. Neither Ramsey nor Braithwaite ever had any idea about what an interval (bounded) probability was in their lifetimes. Ramsey and Braithwaite never read beyond chapter III of Part I of A Treatise on Probability A number of philosophers, such as I J Good, Harold Jeffries, R. Monk, I Hacking, H. Mellor, etc. simply took Ramsey’s claims as having destroyed Keynes’s theory as being self-evident. Unfortunately, I J Good, Harold Jeffries, R. Monk, I Hacking, H. Mellor, etc. never read beyond chapter III of Part I either, although Good made a horrible mess of Keynes’s chapter 6 on the evidential weight of the argument, while apparently also reading only one page of chapter 26, p.312. Of course, if you are going to read only one page of chapter 26, it needs to be p.315 (Keynes,1921). Starting in the late 1970’s, a number of economist followers of the English economist, Joan Robinson, banded together to start a school of economics called Post Keynesianism. The same identical errors made by I J Good, Harold Jeffries, R. Monk, I Hacking, H. Mellor, etc., also appear in the work of G. Meeks, R. Skidelsky, D. Moggridge, B. Bateman, R. O’donnell, A. Carabelli, etc. The common error running through all of the work on Keynes done by I J Good, Harold Jeffries, R. Monk, I Hacking, H. Mellor, etc., and all of the work on Keynes done by G. Meeks, R. Skidelsky, D. Moggridge, B. Bateman, R. O’donnell, A. Carabelli, etc., is a complete and total ignorance of the basic Boolean foundation for Keynes’s work in the A Treatise on Probability. C. Misak has very recently resurrected the foolish, funny, silly and stupid claim, first made by R. B Braithwaite, that Ramsey destroyed and demolished Keynes’s logical theory of probability, as contained in the A Treatise on Probability in 1921, in a very tiny three page, unrefereed comment published in the Jan., 1922 issue of the Cambridge Magazine when he was 18 years old in her 2020 biography of Ramsey. Misak has continued to support Braithwaite's original claim in a number of other publications as well. The name Boole does not appear in any of her ongoing commentary or in her book, just as the Boolean foundations of Keynes’s work does not appear at all in any of the work on Keynes done by I J Good, Harold Jeffries, R. Monk, I Hacking, H. Mellor, etc., and does not appear at all in any of the work on Keynes done by G. Meeks, R. Skidelsky, D. Moggridge, B. Bateman, R. O’donnell, A. Carabelli, etc. The only conclusion possible is that, due to this giant lacuna, it is advisable that all academics stop using the work on Keynes produced by I J Good, Harold Jeffries, R. Monk, I Hacking, H. Mellor, etc., and G. Meeks, R. Skidelsky, D. Moggridge, B. Bateman, R. O’donnell, A. Carabelli, etc., because of the very misleading conclusions arrived at by these authors, who simply are totally ignorant of the very basic analysis carried out by Boole in 1854 in his The Laws of Thought.