The paper suggests a behavioural definition of (subjective) ambiguity in an abstract setting where objects of choice are Savage-style acts. Then axioms are described that deliver probabilistic sophistication of preference on the set of unambiguous acts. In particular, both the domain and the...

Using the Savage set up, the paper provides a simple axiomatization of the Choquet Expected Utility model where the capacity is an inner measure. Two attractive features of the model are its specificity and the transparency of its axioms.The key axiom states that the decision-maker uses...

This paper is concerned with the representation of preferences which do not satisfy the ordinary axioms for state-independent utilities.

The paper reports the results of a survey designed to elicit probability judgements for different types of events: ‘pure chance’ events, for which objective probabilities can be calculated; ‘public’ events, about which there may be some discussion in social groups and the media; and...

The paper proves that the Bayesian approach to learning and expectations formation implies no propositions that could conceivably be refuted by observation. For a (non-expanding) universe infinite in time but finite at any point of time, it is shown that by a suitable choice of priors, any...