I.J. Good’s Claim, That Keynes’s Evidential Weight of the Argument, V, a Logical Relation, is a Number, is False

  • Michael Emmett BRADY California State University, Dominguez Hills, College of Business Administration and Public Policy, Carson, California, USA


All current assessments of how Keynes’s weight (evidential weight of the argument) concept is measured are erroneously based on a metaphor ignored by I.J. Good, which Keynes used before he presented the mathematical analysis involved in measuring weight in chapter 26 of the A Treatise on Probability, on page 77 of chapter 6 to measure weight.
Keynes’s chapter 26 is the omega while chapter 6 is the alpha. It is impossible to fully grasp Keynes’s evidential weight of the argument concept, first presented as a logical relation designated as V, which is then measured through the construction of an index of weight in chapter 26, without a detailed study of pp. 310-315 of chapter 26 of the A Treatise on Probability.
The misbelief that Keynes ‘s concept of the evidential weight of the evidence, V=V(a/h), in chapter 6 of the A Treatise on Probability, represented a measure of the absolute amount of Knowledge, defined as K by Good to represent a gross measure of weight, can be traced back to numerous book and journal article contributions made by I.J. Good between 1950 and 2000.
The most severe errors about chapter 6 of the A Treatise on Probability were repeated again and again by Good from 1950 to 1990 (Good 1950, 1960, 1962, 1965, 1967, 1967, 1968/70, 1970/71, 1975, 1983a, 1983b, 1985, 1988, 1988, Good and Toulmin 1968).
Good completely overlooked Keynes’s footnote 1 on page 76 of chapter 6 to chapter 26 of the A Treatise on Probability, where Keynes stated that he would discuss how to integrate weight into a discussion of “…the application of probability to practice.” This would require a mathematical analysis and, obviously, would require the restriction that V(a/h)=w, 0≤w≤1, and w is the degree of the completeness of the information so as to be able to combine it with 0≤α≤1, where P(a/h)=α and α is the probable degree of rational belief.


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How to Cite
BRADY, Michael Emmett. I.J. Good’s Claim, That Keynes’s Evidential Weight of the Argument, V, a Logical Relation, is a Number, is False. Theoretical and Practical Research in Economic Fields, [S.l.], v. 14, n. 1, p. 5 - 15, june 2023. ISSN 2068-7710. Available at: <https://journals.aserspublishing.eu/tpref/article/view/7858>. Date accessed: 19 june 2024. doi: https://doi.org/10.14505/tpref.v14.1(27).01.