The operational definitions of uncertainty used by John M. Keynes and Frank H. Knight are based on missing information that will not be available to the decision maker at any time. The founder of this approach is George Boole. This leads to indeterminate interval probabilities. The definition of...

Frank P Ramsey did not consider the possibility of representing the concept of probability by an interval valued approach in his lifetime. Ramsey considered probability to be either ordinal or numerical. There was absolutely no room for interval estimates and interval probability in his...