Platonism has nothing to do with Keynes's A Treatise on Probability or General Theory: On F P Ramsey's critique of an imaginary, Platonic, metaphysical, Keynesian, probability relation that never existed

F P Ramsey’s 1922 review in Cambridge Magazine, his 1923 paper,” Induction: Keynes and Wittgenstein” and 1926 paper ,”Truth and Probability”  are all based on claims and assertions about Keynes’s logical theory of probability  which do not exist anywhere in Keynes’s A Treatise on Probability or in anything written by Keynes in his lifetime. One possible explanation is that Ramsey suffered from hallucinations, delusions or illusions.

The role of Keynes’s non numerical probabilities, evidential weight  and the relations between Keynes’s General Theory and the A Treatise on Probability were first pointed out by Hugh Townshend in 1937-38 in correspondence with Keynes .Townshend was the only economist who had read ,and understood, the role played in Keynes’s liquidity preference theory of the rate of interest of (a) Keynes’s non numerical probabilities ,the name given by Keynes to his Boolean ,interval valued probabilities ,and (b) his evidential weight of the argument , which Townshend  called the weight of the evidence .

In 1969,Hishiyama,who was unaware of the Townshend-Keynes correspondence ,not only validated the points made in the  Keynes-Townshend correspondence  about liquidity preference ,but showed how the imprecise approach to probability (interval valued probability ,decision weights) in the A Treatise on Probability directly supported Keynes’s approach to measurement ,in the form of inexact measurement and approximation ,discussed by Keynes in Chapters 4,11,12 and 17 of the General Theory, where  Keynes demonstrated the impossibility of  applying strict or exact mathematical expectations ,which is the fundamental concept underlying Benthamite Utilitarianism, which underlies all classical, neoclassical ,new classical and new neoclassical approaches to economics ,in decision making.