Journal Article
No. 2016-1 | January 07, 2016
Decision-Making under Radical Uncertainty: An Interpretation of Keynes’ Treatise


Keynes’ mathematical Treatise addresses what some call ‘radical uncertainty’, which he thought endemic in world affairs and whose appreciation underpinned much of his later work. In contrast, the mainstream view in economics, as elsewhere, has been that even if radical uncertainty exists, either there is in principle nothing that can ever be done about it, or that even if one could in theory do something about it then the institutions required would be unreliable, and one would be better off without them. Thus the mainstream has worked as if it were realistic to ignore even the possibility of radical uncertainty. But one needs some conceptualisation of radical uncertainty, such as Keynes’, before one can make such judgments. This paper presents an interpretation, to inform debate. The viewpoint taken here is mathematical, but this is not to deny the value of other views.

JEL Classification:

C62, G18, H12


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Cite As

David Marsay (2016). Decision-Making under Radical Uncertainty: An Interpretation of Keynes’ Treatise. Economics: The Open-Access, Open-Assessment E-Journal, 10 (2016-1): 1—31.

Comments and Questions

Anonymous - Contents.
January 09, 2016 - 00:23

This Article deals with the probability theory starting from the concept introduced by Keynes in the famous treatise and introduce to an important concept the rational expectations which was widely adopted in the macroeconomic conceptualization from the 70s.
The attempt of the author is relevant because although the concept of ...[more]

... ration expectation is widely adopted in the current macroeconomics it has not received a good sistematization in economics, so leave many open questions in the scientific debate.

The author highlight the difference between the Keynesian Concept of probability and the other concepts taken by the other science.

This article is an excellent introduction to these concept, however the link with macro questions is two much sketched.

David Marsay - Reply to Reader
January 20, 2016 - 08:19

see attached file