Adam Smith rejected the use of the mathematical laws of the calculus of probabilities because the basic information-data-knowledge provided in the real world of decision making did not allow a decision maker to specify precise, definite, exact, numerical probabilities or discover the probability...

Both Smith and Keynes have very similar conceptual approaches to what probability is, how it is used and applied and the areas of application in which it can aid a decision maker. They both accept an interval approach to probability based on inequalities and bounds versus ordinal, subjectivist...