The concept of degrees of uncertainty in Keynes, Shackle and Davidson

The aim of the paper is to discuss and define a concept of Keynesian uncertainty capable of both to comprehend the concept of probable knowledge and admit the existence of degrees of uncertainty. Although the economic literature have been discussed this concept based on the discussion of the weight of argument that comes from Keynes’s theory of probability, we claim that this discussion must include the analysis of the relevance of the evidence. Moreover, we claim that this concept of uncertainty is not incompatible with Shackle’s concept of crucial decision and the understanding of the social reality as a nonergodic process.