Brady, Michael Emmett. 2013. “The Economic Consequences of G. L. S. Shackle’s Ignorance of Keynes’s Theory of Probability, Uncertainty, and Decision Making,” SSRN paper, August 13In essence, Brady argues that Shackle did not accept degrees of uncertainty, had a questionable view of inductive reasoning, and rejected the validity of even epistemic probabilities. Shackle’s view is supposedly that “there was only either a state of complete uncertainty or certainty” (Brady 2013: 2).
Perhaps these criticisms of Shackle are valid, but Brady’s claims about Post Keynesianism are problematic. As I have argued here, there are Post Keynesians, even prominent ones, who recognise degrees of uncertainty.
Yet another questionable assertion is that Ramsey thought that “all probabilities are real numbers between 0 and 1” (Brady 2013: 7). But Frank Ramsey seems to have accepted a “two-concept view” of probability: (1) as a concept in logic (and presumably a measure of the subjective belief of a person) and (2) as a concept in the natural sciences, namely, the frequency theory of probability (Gillies 2000: 180–181).
Brady, Michael Emmett. 2013. “The Economic Consequences of G. L. S. Shackle’s Ignorance of Keynes’s Theory of Probability, Uncertainty, and Decision Making,” SSRN paper, August 13
Gillies, D. A. 2000. Philosophical Theories of Probability. Routledge, London.