I consider the interaction between an agent and a principal who is unable to commit not to renegotiate. The agent's type only affects the principal's utility. The principal has access to a public signal, correlated with the agent's type, which can be used to (imperfectly) verify the agent's...

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...