One apparent reason for deferring a decision – abstaining from choosing, leaving the decision open to be taken by someone else, one’s later self, or nature – is for lack of sufficient confidence in the relevant beliefs. This paper develops an axiomatic theory of decision in situations...

Although much of the theoretical literature on ambiguity works under the assumption of uncertainty aversion, experimental evidence suggests that it is not a universal behavioral trait. This paper introduces and axiomatises the family of α-UA (for α-Uncertainty Attitude) preferences: a simple...

The standard, Bayesian account of rational belief and decision is often argued to be unable to cope properly with severe uncertainty, of the sort ubiquitous in some areas of policy making. This paper tackles the question of what should replace it as a guide for rational decision making. It...

Many decision situations involve two or more of the following divergences from subjective expected utility: imprecision of beliefs (or ambiguity), imprecision of tastes (or multi-utility), and state dependence of utility. Examples include multi-attribute decisions under uncertainty, such as some...