Keynes's initial, introductory presentation of his inexact measurement, approximation approach to interval valued probability occurred on pages 38-40 of chapter III of the A Treatise on Probability. Keynes used a simple diagram on page 38 to illustrate the non linear and non additive nature of...

Keynes’s concept of uncertainty from his 1908 Cambridge Fellowship dissertation to his death in 1946 was a range concept like probability-it could be measured on the unit interval between 0 and 1[0,1]. Uncertainty was an inverse function of what Keynes defined to be the evidential weight of...

In 1990,J. Runde presented a formal, mathematical representation of Keynes’s theory of evidential weight, as presented in chapters 6 and 26 of Keynes’s A Treatise on Probability ,as V(a/h)=V = K/(K+I).In 1999,A. Vercelli revised this to read as V =V(a/h) = K/(K+I), 0≤V≤1.We can identify...